mm or TWO METHODS or. DRY HEAT cooxem ON PALATABIUTY Am moms LOSSES or smmmaamosus MUSCLE OF 3255 ROUND Thais {a fits- my“ 65 8A.. 5. MiCRKéAR STATE UNWERSE‘TY Zenov‘ia Jean Lukéancmk 1960 <- : --;$2W_ LIBRARY. Michigan State University WWNOWGDSOFMHEATCOOM ONPMTMMWWWWWW «mm m Zenovia Junlnlduzctmk A 13515 Suhdttod to tho Dean of tho College of Hon Economics of metrical: State Minx-sit: of Agriculture and Applied Science in partial walnut of tummutorthodogrooot MASTEROFSCIENCE Department of Foods and Nutrition 1960 MW Gratitude and deep appreciation are expressed to Dr. Grace Inner for the very generous and invaluable guidance, assistance, and encouragement which she has continual]: given throughout the preparation of this thesis. SincerethanksisextendedtoDr.ElaineMtherfordtorherinterestand helpful suggestions. Grateful aclawwledcnent is due to Dr. Grace filler, Dr. Elaine Rutherford, Rise Mary Morr, Miss Dorie Dame, and Miss Anne Douglas for their faithful participation on the taste panel. A special note of thanks in also expressed to Dr. J. Leon newcomer and Mr. 1". D. Borsenik for their assistance in the stay of heat penetration data, to Dr. Clifford 1.. Bedford for his direction in the intermtation of color reflectance readings. to Mr. Lynn J. Bratzler for his tine and supervision in the procuring and di- secting of the melee, and to Dr. William Baton for his assistance in the statistical treatment of the data. 1181801” cams “Weeeeeeeeeeeeeeeee LISTOF‘I‘ABIES ................. HSTGFIGURES................. mammal! .................. mammm .............. l‘hscleeofBeechmdoo......... HethodsofCooldngBeef.......... Conventionaloven-roeeting ...... Cookinginldeepfat........oo Factors Affecting Rate of Heat Penetration Coupositionoftheneat........ Weightandsurfacearea...ooo.o Initialteuperatureoftheneat.... Coolcingnethod.teuperature.tille... FactorsAffectingCooldagLoms eeeee Coapositionofthenaat........ Meeeeeeeeeeeeeeeee Surfacearea eeeeeeeeeeeee ACi-liceeeeeeeeeee'eeeeee cwmnthdgmhflgMeeeeeeeee .____ Factors Affecting Palatahility Characteristics of Heat CooloederyHeat eeeeeeeeeeeeeeee Aroeaandflavcr eeeeeeeeeeeeeeeee Appearanceandtexture eeeeeeeeeeeeee 111 O \OCDQQGMMFH {3:31:23 e 1“ e 15 e 15 e 18 e23 new or com (contdo) Tenderness ................. Juiciness.......oo..o...... hthodsoflnluatiugPalatahdliw ....... Suhjectiveevaluaticn.......o...o Objectiveevaluation ............ O emanation subjective and objective evaluation MODOFPROCEDURB.................. MaterialsUsed ................. Beefroaste................. Fatforfmr.........oo..o.o Email-lent.................. Prelimimenvestigations ........... Amountandre-usecffat .......... Determinationoffattemperature ...... Collectionofdrippings........... Preparation of samples for objective testing 0 Preparation of samples for subjective testing . Preliadnarytastepaml.'.......... PremastingPreparatim............. Thesanple ................. Cooldngnedia................ coommeflfleeeeeeeeeeeeeeeee commumutweeeeeeeeeeeee. Mfatmthdeeeeeeeeeeeeeee WWCOOMSINPIO eeeeeeeeeee iv 25 30 33 36 39 39 39 39 42 uz uz 43 35323: 88555 TABLE OF CONTEMS (conth Treatmt of roasts before chilling . . matuntofroastsafterchilling .4 Evaluation of Roasts Subjective testing Objective testing e Beat penetration Analysisofthedata RESULTS AND DISCUSSION e Beat Penetration e PH thteeee Cookinglosses .. M1 10.... e Drip 1088” e e Volatile losses Volum 108”. e Palatahility . . e Aroma andflevor Color and texture JdCM’ e e e Tenderness . e SWAIDOOWLUSIOB. anmcm eeee APPENDIX 0 $3338 Table 1. 2. 3. h. 5. 6. 7. a. 9. 10. 11. 13. 1h. LISTOFTABIE Relationhetveenrates ofheat penetrationforcookinginair' andinfat,threeeaapledepths, atfourdegreesofdoneness. . Heanpercentccokingandvolunelossesofsixreplicationsfor twonethodsofcookery..................... Analyses of variance of cooking and volume losses for two ”MOICOOWeeeeeeeeeeeeeeeeeeeeeee Meanpercent volune loss, changes inlinearneasurenents. and totalwightlossfortuonethodsofcookery.......... Average palatahility scores1 of six Judges for six samples for M’MOIOOOMeeeeeeeeeeeeeeeeeeeee Analysesofvarianceofaronaandflavorscoresforhvo nethodsofcooking.o..................... Analyses of variance of color and texture scores for two ’tWOfCOO‘dngeeeeeeeeeeeeeeeeeeeeeee Analysisofvarianceforchangesinpercentcolorreflectance WtIMtWMMOtOOOMeeeeeeeeeeee Averagejuicinessscoresandpressfluidyields...o.... Analysesofvarianceofjuicinessscoresandpressfluid “OmformuthCOOMeeeeeeeeeeeeeee Average scores1 for softness, friahility. residual tissue, and general tandem”, and mean shear force readings (1b.) . e . . Analyses of variance for softness, friatility. residual tissue, and general tenderness scores, and shear fome WIIOI‘WOMOIOOOMeeeeeeeeeeeeee Correlation coefficients for all possible combinations of softness, friahility, residual tissue, and general tendemess scores, andWarner-Bntslershearneasurenents. . . . . e . e e Weightofrounds. mcbwight,mzimlinearneasurenenteof memommmw‘teeeeeeeeeeeeeee 61 67 68 70 72 72 73 7h 75 76 91 Table 15. 16. 17. 18. 19. 20. 21. 1.13? or TABLE (Contd.) Changes in the rate of heat penetration for five replications. forthreesanpledepthsfortvocooldngnethods........o 96 Deteminations oprforrawandcooked sanplesandthechange ianfcrsixroastsfor‘haoI-ethodsofcookery......... 97 Cooking weight losses for six roasts for two methods of OOOblVeeeeeeeeeeeeeeeeeeeeeeeeeeeee 98 Volu-elossforsixmastsfortwonethodsofcookery...... 99 Average palatahility scores of six Judges for six replications fortvocookingnethods.....................100 Per cent color reflectance. Average of six replications for “outhodsofcookeryo..o..................101 Averagepnssfluid yieldsandshear force readingsof cooked sanplesforsixreplicationsfortvocookingnethods.. ... ..102 1e 2. 3. 5. 6. IISTOFFIGURES location of samples for objective and subjective evaluation “GOOMMeeeeeeeeeeeeeeeeeeeeeee Positioning potentiometer leads:g=radius,handg=3/h- andl/h-inchfronsurface eeeeeeeeeeeeeeeeee InnersingsanpleinllS‘Cfat eeeeeeeeeeeeeeee Average tine-temperature relationships during cooking for thressanpledepthsfortwomthods.....o........ Average rate of heat penetration: min/‘0 rise for three WhmrormmmmMQQQQQQQQQQeQQ Reflectance spectra of beef: raw and cooked sanplee for roasts from each cooking method (Average of six replications; two readimsperreplication)................... viii Page “5 '59 71 INTROWCTION Roast beef is a favorite menu item in in house and institutions. Palatahility characteristics and nutritive value are largely responsible for the popularityo Research has contributed substantially to the knowledge of beef cooker: and to the i-provuaant of eating satisfaction in beef. Anon the factors influencing the acceptability of the finished product are the cookingpmcedme,thedegreeofdonenese, andthetypeandextentof connective tissue inherent in the selected cut. Cooking methods used for m. are of two generel types: noist heat anddryheat. Innethodsofcookerybasedonnoistheat, theneatis sur- roundedwliquidaeinsteus, hysteanasincookingaeatinsteaners. or in roasting pens with tight-fitting lids. Dry heat cooking netheds includethoseinvhichtheneatissummdedwmintheoven. under the broiler, aver coals. or by a deep layer of hot fat. The prieary objective of this stunt was to secure comparative infor- nation concerning the effect of two methods of dry heat cookery-conventional oven-roasting and deep fat intereion-n-on cooking losses and palatability of sounenbnanosus muscle of U.S.D.A. Choice steer beef rentals. It is an accepted fact that conventional oven-roasting usually neces- sitates the selection of tender. nore expensive cuts of beef. fender cuts of beef are those which contain relatively small anounts of elastin. Theyincluderoastefrontherib. loin. andsirloinsections ofthebeef carcass. Becausetheavailabilityofthesecutsfronasingleaninalis united. their purchase constitutes a large percentage of the total neat budget. Inconparisoutotheribeyeandtenderloin, the seninenhranosus Insole, from the top round of beef, is less tender and. therefore. less expensive. Cooking tw moist heat is usually recon-ended for this type of neat. During the cooking period, moisture in the presence of heat softens thehrsorporcentage of emotivetissueasvellasthestmturalpro- tein. However. new homes and institutions on limited budgets find it suitable to use selected cuts from top round of beef for conventional oven- roastingsothatheefroastsnaybeincludedintheiraenus. Optimnipastingtenperatuiesinvolvetheuseofovensforconsider- able lengths of tine. For the honemlosr, this factor often necessitates thepreparationofcertainfoodeinadvanceoritlinitsthe-enutothose itensuhichdonotrequireovenspace, ortothoseuhichcanbebakedat the same teaperature used for the neat. lack of ovens at one's disposal creates identical problems in quantity food service operations. Further- more, deep fat fryers in new quantity food service operations main idle for such of the week. Therefore, if comparable palatahility and yield could he naintained. develoneent of an additional uthod of dry heat cookery, perutting utilisation of less tender. lover-priced cuts for roasting as well as none efficient use of equipmentmould be invaluable. Directions for routing neat usual]; indicate tine required for cookinginternsofodnutesperpound. Atbesttheseserveonlyaepoor guides. Tinsrequiredforroastingtoaspecifieddegreeofdoneness depends, inpart, upontherate atwhichheatistransferredfrcntha partimflarcooldngnediunthroughtheneat. Astudytodeterninethe thermal conductivity of beef nuecle when cooked in fat and in air. and consideration of the rate of heat penetration as it relates to weight and shape of the roast nay provide a more accurate basis for predicting cook- ingtineforbeefcookedinthesenedia. Asecondobjectiveofthisstuiv. therafore.vastoexanineheat penetntiondatafmthetwcooldngnethodsudinvestigatethepotmtial forusiugsuchdataasavalidbasisforpredictingcookingtineforbeef round. Itishopedthatfindingsfronthis study will contrihitetothe knouledgeofbeefcooloeryandbeofvaluetothoseinterestedineffecting thepreparation of palatable beef roastsuith nininal cooking losses. an! nan-eleconouiesincooldngtine,intheuseofequipaent,andinfuel consumption. REVIDIOFWTURB Accordingto Iowa (52) i-portant factors which tract the tourism ofskeletalmsclesofaninalsare(a)theageoftheaninl.(b)thelcind andaaountofconnectivetissue.and(c)thepartofthecarcassfroeuhich thecutistaken. mnerauifianlcins(ll5)studiedthetendemessofbeefinrelationto differentmsclesandageintheanilnl. Frontheirworkonfifty-tvo carcassestheyclassifiedthesnsclesuithinagivencarcassintofour najorgroups,rangingfromtheleasttendertothenosttender8 neckand foreshank; rourd; rib. short loin. loinend. chuck atthirdribandacross hmerusboneezandtenderloin. Laue (52) favors the classificationoffiinerandnanlcins andbelieves thatitisabetteronethanthediusionintothetvogmups,lesstender andtender. Shefurtherstatesthat,inadditiontovaryingdegreesof tenderness. nusclee also differ in shape, weight, fat content. collagen content , elastin content, and color. Differences in the size of fasciculi and the amount of connective tissue cause variations in the texture or grainofmsclee. Inastudyoftheidentificationandcuparativetendeanessoffifty of the larger who of beef, Ransbotto- and Strandine (71.) reported that theshearvaluesofcookedbeefofeachnusclethroughthecenterofthe rmmdrangedfroantolZfipomds. Becauseofthevariationintender- nessofmscleeinbefroundtheyreco—end.-vhereverpossible.the separation of tough and tender nuecles for cooking. Muscles of Beef Round rocker. Voegeli, and Wellington (90) divide beef round, out according totheChicagonsthod.intohuoninareas. insideortoproundandoutside or bottoa round. The seninenbranosus and adductor nuscles are the najor muscles oftheinsideround. Other-isclesinthisareaarethegracilie andpectinsus. Theeenitendinosus.alsolmownastheeyeoftherotnd. andbicepsfuorisarethenueclesoftheoutside round. Therenining unclean-sartorius. vastus internedius, vastus lateralis, vastus. aedialis, rectus fenoris, and tensor fasciae latae-beoause of their lesser pro- portionarsgroupedtogetherasthehmcklsortip. HathodeofCookingBeef lbw research studies have been conducted concerning neat cookery. Heat experiments were carried out at the university of Illinois as early as 1898. Extensive investigations by the United States Depart-ant of Agriculture in cooperation with Agricultural hperinent Stations and colleges have resulted in inroved cooking nethods for beef. Directions for the cooking of neat in experimental work have been specified by the Cooking Co-ittee of the Cooperative Heat Investigations (1?). ‘Ihese facilitate the W of results obtained in one ' laboratorywith those in another. Theyarealsodesioied to showdiffer- ences in neat caused by various production and processing factors. lbthods of cookery used with neat are of two basic types: dry heat and noist heat. Tender cuts are usually cooked by dry heat. lhe nest is surroundedbydryairintheoven, underthebroiler. overcoals, or his ' b‘ it! by a deep layer of hot fat. Lees tender cuts are generally cooked by moist heat and at te-peratures at or near the boiling point. (lily research relating to conventional oven-roasting and cooking 11 deep fat inasrsion will be reviewed. mm For roasting neat uncovered pans are ”contended. Although cooking tineissonewhatlonger.cookinglessesandmtritivelossesaxereduced ind the mt is more palatable. Accordingtolewe(52)theoventenperaturethatpmducesthenost palatable product with a adnimm weight and nutrient loss in a reasonable coohngtinewithasnallanountoffnslcouldhecalledthsoptim cooking temperature. Intbeirup.rinente.1eve.t.1(53)eooked.urge neaberofbeef.veal,lanb,aniporkroasts. Theyfoundthsopti-naoven tapereturetobeletoléO‘C. Atlowerte-peraturss.thscoold.ngtins waslcngerandweightlossandfuelconsmtionwereoftengreaterthan at 150°C. Inaddition.roastecooked at lower tenperaturee,towell-dons orverywell-done.weretenderbutalsodry. Athighertenperatures.the scoldngtinswasshorterbuttheanomtoffuslneededaswellascooldmg losses were generally greater. Roasts cooked rapidly were juicier than those cooked very slowly for the same degree of doneness. mama: Reportsontheuseofdeepfatasacoonngnedimforexperiaental work on beef roasts have been re». Harrison (#0) compared the Pentahility ofbeef roasts cooked at the same tenperature in four different mean: air. steam, water. and fat. Harrison. Iowa, McClurg. and Shearer (bl) usedfatheldatte-peratures of96to98°Ctocookbeefnuscleetoan internal twitter. of 70°C. In their study, Ranshotton, Strandine, and Icons (76) cooked beef moles to 76.7% using a fat temperature of 121.1‘0. Recently, Visser et al (92) compared tender and less tender beef Insoles. fronpairedU. S.Goodlonghindquarters. cooioadtcinternaltenperaturee of 55. 70. an! 85°C, t1 oven roasting at 1‘09‘C, cooking in deep fat at 110°C, and cooking in deep fat at 100°C. ante. point. Lows (52) states that the cheedeel and meal character- istics of a fat are ilportant and that it is preferable to use fats with high mung Whitelfor frying. nueugh expednents node on dough- nuts. Iowa. Pradhan, and Kastelic (5“) presented intonation on the aloha points of continuously used coating fate. new found that the initial free fatty acid content was lowest in oils, slightly higher in Ivdrogenated shortening” all! highest in lards. During cooking, the free fatty acid content of all fats increased and the smoke point was lowered. However. this relationship tended to be greater in fats with an initial low fatty acid content. Lows (52) also pointed out that the fatty acid content of animalfatsvariedwiththelocationinthehodyandvdththefeedthe aural had received. Inastuhtodeterunewhethertheenokepoint is affectedtvthe determination method, Swarts (on) used the official cup of the American Oil Chemists' Society, a small iron skillet, an enameled kettle, and an iron Dutch oven. Snake points for all-ludrogenated fats varied fron 171 to 222°C. Those detemined by the official nethod were higher in every caseanltheuseoflargerutensils resultedinalowersnokepoint. Vail and Hilton (91) reported snotdng tuperatures ranging tron 215 to 190°C for 17 vegetable fate and oils. My found that when samples were heatedfor2-, 6-, 12-, andZO—hourperiodethepercentageoffree fatty acids increased with each increment of ties. Although the rate of increase was not consistent, as the percentage of free fatty acids in- creased the smoking tuperature of the fat decreased. Factors Affecting Rate of Heat Penetration rheti-erequrediorcookingneetieoenemeetieotedinteruoi aimtesperpound. Atbeet,thiscanonlyserveasageneralguide. In- portent factors which cause variations in cooking time required for net are: composition, sine, shape, extent of aging, initial tauperature, method of cooking, cooking temperature. and demo of doneness. Witness. The constituents of a cut of neat have different rates of heat can- dnctivity. Tome (89) cooked paired prints rih. of beef at 125 and zoooc to an internal temperature of 63°C. During cooking. tanperatures were recorded at the center, which was 2 inches from either cut surface of the loaded” dorei muscle. and at 0.5 inch below the surface of the fat overthetOpoftheroast. Shefound thatwhenthesurface fatwasdeeper than 0.5 inch, so that the thermometer bulb was inhedded in the fat, heat penetrated the 0.5 inch layer of fat more slowly than the 2 inches of lean. Lows (52) studied the rate of heat penetration in mscular and fatty tisme. Pint Jars were filled with lean beef, lean pork, fat pork, and suet. Athernoneterwaeinsertedthroughtherubbercorkinthelidof eachjarandpoeitionedinthecenterofthefir. Jarswereplacedina prooessingcontainerandheatedinboilingmterandsteanforahours. Results shaved that heat pututed the lean beef most rapidly. followed I: lean pork. fat pork, and lust. thine,wimineon, andibrgan (88) omerinentedwith three-ribbed mastecookedinovenspx'eheetedtoZZS‘CandthennintainedatZlO‘C untilaninternaltuperatuxeoféswwaereached. ‘nlcyfound that fat playedasiaiificantroleintheepeedatwhiohheatpenetntedtheneat and concluded that, because of the change in heat conductivity as fat paseesfronasolidtoaliquid,exteriorfatepeedsuptheheetpenetre- tion rate. but interior fat nay retard it. Accordingtohowe (52).