A COMPARESON OF PALATABILITY AND COOKENG CHANGES 5F BEEF STEAKS PREPARED BY FOUR METHWS Thesis hr the Doom of M. S. WCNGAN 51‘ ATE COLLEGE Marcifla Lamoine Prwgeon 3954 This is to certify that the thesis entitled - ('1' r"‘,"‘h ‘71 "z ‘. '-"- 77"" T 1 ‘fft A KA~JJLHlJKA~I (JP }tda.xi;u.lJ.LJ.lY sud) vas..Ls.U unit-Hugo l. MAJ—J; OLA—Md“) T ixiJi—lgdjl) LI FOUR A‘MJIEELJDS presented by xxx-cilia Lauoizle r rid;_;eon has been accepted towards fulfillment of the requirements for _-'-__~3°_ degree in 1199;5— 0-169 KY 5 55 "7‘7“? 'D'PP'E‘ {\1‘7‘ 11 tLh-Libul-Jdl Land 1 MR 8 '56 nu an!“ lNlFR-BBRPM w. m MR 29 ’58 San “5 '52 A COMPARISON OF PALATABILITY AND COOKING CHANGES OF BEEF STEAKS PREPARED BY FOUR METHODS By Mireille Ltmoine Pridgeon A THESIS w Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Foods and Nutrition 1951+ THESIS J’ )ffijf ACKNOWLEDGMENTS The writer wishes to express her deep appreciation to Dr. Pauline Paul for her interest, guidance and assis- tance throughout this study. Grateful appreciation is also extended to the food research staff for their assis- tance with the experimental work, and to each member of the taste panel for her aid in scoring the cooked meat. 344482 A COMPARISON OF PALATABILITY AND COOKING CHANGES OF BEEF STEAKS PREPARED BY FOUR METHODS By Marcille Lamoine Pridgeon AN ABSTRACT Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Foods and Nutrition »\ Year ,~- ~195h Approved by - ' Four meat cookery methods were compared using the adduc- tor and vastus lateralis muscle of the beef round. The methods compared were two braising methods, a dry heat method called "oven-cooking", and deep-fat frying. The mus- cles were dissected from the left and right rounds of six beef animals, graded U. S. choice. Each muscle was cut into four 1—inch steaks. The steaks were weighed, wrapped in moisture-vapor proof cellophane, frozen and stored until 2h hours prior to cooking. 5 Steaks were cooked by all four cooking methods for each scoring period. A panel of five judges scored the steaks for aroma, appearance, tenderness, Juiciness, flavor and general acceptability. The change in moisture and fat content with cooking, the pH of raw and cooked samples and the percent cooking losses were determined. Objective measurements were made of volume and surface area changes with cooking. The chief source of variation among the palatability scores was cooking method as shown by an analysis of vari- ance made on each palatability factor. The variation in Juiciness scores was assigned, however, to both cooking method and difference between muscles. The Judges preferred the oven-cooked and deep-fat fried steaks over the braised steaks, as indicated by general acceptability scores. There was a significant difference in cooking losses as a result of cooking method. The steaks cooked by braise I had the highest percent total cooking loss and the oven- cooked steaks had the lowest. The average weight of drip- pings plus water was greater for braised II steaks than for braised I steaks. Results of objectivetests were similar to the results of subjective scores. Correlations between shear force and tenderness scores and between juiciness scores and total moisture were highly significant. Volume and surface area changes followed the same general trend as cooking losses. However, a significant difference found between muscles for surface area changes was not present for total cooking losses and volume changes. Highly significant correlations were found between percent total cooking loss and volume change, percent total cooking loss and surface area change, and between volume change and surface area change. The pH values for cooked meat indicated that cooking method had an effect on the degree of change in pH with cooking. The oven-cooked steaks tended to be more acid while the deep-fat fried steaks were generally more alkaline than the braised steaks. An analysis of covariance on the fat data showed that there was a difference in the fat content of cooked samples due to cooking method. The deep-fat fried steaks showed quite a definite increase in fat content with cooking. TABLE OF CONTENTS INTRODUCTION . . . . . . . . . . . . . . . . . . REVIEW OF LITERATURE . . . . . . . . . . . . . . . . . Factors Affecting Cooking Losses and Palatability . Effect of Freezing . . . . . . . . . . . . . . Effect of Grade . . . . . . . . . . . . . . . Effect of Muscle . . . . . . . . . . . . . . . Effect of Aging . . . . . . . . . . . . . . . Effect of Temperature of Cooking and Degree of Doneness . . . . . . . . . . . . . . . . . The Effect of Method of Cooking on Palatability and COOking Losses 0 e o o e o e o o o e e o o Roasting . . . . . . . . . . . . . . . . . . Aroma, appearance and flavor . . . . . . . Tenderness . . . . . . . . . . . . . . . Juiciness . . . . . . . . . . . . . . . Cooking losses . . . . . . . . . . . . . . Braising . . . . . . . . . . . . . . . . . . Aroma, appearance and flavor . . . . . . . Tenderness . . . . . . . . . . . . . . . . Juiciness . . . . . . . . . . . . . . . . Cooking losses . . . . . . . . . . . . . . ii Page a> O\ 0\ ¥? 4? In F‘ .11 .12 .13 .11. .11; .15 .15 .16 TABLE OF CONTENTS (Cont.) BrOiling e e e e e e e e Aroma, appearance and flavor Tenderness . . . . . . Juiciness . . . . . . Cooking losses . . . . Deep-fat Frying . . . . . Temperature of fat . . Palatability . . . . . Cooking changes . . . Sh‘llow-fat Frying e e e e Methods of Evaluating the Palatability Subjective Methods . . . . Objective Methods . . . . Shear force . . . . . pH . . . . . . . . . Volume and surface area Moisture . . . . . . . Fat . . . . . . . . . EXPERIMENTAL PROCEDURE . . . . . . Description of Experiment . . Preparation of Samples . . . . General Procedure . . . . . . Methods of Cooking . . . . . . iii Page .18 . 19 . 19 . 20 . 21 . 21 . 21 . 22 . 22 . 22 . 22 . 23 . 2S . 26 . 27 . 29 . 29 . 29 TABLE OF CONTENTS (Cont.) Braise I . . . . . . . Braise II . . . . . . . Oven-cooking . . . . . . Deep—fat Frying . . . . Palatability Scores . . . . Objective Scores . . . . . . Shears . . . . . . . . Volume . . . . . . . . Surface Area . . . . . . pH eeeeeeeeee T0133]. 140181311136 0 e e e e ' Fat . . . . . . . . . . Statistical Methods . . . . DISCUSSION OF RESULTS . . . . . . Freezing and Thawing Losses Palatability Factors . . . . Appearance . . . . . . . Aroma . . . . . . . . . Flavor . . . . . . . . . Tenderness . . . . . . . Juicinese . . . . . . . General Acceptebility . iv Page - 33 .311 .35 . 36 . 36 . 36 . 36 . 37 - 37 . 38 . 38 . k0 . ko' . kl gag.- TABLE OF CONTENTS (Cont.) Page Cooking Changes and Time-Temperature Relationships . Sh Total Cooking Losses . . . . . . . . . . . . . . Sh Drip and Volatile Losses . . . . . . . . . . . . 57 Change in Surface Area . . . . . . . . . . . . . 58 Change in Volume . . . . . . . . . . . . . . . . 60 Time-Temperature Curves . . . . . . . . . . . . 66 Objective and Chemical Tests . . . . . . . . . . . . 7O Shear Force . . . . . . . . . . . . . . . . . . 70 pH . . . . . . . . . . . . . . . . . . . . . . 73 Total Moisture . . . . . . . . . . . . . . . . . 73 Fat . . . . . . . . .-. . . . . . . . . . . . . 76 SUMMARY AND CONCLUSIONS . . . . . . . . . . . . . . . . . 8h LISTOFREFERENCES...................87 APPENDIX . . . . . . . . . . . . . . . . . . . . . e . e 93 LIST OF TABLES TABLE 1. Use of two adjacent steaks cooked by each method 2. Average percentage thawing losses . . . . . . . 3. Average scores and analysis of variance for appearance scores . . . . . . . . . . . . . u. Average scores and analysis of variance for aroma scores 0 O O O O O O O O O O O O O O O 5. Average scores and analysis or variance for _ flavor scores . . . . . . . .'. . . . . . . . 6. Average scores and analysis of variance for tenderness scores . . . . . . . . . . . . . . 7. Average scores and analysis of variance for juiciness scores . . . . . . . . . . . . . . 8. Average scores and analysis of variance for general acceptability scores . . . . . . . . 9. Average total, dripping and volatile losses . . 10. Analysis of variance for percent total cooking loss 11. Surface area of raw and cooked steaks in square centimeters O O O O C O O O O O O I O O O O 12. Average percentage and analysis of variance for decrease in surface area . . . . . . . . l3. Correlation between various scoring measures . 1h. Percentage decrease in volume with cooking . . 15. Analysis of variance for decrease in volume With COOking O O O O O O C O O O O O O O I O 16. Average reading and analysis of variance for shear force in pounds . . . . . . . . . . . vi Page 32 kl 1+3 us as RB 51 53 55 S6 59 61 62 6h 65 72 17. 18. 19. 2’0 . 21. 27. 28. 29. 30. 31. 32. 33. 3&- LIST OF TABLES (Cont.) Average pH readings for raw and cooked steaks . . Percent moisture in raw and cooked samples . . . Average percentages and analysis of variance for decrease in moisture content wit? cooking Percent fat in raw and cooked steaks (dry basis) Analysis of covariance for fat content of raw and cooked steaks . . . . . . . . . . . . . . . . Average original and adjusted fat percentages for COOkea Steaks e e e e e e e e e e e e e e 'e e Analysis of variance for fat in cooked steaks . . Score sheet for steaks . . . . . . . . . . . . . Average daily scores for appearance . . . . . . . Average daily scores for aroma . . . . . . . . . Average daily scores for flavor . . . . . . . . . Average daily scores for tenderness . . . . . . . Average daily scores for juiciness . . . . . . . Average daily scores for general acceptability . Percentage total cooking losses . . . . . . . . . Percentage decrease in surface area with cooking Shear force values for cooked steaks . . . . . . Percentage decrease in moisture with cooking . . vii Page ”I‘LL 75 -— 1 Ed 7s 60 so 82 9h 95 96 97 98 99 100 101 102 103 10k LIST OF FIGURES FIGURE Page 1. Paired rounds out into l-inch steaks. . . . . . . . . 30 2. Average time-temperature curves for beef steaks frmm the adductor muscle . . . . . . . . . . . . . . . . 67 3. Average time-temperature curves for beef steaks from the vastus lateralis 111118016 e e e e e e e e e 68 tr'lili INTRODUCTION All laboratory experimental work requires that the investigator follow particular methods of procedure. In meat cookery, roasting is the only method that is well established. Years of experimentation with various roast- ing procedures have resulted in one generally accepted cooking method. This is not true, however, for other methods of cooking meat. Rather recent investigations in several laboratories have resulted in a number of tentative methods for cooking steaks, particularly those from.the round of beef. It was the purpose of this study to compare four cooking methods, in an effort to contribute some information that might lead to greater standardization of braising, deep-fat frying and dry heat cookery methods for beef steaks. REVIEW OF LITERATURE Characteristics of Beef Muscle Structure Skeletal muscle is surrounded by fibrous tissue called epimysium, which is continued into the muscle as the peri- mysium.and breaks the muscle into bundles of fibers called fasciculi. Each fiber is surrounded by connective tissue called endomysium.and has its own thin, colorless, elastic covering membrane, the sarcolemma (6, k3). Composition The two types of protein found in muscle are (a) struc- tural proteins, consisting largely of collagen and elastin and (b) intercellular proteins. The principal intercellular proteins are myosin, actin, myogen and globulin x (6). These proteins coagulate on cooking at a temperature of about 65° C. According to Cover (23), the toughness of meat can be attributed to two structures, muscle fiber and connective tissue. Lowe (AB) states that the toughness of connective tissue depends upon its thickness and density, upon the proportion of collagen to elastin and possibly upon animal age. Investigators seem.to agree that collagen is changed