'-'vvvuw— ‘3‘ v' -. c- ”Hm m N m .658 mxmq nmmm mm mOH mos cam N coflumafluam> “Hm m m e .654 muflo mmum>mue 2m m coflumaflucm> Hfifi m m mm hash coumcfipsq om m coflumaflucm> Ham m m ma mash umHH>umum3 34 l.musc l.muec i.muac weds mGOHuwccoo «enmq *Hm3ouw Aahmav Acmmaaoazv . m... H. on log mo>umm U a o cowumuuommcmua mafia xmom u .mmfluuwso mo mafiaccms.umm>umalumom .H manna LOT : LOT: LOT: LOT: Figure 1. Processing scheme for various lots of cherries. 14 ‘-—PITTED —|-—— AW -—UNPITTED-—— F—PITTED-—-l—— EO -——UNPITTED ——PITTED—- PM——————‘ ‘—UNPITTED—' ‘-—-PITTED—— RB—‘fi ——UNPITTED-——- AIR FROZEN AIR FROZEN R-12 IMMERSION AIR FROZEN R-12 IMMERSION AIR FROZEN R-12 IMMERSION ‘____T 15 Air-Freezing Certain subdivided lots were transferred directly from the sorting belt onto solid stainless steel trays (30" length; 20" width; 2" depth). Each tray, holding approximately 10 lbs. of unpitted cherries in a single layer, was placed in a -10°F Chrysler-Koppin freezer. Other subdivided lots were transferred to a laboratory scale Dunkley Cherry Pitter (Dunkley Co., Kalamazoo, Michigan), pitted and collected in a single layer on perforated stainless steel trays (28" length; 18" width; 2" depth). Trays of pitted cherries were frozen in the same -10°F Chrysler-Koppin freezer as unpitted cherries. They were kept in the freezer for approximately 5 hours. To moniter freezing rate, thermocouples (copper, 0.18" diam.; constantan, 0.19" diam.) were inserted into a few pitted and unpitted cherries and attached to a Texas Instruments Inc. Multi/Riter Recorder. Freezing rate was determined by a modification of the method proposed by Fennema and Powrie (1964) for "time to traverse a speci- fied temperature range." A temperature range from 30 to 10°F was chosen because it could easily be measured during slow freezing in relatively short time. Measured freezing rates were as follows: 16 Lo: Condition No. Cherries* FreQZIfiggRate AW Unpitted 3 145 min. AW Pitted 3 97 min. E0 Unpitted 3 177 min. E0 Pitted 3 90 min. RB (not recorded) PM (not recorded) *one thermocouple inserted per cherry. R-12 Freezing ("Freon"-Freezing) Unpitted cherries were collected directly from the sorting belt in 3 1b. quantities in the "freezer basket" of a Du Pont Laboratory Scale "Freon" Food Freezant System (Skwara, 1970). The basket of cherries was immersed in "Freon" 12 (Food Grade Dichlorodifluoro— methane) at -25 to -35°F for 20 seconds, withdrawn and held in air at ambient temperature for 20 seconds, then reimmersed in “Freon" for 20 seconds. This procedure prevented excessive (50% or greater) cracking, observed when longer immersion times or lower "Freon" temperatures were used. The Du Pont Laboratory Scale "Freon" Food Freezant System, as described by Skwara (1970), consists of an insulated drum (31“ height; 23" diam.) with two internal chambers. "Freon" ll (Trichloromonofluoro- methane) along with dry ice are placed in the outermost chamber and "Freon" 12 in the innermost chamber. Dry ice l7 immersed in "Freon" ll maintains a temperature of approxi- mately -100°F and acts as refrigerant for "Freon" 12. After a period of contact with the "Freon" 11, dry ice mixture, "Freon" 12 also reaches -100°F. By immersing a 30 lb. capacity tin can, holding hot water, directly into the innermost chamber, temperature of "Freon" 12 could be raised to the desired temperature range of -25 to -35°F. Cherries pitted in the Dunkley Cherry Pitter were also collected in 3 to 3 1/2 lb. quantities in the Du Pont "freezer basket" and immersed in "Freon" 12 as described for unpitted cherries. Accurate freezing rate determinations were not made. Thermocouples were inserted in a few cherries and flesh temperature recorded during immersion in “Freon" on the Multi/Riter recorder. Data obtained indicated that both pitted and unpitted cherries were frozen to 0°F within the 40 second immersion period. However, due to movement of the freezer basket and motion of cherries upon immersion, the thermocouple tips could have moved out of position, introducing possible errors in recorded temperatures. II. Storage of Pitted and Unpitted Frozen Cherries Pitted and unpitted cherries, frozen in air at -10°F and by immersion in "Freon," were placed in 18 polyethylene bags (16" X 25", W. R. Grace Co., N. Y.) which were placed inside 30 1b. capacity tin cans. Approxi- mately 20 lbs. of cherries were stored in each bag and the bags sealed with rubber bands. A study of temperature fluctuations in the -10°F freezer was conducted by placing thermocouples (copper, 0.18" diaml; constantan, 0.19" diam.) at various locations from floor to ceiling, front to rear, of the freezer. Temperature was monitered for a one hour period while the freezer door was opened, held briefly, and closed at 15 minute intervals. Freezer temperature warmed up as much as 8°F in areas nearest the door, but quickly returned to -10°F. Freezer temperature was recorded, using a mercury thermometer (Taylor Co.), for 3 weeks and found to fluc- tuate from -10 to -8°F occasionally. This study indicated that fluctuating storage temperature would not be a prob- lem to consider in further studies. III. General Thawing Procedure Preliminary tests were run to develop a general thawing procedure and to decide upon variables to consider in processing unpitted frozen cherries (Appendix Tests 1 through 9). Unpitted air- and "Freon"-frozen cherries, stored for at least a month, were removed from -10°F storage, weighed on an Exact Weight (35 kilogram capacity) l9 Shadowgraph Balance and placed in 1/4" mesh wire "thawing baskets" (6 1/4" diameter; 4" height). Specific quanti- ties weighed are given for each study in section IV below. Cherries were immersed in one of two thawing solutions (see "Preparation of Thawing Solutions" below). The solu- tions were held in a Constant Temperature Laboratory Bath (Cat. no. 4-8600 by American Instrument Co., Inc.) equipped with a "Quickset" Bimetal Thermoregulator (Cat. no. 4-235F by American Instrument Co., Inc.). A mercury thermometer, calibrated by immersion in ice water slurry, was used to set the thermoregulator for desired thawing temperatures of 20, 25, 30, 35 and 40°F (specific tempera— tures used for each study are given in section IV below). Immersion time of cherries in thawing solution, in all studies, was based upon time necessary for frozen cherries to reach thawing solution temperature plus 10 minutes (Appendix Test 6 and Table 35). Results of Appendix Test 9 (Table 37) showed that thawing solution temperature corrections were necessary when thawing quantities of frozen cherries were in excess of 2700 grams at 40°F. Preparation of Thawing Solutions Thawing solution I (Aqueous Ethylene Glycol) Antifreeze obtained from the Michigan State University Motor Pool, containing 96% ethylene glycol, 20 was mixed with water in the following proportions (calcu- lated using Pearson Square Method as given by Sommer, 1949): To: Prepare 16 gallons of 40% (by wt.) Aqueous Ethylene Glycol Thawing Solution Add: 81.6 lbs. water to 58.4 lbs. "Antifreeze" (containing 96% ethylene glycol) Calculations: Specific gravity of 40% (by wt.) E.G. according to Lange (1946) is = 1.053 (at 59°F): 1 gal. water = 8.34 lbs. 0% 56 (15)(3.34)(1.053) = 140 (lbs.) 40% 56 — ‘ ‘ §E¢ZU'X 140 - 81.6 (lbs. water) 95% 40 140 - 81.6 = 58.4 (lbs. "Anti- freeze") Thawing solution II (Aqueous Propylene Glycol) Dowfrost Inhibited Propylene Glycol (Dow Chemical Co.) was mixed with water in the following proportions (calculated using Pearson Square Method as given by Sommer, 1949): To: Prepare 16 gallons of 20% (by wt.) Aqueous Propylene Glycol Thawing Solution Add: 108.9 lbs. water to 27.1 lbs. "Dowfrost" Calculations: Specific Gravity of 20% (by wt.) P.G. (Dow Chemical Co., 1965) is = 1.020 (at 40°F); 1 gal. water = 8.34 lbs. 0% 80 (l6)(8.34)(1.020) = 8.34 lbs. 80 _ 20% 1 80:25 x 136 — 108.9 (lbs. water) 100%- -20 136 - 108.9 = 27.1 (lbs. Dow- frost") 21 Thawing solution concentration was checked through- out processing operations by measuring density of the solu- tion with a hydrometer (Fisher brand 8023) and comparing it to desired density for the percentage of solution used (Lange, 1946 or Dow Chemical Co., 1965). IV. Studies Related to Freezing and ThaWing Unpitted Cherries A. ‘Effects of Freezing Method, Thawing Tem erature—and Immersion Time on % Wei ht Loss During and After Pitting A.l Freezing Method and thawing Temperature To study the effect of thawing solution tempera- ture on % weight loss, 200 gram samples from air- and "Freon"-frozen unpitted lots (3 replicates of each) were placed in 1/4" mesh wire "thawing baskets" (section III) and immersed in thawing solution I at temperatures of 20, 25, 30 and 40°F. Immersion time of each sample, based on results of Appendix Test 6 (Table 35), was as follows: .m 22 Thaw Immersion Thaw Immersion Lot Temp. Time Lot Temp. Time (°F) (min.) (°F) (min.) AW 20 22 PM 20 29 AW 25 38 PM 25 40 AW 30 19 PM 30 21 AW 40 14 PM 40 18 E0 20 25 RB 20 24 E0 25 35 RB 25 33 E0 30 19 RB 30 20 E0 40 14 RB 40 17 Samples were removed from thawing solution, held over thawing bath for 10 seconds to allow excess solution to drain, then immediately pitted in the Dunkley Cherry Pitter. Pitted samples were collected on 1/4" mesh wire "drained weight" screens (10" length; 7" width; 1 1/4" depth) and weighed 2 minutes after pitting and at 10 minute intervals thereafter for 1 hour. Pits were col— lected in a basket attached to the cherry pitter, dried at ambient temperatures for 6 to 8 hours and weighed. Percentage pit loss was calculated by dividing weight of dried pits by weight of frozen cherries prior to thawing. Percentage weight loss, calculated as juice and flesh loss, during pitting was determined using equation 1: Equation 1. (Frozen Wt. Sample - Pit Wt.)-2 min. Dr. Wt. (Frozen Wt. Sample — Pit Wt.)’ X 100 %Wt. Loss = 23 Percentage weight loss after pitting, calculated as juice loss, was determined by substituting for 2 min. drained weight in equation 1, the drained weight measured at 10 min. intervals after pitting. Relationships between temperature used to thaw unpitted air- and "Freon"-frozen lots and % weight loss during pitting and 62 minutes afterwards, were evaluated by calculating correlation coefficients (r) and linear regression equations with standard errors of estimate (Se) and regression coeffi- cients (Sb). These calculations were also used to show the relationship between thawing temperature and pitting efficiency, as measured by number of pits remaining per pound of cherries pitted. Calculations were made using a Wang calculator (Wang Laboratories, Inc., Tewksbury, Mass.) with a Wang series program for linear regression analysis (Wang 520/600 Series Program Description). It was noted that the equation used for linear regression by Wang does not account for "degrees of freedom" (as described by Sokal and Rohlf, 1969; p. 54) due to regression of one variable upon another or for "degrees of freedom" customarily used to compute variance or standard deviation (Sokal and Rohlf, 1969). Since the statistics used in this study were intended as estimates of population parameters, incorporation of "degrees of freedom" into calculation of standard errors was accomplished using the following correction equation: 24 _____“N Se = SY.X fN—T—Z— where: Se = Corrected standard error of estimate. Sy.x = Wang's standard error of estimate. N = Number of observations. A-2. Freezing method and immersion time To study the effect of immersion time, at constant thawing solution temperature, on % weight loss during and after pitting, 200 gram samples from unpitted air- and "Freon"-frozen lots (3 replicates of each lot) were im- mersed, individually, in thawing solution I for the time it took samples to reach bath temperature (Table 35) plus 5, 10, 30, and 90 minutes. Samples were removed from thawing solution, pitted and drained weights recorded as in study A-l. Correlation and regression analysis was made, as in study A-l, to determine the relationship be- tween immersion time and % weight loss during pitting and at 10 minute intervals for 62 minutes afterwards. B. Effects of Freezing Method and Thawing Temperature on % WEight_Loss and Textural_guality of Cherries Processed as Canned' Pie Filling Samples from lots of unpitted air- and "Freon"- frozen cherries were removed from -10°F Chrysler-Koppin 25 freezer after approximately 5 months of storage, weighed into 3000 to 4400 gram quantities, placed in specially designed 1/4" mesh wire baskets (18 1/2" length; 13 1/4" width; 3" depth) and immersed in thawing solution II at 20, 30, 35 and 40°F. Temperature corrections of 5°F were made when thawing at 35 or 40°F according to results ob— tained in Appendix Test 9 and Table 37 (i.e., for desired internal cherry temperature of 40°F, when using greater than 2500 gram quantities, thawing solution temperature was set at 45°F). The following immersion times were used, based upon average time for lots to reach thawing solution temperature plus 10 minutes: Thawing Solution Temperature Immersion Time (°F) (Minutes) 20 15 30 36 35 25 40 25 Samples were removed from thawing solution and washed by immersing in a tub (24" length; 14 1/2" height; 10" depth) of water at 55°F for a total of 3 seconds (quick in-out immersion, repeated twice). Samples were pitted, collected on 1/4" mesh wire "drained weight" screens and divided into 12 or 13, 256 gram quantities, which were immediately filled (within 3 minutes) into No. 303 x 406 Cherry Enamel Lined cans along with 256 26 grams of prepared slurry (described below). Pits were collected in a wire basket, dried for 6—8 hours (Sec. IV A) and weighed. Juice was collected in pans placed under 1/4" mesh wire "drained weight" screens and weighed. Procedure used for filling cans was suggested by Bedford (1972 - Personal Communication) as that used by Weil, gt_§l., (1970) in which approximately 1/4 of the 256 grams of cherries were added to 1/4 of the 256 grams of slurry. This was repeated until each can contained 256 grams of cherries plus slurry. Immediately after filling, cans were placed in a basket and immersed in boiling water in a steam jacketed kettle until can center temperature reached 140°F. Immediately, cans were sealed using a Canco 00—6 Vac Closing Machine and immersed in vigorously boiling water for 25 minutes. Can center temperature reached 190°F as measured by inserting a thermocouple through a small hole punched in can after processing. Vigorously boiling water was maintained in a FMC Pilot Plant Retort (Food Machinery Corp., no model number given) by injecting steam into the retort, half-filled with water. Cans were cooled by immersion in continuously running tap water at 55°F for 15 minutes (pilot plant sink) and stored at 70 to 75°F on bench top in Room No. 130 of Food Science Building. 27 Preparation of canned pie filling slurry Formula.-- Contents of the slurry used were sup— plied by Michigan Fruit Canners, Benton Harbor, Michigan, and consisted of modified food starch, salt, citric acid and artificial color. Exact proportions and further de- scription of these contents were not provided. According to instructions given by Michigan Fruit Canners, 1 1b. of dry content (starch, salt, citric acid) was mixed with 5.7 lbs. of sugar to make 6.7 lbs. of dry mix; 1 1b. of dry mix was mixed with 1.2 lbs. of water to make the slurry. This formula did not give best slurry results, per- haps due to excessive evaporation of water when prepared as described below. Modifications of the above formula were made to allow for 3 ounces of evaporation during preparation of heated slurry. The following formula was used in processing canned pie filling: 5.06 oz. Dry Mix (Starch, sugar, salt, citric acid) + 7.62 oz. Water 12.68 oz. Prepared Slurry7Can of PieFilling Preparation.--Slurry was prepared in 54 oz. batches in a Mirro (8" X 4") sauce pan over an open flame Criswald 201 burner. Water was added to sause pan, heated to ap- proximately 120°F before dry mix was slowly added. As slurry thickened (170 to 180°F), slight clumping occurred, 28 then disappeared, and a smooth consistency resulted. Color changed from light Pink to red. Optimum conditions were reached when slurry just barely ran off of wooden mixing spoon. Slurry was cooled slightly before mixing with cherries. Evaluation of canned cherry pie filling Sensornganel Procedures.—-Textura1 quality of cherries for canned pie filling was evaluated using a sensory panel composed of 20 to 22 students and faculty from the Department of Food Science and Human Nutrition. Preliminary screening of panel members was accom- plished by presenting panelists with samples of known textural differences. Screening was conducted according to "Triangle Test" procedures suggested by Amerine, gt__al_. , (1968) . The following coding and replication procedure was used: Sample Code-Letter: - Description of Sample A Lot AW; Pitted prior to air freezing; processed without thawing B Lot AW; Unpitted prior to air freezing; thawed in air at 70°F for 1 hour prior to processing .Arrangement: AAB; ABA; BAA; BBA; BAB; ABB Order of Presentation 2 3 4 1 6 5 Coding: Each letter was given a two digit number chosen 29 at random from "Statistical Tables" (Rohlf and Sokal, 1969). Serving: 3 plastic cups (Edward Don and Co.) of samples on paper plate per test serving, 5 cherries per cup. The panel received the same samples, in various arrangements, at 6 times (2 times per day for 3 days). Statistical results were obtained using Table E (Signifi- cance in Triangle Tests — Appendix, p. 256, Amerine, gE_§l., 1968). Very few panelists were able to make the minimum correct judgments (5 out of 6). Therefore, panel- ists making 4 out of 6 correct judgments were asked to serve on further panels. Kramer shear press measurements (described below) were run on same samples used to screen panelists and re- sults were analyzed by the “t" test (Sokal and Rohlf, 1968). Evaluation of all experimental lots.—~Samp1es for evaluation were taken directly from a can of pie filling. Five cherries from each sample were placed in one of four or five plastic 1 oz. cups (Edward Don Co.) on a plate. Each plate represented a test comparison (described below) and two tests were run per panel session. Panelists were presented a plate of samples and asked to score each sample for firmness on a 9 point scale with the following descriptions: 30 Description Score Extremely Firm Very Firm Moderately Firm Slightly Firm Neither Firm nor Soft Slightly Soft Moderately Soft Very Soft Extremely Soft l—‘NWhU‘lQOkD A test comparison consisted of 4 or 5 experi- mental samples, frozen and thawed by procedures described in Section IV A. The first test comparison was four samples of unpitted air-frozen cherries, thawed at 20, 30, 35 and 40°F. Scoring results were statistically analyzed by analysis of variance (Kramer and Twigg, 1966; LeClerg, 1957) for differences between mean scores. Sam- ples showing significant differences were identified using Duncan's Multiple Range Test (LeClerg, 1957). These statistical procedures were used to evaluate results of all test comparisons described below. The sample found firmest in the first test com- parison presented to the panel a second time, along with a sample found significantly different from the "firmest" sample, plus a "control" sample (cherries from same lot pitted prior to freezing and not thawed prior to process- ing). If no significant differences were found in the 31 first test comparison; samples for the second test were chosen according to greatest difference in mean score. A third test comparison was run by presenting the panelists with four samples of unpitted "Freon"- frozen cherries thawed at 20, 30, 35 and 40°F and then pitted. The two samples showing the greatest statisti— cally significant difference were presented a second time, along with a control sample (fourth test comparison). Finally, "firmest" samples from first and third test comparisons were presented to panelists, along with con— trol samples from second and fourth test comparisons. Samples were also evaluated using a ranking test (Amerine, 1968) and Kramer's statistical method for difference between rank sums (Kramer, 1963). Panelists were asked to rank the samples according to firmness by assigning a rank of 1 to firmest sample. They were also asked to indicate the sample "most" preferred. Objective procedures The Allo-Kramer Shear Press with a Food Techno- logy Corporation Recorder was used for measuring firmness of processed cherries. A standard cell box was filled 3/4 full with 125 grams of cherries. Cherries were indi- vidually examined for pits by probing flesh with a dissecting needle. Cherries found to contain pits were excluded from the 125 gr. sample. Maximum peaks were m r”! 32 measured at range setting of 5 during a 30 second down— stroke by standard blades against a 3000 lb. ring. Peak values were converted to Lbs. Force/125 Grams Product by the following equation: Rangiogettlng X Maximum Peak = Lbs. Force/125 Grams Prod. Additional tests were made using the Instron Uni- versal Testing Instrument (Model TTBM, Instron Corp.) with CCM compression cell (see Appendix Test 13 and Table 42). Measurement of % weight loss Per cent weight loss was determined from drained weight measurements, using the following procedure de- scribed by Bedford (1971 - Personal communication): 1. Empty contents of can "over the surface of a tared 8 or 12 inch U.S. No. 8 sieve stacked on a U.S. No. 20 sieve. 