-eet composition affectstheduration of temperaturerisenorethantheextent. Heatcontainingagreatdealof fatandneatthathasaveiythicklayerofsurfacefatrequireealong unfortheimertenperatmtoreachitsnaadmpoint. Sucharoast nytakeltoLShourstoreachitsI-aminnertenperatureafterthe coaungprooeeeiestOpped,whilea1esnroastofthesaneweightam shape,cookedm:dertheemconditions,mytakeonly12t030mtes. Magnetism Asthesiseofapieceofneatincreases. itsweightincreasesin greater ratio than its cflnnsions. Because heat not travel free the surfaoeiwazd,thegnatertheeurfaceareatheshorteriethecooldng tine. Thus, ifother eonditionsarestanduwdised, largeroastewillre- quire fewerninutes perpomnthenmnereinnrcote (52). 10 Intheirstulyofs-,lO-,and15-pcundtoproundheefroaets, Her-hen. wood. and Patton (57) found that a 1cm» total cooking tine wasrequixedaseiseanddegneofdonenessincreaeed. However. fewer ainutespsrpeundtnrerequiredforoooungthelargerroaete. Thedif- fennoeineveragetotalcoenngtineincreaseduththedegreeofdcne- nees until an internal teemrature of 75“} was reached, afterwhich it appeared to statdliae or decrease. This difference was greater between theS-andIO-poundroaetsthanhetwunthelO-andls-poundmasts. Whlyltoldhourslongerwererequiredtocookthelo-pound roaststhantheS-poundonee. AveragetotalooomtileofthelS-pound roastewasappedntelyOJtothourenorethanforthelO-pomd roasts. Inve(52)eteteethetin1u-gerpieceeorneet,theeiceotthepiec. eaynothetooimortantafactorinaffectingtheteuperatmrieeofthe interioraftercooldnghasheenstopped. However,apieceofneatnyhe sonallorthinthattheimerteuperaturedoesnotriseafterthecook- immoeeehaestopped.heoaueeofrepidooolingfrcntheeurfaoe. mas PaulandBratsler(65) etudiedtheetreototetcrcgehyooolcing steaksfronsesdnenhranoeueandadductornuecleeindeepfat. whenthe msclesweoeoaisideredseperetely,inomsedstoragetendedtoehorten coating time, but to increase cooldng losses for seedmbranosus steaks. Intheadductor.cookin¢tilna1eodecreaeedslight1yuthincreased storage. while cooldng losses did not differ significantly. Hanson. Stewart. and Lowe (39) observed that oooldng tine decreased significantlyuthetiuhetweenkillingandooomofhlorkdnseed broilers increased. Beat penetrated the muscles acre rapidh as post- norten changes progressed. mmafleefi Cookingtinisinflnencedwthetuperatureoftheneatatthsbe- winingofthecocldngpericd. hathavingatuperatureofOtoSqS requireealongertisethan-sathavinganinitialtelpsretnreof20°0. Heat frozen when cooking is started requires a longer cooldng tine. Part oftheheatisusedtonelttheicebeforethetmperaturscanbeelevated above the freezing temperature of the meat (52). 222193 anthem. tun Heat may be cooked in four mediums—water, stean, fat, or air. If thetaperetoreottheeeeoomnediaieconetont,ccomtinedepende largely upon the rate at which heat is cmducted in the particular cook- ingnsdiunbsingused. SincetheepecifichestofairisO.2handofoi1 is 0.131 to 0.16, neat reaches a definite interior temperature faster in oilthaninsirofthesanetenperatuxe(52). Cover (18) investigated the rate of heat penetration in beef cached inveterandinanovenofthesanetanpentm. Shereportedcooking tinewasshortin‘noistheat“asccnpandwith'dryheat'oftheoven. Harrison (‘10) found that cooking tine for beef was shortest in water followedtyfat,stean.andair. Shoalsonotedthattherateoftamerb attire rise forroastsccokedintheoil-sdiunuasappronnatelythesane throughoutcooldng. Haemr.afterovenroastsreachedatenperatuieof 5015055°C.theriseinte-peretunatthecenteroftheroastswas slanrthaninthefirstpartofthscooldngpsricd. Marshall, wood. and Patton (58) also observed that the rate of in- crease in internal temperature lessenedas roasts approached the rare stage. They suggest that since this is an endothermic process, less heat is available to raise the temperature of the roast. Marshall and co- workers (58) found the rate of increase in internal teeperetme was least in a 93°C oven. that cooked to well-done at this temperature had a final internaltwapentunonlyswleesthsnthatofthecven.' If other conditions are constant, cooking neat rare requires less tine than cooking it nsdiun or well-done. tax-shin. wood, and Patton (58) also reported a wide variability in cooking time which was particularly strildng formstscoobedto70and80°0ina93°c oven. Iessvariation was evident for roasts cooked at the higher taperetnree. 107 and 121°C. Cooking tines were nost uniform for roasts cooked to 60°C. Fran their experiment, Visser et a1 (92) reported tine-teaperaturs curves for roasts cooked in fat were steeper and shorter than those for comparable oven roasts. They estimated that at a given tanperature the heat conductivity of liquid fat is about 6 tiles that of air. The fat transferredheattotheneatnorerapidlythandidtheairintheoven, althoughthetenperatureofthefatwae lowerthanthatoftheoven. ‘ According to Iowe (52). the lower the imer tanperature at which the ccokingis stopped, thegreateristhetendencyfortherise ofinnsr temperature. This is due to the variation between the itmer and surface heat. At internal temperatures of 75°C or above there is usually little or no rise in temperature after cooking is stopped. Visser et a1 (92) reported no intexnal temperature rise of oven roasts cooked to 55, 70, or 85°C. However, when meat was cooked in deep 13 fat at 110 °C, the internal temperature of roasts cooked to 55°C rose 10 to13°C,andthetulperatureofroastscoobedto70°Crose5toé°C. The rise in tuxperature of roasts cooked to 85°C was negligible. Internal temperature rise for route cooked in deep fat at 100°C to 1&5 and 65°C was approximately 10 and 5°C, respectively, whereas the rise for roasts cooked to 85‘0 was negligible. Thus. for roasts cooked in deep fat, there were no samles representative of rare and medium-done neat. Factors Affecting Cooking losses 'lhe total loss that occurs during the cooking of meat includes both volatile and dripping losses. The greater portion of volatile loss is from the evaporation of water, while the drippdngs include fat, water. salts, and nitrogenous and non-nitrogenous extractives. Depending on the temper- ature of the cooking medium and the stage to which the meat is cooked, total losses occurring during the cooking of neat may vary from approxi- mately 5 to more than 50 per cent (52). In general, factors which may influence cooking weight losses are the same as those which affect the rate of heat penetration. Mahatma: , In early research on the cooking losses of neat, Why and Hojoxmier (35) observed that both water and fat accounted for weight loss in roasted seats. Lowe ( 52) pointed out that the ratio of evaporation losses to dripping losses was higher for lean meat and lower for fat neat. Black, “arner, and Wilson (6) found meat from supplemnt-fed steers showed more dripping loss and less evaporation loss during cooking than did mat from 11+ thinner, grass-fed cattle. mine. Williamson, and Morgan (88) roasted standing ribs of beef at 210°C to an intemal temperature of 65°C and found the average total weight loss was 29 per cent for lean roasts and 33 per cent for fat-covered roasts. These workers attributed the differ- ence in total weight loss to the rendering out of surface fat. in}: Free studies of beef roasts ranging from Choice to Canner grade, Alexander (2) reported well-fattened beef ribs of high grade had greater dripping losses and lower volatile losses than did lean ribs of low grades. Dripping losses from roasts cooked at an oven temperature of 125°C to 58°C internal tenperabare varied from 3.7 per cent for Choice grade to OJ» per cent for the Canner grade; evaporation losses ranged from 6.5 per cent for Choice to 10.9 per cent for the Cazmer grade. lhe results of Black et al (6) were in agreement with these findings. In their work, Alennder and Clark (3) noted that among roasts classified according to grade, those in the highest grade usually showed smaller evaporation losses and larger dripping losses, irrespective of style of cutting or method of cooking. hands (59) reported no significant difference in volatile losses attributable to grade; differences in dripping losses due to grade were significant only at 90°C internal temperature. his average dripping losses at 90°C for Good and for Choice grades were significantly higher than for Commercial grade. There was no significant difference between average total cooking losses attributable to grade at azw of the internal temperatures. In working with longissinus dorsi muscle of U. 8. Utility. Cmrcial, and Good grades of beef cooked to soec at 1‘09‘0, Dav (29) found 15 no significant difference attributable to grade in average total cooking losses, volatile losses, or drip losses. Surface gm ktensive investigations (11.2.53) showed that compact pieces of neat with wall surface areas have less cooking weight losses than cuts which haveirmgular shapes and greater surface areas. Intheirworkwith 5-, 10-,and15-pmnulcuteofchoicetopmundsofbeef, Marehall,"ood.and Patton (57) found that the rise of the mast affected total preparation losses. Cooking losses for 10- and l5-pound masts were significantly less than for the 5-pound masts at all degrees of doneness except rare. m Moran and Smith (61) observed that longer ripening periods after slaughter reduced cooking losses. Harrison (‘40) noted masts with a longer ripening period had less weight loss when cooked in air than when cooked in steam, fat, or water. In cooking steaks in fat, Paul and Bratzler (65) found cooking ties decreased with increased storage, and cooldng losses tended to increase with cooking time. was mm mm tin Cline and coworkers (16) reported that both cooking losses and cook. ing ties were affected by the initial temperature of masts. Roasts with low internal temperatures at the beginning of the cooking period showed greater cooking losses than did masts with higher initial temperatures. The effect of four methods of defrosting neat and the mnnar and twemture of cooking upon weight loss and palatability of masts were compared ‘w lows and associates (53). Fmsen cuts of neat mquired a .eus 16 longer cooking tine than comparable cuts which were thawed. However. data for #1 groups of masts indicated cooking losses for froaen cuts were not always greater than those of the defmstad neat. In 31 of these groups weight loss was greater for masts which were fmzen when cooking started. The other 10 gmms of masts gave opposite results. Cline et al (16) reported results of several methods of meeting beef. They seared psi-e ribs and cooked thm at different oven tnperatures. Theyconcludedthatsearingincreasedoookingloasesandlowoventsuper- atums were correlated with low cooking losses. From their studies, Child and Satorius (11!) found cooking losses in beef were greater when neat was masted at constant temperatures of 200 and 175°C or seared at 260°C for Zomtesandfinishedat150°0thanwhenmastswemcookedataconstant temperature of 150°C. Cover (23) observed cooking losses for paired three-rib masts cooked Iodine-rare averaged 7.1 per cent when a 125°C oven was used and 20.2 per centwhena225°Covenwasused. Iowe (52)found12 pairs oftwo-rib beef masts cooked at 150°C showed 7.7 per cent cooking loss at 55°C internal teaperature and 1.6.6 per cent coohng loss at 75°C internal temperature. Other workers (2, 53) have reported similar findings. The effect of five different intemal temperatures on the cooking weightlossesofmastspreparedfmmtendercuts ofbeefwasstudiedby heads (59). As was expected. the total cooking losses increased with eachriseintheinternalteuperature oftheneat. Thecookinglossesof the strip loin at each of the internal tenperatures were significantly lswerthanthoseofawoftheothercutswiththeeaceptionofthe posterior mund at 50°C internal teaperature. Generally, at 50, 60, and l7 70°C internal temperatures, the average total cooking loss of the mlled ribmastswashigherthanthatofthetopmundcuts; butat80and90°c, mund cuts showed higher cooking losses than mlled rib cuts. In their eaperinent with top mund beef masts cooked to internal tenperaturesof60, 65s 70. and80°Cinalh9°C oven, Harehallandco- workers (57) femidcoounglessesincreasedwithdegreeofdonenessupto theneditn-welldonestageandwere giieaterinlO-andlS-poundmasts thanin5-poundmastsatalldegreesofdonenessmeprtrare. In a (recent study, Marshall, Wood, and Patton (58) compared prepa- ration losses, cooking tins, and yield of lO-pound pieces of Choice grade top beef mund masted to three internal teeperetnree (6o, 70. and 80°C) at three oven temperatures (93. 107, and 121%). They concinded that total losses were gmatest in the 93°C oven, and at all oven temperatures there were greater losses at the higher internal temperatures. Evaporation lossesvariedwithoventsupentm‘eandincmasedwithinternaltupsra- tureinlowtenperatureroastingofbeef. Driplossesincreasedasboth oven temperature and internal temperature of the mast increased. V Cover (20) studied the effect of natal skaters on coonng tins and cooking losses. Paired mend, anabone chuck, and starding rib masts were cookedto thewell-done stagewithandwithont skewers atanoventespers- ture of 125°C. Total loss of weight was reduced in skewered masts In about BSPOrcentwhilecooungtinewasshortenedbyappronnterBOto “5 per cent. lhetotallossesofneats mastedincoveredanduncoveredpanswere compared by Grindley and Hojonnier (35). Analysis of the data showed that weight losses were greater for covered than for uncovered masts. 18 Harrison (40) noted roasts cooked in deep tat had the greatest loss in weight and volnae, while those cooked in air had the least loss. Total losses Obtained tron.couparahde cuts cooked in steam and in water'were similar and gave intermediate values. In their recent study, Visser et al (92) found that as the internal temperature of the neat increased, average cooking tile increased signifi- cantly; and was accompanied hy'a significant increase in cooking losses for all beef round.roasts except those tronxthe adductor and posterior seninenbranosus muscles cooked in 100°C fat. The effect of internal tempera ature on cooking time and losses was most pronounced in.oven roasts and least pronounced in those cooked in.deep»fat at 110°C. ‘Hhen.the end ‘temperature was 55 or 70°C, losses were greater for roasts cooked in.deep fat than for’oven roasts. Howevere'when.the meat was cooked to 85°C, losses were similar for all methods. Factors Affecting Palatahility Characteristics of Meat Cooked hy Dry'fleat Extensive research has shown that the eating quality of'neat is dependent upon numerous and varied factors. Carcass grade, sax, breed. Insole differences. aging; freezing, and method and.eaient of cooking are included among factors influencing the acceptability of'the finished prods not. The palatahility characteristics considered in.Judging cooked meats are: aroma, flavor. appearance, texture. tenderness. and juiciness. Aroma Egg’tlavor Although flavor and odor components of meat are not well defined. these qualities,.in a properly cooked piece ot.neat, are largely responsible for appetite appeal. The weak, blood-like flavor of rat neat, Crocker (26) points out. is primarily in the Juice, rather than in the fiber. The slightly salty taste, characteristic of rm: beef, is probably due to the presence of lactic acid, phosphoric acid, sodium chloride, potassium chloride, and other salts. KrenJich and Pearson (#9) found the flavor constituents of raw beef and beef Juice fractions largely water soluble. Cooking develops the “meaty“ flavor which Crocker (26) states is presumably brought about In certain chemical-changes in the fiber, not in the Juices. The variety of chemical compounds foreed during cooking in- clude anemia, shines, an iniole-like odor, demgen sulfide, and acids such as acetic and propionic. Complex conunations of shell amounts of these compounds result in the fragrant and distinctive ”meaty“ flavor, which is largely an odor. These pleasant, slightly burnt, moderately acid, sulfnryodorsandflavorsintensifytoaboutBhoursofcooldngand then gradually decrease. ‘ Howe and Bea-hens (no) attribute flavors of cooked neat to the stimli given to the teste buds by inherent organic and inorganic sub- stances such as uaterusoluble extractives, lipids, small amounts of carbolwdrates, and salts, or compounds resulting frond these pmducts and the proteins. Kraniich and Pearson (n9) found flavor constituents of longissi-ls dorsi muscle ofbeefribwere largelyvater soluble inboth rawand cooked fractions. Cooking before extraction of the sample increased flavor threshold. This suggests that full flavor development m be due to heat- ing of Juice and fibers together. If} D J ' £33.: 20 Egg. Several investigators (29,36,59) have observed that carcass grade influenced the palatability of cooked meat. Day (29) reported significant differences in grade for aroma and flavor when longissimus dorsi muscles of 0.8. Good, Commercial, and Utility grades were compared after meeting. Hasuds (59) worked with top rounds, sirloin butts, strip loins, and rolled ribs cut from three grades of beef carcasses, Choice, Good, and Commercial. Statistical analysis showed average amma and flavor scores of Cosmercial grade masts to be significantly higher than those from Good and Choice grade masts. In comparing 140 Choice, 76 Good, and 21+ Com- mercial grade rib masts, Lowe et a1 (53) obtained highest scores for arena and flavor from the Choice grade. Griswold (36) found Prime grade beef gave higher palatahility scores than Connemial grade. Dem of finish and fat content. me their stunt; on the relation of demo of finish in cattle to meat flavors, Brahman and co-workers (10) observed that the scores on intensity and desirability of flavor of lean neat showed progressive improvement in the meat with increased fat. Simon, Carroll, and Clegg (80) studied the effect of degree of much on differences in quality factors of beef. Results indicated that flavor, Juiciness, and tenderness differences became more apparent with increas- ingly wider differences in degree of finish and carcass grade. Flavor appeared to be associated with intramuscular fat. Howmrer, the relation- ship of per cent carcass fat with quality scores did not show striking correlation. Dunnigan (32) worked with choice and Utility grades of sin- loin butts cut in two styles, bone-in and bone-out, and reported fat roasts scored significantly higher than lean roasts in aroma, flavor, and tenderness. 