to gelatin by heat in the presence of water. According to Bendall (ll) this conversion-takes place in three stages: (a) conversion of collagen A to collagen B which occurs at 56-60° C. and results in the shortening of collagen fiber, (b) the uptake of water by collagen b and consequent swelling and softening of the connective tissue and (c) the dissolu- tion of collagen B to form.a gelatin sol. The third step occurs only if cooking at 100° C. is abnormally prolonged or in pressure cooking at temperatures above 100° 0. Rogue (12) found that the hydrogen-ion concentration of the hydrolyzing solution, the temperature of heating and the duration of heating affected the hydrolysis of collagen to gelatin. Hydrolysis was slowest at a pH of h.5 to 6.0. A temperature of 80° C. seemed to be most favorable for con- version of collagen and a heating period of eight hours was needed for complete softening of connective tissue. Strandine, Koonz and Ramsbottom (62), after a chemical analysis of beef and chicken.muscle, concluded that the chief cause of variation in tenderness of:muscle was the difference in structure and arrangement of the constituent anatomical elements, the difference in structure within the muscle fibers, «or both factors. They felt that these causes had greater effect on tenderness than did pH, fat, total protein or Inoisturc. In a classification of beef muscles on the basis (bf bundle size and connective tissue pattern, they described the vastus lateralis muscle as being composed of small fas- ciculi having very thin perimysium, and containing a medium amount of both collagenous and elastic connective tissue. The adductor was found to be a muscle with indistinct fas- ciculi and very uniform texture, to contain a medium.amount of collagenous connective tissue and only small amounts of elastic tissue. In general, muscles with distinct fasciculi and abundant connective tissue were found to be much less ten- der than those with smooth or homogeneous patterns. The vastus lateralis and adductor muscle of the beef round were chosen for the experimental work in this study. Factors Affecting Cooking Losses and Palatability After many years of study and investigation of meat cookery, it has been shown that many factors are responsible for losses from meat on cooking. These, in combination, re- sult in shrinkage of animal fibers and loss of nutritive value. Some of the major contributing factors are freezing, grade of carcass, muscle, aging, temperature of cooking and degree of doneness. iEffect of Fgeezing During the freezing of meat, ice crystals are formed ‘which expand the muscle and put the center under pressure. Ice crystals may rupture the tissue somewhat depending on the freezer temperature and time of storage (15, #3). Since there is some tissue damage, a frozen steak on de- . frosting has a tendency to drip. Callow (15) found thawed frozen.meat to have a more open microstructure than fresh meat, therefore leading to a greater loss of fluid. The percentage of drip and loosely held muscle fluid as reported by Empey (29) was less in.muscles having a relatively low concentration of hydrogen ions. Drip was reduced by in- creasing either the osmotic pressure or the pH or both, prior to freezing. In a study using the 9-10 and 11-12 rib roast, Paul (52} found that unfrozen beef had a significantly lower total cooking loss than frozen beef, when roasts were cooked to an internal temperature of 56° 0, uncovered in a 175° C. oven. Unfrozen beef also had a significantly higher press fluid content than frozen thawed beef. Orr (50), however, using frozen steaks from.the longissimus dorsi muscle versus unfrozen steaks, found no appreciable effect in total cooking loss through freezing. Any difference in losses was attri- buted to difference in total cooking time. It is generally agreed that freezing makes beef more tender. In comparing frozen and unfrozen beef loin steaks, flankins and Hiner (36) found increased tenderness with steaks frozen at -lO° F. and -h0° F. These temperatures had greater tenderizing effect than +20° F. Effect of Grade Several investigators have found that the grade or quality of the carcass affects the palatability of cooked meat. This was especially marked when Good or Choice grades were compared with Commercial or Cutter grades (3, 25, 37, 66). After comparing the longissimus dorsi muscle of U. 3. Good, U. 8. Commercial and U. 3. Utility grade beef by roasting, Day (25) reported significant differences in grade for aroma, flavor and tenderness. No consistent pattern was noted for juiciness and no significant differ- ence was found for appearance and texture of the three grades. Aldrich and Lowe (1) found no significant difference between U. 3. Choice and U. 8. Good grades, except for a slightly higher percent of press fluid in the choice grade. Six.muscles of the beef round were cooked by moist heat for this study. In a study of beef tenderness, Paul and co-workers (51) J concluded that cooking losses were not appreciably affected. by grade. Two prime, two good and two commercial animals were used in this study. The meat was cooked by oven roasting and deep-fat frying. Effect of Musclg Where.musc1es from.the same animal have been compared ‘by the same cooking method, investigators have concluded that there is a definite difference in palatability factors between muscles and in some cases differences within the same muscle (1, 13, 26, Sh, SS, 57, SB, 62). Satorius and Child (Sb) reported that coagulation of the protein of meat did not affect the tenderness of the triceps brachii and adductor but the longissimus dorsi became more tender with coagulation. In a second study using the same muscles (59), the adductor required more pounds of force to shear than the other two muscles and was found to contain a smaller number of muscle fibers per bundle when examined histologically. The press fluid did not vary significantly mmong the cuts but the triceps brachii contained more total moisture than the longissimus dorsi. The adductor had the greatest cooking loss and graded lowest in texture, tenderness, and quality and quantity of Juice. Brady (13) made a histological study of the same three muscles used in the above study and reported no significant difference in the diameter of different muscle fibers but a significant difference in the number of fibers per bundle. The adductor contained 138 fibers per bundle compared to 260 for the longissimus dorsi and 25h for the triceps brachii. The vastus lateralis muscle of veal is described by Paul and McLean (Sh) as a muscle containing a large amount of connective tissue, having many collagenous fibers and a medium.number of elastic fibers. The fasciculi were not parallel. Fatty tissue was noticeable within the muscle. Ramsbottom.(55) found the vastus lateralis of U. S. Good beef to contain.medium amounts of both elastin and collagen. he described the muscle as being "slightly tough”. In comparing the tenderness of representative beef mus- cles, graded U. 3. Good, Ramsbottom (57) reported the following shear force readings using the Warner Bratzler shearing machine: adductor (cooked), 10.6; vastus lateralis (cooked), 11.3; adductor (raw), 5.2; and vastus lateralis (raw), 5.8.. Brady (13) found a much higher average shear force reading for the adductor (25.5), but his study included both cows and steers. Effect of Aging The primary effect of aging on.meat seems to be changes in tenderness and flavor. It is thought that increased ten- derness with aging is due to an effect upon muscle fibers. Aging also results in an increase in soluble protein products which when heated play an important part in the flavor of meat (39). Orr (50) concluded that appearance, aroma and Juiciness were little affected by cold storage and that flavor of fat, flavor of lean, texture and tenderness were more noticeably affected. Studying the histological, physical and organoleptic changes in three grades of beef during aging, Harrison and ."_/ . (co-workers (37) found the aroma and flavor scores reached 'their maximum.within 10 days of aging and decreased after .30 days of aging. Aging of roasts increased tenderness as indicated by shear force and Judges' score. Griswold (3h) was able to find only small differences in flavor and tenderness of meat aged 9 and 37 days at 3h° F. Deatherage (25) reported increased tenderness of U. S. Good and U. S. Choice loins until 17 days, with no improvement or a decrease in tenderness at an days, and some improvement at 31 days. over 17 days. ‘Uork that has been carried on concerning the tenderness of beef carcasses immediately after slaughter has shown ‘varying results. Ramsbottom.and Strandine (56) stated that ‘beef was more tender two hours after storage than at any time after from.two to six days. By the 9th to the 12th day after slaughter the beef had improved in tenderness so that it was more tender than two hours following slaughter. Paul and co-workers (SZL'however, found that roasts cut from.the semitendinosus and biceps femoris muscle of beef ‘were less tender immediately after slaughter, and that ten- derness increased with storage. Beef steaks, they found, 'were tender immediately after slaughter, became less tender 'with cold storage up to 2h.hours, and returned to approxi- Inately their original tenderness with storage of luh to 1&9 hours. '10 Alexander (3), roasting lamb at various stages of aging, reported that increasing the ripening period after slaughter decreased the cooking shrinkage and shortened the time required to roast leg of lamb. Cooking losses tended to increase with storage through 2h hours and then remain constant, according to Paul and co-workers (51) from their study on the aging of beef. Effect of Temperature of Cooking and Degree of Doneness It is well known that cooking of any type causes meat to shrink. Shrinkage may beciue to some change in the fibrous tissue or to coagulation of the muscle fiber. Ac- cording to Andross (6) this shrinkage takes place during the first 15 to 20 minutes of heating, owing to expulsion of water, the process being greatest in boiling and stewing. Roasting and grilling he states also cause a loss of water by evaporation and some shrinkage;// McCance and Shipp (h6) stated that muscle tissue shortens without change in volume or loss of weight wnen heated to hflo C. At 60° 0., however, there is loss of weight caused by increased shrinkage of the meat proteins, resulting ,/ in expression of juices. It is quite well accepted by most investigators that a low oven temperature, especially for roasts, results in smaller cooking losses and juicier meat (3, h, 19). 11 The internal temperature to which the meat is cooked has also been shown to have a marked effect on cooking loss and palatability (16, 23, 53). in general, with dry heat cookery, juiciness and tenderness decrease with increasing internal temperature. Lowe and co-workers (uh) found little difference in juiciness scores or percent of press fluid of beef roasts cooked at oven temperatures of 1200 C., 150° C. or 1750 C., provided the roasts were cooked to the -same internal temperature. The Effect of Method of Cooking on Palatebility and Cooking Losses Roastigg After many years of study, roasting in the oven by dry heat is quite standardized. This method for roasting has resulted in a palatable meat with a m1nimum.of cooking losses, maximum retention of nutritive value and a minimum cost per serving. Numerous studies have been made on meat since Grindley and co-workers (37) first studied the losses involved in meat cookery in 1896 at the University of Illinois. Their initial study involved the nature and extent of cooking losses, nutritive value of meats, changes taking place in various cooking methods and the influence of cooking upon the flavor and palatability. 