2. Wash cherries and fragments free from slurry with water under pressure obtained from a "40-inch head water spray at 70 to 75°F for 45 seconds. The water is delivered through 1/2 inch I.D. tubing and a 3/4 inch diameter shower head with 26 to 30, 0.035 - 0.040 inch diameter holes." 3. Remove U.S. No. 8 sieve, place in an inclined position (15 to 30° slope) and drain the cherry contents 33 for 2 minutes. Wipe off excess moisture on sidewalls of drained weight screen. The sieve and contents were weighed on a 10 kilo- gram capacity Exact Weight Shadowgraph Scale to the near- est gram. Percent weight loss (joice loss) was calculated using the equation: Equation 2 % Weight Loss = Put-In Wt. of Cherries - 2 Min. Dr. Wt. *fiht-fh Wt. of Oherries X 100 Statistical analysis of the drained weight data consisted of an analysis of variance (Kramer and Twigg, 1966; LeClerg, 1957) for significant difference between mean scores; Duncan's Multiple Range Test (LeClerg, 1957) to identify the significantly different mean scores; and linear regression analysis and correlation to show rela- tionship between % weight loss during processing and thawing temperature for air- and "Freon"-frozen samples (Wang 600 Computer Calculator was used for regression and correlation computations). 34 C. Effect of FreezingMethod and Thawing Temperature on % Weight Loss and Textural Quality of‘Cherries Processed as Frozen Pie Samples from lots of unpitted air- and "Freon"- frozen cherries were thawed at 20, 25, 30 and 40°F by immersion in thawing solution II as described in Section IV B. After pitting, samples were refrozen in air and by immersion in "Freon" following the same procedures de- scribed in Section I, page 12, for freezing fresh cherries, except for changes in "Freon" immersion times. Cherries, in 3 1/2 lb. quantities, were immersed in liquid "Freon“ for 15 seconds, withdrawn and held in air at ambient temperatures for 15 seconds, then reimmersed in "Freon" for 15 seconds. Refrozen cherries were stored as described in Section I, page 12, for 3 weeks, then used in the pre- paration of frozen cherry pie. Preparation of frozen cherry pie Preliminary tests were used (Appendix, Test 12) for formulation of pie filling intended to be comparable, in consistency of slurry and appearance of fruit, to that of a Gourmet Hi-Pie (37 oz.) produced by Chef Pierre, Inc., Traverse City, Michigan. The formulation developed is as follows: 35 Ingredient: Quantity/Pie Description Cherries 568 grams Lots PM and AW Sugar 220 grams "Pioneer" pure granu- lated Starch 22 grams Cold-flow No. 67- National Starch and Chem. Co. Salt 0.4 grams Diamond Crystal Dry mix ingredients (sugar, starch, salt) were mixed and packaged in wax paper until used. One package of dry mix and 568 grams of cherries were blended in mix- 1."...'A_'_n'_..l_" . .‘r" ".‘_ v ing bowls and moistened with water. The mixture was placed in a 10" frozen pie shell (Lloyd J. Harris, Institutional Size #279; Saugatuck, Michigan) and covered with top crust prepared according to directions on a "Pillsbury Pie Crust Mix" box. Pies were frozen on stainless steel trays (30" length; 20" width; 2" depth) in the -10°F Chrysler-Koppin freezer (approximately 2—4 hours). After freezing pies were placed in polyethylene bags (16 x 25") and remained in frozen storage for 2 weeks prior to baking. Baking procedure Baking directions from Chef Pierre Hi—Pie label were followed: 1. Preheat oven to 400°F 2. Place frozen pie on cookie sheet 36 3. Bake for 60 to 70 minutes." Pies were baked at Holmes Hall Cafeteria, Michigan State University, in a large Fish oven (Heavy Duty, serial no. 21127, no model number given, A. J. Fish Co., Beloit, Wisconsin) at 400°F for 65 minutes. All pies used for further evaluations were baked simultaneously (30 to 40 pies). Pies were cooled in air at 70 to 75°F for 12 hours prior to evaluation. Evaluation of cherries from baked pie Sensory evaluation.--Top crusts were removed from pies and cherries placed in 1 oz. plastic cups, 5 cherries per cup. The procedure for sensory evaluation was similar to that used for canned pie filling. The first test com- parison presented to the panel consisted of three samples of unpitted air-frozen cherries, thawed at 20, 30 and 40°F and then pitted, plus a control sample (cherries pitted prior to freezing, not thawed and refrozen prior to pro- cessing). Panelists were asked to rate samples for firm- ness on a 9 point rating scale using terms described in Section IV B, page 24. Results were statistically analyzed by analysis of variance (Kramer and Twigg, 1966; LeClerg, 1957) for difference between mean scores and significantly different samples identified using Duncan's Multiple Range Test (LeClerg, 1957). imam 37 The second test comparison consisted of three un- pitted "Freon" frozen samples (from same lot as first test), thawed at 20, 30 and 40°F and then pitted, plus a control sample. The third test comparison consisted of 4 samples: the firmest air-frozen sample (first comparison); the 6 W firmest "Freon"-frozen sample (second comparison); and air- and "Freon"-frozen control samples. Limited sample g prevented evaluation of all lots. Only lots PM and AW were processed as frozen pie. ”1‘- A study was made of the effect of refreezing and pie formulation on texture and % weight loss of cherries from frozen, then baked, pie (Appendix Test 14). Measurement of % weight loss Drained weight measurements were made by removing top crust from pies and pouring filling into U.S. No. 8 sieve. The same washing procedure was used as for canned pie filling (Bedford, 1971 - Personal communication) in Section IV B, page 24, except that cherries were washed for 2 minutes instead of 45 seconds. Percent weight loss was calculated as follows: Equation 3. Put-in Wt. of Cherries - 2 Min. Dr. Wt. X 100 %Wt- LOSS = Put-in Wt. of Cherries 38 Analysis of variance (Kramer and Twigg, 1966; Le Clerg, 1957) was used to test for significant differ- ence between mean scores and Duncan's Multiple Range Test to identify significantly different samples. Linear regression and correlation were used to show relationship between % weight loss during processing and thawing temperature used for unpitted air- and "Freon"-frozen samples. The Wang calculator was used for correlation and regression analysis with standard error corrections as described in Section IV B, page 24. RESULTS AND DISCUSSION Effect of Freezing and Thawing Method on % Weight Loss of Cherries During and After Pitting V! Preliminary tests showed that it was possible to thaw unpitted frozen cherries by immersion in a 40% _-'F .. um; (by wt.) ethylene glycol thawing solution, and pit the thawed cherries with minimal damage. 1 Immersion of cherries for 10 to 30 minutes in thawing solution at 32 and 50°F resulted in only slight tearing of cherry flesh and skin during pitting, with no detectable flesh adhering to pits (Appendix Test 1, Table 30). For a 200 or 250 gram sample of frozen cherries, it took 4 minutes after immersion in thawing solution at 20°F for internal cherry temperature to reach thawing solution temperature and 25 minutes for internal cherry temperature to reach 30°F thawing solution tempera- ture. Immersion of unpitted frozen cherries for 10 to 39 minutes in thawing solution at 30°F had only a slight effect on drained weight of fruit after pitting (Appendix, Test 3). 39 40 Immersion of unpitted frozen cherries for 10 minutes in thawing solution at 20°F resulted in higher drained weight of fruit 2 minutes after pitting as com- pared to cherries immersed in thawing solution at 30°F. However, 62 minutes after pitting, there was essentially no difference in drained weight of samples thawed at 20 and 30°F (Appendix, Text 4). Sample size, as determined by frozen weight of cherries prior to thawing, was shown to influence % weight 9 loss during pitting (Appendix, Test 5). Results are given in Table 34. Time required for frozen cherries to reach thawing solution temperature was shown to vary according to the lot of cherries used and temperature of thawing solution. Using a thawing solution temperature of 20°F, 4 to 8 minutes were required; at 30°F, 25 to 30 minutes were necessary; and at 40°F, 12 to 19 minutes would result in temperature equilibration between cherries and thawing solution (Appendix, Test 6). Drained weight measurements were made under ambient temperature conditions ranging from 76 to 84°F and ambient relative humidity ranging from 51 to 64% (Appendix, Test 7). The % weight loss calculated for these drained weight mea- surements indicated that relative humidity and ambient temperature had only a slight effect on replication of results (Table 35). 41 Results of more extensive studies showed that freezing method and thawing temperature had a definite effect on % weight loss during and after pitting of un- pitted, frozen cherries. Figure 2 shows the results of % weight loss during pitting, as calculated by equation 1, p. 22, from drained weight measurements made two $1 minutes after pitting (Table 2) for air and "Freon" (R-12)-frozen cherries from various lots. These results showed that less % weight loss (juice & flesh loss) Table 2. Effect of freezing method and thawing tempera— IL; ture on 2-min. drained weight of pitted fruit. Thawing 2—Min. Drained Weight (grams)* Temp. Freezing 20°F 25°F 30°F 40°F Method Air R-12 Air R-12 Air R-12 Air R-12 Lot PM 181 182 185 186 174 184 171 184 Lot E0 186 187 183 187 163 183 166 184 Lot RB 186 187 185 189 177 184 172 182 Lot AW 185 -- 185 -- 167 -- 167 -- *Average value of 3 replications based upon 200 9. frozen weight of sample, and includes juice, flesh and pit loss. occurred when thawing unpitted air-frozen cherries in thawing solution at 20 or 25°F as compared with thawing at 30 or 40°F. This may be explained as a result of only partial thawing of cherries at 20 or 25°F. Liquid, lost % weight loss during pitting 42 + Air Frozen Lot: PM r=.93 y=.69x-ll.68 Se=2.90 Sb=.18 E0 r=.80 y=.58x -8.26 Se=4.59 Sb=.30 AW r=.84 y=.57x -8.42 Se=3.84 Sb=.26 RB r=.95 y=.40x -5.95 Se=1.28 Sb=.08 PM+ * R-12 Immersion Lot: + 15 4 PM r=-.04 y=-.01x+3.43 Se=1.09 Sb=.07 E0 E0 r= .72 y= .11x- .14 Se=l.10 Sb=.07 + RB r= .84 y= .17x-2.13 Se=1.l8 Sb=.07 AW 10 , RB+ 5 .. R3,, EO* PM* 0 . 