21 Web and Pearson (“9), in working with beef and beef juice fractions, found that neither fat content nor fat-free dry matter were responsible for differences in flavor when flavor threshold and gross chemical analysis were caspamd. Deterioration in palatability of beef, pork, and lamb during freezer storage at temperatures between -7.78 and 47.8%, was found by Hiner, Caddie, and asnkins (43) to be due primarily to the oxidation of fat. They also noticed that the desirability of the flavor of the fat was the best subjective hide: among the psistshiiity factors studied. m. According to Lows (52), aging includes the entire storage period frm the time of slaughter until the time the mat is cooked. lbs effects of aging have been shown to have a marked influence on palatability. From observing histological, plusical, and organoleptic changes in beef during em, Harrison et al (41) found little variation in am and flavor scoresformastsagedfmnltoZOdays, althoughtheMgheetaverage scores were received by masts aged 10 days. When masts were stored longer than 20 days, aroma and flavor scores were definitely lower than for roasts stored less than 20 due. Lowe (52) observed that aging neat 20to nodsysinpsrtedoptinmmvcr. Meatsgediongerthsnuodm usually had too "high“ a flavor for most of the Judges in her laboratory. Griswold and Wharton (37) studied the effect of storage conditions on the palatshiiity of beef. The aroma and flavor of neat stored 37 days at 1°C um slightly stmnger than for meat stored 9 days at. the same temper- atm. Meet which had been stored as hours at 15°C under ultra-violet “8"" was mm desirable in appearance and odor than nest held under similar conditions without ultra-violet lights. These lights decreased the growth of bacteria on the neat surface. From their investigation on the changes in beef induced by storage, Paul, lows, and McClurg (68) reported that the greatest increase in palata- hility of small cuts was obtained with a 9-day storage period at 1.7%. Further storage resulted in decreased desirability of aroma ani flavor and development of “goodness“ in the lean and rancidity of the fat. 122234550 Biner, Caddie, and Haitians (1&3) stored cellophane wrapped, lard-coated, vacuum packed, and exposed beef, pork, and lamb chops at -7.78, -9sl|’+s 4.7.8, and -81.1°C. The exposed meat had a good covering of fat, which partially prevented it from drying out. Cellophane and lard-coating were equally satisfactory in pmtecting fmsen cuts from noisture loss. The most dessication occurred in the exposed cuts. Developient of un- desirable flavor was not attributable to fat oxidation alone but appeared to be related to moisture loss as well. The orifinal quality of all the neat declined rapidly in all types of protection studied except the vacuum pack. Tenperatms of -l7.8°C and below gave the best protection to the neat. ‘ In a study concerning the effect of four different packaging materials on fmaen nests, Sinpson and Chang (81) founi that aluminum foil or glassine- landnated paper was more effective than polyettwlene-coated paper or butch- er wrap in retarding rancidity development. They used storage temperatures of -l7.8, -28.8, Junk, and 40°C and observed that temperatures of -28.8°C or lower gave the best protection to the neat. 23 W. In comparing the effect of different cook- ing methods, Griswold (36) found beef round roasted at 121°C scored high in acceptability and flavor. Stech and West (83) reported similar firdings. From their «peanuts with 10 methods of roasting prime ribs of beef, Cline et al (16) observed a definite con'elation between cooldng losses and flavor of the lean. All roasts which ranked low in cooking losses rated highinpalatahility. Theyalsonoted tendercuts cookedintheovenat 125°C with the addition of water had lower flavor and aroma scores than camarable cuts cookedintheovenbydryheat at 125°C. The findings of curl: and Van Dcyne (15) indicated that oven cooking resulted in more palatable top rounds than did cooldng similar roasts in the pressure saucepan. Judges preferred the flavor of the lean and fat of theneat roastedintheovenandconsideredthemat cookedinthepressure sauce pan too dry. 5222.19.22 2.1!; m Because eye appeal influences food selection, texture, appearance, and color are ilportant characteristics of neat. Fronastudyoffactorsinfluencingthetendernessandtutureof beef, Brady (8) stated that texture is dependent on the size of the fiber bundles in the muscle. the larger bundles being associated with finer texture. M. Satorius and Child (78) reported that Judges' scones showed no sigrdficant difference between medium and good grades in the external appearance of loogissinus dorsi and adductor muscles roasted to 58°C in a 150 ‘C oven. However, they observed a significant difference between 21+ grades in the estemal appearance of the raw muscles. In her work with the longissisms dorsi of beef from 0.5. Good. conserciar, and Utility grades, Day (29) reported that, for appearance and texture. the analysis of taste panel scones indicated little difference between grades. Masuda (59) found the average appearance scores from cooked samples of Comercial and Good grade roasts were significantly high— er than scores for samples from comparable cuts of Choice grade roasts. No significant difference in texture scores attributable to grade was observed. 293.25. Although some red corpuscles with their banglobin raisin in the capillarieswhenthebloodisdrainsdfrontheaninalatthstineof slaughter, mglobin is the chief pigment producing the pink to red color in muscle. Bernorsxq. Fox, and Schweigert (5). in stnmng the effect of cooking on mglobin, reported that pignents extracted from cooked fresh beefconsistnainlyofmoglobin. 'lheanountofpignsntreminingun- denaturedinapieceof cookedneatdepends uponits turpentureandhow long it has been held at that temperature. hppel (87) found reflectance spectrophotometry useful in studying hematin pigment changes in the ccotdng of beef and in characterizing the henstin pigments of cooked beef. Choice beef tenderloin steaks were broiled to median-rare and well-done. The entire visible spectra from #00 to 600su was recorded. He observed that henatin pigments have a rela- tively sharp and characteristic reflectance spectra minim. Brown pigments of cooked bef are characterized as mixed denatured globin nicotinardde hedchrones. 25 mm. m-anblett et al (9) studied five mscles frcnpairedbeefroundswhereinonemrsclefroneachpairwascookedat 63°C for 30 hours and the other at 68°C for 18 hours. The meat cooked at 63°C yielded higher appearance and texture scores than the neat cooked at 68°C. Marshall and co—workers (58) roasted top round of beef at three oven temperatures to three internal temperatures. They found that appearance tended to be scored lower as degree of donensss increased, possibly due to the relatively drier appearance and the ragged edges. Roasts cooked to well-done deveIOpsd a hard crust which was difficult to cut, causing the neat to tear during slicing. From their study, Visser et a1 (92) reported that the external appearance of all roasts cooked in the oven or in deep fat was similar. However, the surface of neat cooked in hot fat was the gray-brown color of cooked meat, but not the rich brown characteristic of the oven roasts. The center of deep fat roasts cooked to 16°C was a bright pink which grad- uallyfadedtoagrsy-brownaroundtheedge. Thecenterofreastscooked to 65°C was a light pink that faded to gray-brown about half wav through the roast, whereas the interior of roasts cooked to 85°C was a uniform gray-brown. The inside appearance of even roasts was typical of rare. medium-, and well-done meat. lameness Since nearly everyone who eats meat notes its tenderness, this quality in meat is universally desired. Factors which affect the tenderness of neat have been the subject of many investigations. 26 Composition of the meat. Black, Warner. and Wilson (6) studied the effect of grade and feeding of grain supplement to steers on the quality of beef. From Judges' scores and mechanical shear tests they found meat from steers fed the grain supplement was more tender than meat from grass-fed steers. Simon, Carroll, and Clegg (80) observed that differences in tenderness became more apparent with increasingly wider differences in degree of finish and carcass grade. Cover, King, and Butler (25) measured the per cent separable fat and the per cent ether extract in stucUing the effect of fatness. They reported a wide scattering of tenderness rating for meat from different carcasses. Agreement between fatness and tenderness was low enough to indicate that a consumer who bvws fat or well-marbled loin steaks may be disappointed in tenderness. Using sixty-nine grain-fed cattle, Rankine and Ellis (38) found no significant correlation between fat content determined by ether extract, and tenderness of cooked longissimus dorsi muscle. They concluded that variations in tenderness are caused mainly by factors other than fat content. Ramsbottom and Strandine (71;) investigated the comparative tenderness of samples from eight mscles of U.S. Good beef and observed no relation- ship between the amount of fat within the muscle and shear force results for raw or cooked samples. They emphasized that the amounts of collagenous and elastic connective tissue in the mole influenced the tenderness of the cooked mscles. Brady (8) stated that texture is an indication of tenderness and, the ”finer“ the texture , the tenderer the meat. 27 Agg‘_gg§h_gn§_g:§§§. To determine the effect of animal age on the tender— ness of the meat, Hiner and Hankins (#4) used animals varying in age from 25 months to 5.5 years. Tenderness decreased as the age of the animals increased. From their experiments, Satorius and Child (78) concluded that neat from.steers was more tender than that from cows. Lowe et a1 (53) cooked #0 Choice, 76 Good, and 2h Commercial prime ribs at oven temperatures of 120, 150, and 175°C to internal temperatures of 58 and 75°C. According to palatability scores, tenderness was in- fluenced by carcass grade. Commercial grade roasts received lower tender- ness scores than roasts from Choice and Good grade carcasses. Choice grade was scored slightly’higher than.Good. Hasuda (59) also reported that average tenderness scores for samples from Choice grade roasts were significantly higher than those from Commercia1.and Good grade roasts. Shear force readings and tenderness scores indicated a probable high negative correlation. In their study. Cover. King. and.Butler (25) obtained a wide scatter- ing of tenderness ratings for different animals within a grade. Tenderness ratings were as high for meat in some carcasses of lower grade as for meat from other carcasses in higher grades. This would suggest that, for their sample, carcass grade was not satisfactory as an exact indicator of tenderness in meat. Animal and Insole variations. Noble, Halliday, and Klaas (62) found very small differences between tenderness averages for corresponding left and right wholesale rib cuts when the cuts were cooked in the same manner. They also noted that rib cuts were one and one-half times more tender 28 than first round cuts from the same animal. Ransbotton and Strandine (7h) observed individual muscles within a carcass varied markedly in tenderness. They reported the longissims dorsi and the psoas major averaged higher in tenderness than an other mscles with the exception of the internal oblique. However. Griswold (36) found no significant difference in palatability or shear values batman the sendnembranosus and biceps fenoris mscles of beef. gm. Ransbotton and Strandine (75) reported that beef was more tender two hours after slaughter than at am time after two to six days. Bettveen the 9th to 12th day after slaughter, beef was even more tender than it had been two hours following slaughter. Paul and co-workers (66) used the semitendinosus and biceps femoris moles in comparing steaks fried in deep fat with roasts cooked in the ovenaftero, 5, 12, 2h,l+8t053,andlh4tolh9hoursofcoldstorage following slaughter. They found tenderness changed with storage. Roasts were least tender iniediate]: after slaughter and as storage ties in- creased. tendemess increased. Steaks were tender immediately after slaughter. became less tender with storap up to 24 hours. and returned to their original tenderness at the end of the storage period. These results are in agreement with the earlier and sindlar findings of Paul and Child (67). Freezing. In her study on the tenderness of precooked and fresh frozen mate of beef, Dahlinger (27) reported that Warner-Bratzler shear measuzne- nsnts were significantly higher for precooloed masts. Taste panel scores for tenderness, however, indicated a preference for the fresh frozen beef mata e 29 Paul and Child (67) observed no significant difference in the tender- ness of meat which was not frozen and meat which was frozen at 48%. According to Ransbotton (73). freezer storage at -23°C or lower for seven years did not significantly change the tendemess of beef steaks. We From their studs. Rambottm. Strmdine. and Room: (76) found most beef muscles were made less tender w cooking, some did not change significantly, and other mscles became more tender. They concluded that since connective and fatty tissues were made more terlder tw cooking. decreased tenderness of certain cooked Insoles night be associated with factors such as coagulation and denaturation of mole protein together with varying degrees of shrinkage and hardening of the muscle fibers. Cover, semester, and Kehlinbrink (214) showed that tendemess has sore than one component and that longissinus dorsi and biceps fenoris muscles differed marked]: in tenderness response to certain cooking conditions. Child and Satorius (14) roasted semitendinosus muscles from beef round at oven temperatures of 125, 150, 175, and 200°C to an intemal temperature of 58°C. They reported no difference in the shear force tests for these roasts. In studying the relationship between oven tem- perature and tenderness, Cover (23) used constant oven temperatures of 125and225°Ctoroastbeeftoaninternaltasperatureof80°C. nomad. bons chuck, rib, and rump roasts were more tender when cooked at lZS‘C than when cooked at 225‘C. However, no difference in tenderness was shown in nsdiun-rare rib and chuck roasts cooked at 125 and 225°C. Relatively small differences in total cooldng time were observed. In 30 another study, Cover (19) noted the effect of oven temperatures of 80 and 125°C on beef terrierness. Results of this experin‘ent showed that roasts were always tender when cooked at 80°C. Bowover, they were dry. nicely, and flavorless. . Several investigators have studied the effect of mating rent at lZl‘C. Stech and west (83) reported products were tender. moist, and had good flavor. (hiswold (36) stated that roasting at 121°C was a superior nethod for cooung beef round except for the dry appearance of the surface. Noble, Halliday. and Klaas (62) detorained the tenderness of beef cooked to'61 and 75°C internal temperature in a 1h9°c oven. Pro- the penetroneter readings, they concluded that toughening occurred during heating from 61 to 75°C. Fran her study Harrison (no) reported that the taste panel found neat cooked in fat more tender than oven roasts. However, shear score values were lower for masts cooked in air. Visser et al (92) found little difference in subjective tenderness scores for samples roasted in a 1‘19’0 oven and those cooked in fat at 110°C whereas, scores for samples cooked in 100°C fat were slightly lower. Generally. shear values were a little lower for even roasts than for those cooked in fat. These workers observed that, irrespective of degree of domes, shear values and tenderness scores did not vary significantly for a given mscle. Juiciness Juiciness enhances palatability and quality and. therefore, influences the acceptability of cooked neat. Frol- her studies in stewardizing methods of mating beef, Latzke (50) stated that juiciness can be assured 31 to some extent by the amount of cooking losses in meat. Other workers (9,69) have also observed an inverse relationship between juiciness and cooking weight losses. Composition of neat. Barbells et a1 (a) used 728 rib roasts to study the flavor and Juiciness of beef in relation to fatness and other factors. They noted that Juiciness of roasts increased quite rapidly with increase of fatness up to 22.5 per cent and more slowly from that point to 52.5 per cent. There appeared to be no apparent relationship between fatness and juiciness beyond the “2.5 per cent level. Thine, Willis-eon. and Morgan (88) reported that fat-covered beef roasts were less dry than lean roasts. . From their study. Child and Esteros (l3) observed that standing rib roasts scored higher than comparable boned roasts when tested with a pressoneter or scored for juiciness by a panel. WM)... Day (29) concluded that there was little difference in average subjective scores for Juiciness of 0.8. Utility, Connercial. ard Goodgradecuts cookedtothesanedegreeofdoneness. Sheobtaineda significant positive correlation between press fluid tests and juiciness scores at the 5 per cent probability level. Hasuda (59) found no significant difference in Juioiness attributable to grade. However, average Juiciness scores of strip loin were signifi- cantly higher than those of am other cut whereas , scores for center cuts ofteproundaveragedlowerinjuicinessandtenierness thandidaxvof the other cuts. 1 32 m and fmeggg. Harrison (no) observed little variation in Juiciness scores of roasts aged from 1 to 20 days at 0°C. From their investigation. Paul, Iowe, and McClurg (68) reported a gradual increase in Juiciness scores during 18 days of aging. Press fluid decreased and then increased sharply during storage. They attributed this to changes in the water- binding powers of the proteins and the permeability of the cell membranes. Paul (6h), in studying the effect of storage on palatability characteristics and physical changes in beef, also noted a reduction in press fluid during the first few days, followed by a sharp increase between the 9th and 18th day of storage. From a stew concerning the effect of fussing, Paul and Child (67) reported that unfrozen beef roasted at 175°C to 58°C was significantly higher in press fluid than frozen beef cooked at 175°C to the same degree of doneness. W. Noble, Halliday, and Does (62) found beef rib roasts cooked to 61°C Juicier than canparable roasts cooked to 75°C. According to their findings. beef rounds yielded more Juice than rib roasts at both degrees of doneness. Satorius and Child (79) reported a decrease in press fluid in the semitendinosus of beef w increasing the internal temperature from 67 to 75°C. However, they obtained no such decrease by increasing internal temperature from 58 to 67°C. Cline et al (16) cooked beef at oven temperatures of 110, 163, 191. 