12 These workers concluded that the chief loss in weight during the boiling, sauteeing and the pan-broiling of meat ,is due to loss of water and fat. They also reported that the longer the time and the higher the temperature of cooking, other factors being the same, the greater the losses resulting (33). Aroma, appearance and flavor. One of the characteristic changes produced by cooking meat is a change in color (#3). This change is due to an alteration in.myoglobin; the myo— globin becoming denatured, changing from red to pink, and then to brownish grey (6). Variation in aroma in roasting studies has been attri- buted to grade (25) and to length of frozen storage (hh);. the longer storage meat having lower aroma scores. Latzke (kl) reported that high roasting temperatures of 150° C. to 175° C. resulted in a browner, more pleasing color but palatability was sacrificed. The cooking of animal muscle results in a "meaty" flavor apparently owing to chemical changes taking place in the fiber rather than in the juice. This "meaty" flavor accor- ding to Crocker (2k) is due to volatile substances detected by the sense of smell, even though chewing is needed to re- lease themi he states that beef flavor is complicated chemically and consists more of odor than taste. It is thought that the flavor of meat created by low temperatures is due to the cracking of amino acid units of protein, 13 jparticularly those of the fiber. Meat cooked at low tempera- tures retains all of the salts and sugars noted in the raw :neat and therefore is mmre flavorful. Andross (6) stated the flavor of meat was the summa- tion of three factors: (a) odor affecting olfactory organs, (b) taste, affecting the taste buds of the tongue and buc- cal surfaces, and (c) texture. Tenderness. Many studies of the roasting of meat have shown that a low oven temperature for all or a :maJority of the roasting period results in greater ten- derness (3. h. 19, 22). Using constant oven temperatures of'125o C. and 2250 C. for roasting various cuts of beef, Cover (23) reported greater tenderness for roundbone chuck and rump cooked at the lower temperature as Judged by a scoring panel. Rib roasted at the lower temperature was preferred by 69 percent of the Judges. No significant maJority was in favor of the low temperature for lamb. The author felt that the differ- ence in tenderness results might be due to the longer time of cooking and not Just the oven temperature. Satorius and Child (58) compared the tenderness of individual beef muscles. With increasing internal temper- ature the semitendinosus was found to be more tender until 750 C. was reached, when it was found less tender than that cooked to 670 C. The authors stated that from5t5o to 670 C. collagen was being hydrolyzed with some coagulation of pro- tein but from.67o C.to 750 C. muscle protein increased in density and decreased in tenderness. The diameter of the muscle fibers decreased with increasing temperature to 67° C. No difference was noted in diameter of fibers at 75° c. Noble and workers (149) reported that toughening of beef muscle took place during heating from 61° C. to 75° C., as shown by penetrometer readings. Juiciness. Lowe ((41+) reported Juiciness scores were influenced by the kind of roast, whether boned or not, the stage of cookery and the oven temperature. That is, the lower the internal temperature and oven temperature, the Juicier the cooked meat. A greater amount of fat in a roast has also been found to increase Juiciness (7, 30, 60, 66). Barbella (7) concluded that the Juice of beef rib roasts increased quite rapidly with increase in fatness to 22.5% rat and more slowly to h2.5%, after which there was no ap- parent effect. Cookigg losses. Cooking losses during roasting are affected primarily by cooking temperature, degree of done- ness, and composition of meat (.33. ’41, I414, 614.). The higher the internal temperature and the higher the oven temperature the greater the cooking loss. Thille (63) reported that the greater the degree of surface fat, the larger the cooking loss. Satorius and Child (59) found the opposite true, however. It appears that a layer of fat not in excess 15 xnay help hold in Juices and not contribute greatly to drippings, while a large layer of fat on.melting will increase cooking losses considerably. Grindley and MoJon- rder’(53) stated that in the roasting of meat the chief loss was due to the removal of both fat and water. The semitendinosus muscle was found by Child (17) to have a 2h% to 37% cooking loss when cooked to an inter- :nal temperature of 750 C., while an internal temperature of 56° C. yielded a loss of only 9% to 15%. An average loss of 27% for well-done lamb roasts was reported by .Alexander (3). The adductor muscle averaged a cooking loss of 18.2h% when cooked by roasting to an internal temperature of 58° C. (59). Braisigg Braising is browning meat and cooking slowly in a covered utensil in a small amount of liquid (5). Aroma, appearance and flavor. Using temperatures of 90° 0., 90° 0. + no minutes, 90° c. + 50 minutes and 90° c. + 120 minutes for beef pot roasts, Lowe and workers (uh) .found.aroma and flavor scores varied only slightly. Cline (18) reported little change in flavor in heel of round pot Inoasts, braised with or without water. Tests made on 88 Pairs of less tender cuts from U. S. Medium grade beef cattle showed the flavor of the lean to be more desirable 16 'when braised to internal temperatures of 750-850 C. than 'when oven roasted (18). Aldrich (1) found an internal temperature of 900 C. + one hour for pot roasts resulted in the development of undesirable sulphury flavors, undesirable odors and a loss of attractive appearance. The meat braised to an internal temperature of 900 C. was found to be more acceptable. Tenderness. The few braising studies that have been conducted have shown that long cooking periods have a slight tenderizing effect on meat (1, 18, uh). This was thought to be due to greater conversion of collagen to gelatin. As braising studies were generally performed on cuts containing considerable amounts of connective tissue, this reason semms probable. ' Cline (18) reported heel of round cuts braised with water, to be slightly less tender than cuts braised without water. The cooking period, however, was shortened when water was added. Pork chops braised without added water scored higher in all palatability factors including ten- derness when compared to chops braised with added water (h7). Juiciness. In general, braising methods resulted in greater cooking losses than other cooking methods described in several studies.) Therefore, braised meat was found to be less Juicy (18, h8, 60, 67). Cline's (18) results on less tender cuts of U. S. Medium.beef braised to varying 17 internal temperatures from 75-85° C. were not in agreement. She found decreased cooking losses, decreased cooking time per pound and a slightly more Juicy meat when the cuts were braised rather than oven roasted. Most investigators cooked their meat to higher internal temperatures, however. Low Juiciness scores and high weight losses for all braised meat were reported by Lowe and workers (uh). Long holding periods after pot roasts had reached 900 C. resulted in drier meat than roasts cooked to Just 90° C. (1, Ah). Cookigg losses. As was mentioned earlier, the cooking losses of braised.meat are large. Experiments on braising that have been reported in the literature showed a cooking loss or,33-uo% (1, an, 65). The longer the meat was braised the higher the internal temperature up to the maximum, and the greater the cooking losses (1, kh, 60). The reason for higher internal tempera- tures and longer cooking periods than for other cooking methods was the need for the softening of larger amounts of connective tissue. Broiligg Broiling is to cook by direct heat (5). Agoma, appearance and flgvor. Lowe (uh) stated broiler temperatures of 150° C. and 1750 C. produced attractive 18 looking steaks while a 2000 C. temperature resulted in con- siderable charring. The higher temperature also produced steaks of poorer flavor. hayes (38), however found the 200° C. oven to give more attractive steaks than either a 175° C. or 250° C. oven. She worked with l-inch steaks, broiled to an internal temperature of 58° C., three inches from the heat, while Lowe broiled l-inch steaks two inches from.the heat and 2-inch steaks four inches from.the broiler unit, to internal temperatures of 58° C. and 75° C. McLachlan (h?) reported a 225° C. oven produced steaks which.were rated higher for aroma and appearance but lower for flavor than steaks cooked in a 175° C. oven. Tenderness. Cline (21) found the porterhouse and rib steaks to be more tender than sirloin or round. The range of the Judges' tenderness scores was 2.8 to 6.8 with 2.8 being the score for the center muscle of the bottom round. Averages for the tenderness of the round were h.0 or "slightly tough“ as indicated by the score sheet. In a second study Cline (20) found the rib and round less tender than the porterhouse and sirloin. The muscle of the bottom round graded low in tenderness even in the steer and heifer. McLachlan (h?) reported broiling temperature had an effect on the tenderness of steaks from the beef loin. Steaks broiled at,an oven temperature of 175° C. required fewer pounds to shear than steaks broiled at 225° C. l9 Porterhouse steak was reported the most tender in this study. Cline's (20) "modified roasting method" which consisted of searing the steak with one turning in a closed gas broiler, pre—heated to 500° F. and transferring to a gas broiler set, at 275° F., produced a more tender steak than the constant oven broil of 350° F. Lowe and workers (uh) felt there might be a trend for well-done steaks to be scored less tender than those cooked to a lower internal temperature. Juiciness. Steaks broiled at an oven temperature of 225° C. were Juicier than steaks broiled at 175° C., accor- ding to McLachlan who cooked steaks from the beef loin to an internal temperature of 58° C. Lowe and workers (uh) compared medium-done loin steaks to well-done steaks and reported the well-done steaks were always scored less Juicy. They recommended broiler temperatures of 135° C., 150° C. and 175° C. for all palatability factors. Lower temperatures did not improve palatability and required a longer time for cooking. The 2000 C. temperature was considered acceptable for 2-inch steaks. _ngkingglosses. The cooking losses of broiled beef steaks seem.to be dependent, in general,on the final inter- nal temperature and the broiler temperature (38, an, h7, 65). Lowe and workers (uh) found, as did Tucker (65), that well-done steaks always lost more weight in cooking than 20 less well-done steaks. Lowe reported a 35% greater weight loss in well-done steaks, than medium-done steaks, while Tucker reported an average weight loss of 28% forivell-done loin steaks and 20% for the same steaks cooked rare to mediumedone. McLachlan's (h?) results for her work on porterhouse, club _and sirloin steaks showed a 2250 C. oven temperature gave greater cooking losses than a 1750 C. temperature. The range for the percent total loss for the higher temperature was 25.36% to 26.2u%, and 20.lh% to 25.36% for the lower tem~ perature. hayes (36) agreed that a 250° 0. even resulted in greater cooking losses than a 175° C. oven. Cline (21) compared the percent cooking loss of rib, porterhouse, sirloin and round steak with results showing that cooking time and thickness of the steak influenced losses. her data showed a loss of 17.93% for the round as compared to 21.2h% for rib, 21.h2% for porterhouse and 23.95% for the sirloin. The round steak was not as thick as the other steaks compared, therefore a shorter cooking time and a smaller cooking loss resulted. Deep-fat Frying Deep-fat frying is cooking in a deep layer of fat (5). Little has been reported in the literature on cooking losses and palatability of meat as affected by a deepéfat frying method. 