20 5b” 40 Thawing temperature (°F) Figure 2. Effect of thawing temperature on % weight loss (excluding pit loss) during pitting for air- and R—lZ-frozen lots. 43 from cherries thawed at 30 to 40°F was held as ice in cherries thawed at 20 to 25°F. The % weight loss of unpitted "Freon"-frozen cherries was influenced only slightly by thawing solution temperature. It is possible that rapid freezing by immer- sion in "Freon" 12 at -25 to -35°F resulted in less tissue damage and less juice loss than for air frozen cherries. Fennema and Powrie (1964) reported that rapid freezing may minimize cell damage and decrease loss of fluid due to the formation of small uniformly dispersed ice crystals. Variation in % weight loss during pitting, between differ— ent lots of cherries, might be due to different harvest dates or climatic conditions at the orchard from which they were obtained (Table 1). Bedford and Robertson (1955; 1962) found that climatic conditions and fruit maturity influenced the firmness and drained weight of frozen and canned cherries. Figure 3 shows the effect of immersion time of unpitted air-frozen cherries (Lot AW) at various thawing temperature on % weight loss during pitting, as calculated by equation 1, page 22, from drained weight measurements made two minutes after pitting (Table 3). Immersing unpitted frozen cherries in 20°F thaw- ing solution for periods of 5 to 90 minutes had little effect on % weight loss during pitting. With 25°F thawing solution, a slight increase in % weight loss resulted from ‘narf Air Frozen - Lot AW: 15 44 40°F r=-.96 y=13.16-.01x Se=.l7 Sb=.01 30°F r=-.90 y=13.51-.03x Se=.66 Sb=.01 25°F r= .91 y= 3.05+.03x Se=.74 Sb=.01 20°F r= .20 y= 3.85+.01x Se=.99 Sb=.01 g" — 40°F -r-l . 4.! . 44 '3. 30°F 5 2 310 a ,2 .3 'L :3 'U U) U) O H 4.) '8. .,.. 25°F 0) 3 w 5.. "20°F 0 . 0 3'0 60 9b soak time (min.) Figure 3. Effect of immersion (soak) time on % weight loss (excluding pit loss) during pitting for air- frozen lot AW. 45 Table 3. Effect of immersion (soak) time at various thaw- ing temperatures on 2-min. drained weight of air- frozen cherries (lot AW). 2-min. Drained Weight (grams)* Thawing Temp. Immersion Immersion Immersion Immersion (°F) Time Time Time Time 5 minutes 10 minutes 30 minutes 90 minutes 20 183 185 182 184 25 186 185 181 180 30 165 167 168 171 40 167 167 166 169 *Average value of 3 replications based upon 200 g. frozen weight of sample, and includes juice, flesh and pit loss. increased immersion time. Using 30 and 40°F thawing solu- tion temperatures, increased immersion time resulted in slight decreases in % weight loss. Again, as shown in Figure 2, lower thawing temperature (20 to 25°F) resulted in lower % weight loss of cherries during pitting. The relationship between low thawing temperature and low % weight loss can be explained in that cherries were only partially thawed during and shortly after pitting. Drained weight measurements were made at 10 minute intervals after pitting (Tables 4-7) and the % weight loss at each interval was calculated by equation 1, page 22, as shown in Figures 4-8. Figure 4 shows that thawing unpitted airdfrozen lots at 20°F resulted in lower % weight loss, 2 '5' 'I. 46 Table 4. Effect of freezing method and thawing temperature on drained weight of pitted fruit (lot E0). Drained Weight (grams)* Thawing Thawing Thawing Thawing Temp. 20°F Temp. 25°F Temp. 30°F Temp. 40°F Sgifiggng Air R-12 Air R-12 Air R-12 Air R-12 F 2 186 187 183 187 163 183 166 184 ' 12 184 186 180 187 158 182 161 182 E 22 173 182 170 186 154 180 158 180 32 159 175 157 181 149 177 156 177 _ 42 148 167 148 177 148 175 154 175 L 52 142 163 143 172 147 174 152 174 62 137 159 140 170 149 173 150 172 *Average value of 3 replications based upon 200 g. frozen weight of sample, and includes juice, flesh and pit loss. minutes after pitting, when compared to thawing at 40°F. However, as time after pitting increased, % weight loss increased more rapidly for cherries thawed at 20°F when compared to those thawed at 40°F. This may be a result of tissue damage caused by greater recrystallization in cherries thawed at 20 and 25°F. Luyet (1968b) related increased recrystallization to slow thawing. Cherries thawed at 20 to 25°F were held at these temperatures for 10 minutes. They were not completely thawed until after pitting and holding for a period of time at ambient 47 Table 5. Effect of freezing method and thawing temperature on drained weight of pitted fruit (Lot PM). Drained Weight (grams)* Thawing o o o 0 Temp. 20 F 25 F 30 F 40 F Freezing . _ . _ . _ . _ Method Air R 12 Air R 12 Air R 12 Air R 12 Time After -wEd-nfi Pitting (min.) 2 181 182 185 186 174 184 171 184 12 181 182 183 186 170 184 168 183 i 22 174 181 175 185 166 183 165 182 32 161 175 161 180 164 181 164 180 42 150 169 153 176 162 180 162 179 52 144 163 147 172 160 179 160 178 62 139 160 146 170 159 178 160 176 *Average value of 3 replications based upon 200 9. frozen weight of sample, and includes juice, flesh and pit loss. conditions. Cherries were completely thawed in 30°F thawing solution after 25 to 30 minutes, and after 12 to 19 minutes in 40°F thawing solution. Difference in rate of weight loss as well as total weight loss may be related to the observation that pitting cherries in the partially frozen condition (20 or 25°F) resulted in formation of smooth channels which could 48 Table 6. Effect of freezing method and thawing tempera- ture on drained weight of pitted fruit (Lot RB). Drained Weight (grams)* Thawing O 0 Temp. 20 F 25°F 30°F 40 F Freezing Air Method R-12 Air R-12 Air R-12 Alr R-12 Time After Pitting (min.) 2 186 187 185 189 177 184 172 182 12 184 187 181 189 171 183 168 182 22 171 184 168 184 167 180 165 179 32 159 177 160 179 165 179 162 178 42 151 170 156 176 163 177 160 176 52 146 166 152 173 160 174 158 174 62 143 163 150 171 160 174 158 174 *Average value of 3 replications based upon 200 9. frozen weight of sample, and includes juice, flesh and pit loss. have allowed for rapid flow of juice out of cherries upon thawing. Rough, partially collapsed channels were observed in cherries pitted after thawing to 30 ro 40°F allowing for slower flow of juice as compared to cherries thawed at 20 or 25°F. Rate of weight loss as well as total weight loss could have been influenced by flesh flabbiness and loss of spherical shape during thawing and pitting. Cherries thawed 49 Table 7. Effect of freezing method and thawing tempera- ture on drained weight of pitted fruit (Lot AW). Drained Weight (grams)* Thawing Temp. 20°F 25°F 30°F 40°F Pfizifiigg Air Air Air Air Time After Pitting (min.) 2 185 185 167 167 12 183 181 160 160 22 171 171 155 157 32 160 159 152 154 42 147 150 150 153 52 142 147 148 153 62 139 144 147 151 *Average value of 3 replications based upon 200 9. frozen weight of sample, and includes juice, flesh and pit loss. and pitted at 20 or 25°F did not loss their shape and, as a result, did not retain as much juice in the fruit or on the drained weight screen in comparison to cherries thawed and pitted at 30 or 40°F which lost their spherical shape. Greater mechanical damage may have occurred during pitting to cherries in the partially frozen state as shown by preliminary test 1 (Table 30). The effect of such tis- sue damage on drained weight would tend to become % weight loss after pitting 50 + 20°F Thawing Temp. Lots: EO r=.98 y=.47x -.06 Se=2.34 Sb=.04 AW r=.98 7=.45x+l.08 Se=2.56 Sb=.04 RB r=.98 y=.42x+1.17 Se=2.49 Sb=.04 PM r=.98 y=.42x+1.52 Se=2.37 Sb=.04 * 40°F Thawing Temp. Lots: E0 r=.98 y=.13x+l3.76 Se= .70 Sb=.01 EO ' AW r=.94 y=.12x+l4.25 Se=1.28 Sb=.02 RB r=.97 y=.12x+10.72 Se= .87 Sb=.01 AW PM r=.97 y=.09x+10.72 Se= .64 Sb=.01 30 + -+ + -+ PM EO* AW* 20L RB* PM* 2 £2 42 62 Holding time after pitting (min.) Figure 4. Effect of holding time after pitting on % weight loss (excluding pit loss) after pitting for 4 air-frozen lots thawed at 20 and 40°F. 30 N O % weight loss after pitting i-‘ LO 20°F 25°F 30°F 40°F 25°F 30°F 40°F Figure 5. 51 + Thawing Temp. (°F) for Air Frozen Lot EO; r=.98 y=.47x - .06 Se=2.34 Sb=.04 r=.98 y=.42x+ 2.81 Se=2.24 Sb=.04 r=.95 y=.l4x+15.84 Se=l.36 Sb=.02 r=.98 y=.13x+13.76 Se= .70 Sb=.01 * Thawing Temp. (°F) for R-12 Frozen Lot EO: 120°F r=.98 y=.27x- .20 Se=1.23 Sb=.02 20+ r=.97 y=.16x+ .47 Se=1.23 Sb=.02 25+ r=.95 y=.11x+3.39 Se=1.08 Sb=.01 r=.99 y=.10x+3.56 Se= .34 Sb=.01 30 40 * 20 30* 25* 40* / 22 4'72‘ 65 holding time after pitting (min.) Effect of holding time after pitting on % weight loss (excluding pit loss) after pitting for air- and R-lZ-frozen Lot E0 thawed at various temperatures. .I I 52 + Thawing Temp. (°F) for Air Frozen Lot PM: 20°F r=.98 y=.42x+1.52 Se=2.37 Sb=.04 25°F r=.98 7=.39x +.88 Se=2.56 Sb=.04 30°F r=.98 y=.13x+9.18 Se= .80 Sb=.01 40°F r=.97 y=.09xfll172 Se= .64 Sb=.01 *Thawing Temp. (°F) for R-12 Frozen Lot PM: 30 ‘20°F r=.96 y=.21x+l.88 Se=l.68 Sb=.02 25°F r=.97 y=.l6x+ .52 Se=1.09 Sb=.02 30°F r=.98 y=.01x+2.96 Se= .28 Sb=.01 + 40°F r=.99 y=.01x+3.26 Se= .17 Sb=.00 20 25+ U) a -H 4.) 4.) -H Ch20_ H m 4..) “.3 + m 30 + 8 40 H 20* :3" / .S‘ / m 3 0° 10 1 25* 40* 30* I/ / 0 F 22 42 62 holding time after pitting (min.) Figure 6. Effect of holding time after pitting on % weight loss (excluding pit loss) after pitting for air- and R-lZ-frozen Lot PM thawed at various temperatures. 30. 53 + Thawing Temp. (°F) for Air-Frozen Lot RB: 20°F r=.98 y=.42x+1.12 Se=2.49 Sb=.04 25°F r=.97 y=.32x+3.33 Se=2.39 Sb=.04 30°F r=.96 y=.14x+8.65 Se=1.16 Sb=.01 40°F r=.97 y=.12xflll72 Se= .87 Sb=.01 * Thawing Temp (°F) for R-lZ-Frozen Lot RB: 20°F r=.97 y=.23x -.05 Se=1.48 Sb=.02 25°F r=.98 y=.l7x +.01 Se= .86 Sb=.01 30°F r=.99 y=.09x+3.74 Se== .25 Sb=.01 40°F r=.98 y=.07x+4.54 Se= .38 Sb=.01 . \‘TA‘HR I. Figure 7. 20" + g 25 -H 4.) 3;} mo . “.3 40 30+ m (D 3 / 20* 1:” U‘ °I~I / Q) 3 25* ”0101 30* 40* / a T ‘ 2 22 42 62 holding time after pitting (min.) Effect of holding time after pitting on % weight loss (excluding pit loss) after pitting for air- and R-lZ-frozen Lot RB thawed at various temperatures. % weight loss after pitting 54 + Thawing Temp. (°F) for Air-Frozen Lot AW: 20°F r=.98 y=.45x +1.08 Se=2.55 Sb=.04 25°F r=.98 y=.40x +2.02 Se=2.17 Sb=.04 30°F r=.95 y=.16x+l4.17 Se=1.55 Sb=.02 40°F r=.94 y=.12x+l4.25 Se=1.28 Sb=.02 304 20+ 25+ 30+ 40+ 20- 10- 0 2 2’2 4'2 6'2 holding time after pitting (min.) Figure 8. Effect of holding time after pitting on % weight loss (excluding pit loss) after pitting for air-frozen Lot AW thawed at various tem- peratures. 