218, and 260°C, to an internal tuperature of 57°C. Frost their investi- gations, it appeared that high temperature decreased the Juiciness of roasts. Child and Satorius (14) found that oven temperatures of 125, 150, 175, and 200°C did not affect the press fluid of beef mscles cooked at 33 58°C. In their study, Bramblett and co-workers (9) noted that meat cooked at 63°C for 30 hours gave greater press fluid yields and higher scores for juiciness than neat cooked at 68°C for 18 hours. According to Harrison (1+0), panel members found no significant differ- ence in juiciness of meats cooked in four media. more was no significant difference in the amunt of press fluid at the center of roasts due to cooking mediuna; but there was a highly significant difference in the amount of press fluid from samples one-half inch below the surface of roasts which was attributable to different cooking mediums. Heats cooked in air had the nest press fluid. Cuts cooked in fat were next. followed by water and steam. In their stun, Visser et a1 (92) noted beef. cooked in a 1h9°c oven or in deep fat at 100°C was juicier than beef cooked in fat at 110°C. Juiciness scores and press fluid yields for oven roasts and those cooked in deep fat at 100 °C usually decreased simificantly as the internal tmerature of the roasts increased. There were fewer differences in Juiciness attributable to internal temperature for roasts cooked in deep fat at 110 cc. lbthods of Evaluating Palatabdlity Food acceptability is primarily depexldent upon the stimulus of the sense organs of the individual. Although some objective tests provide infomation which substantiates subjective appraisals of color. texture. tenderness, and juiciness, detendnation of odor and taste in food can not be made objectively. __J_.£i.s5nb ac v Me In subjective scoring nethods the qualitative and quantitative aspects of the characteristics under consideration are based on the opinions of judges. love and Stewart (55) classify subjective tests into two categories: (a) preference or acceptance tests and (b) difference or psychometric tests. Because psychosetric tests can determine quantitative difference by scoring or rating food quality factors, they are valuable research tools. Seem tests, According to Iowa (52), scoring tests are made more fre- quently than aw other sensory tests. Single palatability factors are assigned a numrical rating by the scorer. The scorer is expected to detect differences in the samples, if they exist, and to assign a quantity factor to these ratings. Paired samples. Cover (22) used paired samples for scaling neat. In this method, the scorer was asked to detemine which of two samples was the rare tender. A recent experiment by Cover (21) showed trained personml were able to distinguish successfully between the following components of tendernessoosoftness, friabdlity, and tenderness of connective tissue. This method of partitioning tenderness into several components seems to offer increased opportunities for relating chemical and physical changes to certain kinds and degrees of tenderness. ngerence tests. Three methods of conducting subjective difference tests were discussed by Per-yam and Swartz (71). In the triangle test I three samples were presented to the judges at the same time. They were asked to select the odd sample from the other two identical samples. In 35 the duo-trio test, judges were presented a control and then two samples of unknown order. They were asked to pick the sample which was different from the control. In the dual standard test two odor samples were presented to the judges. Theywere asked to studythenandnote differences. A second pair of sampleswas givento the judges andtheywerenatchedwith each of the first samples. Peryam’and Swartz (71) recounended the triangle test for discrisdnation, the duo-trio test for taste, and the dual standard test for odor. According to Davis and Hanson (28) considerable infomation was lost in the use of the triangle test if intensity designation was not undo or if the test was utilized only for those jlxlments in which the odd sample was recognised. They presented a new method of evaluating the results of the triangle test in which intensity designation was required. All judg- ments were evaluated in toms of an I-value which was directly related to the probability of chance occurrence of the judgment. The inclusion of partially corrected judgments provided for increased efficiency In re- ducing the number of trials necessary to detect a difference at a given level of significance. Simon, Carroll, and Clegg (80) compared the tri- angle method with a quality judgment procedure (scoring) in evaluating the effect of degree of finish on differences in quality factors of beef. Although the results of the two procedures were in agreement, they reported that triangle testing was not as sensitive as scoring in evaluating products of a high degree of variability. Several investigators (7, 1+7, 51) have discussed problems involved in the subjective method of testing. Boggs and Hansen (7) observed that each judge tends to weigh the various 36 factors by his own standards. In some cases, fatigue was found to be a disadvantage, but in meat, it was not necessarily important (51). Psychological and plvsiological factors have also been shown to influence judges' scoring (55). The importance of scientific technique for constructing score cards was emphasised by Sweetnan (85). Qualities should be selected and weighed according to the investigation being made. Authorities in the field of taste panel work suggest that equipent and enviromnent be controlled. Air-conditioned rooms were advantageous in preventing odors of paint, coffee, smoke, or other such aromas from inter- fering with accurate detection of differences in samples (31) e According to Foster, Pratt, and Schwartz (33) isolation of the judges gave more accurate results. To assure optimum results, china, silver, and glass _ mat be used: placing the samples on paper dishes was unsatisfactory (70). Overman and L1 (63) recomnded that the reliability of the judg- ments should be checked to obtain maximal validity from taste panel scores. My suggested methods for measuring the consistency and discriMnating ability of taste panel members. Despite the linitations, subjective testing is considered essential in determining food acceptability. 0!: active nation According to Lowe and Stewart (55), objective tests can be repro- duced and are more applicable to the needs of the control laboratory. Subjective ratings of tenderness, juiciness, and color of meat m be substantiated by objective measurements. 37 W Dinnerous devices for measuring the tenderness of meats have been invented. Noble, Balliday, and was (62) were successful in using the New York Testing laboratory penetrometer for comparing the tenderness of left and right sides of the same animal. Proctor et al (72) reported a recording strain-gage denture tenderometer. The instrument consisted of a complete set of human dentures. According to initial tests, the machine had good potentialities for aiding in solving the problem of standardization of criteria for tenderness. measurements. Bratsler (ll) improved the Warner shearing machine by standardising theshapeandsiseoftheopeningandthetypeofcuttingedge. This modified machine, known as the Warner-Bratsler Shearing apparatus, has been widen used for tenderness determinations. Several investigators (1,78) have established a high degree of correlation between taste panel scores for tenderness and shear force readings. @fld co-workers (82) determined tenderness in raw and cooked beef muscles with a tender- ness press, which was a modification of the Carver juice press. A panel and the Warner-Brawler shear apparatus were also used to measure tender- ness of the cooked neat. Correlations between press and Wanier-Bntsler shear were sigldficant. 923%. Development of a method for objective evaluation of juiciness of meats was based on the principle of expressing fluid from neat samples of brown weight. In 1931+, Child and Baldelli (12) reported an apparatus called the pressometer and standardized a method for determirdng the percentage of press fluid. Studies (13 .29) have shown a correlation be- tmen pressomter readings and taste panel juiciness scores. 38 Tannor, Clark, and Rankine (86) reported the development of a ludraulic press which determined expressible juice content of seat. However, their findings showed no close correlation between results ob- tained by the mdmalio press method and the taste panel scores for juiciness of beef cooked to an internal temperature of 58°C. Color. Tappel (87) illustrated the usefulness of reflectance spectro- photometry for measurement and identification of hematin pigments in meats. The entire visible spectra from lI-OO to 600m was recorded. He found that hematin pigments have a relatively sharp and characteristic reflectance We Combination subjgctin 2E objggun $212932}! Perhaps the type of evaluation most widely applicable to all foods is the subjective-objective approach. Lowe and Stewart (55) pointed out that objective tests for organoleptic qualities must measure those characteristics which are correlated with acceptability. A partly subjective, partly objective method for comparing tenderness of different meat samples was described by Lowe (52). It consisted of counting the number of chews necessary to masticate the sample to a predetenlined end point. The surples were sliced on a machine so that the fibers were all the same length, and samples of the controlled dimensions were used. Scorers standardized the end point of mastication and determined a specific gradation of their own scores in relation to the number of chews muired for complete mastication of the sample. Examples of the use of a combin- ation of subjective and objective methods of evaluation are shown in the research done on tenderness and juiciness (59.77). 39 WODOFPRCXIEDURE To compare cooking losses, palatability, arri rate of heat penetration, roasts were cooked by two methods under controlled conditions. The con- ventional roasting method employed by Douglas (30) in a related project has been followed as closely as possible. Standardized procedure for cooking by deep fat innersion was established through preliminary investigations in the laboratory. Materials Used 22:; 122.91.! Six pairs of U.S.D.A. Choice grade steer beef rounds, rump on, weigh- ingapprmmately65to75poundspermund, were procured throughthe Michigan State University Department of Animal Husbandry. Six days after slaughter, the sendmhranosus nuscles were dissected and surface fat was removed. The muscles were trialled to provide roasts of approximately 1M0 grams each, and standardized with respect to linear measurements for length, width, and depth. The samples for roasting were individually wrapped in heavy freezer paper, coded, blast frozen, and stored at -20°C until defrosting prior to cooking. Storage periods ranged from 173 to 189 We. Data relative to weight of rounds, weight of muscles, muscle linear measurements, and trimed sample weight are shown in Table 11+, the Appendix, page 91. El $2.: £1.22: Two 50-pound boxes of all-purpose, hydrogenated vegetable fat were obtained from the Michigan State University Food Stores. W Most of the equipment used in this study is cOMparable to that found in.institutional kitchens. However, special pieces of'equipment*were used to facilitate accurate collection of data. flairhiax_and_asasnrinao [A h.5-kilogram.capacity torsion balance was used to weigh the samples, fat, pans, racks, and drippings to the nearest gram. Total drip obtained from cooking by deep fat immersion was collected in a graduated beaker. Readings were recorded in milliliters and converted to grams. .A device consisting of three rulers was used to measure the length, width, and depth of each sample. Two vertical 18-inch rulers, numbered from the bottom to the tOp, were connected by a horizontal Zh-inch ruler with numbers reading from left to right. The left vertical ruler, secured on a metal foot, could stand alone. The horizontal ruler could be moved up and down; while the right vertical ruler could be moved toward or away from the left ruler. To measure the length, each sample was placed between the vertical rulers so that the rulers touched the meat on both ends at the longest point. For width determination, the rulers were.adjusted so they touched both sides of the sample. To measure the depth of the sample, the horizontal ruler was lowered until it touched the meat. Each time the ruler was adjusted until it matched both vertical rulers at the same inch marking. Measurements for‘width and depth were recorded at the anterior, middle, posterior, and maximum portions of the sample. A large pyrex cylinder, two loco-milliliter graduated cylinders, a rubber hose, a clamp, and a 12-inch thermometer with a temperature range of -20 to 100°C were used for volume measurements. 1+1 The smoke point of the fat was measured with a 9cinch thermometer, with a temperature range of ~10 to 250°C, positioned in a sillimanite casserole, 3.5 inches in diameter, containing 100 grams of fat. An 8-point Brown Electronik Potentiometer High Speed Multiple Point Recorder was used to record data relevant to time-temperature relation- ships of the roasts throughout the cooking and cooling periods, the internal oven temperature, and the temperature of the frying medium Oven roam. Each conventional]: roasted sample was placed on a trivet, 14.5-inches long by 10.25-inches wide, with one-half inch legs, in a standard aluminum roasting pan, 17.25-inches long by 11.25-inches wide by 2.25- inches deep. The lower deck of a 2-deck, themostatically controlled Hotpoint roasting and baking oven, Model No. HJ225, was used throughout the study for these samples. W. Samples immersed in deep fat were placed in a single, full size wire fryer basket, ll-inches long by ll-inches wide tar b.75-inches deep. A thermostatically controlled Hotpoint comercial electric deep fat fryer, Model No. HKGh, was used to cook samples in hot fat. Slim. Samples for taste panel scorug were cut t-inch thick on a HOW Outta-c slicer, l‘bdel ”Co “10. Objective testig0 A Bechnan zeromatic pH meter and a Bausch and lamb spectronic 20 calorimeter with reflectance attachment were used to deterb mine the acidity and per cent reflectance of both raw and cooked samples. Tenderness and juiciness of cooked roasts were evaluated by a Warner» Bratzler shear apparatus, and a Carver press machine, respectiveh. 1&2 Preliminary Investigations Before the actual experiment began, a series of cuts from the top round of beef, resembling the test samples, were conventionally roasted and cooked by deep fat innersion. ' Preliminary investigations served to establish the approximate amount of fat required for immersion of the sample, a temperature for cooking in hot fat, and a technique for collection of the drippings. hthodology for the preparation of samples for objective testing was developed. Samples from the roasts were used for preliminary taste panel instruction. Amount and re-use of fat Cuts ofbeeffromthetopround, similarinweightandshapetothe actual test samples, were used to determine the quantity of fat necessary to suhnrge the meat. In preliminary trials, fat was re—used a total of 6 times. To insun that the smoke point was safely above the desired cooking temperature, smoke point determinations were made before and after each cooking period. Since re-use of the fat showed no unfavorable results, this procedure appeared to be of no disadvantage for this stutw. Determination 9; £53 Mature Roasts were innersed in fat at temperatures ranging from 100 to 120°C and compared with oven roasts. At lower tapsratms, the surface of the meat was a gray-brown color, not the rich-brown characteristic of a con- ventionally roasmd product. it higher temperatures, the cuts shrank considerably and a thick, hard crust fanned on the surface. Temperatures between. 110 and 118°C seemed most desirable. After further work, it was decided that a fat temperature of 115°C gave a product which most nearly resembled an oven roast. 