21 Temperature of fat. Temperatures that investigators have used for fat in which meat has been cooked are quite varied. Ramsbottom, Strandine, and hoonz (57) cooked beef in lard at 121.10 C. harrison and workers (37) used a tem- perature of 96-960 C. for the lard in which they cooked beer roasts. Orr (50) fried beef steaks in vegetable shortening at 1500 C.- According to Lowe and workers {uh} 1350 C. and 1500 C. were found to be the best temperatures for deep-fat frying beef patties. Palatability. Lowe and.workers (uh) reported that beef patties fried in deep-fat had a browner, crisper crust than patties fried in shallow fat. They also found consid- erable variation in the palatability scores of shallow and deep-fat fried meat. Cooking chagges. McCance and Shipp (h6) thought that in deep-fat frying the evaporation of moisture from the meat must be intense since the flesh is surrounded by a liquid immiscible with water at a very high temperature. They reported the loss of salts quite small, however. Orr (50) reported cooking losses of 17.96% to 23.53% for unfrozen longissimus dorsi steaks aged from 0 to 167 hours and cooked in deep-fat to an internal temperature of 630 C. 22 Shallow-fat Frying A few investigators have been interested in shallow- fat cookery for meat. A very early study on the sauteeing of meat resulted in the conclusion that meat lost 2.15% of its nitrogenous matter and 3.07% of its ash in the fat in which it was cooked, while cooked meat contained 2.3 times more fat than before cooking (33). Tucker (65) determined the total cooking loss of round steaks fried in shallow fat to be 15%, 1h% being volatile loss. Methods of Evaluating the Palatability of Meat Subjectige Methods Although investigators havetrecognized the lumitations of a taste panel for Judging the palatability of food, there are still factors which cannot be judged objectively. In the case of meat, color, aroma and appearance are better scored by a taste panel and are important factors in deter- mining flavor (6, 2h). Juiciness and tenderness are usually analyzed both subjectively and objectively and a highly significant correlation is often found between the two methods of testing (13, 19, 25. 27}. Objective Method; Several tests have been developed for measuring physical Characteristics and determining the chemical composition of 23 meat. Some of the primary objective tests used for meat investigations are shear force, ph readings, volume and surface area changes, fat determinations and moisture de- terminations. Shear force. Mechanical methods for testing the ten- derness of meats have been used for a number of years (h2). Bratzler (1h) developed in 1930 a shearing device which he tested on roast rib of beef and concluded there was a defi— nite correlation between the shearing values and the Judgea' scores. In l93h.Lowe (h2) compared the differences in the Standard New Iork testing laboratory type penetrometer and the dyna- mometer designed by Bratzler. The correlation coefficient calculated for the two devices was not significant for raw, rare and well-done meat. The author felt a shearing device held greater promise than the penetrometer for measuring the tenderness of meat. Recent studies have made considerable use of the Warner-Bratzler shearing device as a tenderness measure (1, 25, h5, 55, 57). This device, which.measures the number of pounds of force required to cut through a core of meat of specified diameter, has proved satisfactory in many ex- periments. Several investigators have reported high corre- lations between shear force results and tenderness scores. Deatherage and Garnatz (27). however, were not in agreement l‘.‘ 1‘ 1‘. ‘31.... ll. [Zilllviieelillilu .II. I III-II .l'l lilllllaeilluililll.ill.ulp ‘1‘!!! {fill—II III‘ J 21+ with these results. They found the differences in shear force in pounds were not as great as differences in taste panel scores. Correlation coefficients were not signifi- cant. These authors felt that tenderness scores and shear strength did not measure the same property of meat and that shears may be only related to tenderness. pg. According to Bate-Smith (10) the ph reached by meat at the completion of rigor mortis depends on three factors (1) the initial ph, (2) the glycogen content of the muscle at the moment of death, and (3) the buffering power of the muscles. The normal initial ph of raw beef muscle has been found to range from.5.h2 to 5.80 (66). Meat, on cooking, becomes more alkaline (8, 11, 15, 31, 50). Bendall (11) reported a rise of .30 on the heating of chuck steak. The same rise was noted 10 minutes after heating at 1000 C., after one hour at 1000 C. and after 3 hours of pressure cooking at 1260 C. Bard and Tischer (8L,in their study, found the pH value of raw beef to range from.5.52 to 5.61 and to increase from 5.95 to 6.05 after no to 120 minutes of processing. It has been shown that shrink in cooked meat is less when the ph is high than when it is low (15). A high.ph also decreases the tendency for thawed muscle to drip (9, 29). Winkler (68) concluded that toughness in pork was at a maximum.at 5.0 to 6.0 and that with either a higher or lower 25 pH the meat was progressively more tender. Results from beef studies were similar but the authors felt that maxi- mum.toughness range was at a lower pH. Volume and surface area. Changes in volume have been determined for roasts by measuring their length, width and depth before and after cooking, and by water displacement tests (1, 25. 37). Harrison (37) found that all roasts decreased in width and all but one increased in thickness. Aldrich's (1) results for pot-roasts were very similar. According to McCance and Shipp (#6) muscle tissue shortens without change in volume or loss of weight when.heated to hOO C. At 600 C., however, there is loss of weight caused by increased shrinkage of the meat proteins causing ex- pression of Juices. Aldrich (1) found volume losses fol- lowed the pattern of total cooking losses. Marked decreases in volume and dimensions of all cuts were noted.at 900 C. Braising roasts to an internal temperature of 90° C. plus one hour resulted in volume losses of 25.3%, while braising to an internal temperature of 900 0. resulted in a 19.6% volume loss. .In cooking small cuts such as steaks, the change in surface area is used as an indication of change in.musc1e fiber diameter. Fluid is lost from muscle fibers as the 26 weight and volume decrease (43). Satorius and Child (58) found the diameter of muscle fiber to decrease with in- creasing temperature to 670 C. No decrease in the diameter of muscle was observed from 670 C. to 750 C. It could be concluded that this shrinkage was complete at 670 C. for that particular cooking method. Moisture. Grindley and Emmett (31), as early as 1905, obtained about 3h% of the juice from raw meet by grinding and then pressing the meat in a compound screw press. The first mechanical device, however, for the determination of the moisture in cooked meat was developed by Child and Baldelli (17) in l93h. This instrument, called a presse- meter, was used to extract muscle fluid from.meat by sub- jecting small samples to a pressure of 250 pounds. Child and co-workers used the pressometer in several cooking studies. Tanner and.arworkers (63) described a method of de- termining juiciness of cooked meat by means of a hydraulic laboratory press. Correlation coefficients calculated be- tween committee scores and percent of expressible juice were relatively low when the hydraulic press was used to extract juice from beef muscle cooked to 580 C. internal temperature. Their study showed that the type of meat scored by the judges made a difference. When beef, pork, and lamb containing the same percentages of press fluid ‘were rated by the judges, beef samples received the highest scores for juiciness. 27 Several investigators have been interested in the total 1moisture content of raw and cooked meat, rather than,or in addition to, press fluid (55, 58, 59). Most of the workers reporting a method of determining moisture have dried sam- ples in an air oven plus additional drying in a vacuum oven, or completely dried samples in a vacuum oven. The percent moisture was calculated by difference in weight of the original and dried sample. In several studies at Michigan State College, meat samples have been dried in a forced air apparatus*, as a method of detenmining total moi sture . Grindley (33) reported the average percent moisture of beef round as being 75.53%. Satorius and Child (58) found the adductor to contain 73.57% moisture, which de- creased during roasting to 70.h6%. The roasts were cooked to 58° C. The vastus lateralis muscle contained 73.9% :moisture according to Ramsbottom.(55). Other muscles of the round have been reported to be 7h.h% and 73.3% moisture (55, 60). £33. In general two types of chemical methods are used for the determination of fat in meat. In the first, dried material is extracted with a suitable solvent, usually ether, in a continuous extraction apparatus, the solvent then evaporated, the residue weighed and reported as fat. * Brabender semi-automatic moisture tester 28 In the second method the material is saponified and the fatty acids which are set free are estimated by suitable means (h6). The ether extract method was used by the majority of the investigators reporting in the literature since they were interested in the total fat content of meat rather than the fatty acids only. Barbella and workers (7) found the fat content of beef rib roasts varied from 7.5% to 57.5%. The whole beef carcass averaged 10.95% fat according to Grindley and Emmett (31). Andross (6) found fat to vary fnam.muscle to muscle, the sirloin having 27% fat, the fillet 22%. Fat determined on the wet basis showed a range of 2.h7% to 3.h9% for muscles of the round of beef (57, 58, 59). EXPERIMENTAL PROCEDURE Description of Experiment Four cooking methods were compared using the adductor and vastus lateralis muscle of the beef round. The methods used were a dry heat method called "oven cooking", two braising method, and deep-fat frying. The rounds of six beef animals were secured from a local meat packer after aging from 10 to 1h days. The two muscles to be used in this study were dissected from the left and right round of each animal. All animals were graded U. S. Choice. The muscles were cut into l-inch steaks. Steaks were compared both objectively and subjectively. One muscle was cooked for each scoring period using all four cooking methods. The cooking treatments were assigned to the muscles so that each two treatments would appear together twice on paired steaks (Figure 1). Preparation of Samples Both muscles of each animal yielded four pairs of l-inch steaks. Two adjacent steaks were used for each cook- 1ng treatment. All steaks were wrapped with a drugstore Anterior Posterior LEFT Oven-cooking (Sous) 0 en-co king v (Song) Braise I (501a) _Braise I (501b) Score 2 3O RIGHT Braise II (503:) L—__. _____ Braise II 2! (503b) D -r t Fr 06(503e) y Deep-fat Fry (502b) Fig. l. Paired rounds out into 1-inch Cooking methods assigned Ste‘ks e in pairs. 31 ‘wrap in cellophane, sealed with scotch tape, labeled and frozen. Each steak was weighed before and after wrapping. The storage period for the steaks ranged from 33 to 110 days, the vastus lateralis muscle having the longest storage. Each steak was allowed to thaw 2h hours in the labora- ‘tory refrigerator before cooking. The weight of each frozen ‘wrapped steak was recorded, in order to check on any weight losses during frozen storage. General Procedure It was necessary to use two steaks for each cooking Inethod, since one steak did not yield enough.material for looth.subjective and objective tests on raw and cooked same ples. After recording the weight of each thawed steak, one of the two steaks used for each cooking method was halved. The steak to be halved was chosen at random.