55 progressively greater during the remainder of the thawing period and during the period of post-thaw holding. Thus, after a period of holding, the increased tissue drip loss of samples thawed and pitted at 20°F could cause them to lose their initial drained weight advantage over samples thawed and pitted at 40°F. Flesh loss could not be directly measured. It is possible that flesh was pulled out of partially frozen cherries along with the pits. However, if a 7-10% pit loss is considered (Bedford and Robertson, 1962), the data in Tables 4 through 7 would indicate that little flesh loss occurred. Again, as in Figure 2, variations were noticed between individual lots of cherries. Lots RB and PM, harvested later in the season that lots EO and AW (Table 1) showed lower % weight loss after pitting when either 20 or 40°F thawing temperatures were used. Freezing method was also shown to affect % weight loss as measured at 10 minute intervals after pitting. Cherries from lot EO (Figure 5) which were "Freon"(R-12)- frozen unpitted, thawed at temperatures between 20 and 40°F and pitted, showed a lower % weight loss at each interval after pitting when compared to air-frozen un- pitted cherries, thawed and pitted by the same procedures. "Freon"(R-12)-freezing also resulted in lower % weight loss after pitting for lots PM (Figure 6) and RB (Figure 7). 56 Cherries from lot AW were not R-lZ—frozen. However, % weight loss after pitting for this lot is clearly shown to be much lower after pitting and to increase at a greater rate when 20 or 25°F thawing temperatures were used in comparison to 30 to 40°F thawing temperatures (Figure 8). TI Immersion time in thawing solution had a slight effect on % weight loss at 10 minute intervals after pitting, as calculated from drained weight data (Table 8) using equation 1, page 22. Figure 9 shows little differ- ence in % weight loss for unpitted air-frozen cherries (lot AW) immersed in 20°F thawing solution for 5, 10, 30 and 90 minutes. The same results are shown in Figure 10 using 25°F thawing solution temperature, Figure 11 using 30°F solution temperature and Figure 12 using 40°F solu- tion temperature for immersion times (soak time) indicated above. There was a trend toward lower % weight loss with increased soak time. Figures 9, 11 and 12 show a slight decrease in % weight loss using 30 and 90 minute soak (immersion) times. Table 9 and Figure 13 show results of a study to determine the number of pits/1b. remaining after pitting air- and "Freon"(R-12)-frozen unpitted cherries, thawed at 20, 25, 30, and 40°F. Using 20 or 25°F thawing tem- peratures, fewer pits/1b. were found as compared to using a 30 or 40°F thawing temperature. "Freon"-frozen samples, 57 .mmOa 9am paw ammam .moasfl mopsaoca cam .mamfimm mo pnmam3 cmuonm m oom coma comma m20apmoaammu m «0 05am> mmmum>¢r ama pea mma ama ama oma mma oma pea mea mea aea eea mea aea Nea mma mma mm mma mea ema Nma mma mma ema ama mea mea pea mea pea pea mea mea Nea eea mm ema oma mma ema mma mma mma mma oma oma ama mea oma ama mma mma pea mma me mma ama mma mma ema mma mma mma mma mma mma mma mma oma mma «ma oma moa mm mma mma oma pma pma mma ama mma mma pma mpa opa apa Npa mpa mpa apa mpa mm aoa mma mma ama oma aoa pea mma oma mma oma ppa ama mma ema mma mma mma ma ewa mma mma mma pwa pma apa mma pma mma oma ama mma mma ema mma mma mma m i .55 meauuam “mama mane . 8 cm on om cm on m cm on on m cm on oa m om om oa m i ”wwwuwaww in v .msme moom mooe moom momm moom .maazmne «Amamumv vnmam3 pmcamuo .Azfl uoav MHDHM Umuuam mo unmamz pmcamwp so cOauSaOm maa3msu ca maau coamnoeaa mo pommmm .m magma loss N O I 58 10* 5* 90* 30* *Soak Time (min.) at 20°F Thaw Temp. 5 r=.97 y=.45x +.02 Se=2.63 Sb=.05 10 4=.98 y=.45x+1.08 Se=b.10 Sb=.0r 30 r=.97 y=.40x+l.82 Se=2.13 Sb=.04 90 r=.98 y=.42x +.97 Se=2.09 Sb=.04 holding time after pitting (min.) Figure 9. N O % weight loss I" O 2'2 [2 6'2 1". Effect of holding time after pitting % weight loss (excluding pit loss) after pitting of lot AW immersed in thawing solution at 20°F for various soak times. " 30* 10* 90*; *Soak Time (min.) at 25°F Thaw Temp. 5 r=.98 y-.40x+1.79 Se=l.63 Sb=.03 10 r=.98 y=.40x+2.20 Se=1.78 Sb=.03 30 r=.98 y=.39x+3.68 Se=l.81 Sb=.03 90 r=.98 y=.36x+3.48 Se=1.74 Sb=.03 22 42 1'7— holding time after pitting (min.) Figure 10. Effect of holding time after pitting on % weight loss (excluding pit loss) after pitting of lot AW immersed in thawing solution at 25°F for various soak times. 30 N O % weight loss |'-‘ 0 Figure 30- 20 % weight loss Figure 4» 10 r 59 5 r=.96 y=.l4x+l4.85 Se= .95 Sb=.02 =.95 y=.16x+l4.17 Se=1.27 Sb=.02 30 r=.95 y=.15x+l3.05 Se=1.08 Sb=.02 90 r=.97 y=.14x+ll.59 Se= .81 Sb=.01 e 2 2'2 4? 62' — holding time after pitting (min.) 11. Effect of holding time after pitting on % weight loss (excluding pit loss) after pitting of lot AW immersed in thaeing solution at 30°F for various soak times. 5* 10* u 30* 90* *Soak Time (min.) at 40°F Thaw Temp. ‘r 5 r=.93 y=.12x+l4.25 Se=1.05 Sb=.02 10 r=.93 y=.12x+l4.25 Se=1.05 Sb=.02 30 r=.94 y=.12x+l4.14 Se=1.00 Sb=.02 90 r=.98 y=.13x+12.08 Se= .65 Sb=.01 2 2T2 4'2 6'2 holding time after pitting (min.) 12. Effect of holding time after pitting on % weight loss (excluding pit loss) after pitting of lot AW immersed in thawing solution at 40°F for various soak times. 60 Table 9. Effect of freezing method and thawing tempera- ture on pit removal from cherries of 4 different lots. Number of Pits/Lb. of Cherries* Thawing Temp. 20°F 25°F 30°F 40°F Freezing Method Air R-12 Air R-12 Air R-12 Air R-12 Lot # E0 1 0 4 2 7 3 ll 10 PM 0 0 0 O 7 3 3 6 RB 0 3 l 7 7 7 12 7 AW 0 - 1 - 9 - ** - *Number was obtained by counting the number of pits remaining in 600 grams of cherries after pitting and correcting to 454 grams (1 lbs.) by dividing by 1.3. **Value not recorded. with some exceptions, had fewer pits/lb. than comparable air-frozen samples. This was probably due to the partially frozen, firmer structure of the cherry tissue holding the pits in place. Effect of Freezinggpd Thawing Method on % Weight Lo§§_of_gherries Processed as Canned Pie Filling Results of drained weight measurements made on cherries from canned pie filling (Table 10), when used to calculate (Equation 2, page 33) % weight loss during pro- cessing (Figure 14), showed that lower % weight loss 61 + Air-Frozen Lot: AW E0 r=.99 y=.64x-10.40 Se= .51 Sb=.03 PM r=.60 y=.30x -5.37 Se=4.32 Sb=.28 RB r=.97 y=.84x-17.31 Se=1.97 Sb=.13 AW r=.93 y=120x-25.33 Se=2.70 Sb=.37 RB+ * R-lZ-Frozen Lot: E0+ 15 E0 r=.97 y=.64x-13.40 Se=1.49 Sb=.10 * M r=.95 y=.44x -9.4o Se=1.49 Sb=.10 RB r=.79 y=.25x + .77 Se=2.04 Sb=.13 30* i 10 . RB* ' PM* PM number of pits per lb. of cherries 20 t 36 lo thawing temperature (°F) Figure 13. Effect of thawing temperature on number of pits per lb. of air- and R-lZ-frozen cherries from different lots. 62 .I... ".~.. .1. .bllnflfl..l.vln3iil.‘~| hr" .omouoomu uoc moam>*«* .mcammmooum on Hoaum 3mnu o: Um>aooon paw mcaummum ou “Oahu Uouuam mamEmmIm** .msammooonm o» Hoaum unmam3 satusm Emma mmm com: comma mcoaumoaammu m mo msam> ommum>¢« I «ma I mma I «ma I ema I ama . om uoa I mma I mma I mma I pma I pma 3d poa oom ema mma mma *«« «*4 mma pma ema pma mm poa pma ama oma mma mma mma ama Nma Npa ema 2m uoa NaIm Mad NaIm Ham malm Ham NaIm Had maIm mam ponumz mcaummnm ..m mace momm moon moom .mama mcaamne *AmEmumv unmamz pmcamuo .cazIN .msaaaam mam owccmo Eonm moauumno mo unmams posamuc .caEIm so ousumnmmfimu msa3mau cam ponuma moanmonm mo uommmm .oa magma 63 + Air-Frozen Lot: PM r=-.9 y=43.95-.45x Se= .08 Sb=.08 RB r=-.94 y=43.41-.48x Se=1.39 Sb=.09 AW =-.90 y=49.20-.62x Se=2.22 Sb=.15 E0 r=-.9 y=46.10-.58x Se=2.20 Sb=.15 40.flR—lZ-Frozen Lot: PM r=-.85 y=39.02-.38x Se=1.73 Sb=.1l RB r=-.90 y=32.4l-.25x Se= .88 Sb=.06 m . G a .,..I i m I an) 4 o \ 8 g. 30.. H m .a 4.) E *H PM+ O'- AW-I- .fi RB+ H 'M* 5 0+ m RB* m 3 20¢ 4.) a U\ -a m 3 69 10 l 20 3b 40 thawing temperature (°F) Figure 14. Effect of thawing temperature on % weight loss during further processing of air- and R-12- frozen lots as canned pie filling. 64 resulted from using 40°F thawing temperature as compared to 20°F thawing temperature. "Freon"(R-12)-freezing of unpitted cherries resulted in lower % weight loss at each thawing temperature used as compared to air-freezing (Figure 14). Determination of statistically significant dif— ferences between drained weights of cherries processed as canned pie filling are shown in Table 11. Drained 3 weights of unpitted "Freon"-frozen cherries, thawed and pitted at 30, 35 and 40°F, were significantly higher than those of unpitted "Freon"-frozen cherries thawed and pitted at 20°F or unpitted air-frozen cherries thawed and pitted at 20 or 30°F. They were also higher than drained weights of air-frozen cherries pitted prior to freezing and not thawed prior to processing. Drained weights of unpitted "Freon"-frozen cherries, thawed and pitted at any of the 4 thawing solution temperatures, were not significantly different from pitted "Freon"- frozen cherries not thawed prior to processing. Drained weights of unpitted air-frozen cherries thawed and pitted at 30, 35 and 40°F were significantly higher than those of unpitted air-frozen cherries thawed and pitted at 20°F, but not significantly different than pitted air-frozen cherries not thawed prior to processing (except for lot RB). 65 Table 11. Determination of significant difference in drained weight of cherries from canned pie filling. Lot Freezing Thawing 32:33:? Signif.** Method Temp.(°F) (grams) 5% 1% PM R-12 35 193 PM R-12 30 191 1 PM R-12 40 190 PM R-12 P*** 187 PM Air 40 186 5 PM Air 35 186 ' PM Air 30 182 PM Air P*** 181 ' PM R-12 20 172 l ‘ PM Air 20 164 RB R-lZ P*** 200 RB R-12 35 197 RB R-12 40 196 RB R-12 30 195 RB Air 40 192 ' RB Air 30 187 RB Air P*** 184 RB R-lz 20 184 RB Air 20 167 AW Air 40 189 AW Air 30 187 AW Air 35 185 AW Air P*** 183 AW Air 20 157 66 Table 11 (cont.) ' ' ' ** Freezing Thawing Drained Signif. LOt 0 Weight* Method Temp,( F) 5% 1% (grams) E0 Air 40 188 E0 Air 30 184 E0 Air 35 182 {— EO Air P*** 182 E E0 Air 20 161 . *Average value of 5 replications based upon 256 grams put-in weight prior to processing. **Weights not connected by line indicates signifi- cant difference at l or 5% level. Ii" ***P-samp1e pitted prior to freezing and received no thaw prior to processing. Drained weights of pitted air- and "Freon"-frozen samples, not thawed prior to processing, were signifi- cantly higher than those of unpitted air- and "Freon"— frozen samples thawed at 20°F prior to processing. Table 12 shows the effect of freezing method and thawing temperature on total % weight loss (pitting and further processing) for cherries processed as canned pie filling. Using a 20°F thawing solution, for both air- and "Freon"-frozen unpitted cherries, resulted in lower % weight loss during pitting and higher % weight loss during further processing as compared to using a 30 or 40°F thawing solution. However, there was little differ- ence in total % weight loss. Total % weight loss was 67 Table 12. Effect of freezing method and thawing tempera- ture on total % weight loss (excluding pit loss) for cherries processed as canned pie ‘_ _“‘w. :—.