1+3 The contact heat, for roasts cooked at temperatures of 115°C in fat and lll9°c in air, was considered comparable Iv an engineering consultant. When a product is cooked in heated air there is a stationary layer of air surrounding the surface, which acts as an insulator. This insulator, therefore, slows heat transfer. Thus , a conventional oven heated to 1139 °c' is approdmate]: equivalent to 116°C contact heat. The procedure used for equating contact heat for beef roasts cooked in fat and in air is given in the Appendix, page 92, Collection 95 m v Drippings obtained from conventional]: roasted and cooled samples were weighed to the nearest gram. For samples'cooked in fat, drip obtained during the specified cooling period was poured into a lZS-milliliter graduated beaker and the pan. scraped clean with a rubber scraper. The beaker was covered with Saran, refrigerated overnight, and drip separated from the cooldng fat was added the following day. Drippings were observed at the bottom of the fryer when samples were cooked in hot fat. Thus, an attempt was made to remove drippings from the cooking medium itself. The first portion of fat was strained, through h—layere of fine cheesecloth, into a small container and the rest into a larger container. After overnight refrigeration, fat from the small con- tainer was removed until there was approximately a i-inch layer of solid fat mining above the liquid. The contents were then melted, poured into a lOOO-milliliter glass cylinder, and refrigerated. When the drip and cooking medium had separated, the hardened fat was removed. The liquid portion was combined with drippings collected from the cooling period of the previous day and milliliters of total drip were recorded. Zzsnszaiiaa;atwaemalaa.faxzatnssiixsuiaattna Raw samples for objective testing were obtained from a %—inch slice removed from the posterior end of each roast. The location from which cooked samples were taken is shown in Figure 1. Methodology for objective measurements was developed as follows 8 fl. For the determination of pH, 20 grams of defrosted raw sample or 20 grams of cooked sample were combined with loo-milliliters of distilled water and blended for three ndmtes in a Hotpoint electric blender. Slurries were strained through a fine sieve into two small beakers. This amount was sufficient to permit duplicate readings for each sample. W. Raw and cooked samples of beef were shredded on a coarse grater and tightly packed into a glass cup, 1.75-inches in diameter and l-inch high. Per cent color reflectance was recorded at wavelengths of 415. M5. “75. 505. 535. 545. 565. 59.5. 625. 655. and 685'!!! which were standardized against a magnesium carbonate block. Press fluid. A sharp knife was used to remove the outside slice from the cooked roast. The roast was placed on the electric slicer and the cut surface straightened by removing a second thin slice. Two {3-inch slices were removed from this straight edge, wrapped in Saran, coded, frozen, and stored at -20 °C. Storage periods for these objective samples ranged from 3 to 23 days. Upon completion of the experiment, all wrapped samples were defrosted at room temperature (23 to 2M0) before press fluid deter- minations were made. M. After samples for press fluid detennination were moved, a distance of 3 inches was measured and another cross-grain cut was made. “5 In/. .2524 .330." poxooO mo «Sausage e>avoennsm one 2.30030 no.“ mead—use no "3.3304 \ 22“. 32¢ .H enema o 50—OUV .. W q a a 11/ x514...» ...; _ _ — fl d _ Wm... w...,.,,/.....i/, n _ _ _ _ _ _ ......2, _ ......m _ _ _ . _ _ W,._ .H. ...... _ . _ _ _ _ w ,.....W,.....Mm u. m...” F — _ V L ZWWMW/f M v.‘ ““0; in...“ ....1.H ...,. .1 ..Omcw ..... .... H............. ..m q . A 1-..... . ... ......m. _______ _.,... 1...... _ _ _ _ . a...” u _ cozosgm _ w... u ....w...“ _ _ o>zoo33m . ......H _ _ _ _ _ _ _ _ ”We... , i “..U... _ _ _ _ _ _ a... . n. m U m 4 3:23.... A core, l-inch in diameter, cut parallel to the fiber axis, was removed from the center of each muscle. Each core was wrapped in Saran, coded, frozen, and stored at a temperature of -20°C until completion of the experiment. Storage periods for cores ranged from 3 to 23 days. Wrapped cores were defrosted at room temperature (23 to 21+°C) before shear tests were made. mmmmmmmunnm The section of the roast from which a shear core had been remved was used for subjective scoring. The electric neat slicer was set at 12 so that slices were approximately t-inch thick. M slices from a con- ventionally roasted sample and two slices from a sample cooked in deep fat were arranged on coded plates, covered with Saran, and refrigerated 3 to b hours at 4°C. (be hour before tasting, the. samples were removed from the refrigerator and brought to room temperature. m m anal Slices of beef, from one oven roast and from one sample cooked in deep fat, were presented to a panel of six judges. The evaluators were asked to consider each sample without reference to the other. Score sheets were discussed. Palatability factors to be scored were: aroma, color, texture, flavor, juiciness, softness, friability, residual tissue, and tenderness. A cepy of the score sheet is included in the Appendix, page 9h, For judgments regarding residual emotive tissue and tenderness, the panel was asked to cut a .SO-inch square piece from a slice from each cooking method. To establish a “chew range“ table for each panel member, judges were instructed to chew each .50-inch sample until it was completely “7 masticated. They recorded the number of chews for each sample and also assigned each sample a numerical tenderness score. An individual “chew range" table, based on the number of chews and the scores recorded for these samples, was deveIOped for each judge. These tables were then used by the judges for scoring samples for tenderness throughout this project. Preroesting Preparation hthods for the cooking of samples were assigned according to a randomised arrangement of left and right muscles from the six pairs of rounds. Cooking periods were scheduled twice weekly for a period of three weeks. The preparation for each day of cooking included one sample roasted in the oven and one sample cooked in the deep fat fryer. 2'2 ml; wrapped raw roasts were defrosted for 48 hours in a reach-in refrigerator at M‘C. At the and of the defrosting period, raw samples were wrapped, a posterior portion was rumoved for objective determin- ation of pH and color reflectance, and the gran weight of the remaining sample was recorded. Linear measurements were taken according to pro- cedunss established during preliminary sttxiies. Volume was obtained by the displacement method in 10 to 15°C water. Each of the samples cooked conventionally was placed on a trivet in a shallow alumimnn roasting pan. Samples cooked by inversion in deep fat were placed in the full size fryer basket. hires potentiometer leads, for recording data pertaining to time- temperature relationships, were positioned in the sample as follows: a_ with depth equal to the radius at mardrmm thickness, b 3/h-inch from the surface, and _c_ t-inch from the surface (Figure 2). .....Wi in. For the conventional roasting method, the oven was preheated to lll9°C. A potentiometer lead was central]: mounted in the oven to record the heated air temperature throughout the cooking period. For the deep fat inersion method, the ludrogenated fat was placed in the fryer and preheated to ll5°C. At the beginning of each cooking period, fresh fat was added to fill the fryer to the initial weight of the previous cooking. In addition, in order that all samples be submerged, extra fresh fat was added when necessary and the amount recorded. ‘Pwo potentiometer leads were placed in the cooking medium, one approximately one-inch from the side of the container and the other centrally posi- tioned. A loo-gram sample of fat was removed for preocooking smoke point determination. Throughout the cooking period the temperatures of both media were adjusted to maintain controlled temperatures of 119°C for air and 115°C for fat. Cooking Process 92mm 5222 When the internal temperature of the raw defrosted sample reached 6°C, the sample was placed in the preheated oven. When all potentiometer leads which were positioned in the sample had reached a minimum internal temperature of 80°C, the roast was removed from the oven and cooled at room temperature to 70°C. Then the thermocouples were removed and the roast was allowed to stand for 15 additional minutes. . fit-n - O F . ' »‘ ‘ We 0 :a a ‘. .Im a U. .0 ...?" ~ ~ - . Q m « 0’ q". is (A .‘A' Figure 2. Positioning potentiometer leads: a = radius, b_and g_= B/b— and 1/4—inch from sfirface ,‘ 53x 5mg Figure 3. Immorsing sample in 115°C fat :135 2e 2222 at mam The raw sample stood at room temperature until it reached 6°C before it was innersed in the hot fat (Figure 3). When all potentiometer leads positioned in the roast had reached a minimum internal temperature at 80°C, the basket and sample were removed from the cooking medium and suspended overthefryerfortwominutestoperwdtthefattodrainfromthemeat. Then the cooked sample and basket were placed in a shallow roasting pan; the roast was cooled at room temperature to 70°C before the thermocouples were removed. The meat was allowed to cool an additional 15 minutes. A loo-gram sample of the cooking medium was removed for post-cooking smoke point determination. Handling the Cooked Sample Part of the data was recorded before the roasts were refrigerated. However, the major portion of the data was collected on the following day. ......rmtunt 22. 21%: 2:25: 2512.125 At the end of the cooling period, sample weight, linear measurements, and volume by displacaent in #5 to 50°C water, were recorded. Then the roast was wrapped in Saran, coded, and refrigerated at 18°C. Drippings obtained from conventional roasts were recorded. The total weight of the roasting pan, the trivet, and the roast drippings was recorded. Weight of the total drip in grams was determined by subtracting the known pan and rack weight from the total weight. For the samples cooked in deep fat, drippings obtained during the cooling period were scraped into a graduated beaker, covered with Saran, and refrigerated at 4°C. 5]. W at m m m The day after the roasts were cooked, samples for objective testing and for subjective scoring were removed according to procedures described under Preliminary Investigations. Drippings in the fat were collected according to the method developed in preliminary studies, and combined with pen drippings which had been refrigerated. Total drip, recorded in milliliters, was converted to ounces and than to grams. Evaluation of Roasts Palatability characteristics of the roasts were evaluated sub- jectively. Appearance and flavor of drippings fro. each sample were subjectively judged. Acidity, color reflectance, juicinese, and tender- ness were objectively measured. Data pertaining to rate of heat penetra- tion for the roasts was studied. W mm: Samples free roasts representing each cooking method were presented to each of the six panelists. A particular judge was alrlays served cuts from the same relative position of the roast. Samples, which had been refrigerated, were allowed to stand at room temperature for an hour prior to testing. Classes of water at room tuperature were provided. The panel was seated in an arrangement that discouraged the seashore free exchanging contents or facial expressions. lbs panel scored the samples for arena, color, texture, flavor, juiciness, softness, friability, residual connective tissue, and tender- ness. Scoring was based on a seven point scale. A score of 1 indicated unacceptable quality; a score of 7 depicted excellent quality. Descriptive terminology for each numerical score was considered in assigrdng a score for each palatability factor. Comments of the judges were su-Iarised and applied to the interpretation of the data. Ob active testing Colorreflectanceandpflefrawsanplesweremeasuredonthedayof cooking. Cooked samples were tested for pH and color reflectance on the day after cooking. g. Slur-rise were prepared as previously described. Duplicate readings, taken according to standard laboratory procedure, were averaged. Change in pH behveen the raw and the cooked sample was calculated for each replication. W. Per cent color reflectance at eleven wavelengths, ranging free his to 685m, were recorded for raw and cooked samples of each replication. Duplicate readings for each eanple were totaled and averaged. Kean readings for replications were averaged within lethods for each wavelength and differences between methods of cookery were deter- mined. Press fluid. The Carver press was used to detennine juiciness of the cooked roasts. Two defrosted samples, each weighing 12 to 1“ grass, were obtained free each replication, placed beMen felt pads, and subjected . to a pressure of 15,000 pounds per square inch for 10 minutes. After pressing, samples were separated from the pads and reweighed. Percentage of press fluid was calculated by dividing the difference betwoen the initial and pressed weights by the initial weight of the sample. 53 gigs. Tenderness was objectively measured by the Warner-Bratsler shear apparatus. This machine measures the force in pounds required to cut through a cylinder of muscle one inch in diameter. Five shear readings were taken from each defrosted core. These readings were totaled and averaged for each roast. Coo_ki_ng losges. Total cooking, drip, and volatile losses were calculated for each roast and these values were converted to percentages based on the raw weight of the sample. Values loss was changed to percentage of initial sample volule. is}; penetration Throughout the cooking and cooling periods, progressive time-temperature relationships at three depths of the roasts were recorded on the potentio- meter. Mean progressive time-temperature relationships for three depth measurements (radius, BIA-inch, and t-inch from the outer surface) were determined for each method of cookery. Rate of heat penetration in Inmates per 0(2 taperature rise was calculated. m . 2r :2 92: Objective data pertaining to total cooking loss, drip less, volatile loss, volume loss, shear, and press fluid were statistically evaluated w analysis of variance to determine differences attributable to method of cookery. This statistical neasure was also used to evaluate differences due to method of cookery for changes in pH and color reflectance. To miniadse variance due to judges, scores for each replication were averaged for each palatability characteristic evaluated. To determine differences due to cooking method, analysis of variance, based on mean 5” taste panel scores, was computed for each palatability factor. Correlation coefficients were determined for all possible combinations of tenderness, softness, friability, residual tissue, and shear measure- ment. In addition, per cent total cooking loss and subjective juiciness were correlated. 55 RESUIfl‘S AND DISCUSSION In this study the effects of conventional ovenproasting and of cooking by deep fat inersion on semimembranosus muscles from paired U.S.D.A. Choice steer beef rounds were observed. Data pertaining to rate of cooking, cooking losses, and palatability were collected to determine differences attributable to cooking method. Mean progressive time—temperature relationships were compared to deterb nine differences in rate of heat penetration due to cooking medium. Changes in pH brought about by cooking were recorded. Changes in the smoke point of the hydrogenated fat, which resulted from re-use of the medium, were determined. Analyses of variance, correlation coefficients, and subjective and objective evaluations were considered in the interpretation of results for cooking losses and palatability of the roasts. Beat Penetration Due to difficulty in obtaining accurate potentiometer recordings during one day of cooking, results and discussion of data pertaining to rate of cooking are based on five replications for each method. Patentioueter leads were placed at three depths from the surface of the sample: ilk-inch, B/h-inch, an! 1 l/2~inches (radius). The lead positioned with depth equal to the sample radius was used to determine the end of the cooking period for both methods. 56 Average progressive time-temperature relationships during the cooking period for three sample depths and two methods are shown in Figure "I. The initial temperaturo of all resets was 6°C at the 1 l/Z-inch depth. Initial temperature averages for the 3/10- and lln-depths were 7 and 8°C, respectively. All curves for roasts cooked in deep fat were steeper and shorter than the comparable curves for even roasts. The temperature rise of roasts cooked in fat increased steadily and rapidly throughout cooking. Although the rise in temperature for oven roasts was narch slower than for deep fat roasts, the rate of rise was steacw until an internal temperature of 55°C was reached. As the degree of meals coagulation increased, the rate of temperature rise decreased. Roasts cooked in the even required nearly twice as long to reach the desired and cooking temperature as those cooked ‘ in fat. The average total cooking time was 138.2 minutes for oven-roasted samples and 73.“ motes for samples cooked by deep fat insersion. These results are similar to firflinge reported by Visser et a1 (92). As was expected, the internal temperatures of the roasts at depths of l/h- and 3/ll~inch from the surface exceeded the internal temperature at the radius. End cooking temperatures for these locatiars varied from 81; to 92°C at the l/lh-inch depth and from 80 to 90°C at the B/lI—inch depth for the oven-roasted samples. Variations in end cooking temperature for samples cookedtydeepfat innersicnwerefrom88to98°0and Bhto88°c forthe l/h-inch and 3/lI-inch positions, respectively. Inherent differences in the samples, changes in linear measurements brought about by evaporation and coagulation of the tissue, and experimental error in the placement of the potentiometer leads appeared to contribute substantially to variations within replication. .nvonaoa 03 now Since sagas» 00.53 no.“ mafiooo 9356 3.223330." 093309393... emanate .n 93mg 00. O! 0». ON. 0: 00. 0m cm on ow on O? on ON 0. 0.....3352 57 ..ie_._._._._._._+_.q._q_e___.0 ‘31 \\e . $200: 55¢: Ill \\\\4. .o. :05 «will. \\\.\\ 4 55¢ \\\ . . - . \\ e [ON u>mx \\\ 1 \ \. . \\ \ [on \\\ . . ., \\ \\ now \ L \ \e e \ \ 100 \ e \ . 1 _\‘ \\\\\\.\ \\ .\ 1 on \\ . \ . \\\\ \ _‘|\\ .