(Figure l). The half steak was wrapped securely in cellophane, sealed with scotch tape and returned to the refrigerator to be used later for moisture and fat determinations, and pH readings. The remaining one and one-half steaks were weighed as one steak and the weight recorded for determination of total cooking loss. The one-half steak, which was cooked, was used for determination of volume and surface area loss in 32 cooking, part of the shear values and pH. The center of the whole cooked steak was sliced for judging, and the re- :mainder reserved for moisture and fat determinations (Table l). The volume and surface area of each half steak was de- termined before cooking by methods described later in this section. Thermometers were inserted into the thickest portion of the lean tissue to record initial internal temperature, temperature rise during cooking and maximum temperature reached. The following data were recorded for each set of steaks: vveight before and after cooking, size and thickness, cooking time, temperature during cooking, maximum internal tempera- ‘ture, cooking loss in grams and percent cooking loss. ' TABEE 1 USE OF TWO ADJACENT STEAKS COOKED BY.EACH METHOD W One steak (cooked) One-half steak (cooked) One-half steak (raw) Subjective scoring Surface area Total moisture Total moisture Volume Fat content Fat content pH ph Shear Shear k The internal temperature when placed in the oven, volume of water added and weight of water plus drippings were recorded for the braised steaks. 33 Methods of Cooking Two methods of dry heat cookery and two methods of moist heat cookery were used in this study. Steaks were cooked to the internal temperature found.most satisfactory in previous studies for the particular method. The inter— nal temperature to which steaks were cooked differed for each cooking method. Since investigators have found that the internal temperature of meat continues to increase af- ter removal from the oven, maximum temperature rise was re- corded. A time-temperature curve was made for each cooking method. Braise I This method was developed by the Michigan State College food research laboratory and found to be preferable to other braising methods tested on particular muscles of the beef round. The steaks were browned one minute on each side in a heavy Dutch oven, preheated to 214.60 C. on an electric range. A griddle thermometer was used to determine the temperature of the Dutch oven. A rack with l/Z—inch legs was placed under the steaks. Fifty ml. of water was added, the pan covered and transferred to a gas oven set at 1210 C. The steaks were cooked to an internal temperature of 98° C. 3h plus one-half hour beyond the time of reaching 98° C. The final temperature reached was 99.50 C. Braise 11* The steaks were browned three minutes on each side in a heavy Dutch oven, which had been preheated to 2320 C. on a thermostatically controlled electric grill. A griddle thermometer was used to regulate the temperature of the Dutch oven. A rack with 1/2-inch legs was placed under each steak, 50 ml. of water added, the pan covered, and transferred to a gas oven set at 1210 C. The steaks were cooked to an internal temperature of 800 C. The maximum temperature reached was 8h-85o C. Oven-cooking A rack having h-inch legs was preheated 15 to 20 min- utes at 2320 C. in a gas oven, over a pan 1-inch deep. The steaks were placed on the preheated racks and cooked o to an internal temperature of 71 C. Maximum temperature 0 reached was 72 C. Deep-fat Frying Fifteen pounds of fat** was heated to 1500 C in an electric deep-fat fryer. The steaks were placed on edge a Method used at MSG for work under BhNhE contract AIS-31905. **. Vegetable shortening without added emulsifier 35 in the fat, against the side of the frying basket, so that the thermometer was out of the fat. All steaks were cooked to an internal temperature of 650 C., then drained one minute per side on brown paper toweling to remove excess fat. The maximum.temperature reached was 720 C. Palatability Scores A panel of five judges from.the Foods and Nutrition Department scored the steaks for appearance, aroma, flavor of lean, juiciness, tenderness and general conclusion. The highest possible score was ten and the lowest one, for each factor. A sample score sheet is shown on page 9h of the Appendix. Five l/8-inch slices were cut from the center of each warm steak. The slices were cut across the width of each steak with the grain. Each slice was divided into three parts, the center piece being as nearly uniform.in size as possible and used for recording the number of chews. Each judge was given one slice for scoring, with.the whole steak being available for rating aroma and appearance. Four steaks cooked by the four cooking methods were scored each time, the order of judging being randomized for each scoring period. 36 Objective Tests Shears Five to seven half-inch cylindrical cores were taken from steak cooked by each method. Cores were sheared on a ‘Warner-Bratzler shear stress apparatus. The readings from each steak were averaged. Volume The average weight of a quart saucepan of water was calculated after many preliminary weighings. A string was tied around each steak and the steak lowered into the filled pan of water, causing the water to overflow. The exterior of the pan was wiped free from water, the pan weighed and the weight recorded. This weight was subtracted from the initial weight, thus giving the weight in grams of water displaced. This test was used before and after cooking, the difference in water weight recorded and the percent change in volume by cooking calculated. Surface Area The shapes of the raw and cooked steaks were drawn on brown paper, traced on onion skin paper and measured with a planimeter. The percent change in surface area by cooking was calculated. 37 IS. A pH reading was made for both raw and cooked steaks. A five gram.sample of meat was minced with a sharp knife, added to hS ml. of distilled water and allowed to stand 20 :minutes. The liquid portion was decanted and the pH of the liquid determined with a Beckman pH meter. Duplicate readings were made on each steak. Total Moisture The samples reserved for moisture content were tightly sealed in.moisture-vapor proof cellophane and placed in a refrigerator. The maximum.time any sample was held was 27 hours. Preliminary work showed that a more homogeneous sample resulted if the meat was blended with distilled water in a Waring blender. The amount of water needed for a smooth slurry depended on the method of cooking and whether the meat was raw or cooked. The raw meat required less water for blending than the cooked meat. With most raw samples equal weights of water and meat resulted in a smooth blend. Braise I required 100 to 120 grams of water for a 50 gram sample of meat, while the other three cooking methods needed only 75 to 100 grams of water for a satisfactory mixture. The time necessary for blending was approximately two minutes. 38 Ten gram samples were dried at 1200 C. in a Brabender semi-automatic moisture tester until the weight changed less than 0.05% during a half hour interval. This required two to two and one-half hours. As the ratio of water to meat varied in each sample, the percent moisture was cal- culated accordingly from the Brabender reading. Fat Samples for fat determinations of the raw and cooked :meat were taken from the same'blended.mixture as was used for moisture readings. Ten gram samples were weighed into fat-free filter paper and dried in aluminum.drying pans at a temperature of 1200 C. The samples were held in a dessicator until time for fat extraction. Pat was extracted with ether*. The fat extraction process was carried on for three hours in a closed apparatus. A preliminary analysis showed the three hour period to be satisfactory for complete extraction of fat from.the dried samples. The percentage of fat was calculated on the basis of dry weight. Statistical Methods Analysis of variance was made and correlation coeffi- cients were calculated according to methods recommended by * Goldfisch fat extraction apparatus. 39 Snedecor (61). Correlations were calculated between the .following pairs of items: change in surface area and total cooking loss, surface area and volume change, volume change and total cooking loss, judges' juiciness scores and mois- ture content, judges' juiciness scores and fat content, shear force and judges' tenderness scores. DISCUSSION OF RESULTS Freezing and Thawing Losses The adductor freezing losses were negligible. A few steaks lost as little as 0.5 of a gram during storage. All but ten of the 148 steaks of the vastus lateralis lost weight during frozen storage. This loss generally ranged from 0.5 of a gram to 1 gram except for two steaks which lost 1.5 and 2 grams. The vastus lateralis muscle, how- ever, was stored one to six weeks longer than the adductor. An analysis of variance made on the percent thawing losses showed the difference in animals highly significant. A highly significant interaction was also present. It was noted, for example, that the adductor of animal I showed the highest average thawing loss, 2.1%, while the vastus lateralis of the same animal had one of the lowest thawing losses for that muscle, 0.88%. For animal II the vastus lateralis muscle had the highest average thawing losses, 1.28%, and the adductor had next to the lowest thawing loss for all adductor muscles, 0.59% (Table 2). Looking at the animals, rather than the individual nmscles, animal I had the highest thawing loss and animal VI the lowest, with average percentages. of 1.113% and 0.69%. hl The muscles and animals having the highest thawing loss did not necessarily have the highest cooking and moisture losses except for the adductor of animal I, which showed both the highest thawing loss and the greatest per- cent decrease in.moisture of all adductor muscles. The greater thawing losses for particular animals did not appre- ciably affect the judges' juiciness scores. TABEE 2 AVERAGE PERCENTAGE THAWING LOSSES ‘Animml 4—» Adduct°r nggrziis Nfigzgéa I 2.10 .88 1.h9 II .7h 1.28 1.01 III .59 .95 .77 IV 1.20 ~95 1'07 V .71 1.15 '93 v1 .76. ~63 '69 Palatability Factors The average daily judging scores for each steak are shown in the Appendix, page 95-10], The highest possible score a steak could receive for any particular palatability factor was ten, the lowest, one. h2 Appearance Average scores and analysis of variance for appearance (Table 3) indicate that the chief source of variation among the scores can be attributed to the difference in cooking method. The deep-fat fried and oven-cooked steaks scored higher in appearance than the braised steaks. The braised I steaks, which were browned at a higher temperature and cooked a longer time than the braised II steaks, also re- ceived higher average scores for appearance. The braised II steaks were greyish in color rather than brown. Some of the judges disliked the appearance of the oven-cooked steaks. ‘During the fast cooking of these steaks, the juices were pushed out on top of the meat and partially coagulated. ‘During braising and deep-fat frying this same expression of juices was no doubt present but the Juices were lost in the deep-fat or pan drippings. The material which was left on the surface of the oven-cooked steaks was reddish-brown in color and of soft consistency. The surface of the meat un- der the coagulated material was also a bronze-red color. This condition seemed to improve as the steak cooled. The deep-fat fried steaks were quite dark brown in color and crisp on the exterior. The difference between.muscles was not statistically significant, although the vastus lateralis muscle received slightly higher scores for the oven-cooking and deep-fat J. (illitlzi (I?! i #3 ‘TABEE 3 AVERAGE SCORES AND ANALYSIS OF VARIANCE FOR APPEARANCE SCORES I! Method of Cooking Muscle Adductor Vastus Lateralis Braise I 6.1 5.9 Braise II 5.5 