-:_-, Fl ' filling. Thawing Temp. 20°F 30°F 40°F Freezing Method Air R-12 Air R-12 Air R-12 % Weight Loss (Lot PM) During Pitting* 4.7 4.2 8.6 3.4 10.3 4.2 Further Processing** 35.9 32.8 28.9 25.3 27.3 25.7 Total*** 40.6 37.0 37.5 28.7 37.6 29.9 %ngght Loss (Lot RB)* During Pitting* 2.5 2.0 7.6 4.0 10.1 4.9 Further Processing** 34.7 28.1 26.9 23.8 25.0 23.4 Total*** 37.2 30.1 34.5 27.8 35.1 28.3 % Weight Loss (Lot AW) During Pitting* 3.0 - 13.0 - 13.0 - Further Processing** 38.6 - 26.9 - 26.1 - Total*** 41.6 - 39.9 - 39.1 - % Weight Loss , (Lot E0) During Pitting* 2.4 - 14.9 - 13.1 - Further Processing** 37.1 28.1 26.5 Total*** 39.5 - 43.0 - 39.6 - *Value calculated using equation 1, p. 22; avg. 3 replicates. **Value calculated using equation 2, p. 33; avg. 5 replicates. ***Value does not include pit loss (4 - 6%). IA" ¢ ill. 8...: 68 lower for "Freon"-frozen unpitted cherries, at all thaw- ing temperatures, as compared to air-frozen samples. There was greater total % weight loss when using 20°F- thawed and pitted cherries rather than 30— or 40°F- thawed and pitted cherries. Effect of Freezing and Thawing Methods on % “ f Weight Loss of Ehérries Processed As Baked Pie Results of drained weight studies of cherries for baked pie (Table 13) were similar to those for canned pie 'U'. . zinc...” filling. Figure 15 shows the effect of thawing tempera- ture on % weight loss calculated from equation 3, page 37, from drained weight data in Table 13. Percent weight loss during freezing and baking of pie was lower for cherries thawed and pitted at 40°F than for those thawed at 20 or 30°F. Unpitted "Freon"-frozen cherries showed a lower % weight loss during further processing than unpitted air- frozen cherries. Determination of statistically signifi- cant differences between drained weights of cherries processed as baked pie are shown in Table 14. Drained weights of unpitted "Freon"-frozen cherries, thawed and pitted at 25, 30, and 40°F, were significantly higher than those of unpitted air-frozen cherries thawed and pitted at 20, 25, 30 and 40°F. They were not significantly different than drained weights of cherries pitted prior to air- or "Freon"-freezing and not thawed prior to processing. 69 .mfimnm mam .mfimum mmm unmam3 Galusm««*« usmflm3 Calu5m««« .msammoooum o» Hoaum zone on Uo>aoomh pom mcauwmum on Hoaum wouuam mamEmmIm«« .msammmooum ou Hoaum unmamz saluom coma comma msoaumoaammn M NO msam> ommum>¢4 I 0pm I mem I mem I mem I aNm *¥¥¥3¢ uoa mem mam emm mmm mmm mpm wmm chm mNm mpm «%«EQ 90A Nalm Had NHIM Hfld NHIm Had Nalm Had Nalm Hflfl Oosuwz OGHNwme **A mace moom momm boom .QEmB OGH3MQB 41memnme ugmamz owcamna .aazum .mmam pmxmn Eoum mwauumno mo unmaws Umcamup .caEIN co musumuwmsmu mca3wnu pom ponuofi mnaummum mo nommmm .ma magma 70 + Air-Frozen Lot: PM r=.88 y=56.34—.17x AW r=.79 y=50.39-.18x Se= .94 Sb=.06 Se=1.50 Sb=.10 * R-lZ-Frozen Lot: PM|r=.68Iy=43.80-.08x|Se=.80ISb=.O6 60 ’ g F -a ? m " U) m U o H o. 3 so _ + .c p PM 1 H n— D ‘H a. c -a u .3 m Aw+ m 0 \ ,_I 4.) a 40'- 0\ ——.PM* -a m 3 09 3o - 20 30 4b thawing temperature (°F) Figure 15. Effect of thawing temperature on % weight loss of air- and R-lZ-frozen cherries during further processing (refreezing and baking) of pies. 71 Table 14. Determination of significant difference in drained weight of cherries from baked pie. Lot FreeZing ThaWing fizigfiii Signif.** Method Temp.(°F) (grams) 5% 1% PM R-12 p*** 343 E PM R-12 30 336 5 PM R-12 25 336 PM R-12 40 334 PM R-12 20 325 L PM Air p*** 318 PM Air 40 289 PM Air 30 276 PM Air 20 273 PM Air 25 267 AW Air P*** 370 AW Air 40 348 AW Air 30 345 AW Air 25 343 AW Air 20 321 *Average value of 3 replications based upon put—in weight of 568 grams for Lot PM and 618 grams for Lot AW. **Weights not connected by line indicates signifi- cant difference at 1 or 5% level. ***P-sample pitted prior to freezing and received no thaw prior to processing. 72 There were no significant differences in drained weights of unpitted air—frozen cherries when thawed at 20, 25, 30 and 40°F. Drained weight of cherries pitted prior to air- freezing was significantly higher than that of unpitted air-frozen cherries thawed and pitted at 20°F. Table 15 shows that there was slightly less total % weight loss for unpitted air-frozen cherries thawed and pitted at 20°F as compared to those thawed at 1 30 and 40°F. This was due to the higher % weight loss during pitting for samples thawed and pitted at 30 and 40°F. Again, as for total % weight loss of cherries for canned pie filling (Table 12), "Freon"-freezing resulted in less total % weight loss as compared to air-freezing at each thawing temperature. Comparison of total % weight loss between cherries processed as canned pie filling and baked pie (Table 16) shows that a higher total % weight loss occurred during processing of baked pie, regardless of freezing method or thawing temperature used. The greater % weight loss of cherries in baked pie may be due to tissue damage resulting from thawing and refreezing of cherries prior to processing. Use of a dry mix instead of prepared slurry in the baking operation itself may have resulted in greater % weight loss (see Appendix, Test 14). Values for % weight loss during pitting of fresh cherries, pitted prior to freezing, were not Table 15. 73 ture on total % weight loss for cherries processed as baked pie. Effect of freezing method and thawing tempera— Thawing Temp. 20°F 30°F 40°F Freezing . _ . _ . _ Method Air R 12 Air R 12 Air R 12 % Weight Loss (Lot PM) During Pitting* 4.7 4.2 8.6 3.4 10.3 4.2 Further Processing** 52.0 43.0 51.0 41.0 49.0 41.0 Total*** 56.7 47.2 59.6 44.4 59.3 45.2 % Weight Loss (Lot AWYP During Pitting* 3.0 -- 13.0 —— 13.0 -- Further Processing** 48.0 —- 44.1 -- 43.6 -- Total*** 51.0 -- 57.1 -- 46.6 -- *Value calculated using equation 1, page 22; avg. 3 replicates. **Value calculated using equation 3, page 37; avg. 3 replicates. ***Va1ue does not include pit loss accurately obtained. (4 - 6%). In order to calculate total % weight loss for cherries pitted prior to freezing, literature values (Bolen, et al., 1970); Parker, et al., 1966; Marshall, 1954; Hills, et al., 1953) for average % juice and pit loss during pitting were used in Table 17. 74 Table 16. Comparison of total % weight loss between cherries processed as canned pie filling and baked pie. Thawing Temp. 20°F 30°F 40°F Freezing Method Air R-12 Air R-12 Air R-12 Total % Weight Loss* (Lot PM) Canned Pie Filling 40.6 37.0 37.5 28.7 37.6 29.9 Frozen (Baked) Pie 56.7 47.2 59.6 44.4 59.3 45.2 Total % Weight Loss* (Lot AW) Canned Pie Filling 41.6 -- 39.9 -- 39.1 -- Frozen (Baked) Pie 51.1 -- 57.1 -- 56.6 -— *See Tables 12 and 15. Accurate values are presented (Table 17) for % weight loss during further processing, as calculated using equation 2, page 33 and drained weight data from Tables 10 and 13. Comparing values in Table 17 to those for cherries from canned pie filling in Table 12 shows that: % weight loss during pitting of unpitted air-frozen and "Freon"- frozen cherries, thawed at 20°F, is lower than that of literature values for fresh cherries pitted prior to freezing. The % weight loss during pitting for unpitted air-frozen cherries from lots PM and RB, thawed at 40°F, is within the range of literature values for fresh 75 Table 17. Total % weight loss for cherries pitted prior to freezing and processed unthawed as canned pie filling and baked pie. Lot PM RB AW E0 Freezing . . . . Method Air R 12 Air R 12 Air Air % Wei ht Loss (Canned Pie Filling) During _ _ _ _ _ _ Pitting* 8 10 8 10 8 10 8 10 8 10 8 10 Further Processing* 29 26 28 21 28 29 Total*** 37-39 34-36 36-38 29-21 36-38 37-39 % Weight Loss (Baked Pie) During _ _ __ __ _ __ Pitting* 8 10 8 10 8 10 Further Processing** 44 40 4O — Total*** 52-54 48-50 -- -- 48-50 -- *Average % of commercial pitting loss as indicated by Bolen, et al., 1970: Parker, et al., 1966; Marshall, 1954; Hills, et al., 1953; minus the range of % pit loss as given by Marshall, 1954. **Values calculated directly using equation 2, p. 33 for an average of 5 replications. ***Range does not include pit loss (6.5 to 8.5%) as given by Marshall, 1954. cherries pitted prior to freezing (lots AW and E0 show slightly higher values). The % weight loss during pitting for unpitted "Freon"-frozen cherries from all lots, thawed at each temperature studied, was lower than % weight 76 loss as given in the literature for fresh cherries pitted prior to freezing. Comparing values for % weight loss during further processing as canned pie filling (Tables 12 and 17) shows: that: cherries pitted prior to freezing in air or “Freon," and not thawed prior to processing, had the same or slightly higher % weight loss than that for unpitted air- or "Freon"- frozen cherries, thawed and pitted at 30 and 40°F. The % weight loss was higher in each case of unpitted air- or "Freon"-frozen cherries, thawed and pitted at 20°F, as compared to those pitted prior to freezing. Comparing values for total % weight loss (Tables 12 and 17) shows that: unpitted air-frozen cherries, thawed 20, 30 and 40°F, are comparable, in % of total weight loss, to that of cherries pitted prior to freezing and not thawed prior to processing. The total % weight loss for unpitted "Freon"-frozen cherries, thawed and pitted at 30 and 40°F (but not 20°F), was slightly less than that of pitted frozen cherries. Comparing Table 17 with Table 15, for cherries processed as baked pie, shows that: % weight loss during pitting for unpitted air-fraozen lots, thawed at 30 and 40°F was within the range of literature values for fresh cherries; while, unpitted air-frozen lots, thawed at 20°F, show less % weight loss during pitting than fresh cherries. The % weight loss for unpitted "Freon"-frozen cherries, 77 thawed at 20, 30 and 40°F, was lower than that for fresh cherries during pitting. The % of weight loss during further processing as baked pie, for air- and "Freon"- frozen cherries thawed and pitted at 20, 30, and 40°F, was higher than that for cherries pitted prior to freezing and not thawed prior to processing. Total % weight loss is also higher in all cases for unpitted air- and "Freon"- frozen lots as compared to pitted frozen cherries. Effect of Freezing and Thawing Method 0n Texture of Cherries fromganned Pie Filling and Baked Pie In the first series of sensory panels conducted on cherries from canned pie filling, panelists were presented 4 samples of either air- or "Freon"-frozen cherries, un- pitted prior to freezing, and thawed at 20, 30 and 40°F prior to pitting and further processing (Table 18). Panel- ists found either no significant difference in firmness of air-frozen lots PM and E0 and "Freon"-frozen lot RB or they found that either the 30 or 40°F thawed lot was signifi— cantly firmer, as for air-frozen lots RB and AW and "Freon"-frozen lot PM. In the second series of sensory panels, panelists evaluated samples receiving the highest and lowest firmness scores in the first series, along with cherries pitted prior to freezing and not thawed prior to processing as canned pie filling (Table 19). In some of the comparative 78 Table 18. Sensory evaluation for significant textural difference between cherries thawed and pitted at different temperatures and processed as canned pie filling. Thawing . . Thawing . . Mean Signif.