\ now Qme I om LOO. After cooking was terminated, the roasts were allowed to stand at room temperature until the temerature at the radius had cooled to 70°C. ‘The interior temperature rise of roasts cooked in deep fat ranged from 3 to 7°C, while the rise in temperature of oven roasts varied from 0 to 1°C. Deep fat samples were representative of very well-done meat whereas the interior of conventionally roasted samples was frequently described as atypical for well-done beef. Progressive changes in the average rate of heat penetration during cooking, expressed as minutes per degree Centigrade rise at lO-degree intervals from 20 to 80°C, for three sample depths and two cooking methods are illustrated in Figure 5. Changes in the rate of heat penetration for each replication are given in Table 15, the Appendix. These heat penetration curves indicated that, although the sample contact heat for both methods was comparable (see page 92. the Appendix), the transfer of heat from the cooking medium to the sample was more rapid in fat than in air. This result is in accord with findings reported by Visser et al (92). When lmdrogenated fat is used as a cooking medium, it becomes a liquid composed of molecules having free movement over themselves , but without a separative tendency like that of gas molecules in air. Because of this ptusical characteristic, fat achieves closer contact with the meat than is possible with air and the thickness of the stationary layer of air surround- ing the sample is minimized. In addition, fat molecules carrying heat energy are in greater concentration at the fat/ stationary air interface than is possible with gas molecules at the heated air/ stationary air interface. The insulating effect of the stationary air layer surrounding the sample is 59 .3058. wcflooo 9.5 nou unease madame no.2» now and." .oe\.n«z «soapmavocoa amen we even 09292 .n enema om on cm on O.» on ON a o 00 i W 4 .VJ 36cm ll 1 oo.m EDP: ¢\n lo H>mx 10nd 001.52 E... ammo 1 mm w 250.203 1 00d 8:632 a 1 2... s 9.0 a. m ~ .100; a. . co:o_aoooo . . £20K. ..\ L ow _ I a . _ .\ . fl . I, l on. _ 1 on. om on om on oc on ON 00.. _ q _ «JAE «Seem II. 100.» I oSe I I ..- . \. . I DEN .>mv. 10nd I / DOIPmE ./ ..dzo_kzm>zoo 1m~.~ s IOQN ~ N . s 1mm. a s as 18.. acacia; ...... \. low; 53qu 100.. whom 5:23.30 1 me. Screen. LCD. on 2. on on oc on 8 4r _ _ _ _ _ a L o 0m: 00 \.ES. 6O reduced and the heat enery is transferred to the surface of the meat more efficiently. The heat penetration curves at all sample depths measured in roasts cooked in deep fat were similar in shape. Time required to raise sample temperature one degree Centigrade was always least at the ilk-inch depth. For the major portion of the cooking period, minutes per degree Centigrade rise for the fill-inch location was only slightly less than for the radius of the sample. Rate of heat penetration for all depths increased rapidly until an internal temperature of hooc for the 1/n.ihch depth and 30°C for the BILL-inch and radius depths had been reached. it internal temperatures from no to 80°C the rate of heat penetration at the l/h-inch depth showed a gradual decrease. Although the rate of heat penetration for the other two curves continued to rise up to temperatures of 50°C for the Slit-inch depth and 150°C for the depth at the radius, the rate of increase was mch slower. After these temeratures were attained, the rate of heat penetra- tion for these curves gradually decreased throughout the remainder of the cooking period. Variation in the heat penetration rate for all sample depths was more pronounced in oven roasts. At the l/ll-inch'depth the rate of penetration decreasedeteadilyasthetemparature oftheroastincreased. Atthe alueihch depth the rate of penetration increased until an internal temperature of 30°C was reached, decreased slightly between 30 and h0°C, increased slightlybetweenhOto50°C, andthendecreasedgraduallyduring theremainderofthecookingperiod. Atthedepthoftheradiustherate of penetration increased sharply to an internal temperature of 30°C, in- creased only slightly frem 30 to 100°C, and then decreased sharply during the remainder of the cooking period. 61 According to Lows (52), interior temperatures suggested hy Sprague and Grindley as representative of rare beef range from 55 to 65°C, that which has reached irmer temeratures of 65 to 70°C may be called mediu- done, while beef‘whiCh has attained a temperature of 70 to 80‘szay be termed well-done. To compare the rate of heat penetration for the two cooking:methods, temperaturesof 50, 60, 70, and BO‘C have been.chosen as typical of the following degrees of doneness: muscle coagulation, rare, medium, and wellpdene. Figure 5 illustrates the comparative changes in minutes per degree Centigrade rise between stages of doneness tor the two cooking.nethods tor the three sample depths. The rate of heat penetration for roasts cooked.in.air'or’in fat de- creased as roasts approached the rare stage. Since hoth.protein.coagula- tion and evaporation are endothermic processes, less heat was available to raise the temperature of the tissue. However, for each sample depth measured the rise in temperature for meat cooked in hot fat was faster than that of the oven-roasted samples. Table 1 presents the rate of accelerated cooking for deep fat roasts as compared with oven roasts for three sample depths. table 1. Relation between rates of heat penetration for cooking in air and in.fat, three sample depths, at four’degrees of doneness. A Accelerated Cooking Rate for Deep rat Degree of Doneness . lln-inch Sin-inch. Radius Muscle coagulation 2.69 2.11 2.13 3‘” 2 e6? 2 e 20 2 e20 mm 2 on? 2 enl 2 e 36 Nell-done 2.95 2.10 2.57 62 Table 1 shows that as the degree of doneness prognosed, the degree of protein denaturation and evaporation appeared to affect the rate of heat penetration. This in turn influenced time required for the center of the roasts to reach an internal temperature of 80°C. Meat has an inherent capacity for absorbing heat. During cooking heat is carried to the interior of the neat by conduction. It seas like]: that the shorter tine required for roasts cooked by deep fat insersion m be due, in part,to the faster and nore efficient transfer of heat pro- videdbythefatnediun. llufarthertherawtissueisfronthesourceof heatenergy, thelongerthetimrequiredtoraisetheinternaltelperahlre. As the depth of coagulated protein increased, the rate of heat penetration appeared to decrease. Fran these data, one might conclude that the rate of heat penetration in cooked tissue may be slower than in raw tissue. pH Determination of pH for raw and cooked samples, based on the mean of two readings, and the change in pH for six replications for each cooking nethodarepresentedintheAppendix, Table 16. ’nlspflofraeroastsused for both cooidng methods ranged from 5.1! to 5.7. In all cases cooked roasts were slightly more alkaline than raw roasts. 'lhe pH of convention- ally roasted samples varied from 5.6 to 5.9, whereas the pH values for samples cooleed in deep fat ranged from 5.7 to 5.9. An analysis of variance of the changes in pH brought about by cooking were not significant for We 63 Panel evaluations of cooked roasts indicated that, irrespective of cooking method, all samples were Judged slightly tough. According to Iowo (52). toughness of cooked beef is mximum at a pH of 5.0 to 6.0. It seeded likely that tenderness of roasts was affected, in part, w the pH of the sample. Smoke Point A lowering of the smoking temperature is among the changes which occur in fats during cooking. Results of smoke point deteninations of the cook- ing medium indicated that during re-use the making tenperature of the tmdrogenated fat was lowered only slightly. Smoke points ranged from a temerature of 221°C at the beginning of the experiment, to a temperature of 217°C at the completion of the stub. 'lhe change in smoking temperature, before and after each cooking period, was not consistent and varied from o to 2°C. Cooking losses Data pertaining to total, drip, and volatile losses were converted to percentages of row sample weight. Volume loss was changed to per- centage of initial sample volume. Per cent total, drip, volatile, and volume losses for six replications for each cooking method are recorded in Tables 17 and 18, the Appendix. Average percentage values for cooking and volume losses for samples cooked by conventional roasting and by deep fat immersion are shown in Table 2. Table 2. Mean per cent cooking and volume losses of six replica- tions for two methods of cookery. losses W Convegtjiggal Deep Fat Total cooking . 33.14 33.215 Volatile 31.10 37.01 v01” 31e65 Me 91 Analyses of variance were applied to the percentage data to deter- mine differences attributable to cooking method. Highly significant differences were found for all types of losses. A summary of these analyses is paesented in Table 3. ' Table 3. Analyses of variance of cooking and volume losses for two methods of cookery. I Source of Variance D. F. LSLIalnelT T933]. 2212 Vang]; ng Total 11 Method 1 78.1590“I 1.920” 105.030“ 527.880“ Error - 10 ' 1.716 .190 2.577 22.203 “Significant at the 1% level of probability. 2.9.21 £29m Jam The average total. cooking loss was 33.110 per cent for oven roasts and 38.21! per cent for samples cooked in deep fat. Total losses for roasts cooked in deep fat were significantly greater than for oven roasts (Table 3). A comparison behveen total cooking losses and subjective 65 juiciness scores revealed a negative correlation (r = -.786) significant at the 1% level of probability. These results are in accord with tunings reported by Harrison (#0) . 13.122 19.2222 Mean percentage values for drip losses were 2.0“ and 1.23 for even- - roasted samples and for samples cooked by deep fat immersion, respectively. Analysis of the data showed that the greater amount of drip obtained from oven roasts was significant at the 1% probability level. However, mean Juicdness scores and mean press fluid values indicated that oven roasts were Juicier than samples cooked in deep fat. Volatile 118333 Average volatile losses for oven roasts and for samples cooked by deep fat innersion were 31.10 and 37.01 per cent, respectively. Analysis of variance for these data revealed that volatile losses were significantlv greater (17» level of probability) for samples cooked in fat than for samples cooked in air. 32.1.9.2 leases. I than volume loss for oven roasts was 31.65 per cent compared with M.9l per cent for deep fat samples. Statistical analysis of percentage values indicated that volume losses for oven roasts were simificantly 1... (1% level of probability) than comparable losses for the deep fat samples. Average percentages for volume loss, changes in linear measurements, and total weight loss for each method of cookery are given in Table 1*. 66 Table 1+. Mean per cent volume loss, changes in linear measurements. and total weight loss for two methods of cookery. M 4 Conventional Deep Pat Volume loss 31.69 Mural Shrink in length 1.59 7.47 Shrink in width 16.31 20.61 Total weight loss 33.1“ . 38.215 liverages based on six replications. Duringcookingmeat shrinksalongthelengthofthefibersandin width but may gain in the third dimension until cooked extremely well-done. According to lane (52). the shrink in volume for muscles of beef round is never as great as loss in weight. While data from this limited study for conventionally roasted samples are in accord with findings reported by Lowe. results for samples cooked in 115°C fat do not support this Mae. Palatability Aroma, color. texture, flavor, Juiciness, and general tenderness were the palatabllity characteristics Judged in studying the effects of conven- tional oven-roasting and of cooking by deep fat imersion. Tenderness was partitioned among several components- softness, friahility, and residual connective tissue (21)-to deterMne whether these factors could be dis- tinguished. Factors were scored according to a scale of l to 7. or unacceptable to excellent quality. For each replication, Judges scores were averaged for each characteristic evaluated. Average palatability scores for each replication appear in Table 19. the Appendix. 67 Analysis of variance, based on mean taste panel scores for each method of cooking, was computed for each palatability factor. Grand averages, based on six replications for each method of cooking, fer each palatability characteristic evaluated are summarized in Table 5. Table 5. Average palatability scores1 of six Judges for six samples for two methods of cooking. Palatability Bhihad.af.§aakinae Characteristic Conventional ., Deep Fat Aroma 5.0 5.0 Flavor “.7 “.5 Color “.5 “.9 Texture ' “.5 h.2 Juiciness “.4 3.7 Softness. h.3 ugh Friability 3.6 3.? Residual Tissue 4.7 “.8 General Tenderness “.3 “.5 1Highest possible score, 7 points. mas-19am Aroma and flavor of cooked meat are important factors in product acceptability. The average aroma scores for the two cooking methods were identical. In addition, aroma was scored higher than any other palatability characteristic. This score of 5.0 represents good, full aroma. Descriptive terms checked by the judges ranged from.a rich and meaty to a fair, faint odor. 68 According to taste panel Judgmnts, the flavor of the samples was pre- dominantly a faint to full, good flavor. Adjectives used to describe the samples included very meaty, good. fair, and in a few instances. bitter or unpleasant. Judges indicated only slight preference for the oven-roasted samples. The analyses of variance of aroma and flavor scores are shown in Table 6e Table 6. Analyses of variance of arena and flavor scores for two methods of cooking. Source of Variance D. F. M A m Flavor Total 11 Method 1 .000 p .0150 Error 10 .0116 e055 These analyses shomd no significant differences attributable to cooking method for either arena or flavor. Arena, flavor. and appearance of the drip from each cooking aethod was subjectively evaluated by the investigator. Flavor 0: the rich- ‘ bran drip from oven roasts was described as strong. full. and slightly charred. Drip from samples cooked in hot fat was tamed very good. full in flavor, pleasant in aroma. and wine-brown in color. ‘ mum The external appearance or roasts cooked in the oven at 118°C or in deep fat at 115°C was fairly sinilar. Reliever, the surface of bee! cooked by deep fat immersion was not quite as rich-brown as that 69 characteristic of oven roasts. Visser et al (92) reported that the surface of neat cooked in 100 or 110°C fat was a gray-brown color. In three instances, Juiges noted that the samples cooked in hot fat were crusty and they cemented on the strong fat flavor of the crusty area. It was interesting to observe that crustiness seemed to increase as the experiment progressed. Possibly. re-use of the fat was a factor. On one occasion. panel members marked about the crust on an oven-roasted sample. The flavor of this browned area was acceptable. Samples cooked in deep fat were more representative of well-done neat, although appearance score averages for both treatnenst depict a medium. brown color. Judges frequently described conventionally roasted samples as pinkish-brown. not typical of beef cooked to 80°C. Saples cooked ty deep fat inersion were light gray to grayish-brown. Iargeamsoftheslicesfronbothcooungnethodsbecasehighly iridescent and/or mottled after exposure to the air. Masada (59) also noted that Judges described new of the samples from the top round. sirloin butt. and rolled rib roasts as iridescent. Taste panel where scored the texture of conventionally roasted sasples slightly higher than those cooked in hot fat. Score averages indicate a fair to good texture. One judge consistently described samples cooked by both nethods as spong, slightly coarse. and stringy. In several instances. another Judge noted that oven-roasted samples were porous in a few areas. Themhsesofdatapertainingtooolorandtexture,hble7. showed no significant difference in color or texture scores attributable to cook- ing method. 70 Table 7. Analyses of variance of color and texture scores for two methods of cooking. Source of Variance D. F. W Cole; m... Total 1.1 Error 10 e096 e082 Tappel (87) reported reflectance spectrophotometry useful in measuring lunatin pigment changes in the cooking of beef. Mean per cent color re- flectance readings for roasts of both cooking methods from this experiment appear in the Appendix, Table 20. Mical spectra of the roasts of both cooldng methods are illustrated in Figure 6. Spectral curves for the raw and cooked samples are approximately the sane for both cooking treat- mnts. Allrawsamples showedastrongpeakat535t0565muandaless pronounced peak at 655m. spoctra of cooked samples exhibited a strong peak at stem. This latter finding is in agreement with Tappel (87) who reported a relatively sharp and characteristic reflectance spectra ndnima at 51mm: for hematin pigments of cooked beef. He characterised the brown pig- ments of cooked beef as mixed denatured globin nicotinamide hemichromes. Table 8 presents the analysis of variance of the changes in per cent color reflectance brought about ty cooking for two methods of cookery. This analysis indicated no significant difference in the change in color reflectance between raw and cooked samples due to method of cooking. 71 .3233 5000 on» son.“ season mo nodded» eexooo one son 7.3.3.3390." and handed?” 25 35333.3." Hue no swung: mmw now 0N0 can own Ova own mom who no? 0.? — L _ _ _ _ _ _ P ham now mum mmn nwnmvm one 000 05¢ 0.1» 9v. 5er no «encode consonauom .m snowed o:— _ n mmEEom 30m III 3.9.3.0. 3130 0+] crux 00...sz #4.... ammo 001 _ _ A a _ — fl OOIkws. .._ZOU _ 1E. .;.oco_ O u>o>> n 0. n. on on O? n? on oucSoezom ox. 72 Table 8. Analysis of variance for changes in per cent color reflectance brought about w two methods of cooking. Source of Variance D. F. 1L W _ f Color reflectance Total 21 Method 1 9.820 Error (WI. 1: H) 20 10.5% Juiciness Average press fluid yields of cooked samples for each replication appear in Table 21, the Appendix. The grand averages for juiciness scores and mean per cent press fluid yields are shown in Table 9. Table 9. Average juiciness scores and press fluid yields. Cooking Method Juiciness Score1 f Press Fluid Conventional 14.1; 38.72 Deep fat 3.7 35.56 lflighest possible score. 7 points. For both subjective and objective evaluations. conventionally- roasted samples were juicier than those cooked in deep fat. A positive correlation (r = .758). significant at the 1% level of probability, was found between juiciness scores and press fluid yields. Irrespective of cooking method , the taste panel frequently described the cooked samples as dry or neither dry nor juicy. These observations are similar to findings reported by Visser et a1 (92). 