5-1 Oven-cooking 7.7 8.0 Deep-fat Fry 8.0 8.3 Analysis of Variance Source pggzzagmor Mean Square F Total ’ h? Cooking Method 3 22.6080 79.55** Muscle 1 .0002 <1 Animal 5 .1722 <1 Error 38 .28h2 ##Significant at 1% level frying methods and slightly lower scores for the braising methods. Aroma The average scores and analysis of variance for aroma are shown in Table h. The main variation as shown by the analysis was due to cooking method, and was significant at the 1% level. The braise I and deep-fat frying methods were given the highest scores for aroma by the scoring panel. Both methods resulted in browner steaks, especially the deep-fat fry. This greater browning probably was the chief factor in development of aroma. Flavor The main source of variation in flavor among the steaks was cooking method as noted from average scores and analysis of variance (Table 5). The judges preferred the flavor of the deep-fat fried and oven-cooked steaks, with a slight preference for the oven-cooked. The steaks cooked by either braising method were scored almost identically and more than one full scoring point lower than the other two methods, on the one to ten scale used for scoring in this study. MS TABLE u AVERAGE SCORES AND ANAIXSIS 0F VARIANCE FOR AROMA SCORES T Method of Cooking Muscle Adductor Vastus Lateralis Braise I 7.h 7.h Braise II 6.3 6.1 Oven-cooking 6.9 6.8 Deep-fat Fry 7.k 7.2 Analysis of Variance Degrees of Source Freedom Mean Square F Total h7 Cooking Method 3 3.6991 10.07** Muscle .2002 <1 Animal 5 .3310 (1 Error 38 .3673 *%Significant at 1% level h6 TABLE 5 AVERAGE SCORES AND ANAIXSIS 0F VARIANCE FOR FLAVOR SCORES Method of Cooking Muscle Adductor Vastus Lateralis Braise I 5.8 5.7 Braise II ‘ 5.9 5.6 Oven-cooking I 7.3 7.5 ‘Deep-fat Fry 7.1 7.3 Analysis of Variance Degrees of Source Freedom. Mean Square F Total #7 Cooking Method 3 9 .9502 26.06am Muscle l .0052 <1 Animal 5 .3159 <1 Error 38 .3818 **Significant at 1% level h? The oven-cooked and deep-fat fried steaks reached the same maximum internal temperature of 720 C. as compared to 85° C. and 99.50 C. for the braised steaks. This fact may account somewhat, for the better flavor, since studies have shown that lower internal temperatures and dry heat generally result in a more flavorful meat, through retention of salts and nitrogenous bases. McCance and Shipp (h6) reported very small losses of salts in deep—fat frying. Andross (6) stated that moist heat cookery, such as boiling or stewing, leached out extractives and resulted in loss of flavor. Another factor which may have contributed to a better flavor for the oven-cooking and frying methods is the rela- tively high heat used in their cookery which resulted in a quick browning of the outside of the meat and a shorter cooking period, therefore, flavor was improved and extractives retained. Tenderness Cooking method accounted for the greatest part of the variation in tenderness between steaks as shown by average scores and analysis of variance for tenderness (Table 6). There was a significant difference in cooking methods at the 1% level. Steaks cooked by oven-cooking and deep-fat frying re- ceived the highest tenderness rating, with the oven-cooking u8 TABLE 6 AVERAGE SCORES AND ANALYSIS OF VARIANCE FOR TENDERNESS SCORES Method of Cooking Muscle Adductor Vastus Lateralis Braise I 6.2 6.6 Braise II 5.5 5.5 Oven-cooking 7.6 7.1 Deep-fat Fry 7.h 6.7 Analysis of Variance Source 19352222.“ Mean Square F Total h? ' Cooking Method 3 7.8836 10.36*% Muscle l .3675 <1 AnimAI 5 .8108 1.07 Error 38 .7607 *fiSignificant at the 1% level M9 method being given a slight preference. The braised Il steaks were scored lowest in tenderness by the scoring panel. From the results that have been published for tender- ness studies, it would appear that the protein of oven- broiled and deep-fat fried steaks had not coagulated at 720 C., to the point that it had toughened and become dense. Yet there evidently was some change in collagen as both muscles have been reported to contain medium amounts of col- lagen. The steaks braised to an internal temperature of 98° C. + 1/2 hour, however, were scored more tender than the steaks braised to an internal temperature of 80° C. It would appear from these results that there is considerable more softening of collagen with the longer braising period, which would counteract somewhat the toughening of intercellular protein as far as final tenderness scores are concerned. At a tem» perature of 800 C., evidently both forces are working together to oppose tenderness, that is, the temperature is high enough to coagulate the protein considerably, yet not high enough or the cooking period long enough to convert large amounts of collagen to gelatin. Dean (26) reported that connective tissue was little affected by braising at internal tempera- tures of 850 C. and when an interior temperature which decomp poses the connective tissue is held constant, the tissues eventually break entirely and the fibers of meat separate. 50 No significant difference was found in tenderness be- tween muscles. Juiciness Variation in juiciness scores can be attributed to both cooking method and muscle as seen in Table 7, where average scores and analysis of variance for juiciness are shown. Both braising methods were scored as "dry" with the braiga j[ being the driest, averaging 3.3 for both muscles. One judge described the meat as being "strawy". The oven-cooked steaks were considered to be the juiciest with the deep-fat fried steaks not quite a scoring point lower. Several investigators have concluded that braising re- sults in large cooking losses and rather dry meat. This study agrees with the findings that the longer the meat is braised the less juicy the meat. Since the oven-cooked and deep-fat fried steaks were cooked to a lower internal temperature, cooked.a shorter time and were cooked by dry heat methods, juicier steaks would be the expected result. The slightly higher juiciness scores for the vastus lateralis muscle when cooked by each method were statistic- ally significant at the 1% level. Aldrich (1) also found 51 TABLE 7 AVERAGE SCORES AND ANALYSIS OF VARIANCE FOR JUICINESS SCORES Method of Cooking Muscle Adductor Vastus Lateralis Braise I 3.0 3.6 Braise II h.6 5.1 Oven-cooking 8.1 8.h ‘Deep-fat Fry 7.3 7.8 Analysis of Variance Degrees of Source Freedmm Mean Square F Total #7 Cooking Mashed 3 63.5736 20.19** Muscle 2.5209 8.01** Animal 5 .0983 <1 Error 38 .31h9 **Significant at 1% level 52 vastus lateralis muscle slightly more juicy than the adductor. Satorius and Child (58) reported the adductor scored lower than the triceps brachii and the longissimus dorsi in quan- tity of juice. General Acceptability The scores for general acceptability followed the trend for tenderness scores, with cooking method again being the chief factor in variation of scores (Table 8). The oven-cooking and deep-fat frying methods were equally acceptable with average scores for both muscles being 7.2 and 7.1 respectively. The braising methods were scored prac- tically two scoring points lower and both methods were equally acceptable to the judges. The braise I method received an average score of 5.5 and the braise II an average score of 5.3 for both muscles. Even though the scores were very much alike, the impression should not be left that the braising methods gave the same results. The braised] steaks were scored higher in aroma, appearance and tenderness but were rated very dry, while the braised II steaks were juicier and just as flavorful, so consequently, general acceptability scores were much the same for each.method. The oven-cooked and deep-fat fried steaks, however, paralleled one another on practically all palatability factors. 53 TABLE 8 AVERAGE SCORES AND ANALYSIS OF VARIANCE FOR GENERAL ACCEPTABILITY SCORES ‘Method of Cooking Muscle Adductor Vastus Lateralis Braise I 5.u 5.5 Braise II 5.3 5.2 Ovenpcooking 7.2 7.1 Deep-fat Fry 7.1 7.0 Analysis of Variance Source . Degrees 0f Mean Square F Freedom Total A7 Cooking Method 3 11.7235 h3.92%* Muscle .0352 (1 Animal ‘5 .2632 (1 Error 38 .2669 **Significant at 1% level Sh Cooking Changes and Time-Temperature Relationships The original percentagesfor total cooking losses and decrease in surface area are found on page 101 and 102 of the Appendix. Total Cooking Losses The total cooking losses were greatest for the braised I steaks with an average of h5.0&% for both muscles, and least for the oven-cooked with an average loss of 23.h9% for both muscles (Table 9). The braise II and deep-fat frying losses were similar in the vastus lateralis, but with the adductor the deep-fat fry resulted in almost a A% smaller less than braise II. The analysis of variance showed the variance in total cooking loss attributable to cooking method signifi- cant at the 1% level (Table 10). It appeared that the two muscles might have reacted differently to the cooking methods, but interactions calcu- lated between the various sources were not statistically significant. The 2% greater cooking loss in the vastus lateralis by braising II and deep-fat frying was not signi- ficant. The greater loss by deep-fat frying might be par— tially accounted for by a longer average cooking time for the vastus lateralis. This longer period for cooking was due to a nine-minute cooking period for the deep-fat fried SS venom Hops: no madam om moosHocH H eaaeneeeq ee.nm eseee> ::.Hm eepesee< hem eeuuaoeo . _ ‘ eaaeaeeeu mm.~ oH.HN mm.n~ enemas mo.a oe.am em.m~ aeeeeee< weaseee-eeeo . . . eaaeeeeeq e.maa o:.mm eseee> n.maa eo.mm weeeseea HH eeaeem . oaamaopoq memo-H Hnem: mgpwd> e.eoa e~.:: nepeeeeq H eeaeem omen “memo hopes. anon anon waaxooo esam msaaaaen oaaeefle> dupes mmsamaaan uaooaom pneumom aneoaom odousz convex wndxooo H 1H, mmmmon MHH9440> Q24 GZHmmHmn «H4808 mo< o mumds 56 TABLE 10 ANALYSIS OF VARIANCE FOR PERCENT TOTAL COOKING LOSS F ‘7— Degrees of Source Freedom Mean Square F Total A7 ‘ _ Cooking Method 3 936.h086 110.97** Muscle 1 ' 1.0150 <1 Animal S 5 .3825 <1 Cooking x Muscle 3 9.1598 1.09 Cooking x Animal 15 9.8162 1.16 -Musc1e x Animal 5 9.7166 1.15 C x M x A 15 8.h381 **Significant at 1% level 57 steaks from animal IV. The average cooking time was about six minutes. This steak measured one-quarter to one—half inch thicker than the other steaks. Aldrich (1) found cuts from.the adductor to have higher cooking losses than the vastus lateralis. The adductor consistently averaged over a 35% cooking loss and the vastus lateralis from.30-35% cooking loss in her study. In this study there was a trend toward these results for braise II but not for braise I where total cooking losses were much the same for each muscle. Drip and Volatile Losses The percent drip and volatile losses were not determined as such for any method but oven-cooking. The weight of the added water plus drippings was recorded for the braising methods. The primary loss of weight in the oven-cooked steaks can be accounted for as volatile loss. Only an average of 1.99% was found to be drip loss, while an average of 21.6% was volatile loss (Table 9). As was mentioned earlier in discussion of appearance, the juices tended to be pushed out on top of the steak during the fast cooking at 2320 C. and settled back into the meat on cooling, therefore the juices were not actually lost. There was very little fat covering the meat to contribute to dripping loss. 58 The braise II resulted in a greater average weight of water plus drippings than the braise I. However, there were four cooking periods out of the total of twelve where the opposite was true (Table 9). Two opposing forces were un- doubtedly responsible for these results; drippings lost from the meat and the loss of liquid through evaporation. 