** Mean Signif.** LOt TEmP'Score* 5% 1% LOt Temp. Score* 5% 1% (F) (F) PM 40 5.6 PM 30 7.0 5 PM 35 5.5 PM 20 6.3 N.S. PM 20 5.2 PM 40 5.9 PM 30 5.0 PM 35 5.0 5. RB 30 5.7 RB 30 5.7 RB 40 4.8 RB 35 5.6 N.S. RB 20 4.4 RB 40 5.1 RB 20 4.9 AW 40 6.0 AW 35 5.3 AW 30 5.3 AW 20 4.9 E0 40 6.0 E0 30 5.6 N.S. E0 35 5.4 E0 20 5.3 *Mean score of 22 panelists using a 9 point rating scale; higher score indicates firmer texture. **Mean scores not connected by line show significant difference at the l or 5% level - N.S. indicates no signifi- cant difference between any of the mean scores. 79 Table 19. Sensory evaluation for significant textural difference between cherries thawed and pitted at different temperatures and unthawed-pitted control, processed as canned pie filling. Air-Frozen R-lZ-Frozen Thawing Mean Lot Temp. Thawing Mean . . ** Lot Temp. Slgnlf' Signif.** (°F) Score* 5% 1% (°F) Score* 5% 1% PM 40 5.4 N.S. PM 30 6.2 PM 20 5.1 PM P*** 5.7 N.S. PM P*** 4.9 PM 40 5.4 RB 40 4.1 RB 30 5.2 RB 30 4.1 N.S. RB 40 4.9 N.S. RB P*** 3.9 RB P*** 4.9 AW 40 5.5 AW P*** 4.7 l N.S. AW 20 4.6 E0 40 5.5 E0 P*** 5.1 I | E0 20 4.8 *Mean scale-~higher **Mean difference at score of 22 panelists using a 9 point rating score indicates firmer texture. scores not connected by line show significant the l or 5% level -- N.S. indicates no signi— ficant difference between any of the mean scores. ***P—sample was pitted prior to freezing and received no thawing prior to processing as canned pie filling. 80 groupings (air-frozen lots PM and RB; "Freon"-frozen lot RB) panelists found no significant difference in firmness between unpitted frozen cherries, thawed and pitted at 20 and 40°F, and cherries pitted prior to freezing. The found unpitted air-frozen cherries (lots E0 and AW) thawed and pitted at 40°F, and unpitted "Freon"-frozen cherries (lot PM), thawed at 30°F, to be firmer in texture than unpitted air-frozen cherries (lots E0 and AW), thawed and pitted at 20°F, unpitted "Freon" frozen cherries (lot PM), thawed and pitted at 40°F, and cherries pitted prior to freezing and not thawed prior to further processing. In a third series of sensory panels, panelists evaluated unpitted air- and "Freon"-frozen cherries re- ceiving highest scores for firmness in the previous panels along with cherries pitted prior to air- and "Freon"- freezing (Table 20). Pitted and unpitted "Freon“-frozen cherries from lot PM were significantly firmer than com- parable air-frozen cherries, whether pitted before or after pitting. This is possibly due to less tissue damage as a result of rapid freezing by "Freon" immersion (Fennema, and Powrie, 1964). Unpitted "Freon"-frozen cherries from lot RB, thawed at 30°F, were significantly firmer than unpitted air-frozen cherries, thawed and pitted at 30°F, and cherries pitted prior to "Freon"-freezing and not thawed prior to processing. They were not significantly Table 20. Sensory evaluation for significant textural difference between air- and R-12-frozen cherries thawed and pitted at different tem- peratures and unthawed-pitted control, processed as canned pie filling. Lot Freezing Thawing Mean Signif.** Method Temp.(°F) Score* 5% 1% PM R-12 30 6.4 i _ *** PM R 12 P 6.2 N.S. PM Air 40 4.8 PM Air P*** 4.5 RB R-12 30 5.3 l RB Air P*** 4.7 N.S. RB R-12 P*** 4.5 RB Air 30 4.3 *Mean score of 22 panelists using a 9-point rating scale (higher score indicates firmer texture). **Mean scores not connected by line show signifi— cant differences at the 1 or 5% level -- N.S. indicates no significant difference between any of the mean scores. ***P-samp1e was pitted prior to freezing and re- ceived no thawing prior to processing as canned pie filling. firmer than pitted air-frozen cherries, not thawed prior to processing. Results of sensory evaluation for firmness of cherries from frozen, then baked, pie are shown in Tables 21 and 22. Unpitted air-frozen samples from lot PM, thawed and pitted at 40°F, were significantly firmer than 82 Table 21. Sensory evaluation for significant textural difference between cherries thawed and pitted at different temperatures and unthawed-pitted control, processed as baked pie. Air-Frozen R-lZ-Frozen Thawing . . Thawing . . Mean Signif.** Mean Signif.** LOt Temp. Score* 5% 1% LOt Temp. Score* 5% 1% ( F) ( F) PM 40 5.6 I PM P*** 6.3 PM 30 4.6 PM 40 6.1 PM P*** 4.4 ' PM 20 5.7 PM 20 3.5 PM 30 5.3 AW P*** 6.7 AW 40 6.1 AW 30 5.2 AW 20 4.7 *Mean score of 22 panelists (PM and 19 (AW) using a 9-point rating scale (higher score indicates firmer texture). **Mean scores not connected by line show significant differences at the 1 or 5% level. ***P-sample was pitted prior to freezing and received no thawing prior to processing as frozen (then baked) pie. air-frozen samples, thawed at 30 and 20°F, and also firmer than cherries pitted prior to air-freezing and not thawed prior to processing. Unpitted air-frozen cherries from lot AW, thawed and pitted at 40°F, along with cherries pitted prior to freezing, were significantly firmer than 83 Table 22. Sensory evaluation for significant textural difference between air- and R—lZ—frozen cherries thawed and pitted at 40°F and unthawed-pitted control, processed as baked pie. Lot Freezing Thawing Mean Signif.** Method (Temp.(°F) Score* 5% 1% PM R—12 40 6.7 PM R-12 P*** 6.7 PM Air 40 5.7 PM Air P*** 4.6 *Mean score of 22 panelists using 9-point rating scale (higher score indicates firmer texture. **Mean scores not connected by line indicate signi- ficant difference. ***P-sample was pitted prior to freezing and received no thawing prior to processing as frozen (then baked) pie. air-frozen cherries, thawed at 30 and 20°F. Unpitted "Freon"—frozen cherries from lot PM, thawed and pitted at 40°F, along with cherries pitted prior to "Freon"- freezing were significantly firmer than cherries thawed at 30°F. When unpitted air-and "Freon"-frozen cherries, thawed and pitted at 40°F, along with cherries pitted prior to freezing, were evaluated at the same panel ses- sion (Table 22), "Freon"-frozen cherries, pitted and un- pitted prior to freezing, were found to be significantly firmer than comparable air-frozen cherries, whether pitted before or after pitting. 84 The results discussed above were from sensory panels using a 9-point rating scale to evaluate samples. Results of another series of sensory panels, using Kramer's ranking procedures (Kramer, 1963), are compared to results obtained using the hedonic rating method in Table 23. In general, more significant differences between 4":qu 3 samples processed by different methods were found using the ranking procedure. This would be expected because the ranking test forces panelists to distinguish between samples whereas a rating test allows panelists to assign identical rating scores to more than one sample being evaluated. In most cases, panelists using the ranking procedure showed unpitted air- or "Freon"-frozen cherries, thawed and pitted at either 30 or 40°F, significantly firmer than cherries pitted prior to processing. In 2 out of 3 panel sessions, panelists found no significant differences in firmness between unpitted air-frozen samples, thawed and pitted at 20, 30, or 40°F. Unpitted "Freon"- frozen cherries from lot PM, thawed and pitted at 30°F, were firmer than either unpitted air-frozen cherries, thawed and pitted at 40°F, or cherries pitted prior to (airw-or "Freon"-freezing and not thawed prior to further Prwbcessing. No significant differences were found between airh and "Freon"-frozen cherries from lot RB. Inconsistency in sensory panel results was possibly due to the use of an untrained panel or, as already 85 Ne om Had mm oe «a«& Mad mm m.m Mara Had mm .m.z mm om NHIm mm .m.z a.e om Hafi mm mm saam malm mm H.e 0e Had mm oe oe Ha< 2m m.e ksam HH¢ 2m mm *««m Hafl 2m . . m.e oe Had Sm .m.Z m Z em **am NaIm Sm N.@ «*«m NHIm 2m wa om NaIm Sm e.w om Nalm Em mm *««m Nalm 2m mm om Nalm 2m e.m oe NaIm 2m .m.z mm oe mane zm .m.z p.m 44.6 maum 26 mm om Nalm Em N.m om Nalm 2m we «**m HH< 2m mm ON Had 2m m.e Myam Had 2m .m.z mm om Had 2m .m.z a.m om Had 2m pm oe Hafi 2m e.m oe Had Em ma Mm ream 15.5.5569 scrum: uoq ma wm .muoom 15.5.5569 oorumz non ««.masmam xcmm mca3mse meanwmum ««.macmam cums mca3mse msaummnm conumz meaxcmm ponumz mcaumm .mcaaaam mam cocsmo mm ommmmooum .aonucoo pouuamIcmzmnuss cam mousumummfimu ucouommao um wouuam can po3msu moaunono szoHMImaIm paw Imam How mponumfi msaxsmn cam msaumn mcams moocmuommac amasuxou unwoamasmam How msoaPMSaMPm whomcom mo cowaummaoo .mm magma 86 .msammooonm on moanm mca3mau os woPamomH paw meanomum ou HOHHQ popuam mm3 mamEMMImrrr .mocmuommap unmoamasmam mumoapca mcaa pa Umpomccoo nos monoom smmz*« .mumaamsmm ea on ma mo EDM xcmm .mnsuxwu HwEHam Monmoaoca muoom nonmanv mamom msaumu usaomlm m asams mumaamsmm mm mo whoom smmzr He om Had Om mm om Had om m.e om Had OH mm «a«& Mad Om H.m P**m Had Om pa oe Had om o.m oe Had Om oe %««m Had Bfl mm ON Hfld 3d m.w ON Hfld 3d .m.z rm om Mae 3e .m.z p.e .445 Mae ze mm oe Hafi Sm m.m oe Hafi Bfi mm oe NaIm mm pm om Nalm mm m.e ¥««m Nalm mm .m.Z Nm om NHIm mm .m.Z m.v 0v NHIm mm om «ram NHIm mm N.m om Nalm mm me 0N HH¢ mm 87 mentioned, variations between lots due to geographical location and harvest maturity. Bedford and Robertson (1955, 1962) related variations in firmness of frozen and canned cherries to climatic conditions and fruit maturity. Results of objective evaluation of firmness using the Allo-Kramer Shear Press are shown in Table 24. The results.are difficult to interpret as they are not con— sistent for any given thawing temperature or between all the lots evaluated. Variability among individual cherries within each lot interfered with accurate physical measure— -- ment of texture. Cherry skin also made accurate measure- ment of flesh firmness difficult. As shown in Table 25, correlation between shear force values and thawing temperature were excellent for some lots, such as PM (R-12) and RB (air), and poor for others. Shear force values did not correlate well with either panel scores (Table 27) or values for % weight loss (Table 28) for all lots and methods studied. Results of preference tests for cherries processed as canned pie filling (Table 26) showed that panelists were not consistent in their preference for any one freez- ing or thawing method. During panel sessions in which unpitted air-frozen lots, thawed and pitted at 20, 30, and 40°F, were presented along with cherries pitted prior to air-freezing and not thawed prior to processing, a 88 Table 24. Texture evaluation of cherries from canned pie filling using Kramer Shear Press. Shear Lbs. Force/125 gr.