73 The analyses of variance of juiciness scores and press fluid yields for two methods of cooking are presented in Table 10. Table 10. Analyses of variance of juiciness scores and press fluid yields for two methods of cooking. Source of Variance D. F. M. Sim W M Total ll ’ Method 1 Limo" 30.083“ 31'”: 10 .139 1.538 ”Significant at the 1% level of probability. These analyses showed highly significant differences attributable to method of cooking for both juiciness and press fluid yields. These results do not support findings from a study reported by Harrison (#0). Tenderness General tenderness was based on the number of chews required to completely masticate a sample of predetemined sise. Tenderness was also partitioned as softness. friability, and residual connective tissue. Grand average scores for softness. friability, residual tissue , and general tenderness, and mean shear values for two methods of cooking are shown in Table 1.1. Average shear force readings of cooked samples for each replication appear in the Appendix, Table 21. Most often samples were rated as neither hard nor soft. The descriptive terms recorded for friabllity were slightly to moderately friable. The ease with which muscle fibers broke was readily distinguish- able by some judges while other panel members could determine no friability. 74 Table 11. Average scores1 for softness. friability, residual tissue, and general tenderness, and mean shear force readings ( 1b. ) . Cooking Soft- Friability Residual General Shear Method _ ness Tissue Tenderness (1b.) Conventional “33 3e6 he? "“3 19e36 Deep fat h.h 3.7 4.8 4.5 18.89 A_ ‘ 1Highest possible score, 7 points. A score indicative of a small amount of firm to soft connective tissue was frequently checked. According to taste panel evaluations and shear force readings, samples cooked tar deep fat immersion were slightly more tender than oven-roasted products. However, the usual description of all samples for both methods was slightly tough. Harrison (no) reported that her taste panel found meat cooked in fat more tender than oven roasts. However, shear score values were lower for roasts cooked in air. Visser et al (92) concluded that, in general, shear values were a little lower for even roasts than for those cooked in fat. They found little difference in tenderness scores for samples cooked in air and those cooked in fat at 110 “C, Analyses of variance for softness, friahility, residual tissue. general tenderness, and shear force showed no significant differences attributable to cooking method. These analyses are given in Table 12. The relationship between scores for softness. friability, residual tissue, and general tenderness, and shear measurement was studied. Correlation coefficients for these data are summarized in Table 13. 75 Table 12. Analyses of variance for softness, friability, residual tissue, and general tenderness scores, and shear force readings for two methods of cooking. Source of ELlSl:!3lngg___ Variance D. F. Soft- Fria- Residual Tenderb Shear t t e nes Forge Total 11 Method 1 .030 .Oho .070 . .lflo .568 Error 10 e 152 e260 e 10“ .200 e 39“ Positive correlation, significant at the l$ level, was found between softness/tenderness, friability/tenderness, and softness/friability. Positive correlations, significant at the 5% level, were obtained for residual tissue/tenderness, residual tissue/friability, and residual tissue/softness. The coefficient between residual tissue and tenderness nearly approached significance at the 19% probability level. Correlations for'HarnerbBratsler shear/tenderness, WhrnereBratzler shear/friability, WarnerbBratzler shear/softness, and'whrnerbBratzler shear/residual tissue were not significant. 76 Table 13. Correlation coefficients for all possible combinations of softness, friability, residual tissue, and general tenderness scores, and Whrner-Bratzler shear'measuremsnts. Relationship Correlation Coefficients Softness/Tenderness .711“I Friability/Tenderness .838“ Residual tissue/Tenderness .701‘ WarnerbBratzler shear/Tenderness .077 Softness/Friability .719“ Residual tissuekFriability .585* warmer-Bratzler shear/Friability -.021 Residual tissue/Softness .629‘I WernerbBratzler shear/softness .103 warner-Bratzler shear/Residual tissue -.311 *Significant at the 5% level of probability. *‘Significant at the 1% level of probability. 77 SW AND CONCLUSIONS The objectives of this stucw were to secure comparative information concerning the effects of conventional oven-roasting and of deep fat ismsrsion on cooking losses, rate of cooking, and palatability of semi- membranosus muscle from paired U.S.D.A. Choice steer beef rounds. A total of six replications for each method of cookery were prepared according to standard procedures developed during preliminary trials. . Serdmembranosus muscles were dissected, trimmed, standardised with respect to weight and linear masurements, individually wrapped, frozen, and stored until scheduled for testing. The temperature of the cooking mediums was equated so that the contact but was considered comparable for samples cooked in air or in fat. Prior to cooking, each sample was defrosted and potentiometer leads were positioned at three depths: radius at mum thickness, 3/h—, and l/h—inch from the surface. Roasts were individually cooked at lu9°C in air or at 115°C in fat until all potentiometer leads positioned in the sample had reached a minimum internal temperature of 80°C. Data pertaining to rate of heat penetration for the roasts was studied to determine differ- ences in the rate of heat penetration due to cooking medium. Changes in pH brought about ty cooldng were recorded. Changes in the smoking taper- ature of the Ivdrogenated fat, resulting from rs-use of the Indium, were determined. Total cooking, drip, volatile, and volume losses were recorded. 81: taste panel members scored roasts representing each cooking method for aroma, flavor, color, texture, juiciness, softness, friability, residual connective tissue, and general tenderness. Color reflectance, juiciness, and tenderness were objectively measured. 78 Oven roasts required approximately twice as long to reach the desired and cooking temperature than roasts cooked in fat. The rate of heat penetration was slower in oven—roasted samples than in roasts cooked by deep fat immersion. Beat penetration curves at all sample depths measured were similar in shape for roasts cooked in fat. Rate of heat penetration for all depths increased rapidly from the initial temperature to a maximum point at intern nal temperatures of ho to 50°C. After these temperatures were attained, the penetration rate gradually decreased throughout the remainder of the cooking period. There was more variation in the rate of heat penetration in oven roasts than in samples cooked in fat. At the l/h-inch depth the rate of penetration decreased steadily as the temperature of the roasts increased. Heat penetration rate for the 3/h-inch depth generally increased to internal temperatures of #0 to 50°C and then decreased gradually'as the degree of doneness progressed. Rate of heat penetration for the radius increased rapidly to an internal temperature of h0°C and then decreased sharply during the remainder of the cooking period. For all roasts cooked in air or in fat, heat penetration rate decreased as roasts approached the rare stage. However, for each sample depth measured the rise in internal temperature for meat cooked in 115°C fat was faster . than for roasts cooked in 1h9°C air. As the degree of doneness progressed the rate of heat penetration and the time required for the center of roasts to reach 80°C appeared to be affected by the degree of protein denaturation and evaporation. Heat penetration rate appeared to decrease as the thick- ness of coagulated protein increased. 79 Determinations of pH indicated that cooked roasts were slightly more alkaline than raw roasts. Hortever, changes in pH brought about by cooking were not significant for method. Snake point determinations showed that changes in the smoking temperature of the hydrogenated fat, resulting from re-use of the cooking medias, were slight. Analyses of variance revealed highly significant differences in cook- ing and value losses attributable to rethod of cookery. Total cooking and volatile losses were significantly smaller for even roasts than for roasts cooked in fat. Drip losses were significantly greater for even roasts than for roasts cooked in deep fat. Correlation betaueen total cooking loss and Juiciness m the expected inverse relationship, significant at the 171 level. Volume losses for roasts cooked in deep fat were significantly greater than comparable losses for oven-roasted samples. In addition, roasts cooked in deep fat showed greater volume loss than weight loss. keept for Juiciness, mean palatability scores for oven-roasted . samples and for those cooked in deep fat were very sinilar. Average aroma scores were identical for the two methods. Judges scores indicated only slight preference for the flavor and texture of oven-roasted samples. Scores for color, softness, friability, residual tissue, and general tender- ness favored the samples cooked in deep fat. Statistical analysis revealed highly sipificant differences in Juiciness scores attributable to cooking method. Juiciness score averages for samples cooked by deep fat innersion were significantly lower than those for oven-roasted samples. Arena scored higher than arc other palatability factor for both methods of coating. Flavor was Judged good, but faint. Scores for color and texture averaged fair to good. Average scores of neither dry nor Juicy, and neither 80 hard nor soft, were given for juiciness and softness, respectively. Friability scores averaged moderately friable, indicative of a small amount of firm to soft connective tissue. All samples from both methods were described as slightly tough. Positive correlations, significant at the 1% level, were found behiesn softness] tenderness , fria‘uility/tenderness, and softness/friability. The coefficient between residual tissue and tenderness nearly approached signi- ficance at the 1% probability level. Positive correlations, significant at the 5% level, were obtained for residuu tissue/friability and residual tissue/ softness. Objective measurements of color, Juiciness, and tenderness substantiate subjective evaluation. Spectral curves for raw and cooked samples were similar for both cooking treatments. Raw and cooked samples appear to have a characteristic reflectance spectra minima. Statistical analysis indicated no significant difference in the change in color reflectance between raw and cooked samples due to cooking method. Significantly greater press fluid yields were obtained from roasts cooked in 149°C air than from roasts cooked in 115°C fat. There was a positive correlation, significant at the 1% level, between juiciness scores and press fluid yields. Average shear force readings were slightly lower for roasts cooked in fat than for oven roasts. Correlation coefficients between shear readings and general tenderness, softness, friability, and residual tissue were not significant. From this investigation it appears that cooking time, cooking losses, changes in linear measurements, and palatahility of roasts from swimm- branosus muscles of beef round depend upon the rate of heat transfer from the cooking medium to the sample when contact heat remains constant and 81 sample size is standardized. Within the limits of this study the following conclusions appear to be relevant: } l. The transfer of heat from the cooking Indium to the sample is more rapid in fat than in air. To reach an internal temperature of 80°C roasts cooked in 115°C ludregenated fat required approximately half the time required by roasts cooked in 118°C air. The heat penetration rate during cooking varied more for even roasts than for roasts cooked in deep fat. 2. The rate of heat penetration in cooked tissue is slower than in raw tissue. Irrespective of cooking method, minutes per degree Centigrade rise increased as roasts approached the rare stage. Protein coagulation and cooking losses increased as samples progressed from the rare stage to the well-done stage. As the degree of doneness increased, rate of heat penetration decreased markedly. 3. Method of cooking influences cooking losses. Total, volatile, and volume losses were significantly less for even roasts than for roasts cooked by deep fat immersion. This may be due, in part, to the faster and more efficient transfer of heat provided by the fat medium. Even though significantly greater amounts of drip were obtained from conventionally roasted samples, these roasts were significantly more juicy than samples cooked in deep fat. ll. Suriname” samples cooked in fat compared favorably with Bindlar samples cooked in air for all palatahility characteristics studied except Juiciness. Results obtained seem to indicate that the components of tenderness--softness, friability, and residual tissue-um be distin- guished subjectively. 82 5. The internal temperature rise during cooling is greater for roasts cooked in deep fat than for oven-roasted samples. From the data, it appears that the internal tauperatures of tissues l/h-inch and 3/Lt-inch from the surface of the sample are higher than for comparable tissues in oven—roasted samples. 6. Hydrogenated fats with relatively high smoking temperatures mav be used successfully as ' a medium for roasting beef at moderate temperatures. 7. Method of cooking did not appear to influence changes in color reflectance brought about by cooking. Research concerning the effect of different methods of dry heat cookery on rate of heat penetration, cooking losses, and palatability of beef round muscles is extremely limited. Additional work needs to be done to determine the rate ee extent of weight loss mg cooking, the thereal conductivity of beef muscles, the rate of heat transfer of different cooking media, and the time required for cooking to different degrees of doneness in various cooking media. Results of this study suggest that cooking by deep fat immersion might be acceptable if a method of procedure could be established whereby palatability and rate of heat penetration could be maintained and cooking losses reduced. It is conceivable that losses more comparable to those of oven roasts might be obtained if deep fat roasts were cooked at slightly lower temperatures an! to a lower internal temaerature. lbdification in method, in which a higher fat temperature is maintained until protein coagulation begins, followed by a lower fat temperature for the remainder of the cooking period, may result in increased palatability with lower cooking losses. 1. 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A comparison in total weight loss, volume of drip loss, and tenderness of precooked and fresh frozen roasts of beef. Unpublished M.S. Thesis. Columbus, Ohio. Ohio State University Library. 1953. 28. 29. 30. 31. 37. 38. 39. “l. 85 Davis, J. G. and Hanson, H. L. Sensory test methods.‘ I. The triangle intensity and related test systems for sensory analysis. Food Tech. 88335-338. 195“. Day, J. C. Longissimus dorsi of three grades of beef: comparison of cooking weight losses, palatability, and edible portion. Unpublished M.S. Thesis. East lensing,.Michigan. Michigan State University uere 1953s Douglas, A. L. The effect of two methods of dry heat cookery on the rate of cooking, cooking losses, and palatability of semitendinosus muscle of beef round. Unpublished M;S. Thesis. East Lansing, Michigan. Michigan State University Library. 1960. Dove, w. F. Food acceptability: its determination and evaluation. FOOd TOChe 1339-50e 19"‘7e . Dunnigan, J. H. A study of palatability and price of two grades of sirloin butts. Unpublished M.S. Thesis. East Lansing, Michigan. Michigan State University Library. 1943. Foster, D., Pratt, C., and Schwartz, N. Variation in flavor judgments in a group situation. Fbod Res. 20:539-599. 1955. 010d?” we He mplea or engineering mt tmtfe Princeton, New Jersey. De Van "0an COe. I30. 195?. Grindley, H. S. and Mojonnier, T. Experiments on losses in cooking meat, 1900 and 1903. U. 3. Dept. Agr. Off. Expt. Sta. Bul. 1&1. 190“. Griswold, R. M. The effect of different methods of cooking beef round of Commercial and Prime grades. I. Palatability and shear values. Food Res. 20:160-170. 1955. Griswold, R. M. and'Wharton, M. A. Effect of storage conditions on the palatability of beef. Food Res. 68517-528. 1991. Rankine, 0. G. and Ellis, N. R. th in relation to quantity and quality factors of meat animal carcasses. Proc. Am. Soc. Animal Prod. 32:315-319. 1939. Hanson, H. L., Stewart, G. F., and Tome, E. Palatahdlity and histo- logical changes occurring in New York dressed broilers held at l.7°C (35°F). Food Res. 7:1us.160. 19u2. Harrison, D. L. Shrink, rate of heat transfer, and palatability of beef cooked at the same temperature in air, steam, water, and fat. Unpublished Mis. Thesis. Ames, Iowa. Iowa State College Library. 19 3. Harrison, D. L., Lowe, 3., McClurg, B. R., and Shearer, P. S. Physical, organoleptic, and histological changes in three grades of beef during aging. Food Tech. 3:28h-288. 1999. #2. “3. 50. 51. 52. 53. 5h. 55. 86 Eelssr, M. D., Nelson, P. M., and Lowe, B. Influence of the animal's age upon the quality and palatability of beef. Iowa Agr. Hpt. Sta. Bul. 272. 1930. Hiner, R. Ia, Caddie, A. 14., and Rankine, 0. 6. Effect of methods of protection in palatability of freezer-stored meat. Food Tech. 5:223-229. 1951. Riner, R. L. and Rankine, 0. 0. Temperature of freezing affects tenderness of beef. Food Ind. 1981078-1081. 19'0. Hiner, R. L. and Rankine, 0. G. The tenderness of beef in relation to different muscles and age in the animal. J. Animal Sci. 90157-353. 1950. Howe, P. E. and Barbells, N. G. The flavor of meat and meat products. Food Res. 2:197-202. 