0b- jective and subjective tests showed that braise I was less juicy and contained less moisture than braise II, so even though the drip loss was probably greater from.braise I the greater evaporation from.the pan left smaller amounts of drippings. The juices from the braised I steaks appeared to be slightly more concentrated than the juices from the braised II steaks. Change in Surface Area It has been shown many times by investigators that cuts of meat on cooking become smaller or shrink. A shrink in surface area is one of the factors contributing to this total change in size. This study found all steaks to decrease in surface area with cooking (Table 11). Since the steaks were cut across the grain and were placed out side down for tracing their size, it would seem that a decrease in surface area indicated a shrinkage in the diameter of muscle fibers or a change in connective tissue resulting in greater compactness of the fibers. 59 m.mm m.s: m.o: :.Hm «.m: m.n: m.om m.e: H> e.ee m.em a.ee e.ee e.ee a.ee e.mm e.ee e e.ee ~.ee a.~e e.ee e.mm e.ne e.mm H.Ne en e.H: m.om ~.m: H.e: 0.4: m.mm «.0: e.m: HHH m.em m.am e.em o.mn ere: m.mm m.m~ :.~: HH e.e: o.mm 01mm ~.e~ atom ate: :.om «.m: H eHHuMMwww m.em :.nm m.om o.e: e.mm ~.nm “.mn ~.mm H> hem «em man we: 13 83. ER in e 0.2 0% Tm... eém anew egos hem 4m: ea e.em m.mm m.:m e.m: o.m~ m.on ~.H~ s.nm HHH e.em o.~m n.ae mpem m.mn m.ma m.~n n.s: HH e.em o.e: a.~m :.mm m.em e.om «.mu ~.os H neeeeee< voxooo 3am oomooo. 3am oowooo wen dexooo rum . ham usuuaoon_ wdaxoooaaobo HH endeam H oedema AquuQBAHGeo season may unawam omxooo az<_3H so.:~ o:.oa o~.m~ efi.om Hm.ea :m.ma mo.ma sm.a~ HHH mm.ma mm.aa 00.:H mm.om mm.ma mo.ea em.ea sm.s~ HH oa.ea m:.aa oo.mH oa.m« ms.ma .4:.aa :e.na om.aa H .Hassopsn _ , mspud> ow.m NH.: Hm.o No.9 ma.:d :m.oa m>.oa mo.NH H> sums 3.0 5.3 om; No.1: 31: 2.3 0.9.: s ao.am me.om as.aa ma.mm mo.ma mo.a~ em.oa se.s~ >H ao.em mo.oa ms.mm csm.om Hm.sa as.o mo.ea am.:a HHH ma.aa H:.Hm sa.oa ma.mm so.oa om.:~ om.ea mm.m~ HH me.aa we.a mm.ea _.om.om 0:.nm :o.nH mm.ma wH.HH H soposee< quooo 3am uoxooo 36m comooo 3cm moxoou 3am pdmndeon waaxooonaobo H omfisam HH omddhm Andean haav ages 95800 32 3% 2H 2m azmommm om mamas 79 the difference in cooking method was not due just to the fat content of the raw meat. Variation in fat content as affected by cooking method was statistically significant at the 1% level (Table 21). The average percent fat for all steaks cooked by each method showed the deep-fat fried steaks to contain the highest percentage of fat and the oven-cooked steaks the lowest. When the average percent fat in the cooked sam- ples was adjusted to correct for difference in the raw samples the cooking methods ranked in the same order as far as fat content but the values were somewhat changed (Table 22 ) . It would appear from these analyses that the deep-fat fried steaks absorbed some of the fat in which they were Grindley and Mojonnier (33) reported similar re- They found that meat cooked. sults in an early study of frying. fried in shallow fat contained 2.3 times more fat than be- fore cooking. The deep-fat fried steaks were the only steaks showing quite a consistent trend toward increased rat with cooking. Table 20 indicates, however, that within each cooking method there were many instances of increased fat content. Satorius and Child (58) reported that cooked roasts from the longissimus dorsi muscle showed a 35440;? increase in fat over the raw roast. Thille (61;) studied both fat and lean roasts and reported that the center of the cooked roasts had greater fat content than the raw meat. 80 TABLE 21 ANALYSIS OF COVARIANCE FOR FAT CONTENT OF RAW AND COOKED STEAKS “ 1 - Degrees of Source Freedom Mean Square F Error 37 9.2899 Cooking Method plus Error hO Difference due to Cooking 3 5h.01hh 5,8141% *sSignificant at 1% level TABLE 22 AVERAGE ORIGINAL AND ADJUSTED1 FAT PERCENTAGES FOR COOKED STEAKS M Average Adjusted Cooking ethod Percent Fat Percentages Braise I 16.37 15.86 Braise II 16.72 17.h0 Oven-cooking 15.96 15-h7 Deep-fat Frying l8.h0 18.71 1 Adjusted for variation in fat content of raw samples 81 An explanation suggested by Lowe (A3) for this increase in fat during cooking is that the phospholipins combined with the proteins may be released by coagulation and more readily extracted by other from cooked than raw meat. A factor that must be considered in comparing the effect of cooking method on fat content is the relationship of moisture to fat content. The samples from.cooked steaks with a lower moisture content would undoubtedly have a higher concentration of fat, gram for gram, than steaks containing more moisture. However, the loss of fat in dripping, from the steak cooked a longer time, would counteract somewhat this concentration of fat. Looking at the adjusted averages in Table 22, it would appear that the second factor was more responsible for the fat content of braise II since it had the second highest average percent fat and was cooked a shorter time than Braise I. In the case of the oven-cooking method, the greater moisture content could have accounted for the reduced amount of fat in the sample. Since the percent fat in braise I and the ovenpcooked steaks was much the same, it might be presumed that these two opposite forces produced the same results. An analysis of variance of the percent fat in the cooked meat showed the difference between animals to be significant at the 1% level (Table 23). The chief variation in fat content between raw samples was also attributed to a difference 82 TABLE 23 ANALYSIS OF VARIANCE FOR FAT IN COOKED STEAKS Degrees 0f Mean Square F Source Freedom Animal 5 7h. . 81112 b. . 18% 7 Muscle 1 35.6282 1.99 Method of Cooking 3 13.6815 <1 Error 38 17.9237 *flSignificant at 1% level 83 in animals, as found from an analysis of variance of per- cent fat in the original samples. Realizing that the fat content of both raw and cooked meat might have an effect on the judges' juiciness scores, the percent fat content for each steak was adjusted to re- move the effect of variation in the raw samples. These ad- Justed percentages were then used to calculate a correlation coefficient between fat content and Juiciness scores. A significant correlation, however, was not present. .A slightly better correlation was obtained when the oven-cooking method was omitted from.the analysis, yet not statistically significant (Table 13). The moisture content of the steaks evidently had much more influence on the judges' Juiciness scores than the fat content. SUMMARY AND CONCLUSIONS Four meat cookery methods were compared using the adductor and vastus lateralis muscle of the beef round. The methods compared were two braising methods, a dry heat method called "oven-cooking", and deep-fat frying. The muscles were dissected from.the left and right rounds of six beef animals, graded U. S. Choice. Each muscle was cut into four l-inch steaks. The steaks were weighed, wrapped in moisture-vapor proof cellophane, frozen and stored until an hours prior to cooking. Steaks were cooked by all four cooking methods for each scoring period. A panel of five Judges scored the steaks for aroma, appearance, tenderness, Juiciness, flavor and general acceptability. The change in moisture and fat content with cooking, the pH of raw and cooked samples and the percent cooking losses were determined. Objective measurements were made of volume and surface area changes with cooking. The chief source of variation among the palatability scores was cooking method as shown by an analysis of variance made on each palatability factor. The variation in juiciness scores was assigned, however, to both cooking method and difference between muscles. The Judges preferred the oven- 85 cooked and deep-fat fried steaks over the braised steaks, as indicated by general acceptability scores. There was a significant difference in cooking losses as a result of cooking method. The steaks cooked by braise I had the highest percent total cooking loss and the oven-cooked steaks had the lowest. The average weight of drippings plus water was greater for braised II steaks than for braised I steaks. Results of objective tests were similar to the results of subjective scores. Correlations between shear force and tenderness scores and between juiciness scores and total moisture were highly significant. Volume and surface area changes followed the same general trend as cooking losses. Howeven,a significant difference found between muscles for surface area changes was not present for total.cooking losses and volume changes. Highly significant correlations were found between percent total cooking loss and volume change, percent total cooking loss and surface area change, and between volume change and surface area.change. The pH values for cooked meat indicated that cooking method had an effect on the degree of change in pH with cooking. This was particularly noted with the oven-cooking and deep-fat frying methods. The oven-cooked steaks tended to be more acid while the deep-fat fried steaks were generally more alkaline than the braised steaks. 86 An analysis of covariance on the fat data showed that there was a difference in the fat content of cooked samples due to cooking method. The deep-fat fried steaks showed quite a definite increase in fat content with cooking. On the basis of these findings it appears that: l. Oven-cooking and deep-fat frying resulted in more palatable steaks from.the adductor and vastus lateralis than the braising methods compared in this study. 2. Steaks braised to an internal temperature of 80° C. were juicier than steaks cooked to 99.50 C.plus 1/2 hour but were less palatable as far as aroma, appearance and ten- derness were concerned. 3. Oven-cooked steaks had the lowest total cooking losses and highest moisture content, while the braised I steaks had the highest total cooking losses and the lowest moisture content. _ h. Deep-fat fried steaks increased in fat content during cooking. 2. 3. 10. 11. 12. LIST OF REFERENCES Aldrich, P. J. and Lowe, B. Comparison of grades of beef rounds: Effect of cooking times on palatability and coat. JeAeDeAe 30:39-u30 195,40 Alexander, L. M. Report on the Cooking of meat. Proc. Am. Soc. Animal Prod. 21:117-118 l92 . . Shrinkage and heat penetration during the roasting of lamb and mutton as influenced by carcass grade, ripening period and cooking method. U. S. Dept. Agre TGChe Bu1e MO:23-250 193“». . Shrinkage of roast beef in relation to fat content and cooking temperature. J} Home Econ. 22:915-922. 1930. American Home Economics Association. Handbook of Food Preparation. Rev. ed. ‘Washington, D. C. l9h7. Andross, M. Effect of cooking on meat. Brit. J. Nutr. 3-k:396-u06. l9h9-SO. Barbella, N. G., Tanner, B. and Johnson, T. G. Relation- ships of flavor and juiciness of beef to fatness and other factors. Proc. Am. Soc. Animal Prod. 32:320-325. 1939. Bard, J. C. and Tischer, R. G. Objective measurement of changes in beef during heat processing. Food Tech.5: 296-300. 19510 Bate-Smith, E. C. Muscle and meat. Food Sci. Abstr. 23:209-210. 1951. . Observations on the pH and related properties of meat. J. Soc. Chem. Ind. 67:83-90. l9h8. Bendall, J. B. Effect of cooking on the creatine-creatinine, phosphorus, nitrogen and pH values of raw, lean beef. J. Soc. Chem. Ind. 65:226-230. l9h6. Bogue, R. H. Conditions affecting the hydrol sis of collagen to gelatin. Ind. Eng. Chem. 15:115 -1159. 1923. (1 Til-.In {I‘Jllu‘l ‘ ill '1 13. 15. 16. 17. 18. 19. 20. 21. 22. 23. 250 88 Brady, D. E. A study of the factors influencing tender- ness and texture of beef. Proc. Am. Soc. Animal Prod. Bratzler, L. J. Measuring the tenderness of meat by means of a mechanical shear. Unpublished M. S. thesis. University of Illinois. 1930. Callow, E. H. Brief review of the science of meat. Child, A. M. Effect of interior temperatures of beef muscle upon the press fluid and cooking losses. J. Agr. R88 0 51:655-6620 1935. and Baldelli, M. Press fluid from heated bee? muscle. J. Agr. Res. h8:1127-1l3h. 1936. Cline, J. A. and Dizmang, V. Methods of cooking less tender cuts of U. S. medium grade beef. Mo. Agr. Expt. Sta. Bul. 358:78-79. 1935. and Godfrey, R. S. A study of temperature and time of cooking on the quality and palatability of neat. Mo. Agr. Expt. Sta. Bul. 256:7h-7S. 1927. , Loughead, M. E. and Schwartz, B. C. Methods of cooking steaks from.different classes of beef animals. Mo. Agr. Expt. Sta. Bull. 310:39. 1932. , Trowbridge, E. A., Foster, M. T. and Fry, H. E. How certain methods of cooking affect the quality and palatability of beef. Mo. Agr. Exp. Sta. B111. 293:“,0 pp. 1930. Cover, Sylvia. Effect of extremely low rates of heat penetration on tendering of beef. Food Res. 8:388-39h. l9k3. . The effect of time and temperature of cooking on the tenderness of roasts. Texas Agr. Expt. Sta. Bul. su2:s—33. 1937. Crocker, E. C. Flavor of meat. (Editorial) Food Res. 13:179-183. 19MB. Day, J. C. Longissimus dorsi of three grades of beef: Comparison of cooking weight losses, palatability and edible portion. Unpublished Master's thesis. Michigan State College. 1953. 26. 27. 28. 29. 30. 31. 31;. 35. 36. 37. 38. 89 Dean, J. B. The effect of cooking on the tenderness of meat. I. A comparison of two cooking temperatures on paired tough cuts cooked by moist heat in the oven. Unpublished Master's thesis. Iowa State College. 1933. Deatherage, F. E. and Garnatz, G. A comparative study d? tenderness determination by sensory panel and shear strength measurements. Food Tech. 6: 260- 262. 1952. and Harsham, A. Relation of tenderness of beef to aging time at 330 - 35° F. Food Res. 12: l6h-l71. 19u7. Empey, W. A. Studies on the refrigeration of meat. Conditions determining the amount of drip from frozen and thawed muscle. J. Soc. Chem. Ind. 52:230T. 1933. Gaddis, A. M., Hankins, A. G. and Hiner, R. L. Relation- ships between the amount of composition of press fluid, alatability and other factors of meat. Food Tech. A: E98-503. 1950. Grindley, H. S. and Emmett, A. M. Studies on the influence of cooking upon the nutritive value of meats. U. S. and McCormack, P. Losses in cooking meat. U. S. Dept. Agr. Expt. Ste. Bul. 102: 1901. and Mojonnier, M. 8. Experiments on losses in cooking meat. U. S. Dept. Agr. EXpt. Sta. Bul. 1A1: 190k. Griswold, R. M. and Wharton, M. A. Effect of storage conditions on palatability of beef. FOOd Res. 6: 517-527- 19h1- Hammond, J. Some factors affecting the quality and composition of meat. Chem. and Ind. 18:521-525. 19h0. Hankins, O. G. and Hiner, Lo L. Freezing makes beef tenderer. Food Ind. 12:u9-51. 19h8. Harrison, D. L., Lowe, b., McClurg, B. and Shearer, P. 3. Physical, organoleptic and histological changes in thiee grades of beef during aging. Food Tech. 3: 28h-288. 19 9. Hayes, M. C. A study of the relation of U. S. grades of beef to the palatability of porterhouse steaks. Unpublished Master's thesis. University of Missouri. 1939. 39. no. Ml. ’42 e #3. h5. h6. #7. L18. M9. 50. 9O Howe, P. E. and Barbella, N. G. The flavor of meat and meat products. Food Res. 2:197-202. 1937. Husaini, S. A., Deatherage, F. B., Kunkle, L. E. and Drauit, H. N. Studies on meat. I. The biochemistry of beef as related to tenderness. Food Tech. h:3l3- 316. 1950. Latzke, Esther. Standardizing methods of roasting beef in experimental cookery. No. Dak. Agri. Expt. Sta. Bul. 2h2z2-18. 1930. Lowe, B. Mechanical measurement of the tenderness of raw and cooked meat. Unpublished Master's thesis. Uni- versity of Chicago. l93h. . Experimental Cooker . Second Edition, New fiYork, John Wiley and Sons. 19 3. , Crain, E., Amick, G., Riedesel, M., Peet, L. J., Smith, F. B., McClurg, B. R. and Shearer, P. S. Defrosting and cooking frozen meat. Agr. Expt. Sta. Iowa State College Res. Bul. 385: 1952. Mackintosh, D. L., Hall, J., Lowe, B., and Vail, G. E. Some observations pertaining to the tenderness of meat. Proc. Am. Soc. Antmal Prod. 29:285-289. McCance, R. H. and Shipp, H. L. The chemistry of flesh foods and their losses on cooking. Spec. Rpt. Series No. 187. Medical Research Council, London. McLachlan, Helen. Standardizing methods of broiling beef steaks and methods of cooking pork chops. Unpub- lished Master's thesis. University of Missouri. 1937. Morgan, A. F. and Nelson, M. P. Study of certain factors affecting shrinkage and speed in the roasting of meat. J. Home Econ. 20: 371-378; hhh-th. 1926. Noble, I. T., Halliday, E. G. and Klaas, H. K. Studies on the tenderness and juiciness of cooked meat. J. Home Econ. 26:238-2h2. 193k. Orr, K. J. Effect of cold storage and frozen storage on the palatability and histological appearance of the longissimus dorsi of beef. Unpublished Master's thesis. Michigan State College. l9h9. 55. 56. S7. '58. 59. 60. 61. 62. 63. 91 Paul, P., Bratzler, L. J., Farwell, E. D., and Knight, K. Studies on the tenderness of beef. 1. Rate of heat penetration. Food Res. 17:50h-510. 1952. and Child, A. M. Effect of freezing and thawing muscle upon press fluid, losses and tenderness. Food Res. 2:339-3u5. 1937. and McLean, B. B. Studies on veal. I. Effect of different internal temperature on veal roasts from caizes of three different weights. Fbod Res. 11:107-115. 19 . _1_. Studies on veal. II. Vari- ations between some muscles of the hind quarter. Food Res. 11:116-120. 19h6. A Ramsbottom, J. M. and Strandine, E. J. Comparative tenderness and identification of muscles in wholesale beef cuts. Food Res. 13:315-328. 19u8. . Initial physical and chemical changes in beef as related to tenderness. Proc. Am. Soc. Animal Prod. J. Animal Sci. 7:(abstract) 519. 19h8. __L and Koonz, C. H. Comparative tenderness of representative beef muscles. Food Res. 10:h97-509. 19h5. Satorius, M. J. and Child, A. M. Effect of coagulation on press fluid, shear force, muscle cell diameter and composition of beef muscle. Food Res. 3:619-626. 1938. . Effect of cut, grade and class upon palatability and composition of beef roasts. Minn. Agr. Expt. Sta. Tech. Bul. 131: 1938. Seimers, L. and Hanning, F. A study of certain factors influencing the juiciness of meat. Food Res. 18:113-130. 1953. Snedamny G. W. Statistical methods. th ed. Iowa State College Press., Ames, Iowa. 19 O. Strandine, E. J., Koonz, C. H. and Ramsbottom, J. M. A study of variations in muscles of beef and chicken. J. Animal Sci. 8:h83-h9h. 19h9. Tanner, B., Clark, N. G. and Hankins, A. G. Mechanical determdnation of juiciness of meat. J. Agr. Res. 66: 11.03-1112 0 1911.3 0 611s 65. 66. 67. 68. 92 Thille, M., Williamson, L. J. and Morgan, A. F. The effect of fat on the shrinkage and speed in the roasting of beef. J. Home Econ. 2h:720-732. 1932. Tucker, R. B., Hinman, W. F. and Halliday, E. G. The retention of thiamine and riboflavin in beef cuts durin braising, frying and broiling. J. A.D.A. 22: 877-8 10 1914.60 Wanderstock, J. J. and Miller, J. I. Quality and palatability of beef as affected by method of feeding and carcass grade. Food Res. 13:291-303. 19h8. Wilmeth, M. C. The effect of braising and pressure saucepan cookery on the cooking losses, palatability and nuhfltive value of the proteins of round steak. Unpub- lished Ph. D. thesis, Kansas State College. 1953. Winkler, C. A. Tenderness of meat. I. A recording apparatus for its estimation and relation between pH and tenderness. Can. J. Res. 17D:8-1h. 1939. APPENDIX 93 911 I I||I||I'IL «ozone Ho nonfifiz «xsopm mo nopesz noon soon ooow doom ecoamsaosoo hacsoapum knob noom hash uses: Shapes mafia ooow hao> hHeanme Huaeaow noon aoom doom doom new haosoapxm hue> noom hash mesa: .esHoez spam voow haob hHoSeApKW no ao>mam haw has headw hoafiw haosoapwm. h9c> soom sash «and: .ssacoz mafia coca haeb hHeanaKm umenfioash nwdop nwdop noose» pence» haefieapxm hac> noom sash used: Beads: asam poow hao> haoaoapwm mmocaopcoe soon noon poem coom seen no mHoanawm hae> noom hash mend: .ESdco: exam doom hae> hHeEoAme hoesdm noon hoom ooow poem haofioapnm hao> aoom hash mend: saape: usam doom hao> haeEeAme censuseaad noon noom coom doom haeaonpwm hao> aoom sash mend: agave: usHm doom hao> hHoEeapwm ceded H m m d m o N. o o S moeoé madam mom Em macaw in. am? % TABLE 25 AVERAGE DAILY SCORES FOR APPEARANCE ‘— V1 .4— Muscle Braise I Braise II Oven-Cooking Deep-Fat Adductor I 6.6 . 6.u 6.8 8.0 II 6.8 5.0 7.2 7.8 III 5.8 6.2 7.6 8.0 IV 5.8 5.8 8.2 8.2 V 6.0 h.8 8.2 7.8 WI 5.8 h.8 8.2 8.0 {233311. I 5.6 5.2 7.8 8.1. II 5.8 5.0 7.3 8.8 III 6.6 h.8 7.6 7.8 IV 6.h h.8 8.8 8.8 V 5.8 5.h 7.h 8.2 V1 5.3 5.5 8.8 7.8 TABLE 26 AVERAGE DAILY SCORES FOR AROMA 96 T T Muscle Braise I Braise II Oven-Cooking Deep-fat Adductor I 7.6 6.2 5.0 7.6 . II 7.0 6.h 6.6 7.h III 7.0 6.6 7.6 7.2 IV 8.0 7.0 7.2 8.0 V 7.h 5.h 8.0 6.8 VI 7.2 6.h 6.8 7.6 {:gzgzlis I 7.2 7.0 6.0 6.6 II 7.3 5.5 7.3 7.5 III 8.0 5.0 7.2 6.8 IV 7.11 5.8 6.8 7.2 V 7.2 6.0 6.0 7.8 VI 7.5 7.0 7.5 7.3 TABLE 27 AVERAGE DAILY SCORES FOR FLAVOR 97 Muscle Braise I Braise II Oven-cooking .Deep-fat Adductor I 6.8 6.8 7.2 6.8 II 5.8 5.0 6.6 6.h III 5.8 5.2 8.2 7.2 IV 6.0 6.0 6.8 8.k V 5.0 6.2 7st 6.8 V1 5.6 6.2 7.6 7.2 3223211. I 5.6 5.8 7.6 6.6 II 5.3 5.5 8.0 8.3 III 6.0 6.2 8.h 7.6 IV 6.2 5.2 7.h 7.0 V h.6 5.8 7.0 7.8 VI 6.3 5.0 6.8 6.5 98 TABLE 28 AVERAGE BAIL! SCORES FOR TENDERNESS Muscle Braise I Braise II Oven-cooking Deep-Fat Adductor I 5.0 6.h 8.2 6.0 II 7.6 3.6 6.8 . 7.h III 5.h h.6 8.6 7.8 IV 7.6 5.h 7.0 8.2 V 5.2 6.2 7.0 8.0 VI 6.6 6.6 7.8 6.8 {33:13:11. I 6.0 11.6 6.8 6.1; II 7.0 5.0 7.8 7.8 III 6.6 7.0 7.8 7.0 IV 7.2 6.0 7.0 7.0 v 6.8 11.8 6.0 5.6 v1 ‘ 6.0 5.8 7.3 6.3 99 TABLE 29 AVERAGE DAILY SCORES FOR JUICINESS _ __: Muscle Braise I Braise II Oven-cooking Deep-fat Adductor I 3.0 5.2 8.6 6.6 II 2.8 3.8 7.2 7.2 III 2.6 3.8 8.h 7.0 IV 3.6 h.8 8.h 7.6 V 2.8 5.0 7.2 8.0 VI 3.2 5.2 8.6 7.2 3333211. I 3.1 11.6 7.6 8.!1 II 3.8 5.3 8.5 8.3 III 3.6 6.0 8.2 7.8 IV k.2 h.h 9.0 7.k v 3.0 5.8 8.6 7.0 VI 3.5 14-03 803 7.8 100 TABLE 30 AVERAGE DAILY SCORES FOR GENERAL ACCEPTABILITY Muscle Braise I Braise II Oven-cooking Deep-fat Adductor I 5.8 6.8 7.0 6.6 II 5.8 u.6 6.2 6.2 III 5.2 5.2 8.0 7.2 IV 5.8 5.h 7.h 8.2 v 8.6 5.0 7.0 7.2 VI 5.8 5.h 7.h 7.0 {28332113 I 5.8 8.8 6.8 6.h II 5.3 5.5 7.5 8.0 2111 5.8 5.6 7.6 7.8 IV 6.2 5.0 7.0 6.h V 5.0 5.0 6.6 7.2 VI 5.8 5.3 7.0 7.0 TABLE 31 PERCENTAGE TOTAI.COOKING LOSSES 101 T Braise I Braise II Oven-cooking Deep-fat Adductor I h5.29 35.56 18.36 3h.8h II 83.59 35.63 27.66 29.80 III hh-lh 35.68 2h.15 33.86 IV hh.h1 32.h7 2h.05 32.33 V h7.3h 36.26 29.19 25.89 VI h3.80 3h.91 18.11 31.9h Vastus ‘ Lateralis I h3.79 33.33 20.h7 29.97 11 h6.90 30.82 2n.08 27.98 III hh.98 28.71 25.51 3u.02 IV h5.0h 38.52 25.20 39.88 V h6.h8 35.nu 21.87 36.11 VI uu.67 37.57 23.13 35.81 4.4 . ‘1‘..- 102 TABLE 32 PERCENTAGE DECREASE IN SURFACE AREA WITH COOKING Braise I Braise II Oven-cooking Deep-fat 32.22 3.39 Adductor I 29.85 19.18 II 26.6M 31.35 23.91 23.85 III h3.77 25.71 21.h1 30.29 IV 36.78 36.67 1h.25 20.88 v 38.33 28.88 27.96 21.07 v1 ' '3u.su 31.99 20.00 29.68 Vastus ’ Lateralis I 29.79 20.39 lh.38 15.6h II 38.92 16.58 9.39 28.32 III 17.59 16.67 8.M6 17.30 IV 16.86 19.18 11.0h 17.01 V 29.06 17.91 15.03 30.98 VI 33.33 10.78 3.70 32.6k I 103 TABLE 33 SHEAR FORCE VALUES FOR COOKED STEAKS IN POUNDS ‘— Braise I Braise II Oven-cooking Deep-fat 10.20 Adductor I 6.5h 5.29 8.67 II 5.05 10.18 9.50 7.32 III 10.96 10.95 7.08 8.39 IV 6.33 11.93 9.11 8.82 V 9.11 7.25 9.21 7.6M VI 9.96 9.66 7.89 7.29 {88832118 I 9.82 13.07 9.11 11.07 II 7.h2 10.0h 8.33 10.50 III 7.25 9.6a 10.08 10.83 IV 6.89 9.83 8.00 9.08 v 6.36 9.83 9.32 9.68 VI 12.08 10.93 9.86 11.86 1.4.7:. Jam-nae. 27-10-2- ~_M|__11 753T“? 10h TABLE 38 PERCENTAGE DECREASE IN MOISTURE WITH COOKING Braise I Braise II Oven-cooking Deep-fat Adductor I 25.58 19.96 6.k1 20.77 II 25.12 7.95 10.08 5.67 III 21.39 18.79 10.33 16.78 Iv 19.67 12.57 7.08 15.13 v 22.66 16.27 12.78 9.31 v1 21.30 17.55 7.92 12.20 {;::::118 I 22.03 13.03 5.35 12.63 II 28.33 15.61 10.27 11.hl III 25.32 18.29 15.20 17.12 IV 21.90 11.80 7.00 21.62 V 23.80 18.u7 8.39 17.35 VI 25.78 13.85 10.05 15.77 :p-‘("' I ' guru's at” ||H|l||fljl||1|||2|lfl|||||iIIHUILIHIIIIHI MINI: 3037 18