1937. hChlor’ N. He. 15110, Ee Ae' and 1181118311. As Je Bali-ability of “at. testing and consumer testing methods: II. Code bias in consumer testing. Food Tech. 88389-391. 1954. Jakob, M. Heat transfer. Vol. I, New York. John Wiley and Sons, Inc. 1949. Kramlich, W. E. and Pearson, A. M. Some preliminary studies on meat flavor. Food Res. 238567-57“. 1958. Latzke, E. Standardizing methods of roasting beef in experimental cookery. North Dakota Agr. EXpt. Sta. Bul. 2’42. 1930. Laue, E. A., Ischler, N. R. , and Bullman, G. A. Reliability of taste testing and consumer testing methods: I. Fatigue in taste testing. Food Tech. 8:387-388. 1954. lose, B. Experimental cookery. nth ed. N. I. John Riley and Sons, Inc. pp. 192-251. 1955. Lille, Be. Grain, Es. Anick, as. ”“0801. Me. Post, L. Jo, finith, Fe Be. McClurg, B. R., and Shearer, P. S. Deforsting and cooking of frozen meat. In“ Stat. cOle Acre Ebrpt. Sta. RCBe Elle 385e 1952s 10": 30: We 8., and Kastelic, J. The free fatty acid content and smoke point of some fats. J. Home Econ. 50:778-779. 1957. 1m. B. and Stewart, G. F. Subjective and objective tests as food research tools with special reference to poultry meat. Food Tech. 1330'38e 191‘70 Marks, L. S. hchanical engineers' handbook. New York. McGraw-Hill Mk COep Inc. 1951e 57. 59. 60. 61. 62. 63. 67. 68. 69. 70. 71. Marshall, N., Wood, L., and Patton, M. B. Cooking Choice grade, top round mt Mtse Je Me Diet. Assne 36:569-573e 1959e Marshall, N., Wood, 1... and Patton, M. B. Cooking Choice grade, top round beef roasts. J. Am. Diet. Assn. 36:3141-345. 1960. Masada, G. M. Tender cuts of three grades of beef! effect of extent of cooking on weight losses and cost. Unpublished 14.8. Thesis. East Lansing, Michigan. Michigan State University Library. 1955. Minor, Ce Se and Dalton, Ne Ne Gmfimle New York. Rfiimld Publishing Co. 1953. ‘ ‘ Moran, T. and Smith, E. C. Post-marten changes in ardual tissues. The conditioning or ripening of beef. Great Britain Dept. Scientific Ind. Res. Food Investigations Board. Spec. Rpt. No. 26. 1929. Noble, I. T., Halliday, E. 6., and fleas, H. K. Studies on tenderness and juiciness of cooked meat. J. Home Econ. 263238-2142. 1934. Overrun, A. and Li, J. C. R. Dependability of food Judges as indicated by analysis of scores of a food tasting panel. Food Res. Damn-“119. 1998. . Paul, P. C. Changes in palatabdlityo microscOpic appearance, and electrical resistance in beef during the onset and passing of rigor and during subsequent storage. Unpublished Ph.D. Thesis. Ames, Iowa. Iowa State College Library. 1916. Paul, P. and Brataler, L. J. Studies on tenderness of beef. III. Size of shear cores: end to end variation in the sendmembranosus and adductor. Food Res. 20:635-638. 1955. P‘nl. Pep BratZICr‘ Le Jog Fawn. Es De. ‘1“ Knight, Xe St‘mas on tenderness of beef. I. Rate of heat penetration. Food Res. 1785018- 510. 1952. Paul, P. and Child, A. M. Effect of freezing and thawing beef muscles Sign press fluid, losses, and tenderness. Food Res. 2:339-3h7. 7. Paul, P., Love, B., and McClurg, B. R. Changes in histological structure and palatability of beef during storage. Food Res. 9221-233. 19%. Paul, P. C. and McLean, B. B. Studies on veal. I. Effect of different internal temperatures on veal roasts from calves of three different weights. FOOd Me 113107-115e 1%. Perot, 8. Taste panel tests. Natl. Provisioner. 121212-13. 191‘9. Peryan, D. R. and Swans, V. W. hasunsnent of sensory differences. Food Tech. “8390-395. 1950. 72. 7“. 75. 76. 77. 78. 88 Proctor, B. B., Davison, 8., Nalecki, G. J., and Welch, M. A recording strain-gage tenderometer for foods. Food Tech. 9:h71-h77. 1955. Ransbottom, J. H. Freezer storage effect on fresh meat quality. ”Inge Me 53319-23e 1%70 Rsmsbottom, J. M. and Strandine, E. J. Comparative tenderness and identification of muscles in wholesale beef cuts. Food Res. 138 315-330. 1948. Ramsbottom, J. M. and Strandine. E. J. Initial plusical and chandcal changes in beef as related to tenderness. (Abstract) Proc. Am. Soc. Animal Prod. J. Animal 561. 78519e 19'43. meottom, Je Me. Strarfline, Ee Je. m K0032. Ce H. Comparative tenderness of representative beef musclss. Food Res. 10:197-509. 1945. Ronald, Sister Mary. The effect of methods of reheating upon palatahllity of precooked frozen beef roasts. Unpublished 14.5. Problan. Department of Institution Administration, Michigan State University. East Taming. 1956. Satorius, M. J. and Child, A. M. Effect of cut, grade, and class upon palatability and composition of beef roasts. Minn. Agr. Expt. Sta. Tech. Bul. 131. 1938. Satorius, M. J. and Child, A. M. Problems in meat research. I. Four comparable cuts from one m1. II. Reliability of Judges' scores. Food Res. 38627-635. 1938. Simn, 11., Carroll, F., and Clogs. M. T. Effect of degree of finish on differences in quality factors of beef. Food Res. 23 : 32.1w. 1958. Simpson, J. I. and Chang, I. C. L. Effect of low freezer storage temperature and wrapping material on the quality of frozen meats. Food Tech. 832166-252. 1954. Spin-Eng. D. D., P1att, w. 'r., Hiner, a. L. Tenderness in beef muscles as measured by pressure. Food Tech. 13:155-158. 1959. Stech, 0e P e m WC”. Ge Me Roasting meat at ZSOWe Je Alfie Diet. Assn. 303160e 1951‘s Suartz, V. hoke point affected by detennination method. J. Home Econe “03251-252. 1948. Sweetman, H. D. The scientific study of the palatabdlity of food. J. Home Econ. 23:161-172. 1931. 87. 88. 89. 91. 92. 89 Tannor, B., Clark, N. 0., and Hanldns, 0. G. Mechanical determination of juiciness of meat. J. Agr. Res. éézboa-blz. 19143. Tappel, A. L. Reflectance spectral studies on the hematin piments of cooked beef. Food Res. 22814-015407. 1957. 111111.. Me. Williamson, Le Je. and Ibrgan, Ae Fe The CfICCt or fat on shrinkage and speed in the roasting of beef. J. Home Econ. 21+: 720-733. 1932. Towson, A. M. Palatability studies of beef rib roasts, I. As affected by high versus low even temperatures. Unpublished 14.8. Thesis. Ames, Iowa. Iowa State College Library. 19140. Tucker, R. Q., Voegeli, M. N., and Wellington, G. H. A cross sectional larscle nomenclature of the beef carcass. Hichigan State College Press. East Lansing. 1952. Vail, G. E. and Hilton, R. Edible fats and oils. M chemical characteristics. J. Home Econ. 35:16-46. 1993. Visser, R. T., Harrison, D. L., Goerts, G. E., Human, N., Shelton, M. 11., and Mackintosh, D. L. The effect of degree of doneness on the tender- ness and Juiciness of beef cooked in the oven and in deep fat. Food Tech. 14:193-198. 1960. 90 APPENDIX 91 Table 1». Weight of rounds, muscle weight, maximum linear measure- ments of Insoles, and trialled sample Height. Height Weight Madman linear Triued loft Rump on Muscle Mm)..— Sample b n h w d 1 79.6 3391 12.75 6.50 3.63 1534 2 80.5 3828 13.75 7.13 3.63 151m 3 76.0 3380 12.50 6.88 3.63 11:61 1+ 70.2 3082 12.83 6.75 3.38 1330 5 72.8 2907 11.33 6.88 3.88 1285 6 79.0 3121 117.00 7.25 3.88 1552 Right Round 1 77.0 3373 12.50 7.13 3.63 1392 2 76.2 3752 12.75 6.75 3.88 1560 3 76.1 3315 13.38 7.13 8.00 1356 n 67.2 3066 12.75 7.38 3.25 1213 5 70.8 2890 11.75 6.75 3.50 1526 6 75.0 339“ 13.75 6.63 3.88 1593 \O In) PROCEDURE FOR DETERMINING TEMPERATURE TO EQUATE CONTACT HEAT OF FAT AND OF AIR Conduction Heating tion: q = Ah(t1-t2)T Where: q = heat input (Btu) A a surface area (square feet) h s averate heat transfer coefficient"I t1 - heating medium temperature (qr) t2 a surface temperature (°F) 1’ - time (hours) a .___.__Efim______... ”“1“ °‘ " (sq. rt.)(°F)(hr.) Assumptions: a) constant surface area. b) constant heat input. c) surface temperature = 212°F. Calculations for this investigation based on.material presented in Giedt (3b). Jakob (#8), Marks (56). and tuner and Dalton (60). Average heat coefficients: hair I 1.0 when the t1 is between 250 and 350°F. air hfat = 6.7 when the t1 at is betwoen 200 and 300%“. 93 For this study, average cooking times in air and in fat established by preliminary trials were: I T air = 2.60 hours T = .98 hours fat If t r is 300°F, then t t may be determined as follows: 1 ai l fa hair (‘1 air " tzfl'mm- ‘ h.4:th ”'1 fat '- tzfl'rat 1(300-212)2.60 :- 6.7 (t1 fat - 212).98 8820: -212 (6.7)(.98) t1 f‘t 39.85 = t1 fat - 212 t1 fat 3 212 + 3h.85 t1 fat = 246.85°F (297°F = 119 0) Since these calculations were based on preliminary trials in which cooking time varied greatly, it was decided to use the next lowest temperature on the fryer thermostat. This was 115°C. In addition, products from preliminary trials cooked at 11590 most nearly resembled the con- ventionally oven-roasted samples both in appearance and palatability. 9h 5.33 3.3an 3.3980 how 2.30 no suns no.6» has, huge 58» .815 sons» has 833 .02 + 828.3 38.9.3 has» an 1 £883 .5 8.58am .96 23 .....o Es. .96 she .96 Ed .96 to» .96 £8 no . 833 3.33: no $55.5 no £595 no 9865 Ho acacia no ”Evans $5.38 9.3. 309 £30 oz 3:00 d338," no «83 55o: 58.: H3 32a 33» e5 .3. agate agate an Agate Annie agate so: .392» has hafiflm #8983: 033.; ensure has #953 figure his. 88 to» .85 3 Bag .5» Ram .8: .83 tom £8 has #883 agom pun: ooa 923.32 1 3.33 be soda. sodas be 93> be no: he?“ house how—E h"; 39:33 sees—8.3.. 3 be 8a 8532 ages: so «fine .3: has and .88 due .88 has! has 533 .53 385 .85: mixed 1 huge 39» causes madame." .838 b: 6880 hanmnm e8» 3 an 38 596 8E .93 b: gonna 23005 1 ll .83 .55 has noon 3 has Hana»... .88 .3835 Angus. .9: ~38 sausages: :1 1 .8 aid was an 2.3 .88 as .38 be... Do> 38.. 33m «592 9.3qu III... luv A e WW I Lo m 38 83.3383 amuse J .3 Ana-m 730 9.30% a; Table 15. Changes in the rate of heat penetration for five replications, for three sample depths for two cooking methods. Deep Fat Method Samples 1/u.1nch Depth (Min./°C rise) Temperature °C Replication: Mean mun - 20 .65 1.38 1.00 .82 .75 .92 20 - 30 .16 1.38 060 $5 050 067 30 - “O .35 085 065 035 Ono 052 no - 50 .55 .80 .75 .35 .30 .55 50 - 6° 065 075 070 035 055 .60 60 - 70 .70 1.10 .95 .55 .65 .79 70 - 80 1.20 1.00 .95 .65 .85 .93 3/u.1nch Depth mun - 20 .96 1.39 1.511 1.30 1.60 1.36 20 - 30 .60 .95 .65 .60 .70 .70 30 " no 075 070 06.5 050 .60 .6“ “‘0 ‘ 5° .60 070 e60 055 e60 061 50 - 60 .70 .70 .70 .65 .75 .70 60 " 70 1000 085 .75 e90 .85 .87 7o - 80 1.55 1.00 1.15 1.20 1.05 1.19 1 1/2-1nch Depth (radius) .mtn1 - 20 1.50 2.07 1.57 1.71 1.91. 1.76 20 - 30 .80 .70 .50 .70 .80 .70 30 - “‘0 .65 e70 050 060 .65 .62 no - 5o .75 .75 .60 .70 .70 .70 50 — 60 085 085 075 070 080 079 60 - 70 1.15 .90 .85 .85 .95 .94 7O - 80 1.50 1000 1.20 095 1000 1013 Table 15 (Contd.) 96 Conventional Method Samples lllI-inch Depth (nun/‘10 rise) Replication: Phat) Temperature °C 068 079 e70 e72 e65 071 Initial - 20 1.00 .95 1.20 .60 1.00 1.03 20 - 30 1.121 1.25 1.80 .95 1.60 1.35 30 - 1+0 1.85 1.80 1.05 1.20 1.70 1.60 50 - 60 1.95 1.80 2.70 1.20 2.10 1.95 60 - 70 3.75 2.80 2.50 2.10 2.55. 2.70 70 - 80 3/16-1nch Depth 1.50 1.08 1.31 1.15 1.79 1.37 Imus). -‘-‘ 20 1.30 1.20 1.30 .90 1.00 1.22 20 - 30 1.05 1.00 1.60 1.10 1.25 1.36 30 - 00 1.00 1.00 1.15 1.20 1.30 1.29 no .. 50 1.75 1.90 1.25 1.35 1.16 1.54 50 - 60 2.90 2.15 1.75 1.75 1.50 2.10 60 - 70 2.90 2.50 2.05 2.50 2.15 2.50 70 - 80 1 1/2.1neh Depth (ream) 1093 2.11 2.07 1.6“ 2021 1e99 Initial - 20 1e3° 1e30 1e50 1030 1035 1035 2° ‘,' 30 1.20 1.30 1.55 1.25 1.35 1.33 30 - 40 1.55 1.45 1.60 1.35 1.50 1.49 1&0 - 50 1.75 1.60 2.05 1.50 1.80 1.70 50 - 60 2.25 1.80 2.45 2.05 2.15 2.22 60 - 70 2.95 2.80 2.95 2.85 2.95 2.90 70 - 80 Table 16. Determination: of pH for new and cooked eamplee and the change in pH for six roasts for two methods of cookery. Method Deep m 5.61 5.8 0.2 5.0 5.8 0.0 5.5 5.8 0.3 5.6 5.8 0.2 5.7 5.7 0.0 5.6 5.9 0.3 Conventional 5.6 5.9 0.3 5.6 5.8 0.2 5.5 5.8 0.3 5.7 5.7 0.0 5.6 5.6 V 0.0 5.6 5.8 0.2 lflased on 2 readings. 98 Table 17. Cooking weight loeeee for 812: route for two methods of cookery. Method Rev Cooked Total Totel Drip Volatile of Height Weight Ioee Ion Lou Loee coogg <9.) (510.) (a) 5 5 1 7 Deep Fat 1308 815 #93 37.69 1.32 36.37 1250 737 “63 37.01} 1.76 35.28 1188 705 483 110.66 .81 39.85 1086 660 022 38.86 .71 38.15 937 612 375 37.99 1.36 36.63 1268 796 472 37.22 1.114 35.79 Avenge 1181 730 1+5]. 38.2“ 1.23 37.01 Conven- tionll 1089 727 362 33.20 1.70 31.50 1056 697 359 39.00 2.37 31.63 126“ 327 “37 34.57 1.27 33.31 1212 318 39“ 32.51 2.56 29.95 1298 330 “18 33.99 2.24 31.25 1279 883 396 30.96 2.03 28.93 5"” 1199 797 M2 33.13 2.00 31.10 99 Table 18. Volume loss for six roasts for two methods of cookery. Method . VW Volume 6 of Raw Cooked Lose 9221325~ ' Sagple Sample Change % Deep Fat 1175 650 525 3 00.68 1230 710 g 520 02.28 995 535 .060 h6.23 998 970 . 528 52.91 970 510 060 ' 07.42 1085 695 390 35.95 Average ‘ 1076 595 081 00.91 Conventional 965 620 395 35.75 860 585 275 31.98 1070 795 325 30.37 1000 745 255 25.50 1055 695 360 '- 39.12 1135 770 365 32.16 Average 1010 693 321 31.65 100 0.: 0.: 0.0 0.: :.: m. .:. n.: 0.: 0.0 000022 . - 0.5.5 0.: 0.: 0.0 ...: 0.: 0.: 0.: 0.: 0.: 0.: 0.0 0.0 0.: 0.: 0.... 0.: 0.: «.0 0.: 0.: 0.0 n.: 0.: 0.: a... 0.: 0.0 fired mod “.3 We: 00: Q0: No.0.~ 00“ New. 0.0 0.: ~.n 0.0 . 0.: 0.: 0.: 0.: 0.: 0.0 0.: 0.0 ~.: 0. .: 0.: 0.0 0.: 0.0 0803 1:06:00 0.: 0.: 0.0 :.: 0.0 ~.: 0.: m.: 0.0 000.83 _ 30.5 0.: 0.: 0.0 m .: 0.: 0.: 0.: 0.: 0.0 0.: 0.: 0.0 0.: 0.: 0.: 0.: 0.: 0.: 0.: 0.0 0.: 0.: 0.0 0.: 0.: 0.: 0.0 ~.: 0.: 0.0 0.0 0.0 0.: ~.n ~.: «A 0.: 0.: 0.0 0.: 0.0 0.: 0.: 0.: 0.: 0.0 0.: 0.: 0.0 0.0 0.: 0.: 0.: 0.0 00.0 030 Jug; : {050.08 H2880 H3330 30:33.20 1.000 -83. 83.80. .880 .8er 0.3.2 no 00502 .3932: 9.330 05 no.“ anode—3.300." Kan you coupon 5..» no 0930» 5.3.8.333 50.33: .3 0.30.0 101 .euaepooo 0 oo 0.80H 0. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.: 000000 0.00 0.:0 :.mn 0.00 0.0N m.u~ m.u~ n.0u 0.0m n.m~ H.0N 000000 0.00 «.mm 0.00 m.mm 0.00 0.00 :.ma u.- m.- 0.00 w.ma sum decode anohnoo 0.- 0.- 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.: 000000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.:0 0.00 0oxoo0 0.00 0.00 0.00 :.:... in 0.0: 0.2 0.0... 0.00 0.0” 1.2 .50 000 noun _I.1...nmo...u.wnuuuuu.wmo .000. 7.000, 0000 00071;;4000. we: 70:: a: -..“M .huoxooo mo mvospoa 039 you unedoaodaneh ado Ho ew0h0>< .ooceuoefiuon uoHoo acoo pom .ON OHDmH 102 Table 21. Average press fluid yields and shear force readings of cooked samples for six replications for two cooking MthOdB e Method of Cooking Press Fluid (fl) Shear Force (1b.) Deep Fat 36.961 19.302 34.09 . 19.h5 34.21 17.85 36.52' 17.95 35.78 19.25 35.78 19.55 Grand Average 35.56 18.89 Conventional 40.00 18.65 38.6“ 19.h0 39.50 19.ho 38.94 19.35 38.98 19.35 36.28 20.01 Grand Average 33.72 19.36 1Based on 2 determinations. 2Based on 5 determinations. EFFECT OF TWO METHODS OF DR! HEAT COOKER! ON PALATABILITY AND COOKING LOSSES OF SEHIHEMBRANOSUS MUSCLE OF BEEF ROUND By Zenovia Jean Lukianchuk AN ABSTRACT Submitted to the Dean of the College of Heme Economics of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Foods and Nutrition 1960 Approved by A20— 1 W ABSTRACT In this study, the effects of conventional oven-roasting and of cooking by deep fat immersion on cooking losses, rate of cooking, and palatahility of semimenbranosus muscles from six pairs of U.S.D.A. Choice steer beef rounds were compared. The temperature of the cooking mediums was equated so that the contact heat was considered comparable for roasts cooked in air or in fat. Experi- mental samples, standardised with respect to size and shape, averaged 1200 grams, with linear measurements of 6 x h x 3 inches for length, width, and depth, respectively. Prior to cooking, each sample was defrosted and potentiometer leads were positioned at depths of 1m... 3/u... and 1 1/2. inches from the surface. Roasts were individually cooked at 1149 °C in air or at 115°C in fat until all potentiometer leads had reached a minim internal temperature of 80°C. From the data of this investigation it appeared that cooking time, cooking losses, changes in linear measurements, and palatahility of roasts are affected by the rate of heat transfer from the cooking medium to the sample when sample size, contact heat, and degree of doneness are con- trolled. Transfer of heat was more rapid in fat than in air. To reach an internal temperature of 80°C, roasts cooked in 115°C hydrogenated fat required approximately half the time required by roasts. cooked in 118°C air. Heat penetration rate during cooking varied mar-c for oven roasts than for roasts cooked in hot fat. Rate of heat penetration in cooked tissue was slower than in raw tissue. Irrespective of cooking method, minutes per degree Centigrade rise in internal temperature increased as roasts approached the rare stage. As degree of doneness increased, cooking losses increased and rate of heat penetration decreased markedly. The internal temperature rise after removal from the cooking medium was greater for roasts cooked in deep fat than for oven-roasted samples. In addition, inner temperatures of tissues 1]“; and 3/h-inch from the sur- face of the samples were higher than for’ccmparable tissues in oven-roasted samples. Total, volatile, and volume losses were less for oven roasts than for roasts cooked by deep fat immersion.‘ Although greater amounts of drip were obtained from conventionally roasted samples, these roasts were signifi- cantly more Juicy than samples cooked in deep fat. Changes in color brought about by cooking, as measured by per cent color reflectance, did not appear to be affected by method. Semimembranosus samples cooked in fat compared favorably with similar roasts cooked in air for all palatability characteristics studied except Juiciness. Results obtained indicated that components of tenderness- softness, friability, and residual tissue-omay be distinguished. The findings of this limited study emphasise that rate of heat transfer from the cooking medium to the sample plays a significant role in the determination of cooking time, cooking losses, and palatability of roasts of predetermined size and shape. Additional investigation of the interaction of factors, such as contact heat, rate of heat transfer, thermal ‘ ' 'n' -A‘JP‘ m‘m WM“ conductivity of beef, sample size and shape, and degree of doneness needs to be made before procedures for cooking beef roasts by deep fat inversion can be established.