* Thawing o o o 0 *7: Temp. 20 F 30 F 30 F 40 F P Freezing . _ . _ . _ . _ . _ Method Air R 12 Air R 12 Air R 12 Air R 12 Air R 12 Lot PM 2.7 2.6 2.2 2.3 2.5 2.8 2.5 2.0 1.9 2.1 Lot RB 3.9 2.9 3.8 3.0 *** 2.9 3.7 3.2 3.4 2.8 Lot AW 2.4 - 2.7 - 2.5 - 3.3 - 2.4 - Lot E0 2.6 - 3.1 - 3.0 - 2.7 - 2.8 “ *Average of 5 replicates of 125 grams, calculated _ Rangiogetting X Maximum Peak. **P-sample pitted prior to freezing and received no thaw prior to further processing. as Shear Lbs. Force/125 gr. ***Value not determined. Table 25. Relationship between thawing temperature and shear force for air- and R-lZ-frozen cherries from canned pie filling. Freezing Correlation Std. Error LOt Method Coefficient Regression Eq. Estimate Slope PM Air -.34 y=.01x + 2.74 .23 .01 PM R-12 -.99 y=3.24 - .03x .04 .00 RB Air -.98 y=4.04 - .01x .01 .00 RB R-12 .74 y=.01x + 2.72 .10 .01 AW Air .79 y=.01x + 1.63 .29 .01 E0 Air .37 y=.01x + 2.59 .24 .01 ' “K ‘ 19" 3‘.- '!I =.‘. .- Table 26. 89 Results of texture preference tests for air— and R-lZ-frozen cherries thawed at various temperatures and processed as canned pie filling. Lot AW EO No. Panelists 12 12 Freezing Method Air Air Air Air Air Air Air Air Thawing Temp.(°F) % Preference** 20 30 40 P* 20 30 40 P* 0 0 67 33 PM Lot PM No. Panelists 14 14 Freezing Method Air Air Air Air Air Air R-12 R-12 Thawing Temp.(°F) % Preference** 20 30 40 P* 14 43 36 7 40 P* 30 P* 17 16 25 42 Lot PM RE No. Panelists 14 12 Freezing Method R-12 R-12 R-12 R-12 R-12 R-12 R-12 R-12 Thawing Temp.(°F) % Preference** 20 30 40 P* 29 21 21 29 20 30 40 P* 29 7 29 35 Lot RB No. Panelists 12 Freezing Method Air Air Air R-12 R-12 Thawing Temp.(°F) 20 30 P* 30 P* % Preference** 8 0 25 17 50 .*P-samp1e pitted prior to freezing and received no thaw prior to process1ng. **% of panelists indicated. 90 Table 27. Relationship between shear force and sensory panel score for cherries from canned pie filling. Lot PM - Air-frozen Thaw Temp.(°F) 20 35 40 30 Shear Force* 2.7 2.5 2.5 2.2 Panel Score** 5.2 5.5 5.6 5.0 Lot PM - R-lZ-Frozen Thaw Temp.(°F) 20 30 35 40 Shear Force* 2.6 2.3 2.1 2.0 Panel Score** 6.3 7.0 5.0 5.9 Lot RB - Air-Frozen Thaw Temp.(°F) 20 30 40 Shear Force* 3.9 3.8 3.7 Panel Score** 4.4 5.7 4.8 Lot RB - R-lZ-Frozen Thaw Temp.(°F) 20 35 30 40 Shear Force* 2.9 3.0 3.1 3.2 Panel Score** 4.9 5.6 5.7 5.1 Lot AW - Air-Frozen Thaw Temp.(°F) 20 35 30 40 Shear Force* 2.4 2.6 2.7 3.3 Panel Score** 4.9 5.3 5.3 6.0 Lot E0 - Air-Frozen Thaw Temp.(°F) 20 40 35 20 Shear Force* 2.6 2.8 3.0 3.1 Panel Score** 5.3 6.0 5.4 5.6 r=.44 y=.6lx + 3.80 SE=.30 Sb=.88 r=.52 y=l.62x + 2.37 Se=.88 Sb=1.90 r=-.47 y=20.77 -4.l4x Se=.82 Sb=7.61 r=.75 y=4.85x - 9.18 Se=.33 Sb=3.45 r=.94 y=1.15x + 2.19 Se=.11 Sb=.18 r=.04 y=.06x + 5.39 Se=.38 Sb=1.06 *Values from Table 24. **Values from Table 18. 1“...- Table 28. 91 Relationship between shear force and % weight loss for cherries from canned pie filling. Lot PM - Air—Frozen Thaw Temp.(°F) 20 35 40 30 Shear Force* 2.7 2.5 2.5 2.2 r= .55 y = 1.24 + 11.48x % Wt. Loss** 35.9 27.3 27.3 28.9 Se=4.23 Sb=12.25 Lot PM - R-lZ—Frozen Thaw Temp.(°F) 20 30 35 40 Shear Force* 2.6 2.3 2.1 2.0 r= .87 y=12.39x - .96 % Wt. Loss** 32.8 25.3 24.6 25.7 Se=2.35 Sb=5.06 Lot RB - Air-Frozen Thaw Temp.(°F) 20 30 40 Shear Force* 3.9 3.8 3.7 r= .98 y=66.57x-225.21 % Wt. Loss** 34.7 26.9 25.1 Se=1.06 Sb=9.86 Lot RB - R-12—Frozen Thaw Temp.(°F) 20 35 30 40 Shear Force* 2.9 2.9 3.1 3.2 r=-.56 y=93.24 -22.73x % Wt. Loss** 28.1 23.0 23.8 23.4 Se=2.66 Sb=27.6 Lot AW - Air-Frozen Thaw Temp.(°F) 20 35 30 40 Shear Force* 2.4 2.6 2.7 3.3 r=-.63 y=56.30 - 9.59x % Wt. Loss** 38.6 27.7 26.9 26.1 Se=5.67 Sb=8.45 Lot E0 - Air—Frozen Thaw Temp.(°F) 20 40 35 30 Shear Force* 2.6 2.7 3.0 3.1 r=-.67 y=88.68 -20.03x % Wt. Loss** 40.2 26.5 29.2 28.1 Se=5.76 Sb=15.96 *Values from Table 24. **Values calculated using data from Table 10 and equation 2 of section IV B. 92 greater % of panelists preferred the former, as shown in Table 26 for lots AW, E0 and PM. When presented unpitted "Freon"-frozen lots, thawed and pitted at 20, 30 and 40°F, along with cherries pitted prior to "Freon"—freezing, there was a slight % of preference for the latter. As shown in Table 26 for lots PM and RB, "Freon"-frozen cherries were preferred by a greater % of panelists to comparable air-frozen samples, regardless of whether they were pitted before freezing or pitted after freezing and thawing. ‘1 Relationship Between % Weight Loss and Texture of Chergigg Processed as Canned Pie Filling Low correlations were obtained between shear press values from Table 24 and texture panel scores from Table 18, as shown in Table 27. Correlation between shear force values as a measure of texture (Table 24) and % weight loss (as calculated from drained weight data in Table 10) was generally low, as shown in Table 28. Correlation between panel scores from Table 18.and % weight loss values (Table 10) were also low, as shown in Table 29. Table 29. 93 Relationship between sensory panel score and % weight loss for cherries from canned pie filling. Lot PM - Air-Frozen Thaw Temp.(°F) 40 35 20 30 Panel Score* 5.6 5.5 5.2 5.0 % Wt. Loss** 27.3 27.3 35.9 28.9 Lot PM - R-12-Frozen Thaw Temp.(°F) 30 20 40 35 Panel Score* 7.0 6.3 5.9 5.0 % Wt. Loss** 25.3 32.8 25.7 24.6 Lot RB - Air-Frozen Thaw Temp.(°F) 30 40 20 Panel Score* 5.7 4.8 4.4 % Wt. Loss** 26.9 25.0 34.7 Lot RB - R-lZ-Frozen Thaw Temp.(°F) 30 35 40 20 Panel Score* 5.7 5.6 5.1 4.9 % Wt. Loss** 23.8 23.0 23.4 28.1 Lot AW - Air-Frozen Thaw Temp.(°F) 40 35 30 20 Panel Score* 6.0 5.3 5.3 4.9 % Wt. Loss** 26.1 26.9 27.7 38.6 Lot E0 - Air-Frozen Thaw Temp.(°F) 40 30 35 20 Panel Score* 6.0 5.6 5.4 5.3 % Wt. Loss** 26.5 28.1 29.2 40.2 r=-.47 r= .26 r=-.59 ='.71 r=-.75 r=-.72 y=67.l8 - 7.01x Se=4.5 Sb=9.46 y=l.22x + 19.71 Se=4.59 Sb=3.16 Se=5.6 Sb=6.18 y=47.86 - 4.37x Se=2.07 Sb=3.02 y=82.22 - 9.74x Se=4.79 Sb=6.04 y=112.44-14.61x Se=5.34 Sb=9.67 *Values from Table 18. **Values calculated using data from Table 10 and equation 2 of section IV B. 94 Results of Further Tests on Processing and Evaluation Methods for Unpitted Frozen Cherries Weight of sample immersed in 16 to 18 gallons of thawing solution at various temperatures was found to in— fluence the internal sample temperature, as measured by insertion of thermocouples into a representative sample (Appendix, Test 9). When using 16 to 18 gallons of thaw- ing solution at 40°F for thawing unpitted frozen cherries, the frozen weight of cherries should not exceed 2700 grams. Use of quantities in excess of 2700 grams resulted in fail- ure of internal cherry temperature to reach thawing solution temperature in the time specified in Table 35. Thawing 2700 to 4400 grams of frozen cherries in 16 to 18 gallons of thawing solution at 45°F, resulted in internal cherry temperature reaching 40°F within the time specified in Table 35. Appendix Test 10 compared calculation of % weight loss and % pit loss, as described in Section IV—A (Special Study), with those made during actual processing of canned pie filling as described in Section IV-B. Calculating % weight loss (Table 38) during pitting, by weighing total amount of juice loss during actual pro- cessing (Section IV-B), resulted in slightly lower % weight loss values for some lots, and slightly higher values for others, as compared with calculation of % weight loss made 95 by weighing pitted fruit and pits during special study described in Section IV-A. These differences may be attributed to the difference in sample size used for both calculations. Also, % flesh loss is not included in cal- culation of % weight loss by weighing juice directly (Section IV-B). The results of % pit loss calculations were similar for both studies (Table 39). Table 40 shows results of texture evaluation of cherries processed by 2 procedures (see Appendix, Test 11). Comparable statistical results were not obtained for cherries processed by the different methods described. As shown in Figures 4-7, juice loss increased with in- creased holding time prior to processing. Table 41 shows greater % weight loss of cherries for process I, in which larger quantities of cherries were processed, requiring longer pitting and holding times. Sample "P" which was pitted prior to freezing and was not thawed or held prior to filling, showed little difference in % weight loss. Therefore, pitting time, and holding time prior to fill- ing cherries into canned pie filling are critical periods as far as weight loss and possibly texture of the finished product are concerned. Cherrngie Formulation Preparation of dry mix, using a 1:10 ratio of starch to sugar, resulted in better consistency of baked 96 pie filling, as compared to using a 1:7, 1:9, 1:11, or 1:15 ratio, when compared to commercially baked pie con- sistency (Appendix, Text 12). A better consistency was obtained by using a 1:2.4 ratio of fruit to dry mix, as compared to 1:1 and 1:2 ratios. Baking conditions were very important. Baking at 400°F for 65 minutes in a large commercial over (A. J. Fish Co.) resulted in filling consistency comparable to commercially prepared pies. When using lower baking temperatures (300 to 350°F) and/or shorter baking times (30 to 45 min.), consistency of pie filling was very "soupy." Shriveled cherries were observed in pie fill- ing after baking at higher temperatures (425 to 450°F) and/or longer times (75 to 90 min.). Effect of Freezing Pie After Preparation 27 The results obtained comparing texture of cherries from pies refrozen prior to baking with those baked direct- ly (Appendix, Test 14) showed that cherries from refrozen pies were significantly firmer in texture. However, it was also noted that only when using prepared slurry for re- frozen pies was the general appearance comparable to that of commercially prepared pie. It is possible that shriveled cherries may appear firm to panel members and result in inaccurate evaluation of desired texture quality for cherries in baked pie. 97 Further studies, as those described in Appendix, Test 14, are necessary. Compression Measurement Results of procedures using the Instron Universal Testing Instrument to measure compression values for un- pitted air-frozen cherries, thawed and pitted at 20 and 40°F (Appendix, Test 13), show no significant difference between cherries thawed at those temperatures (Table 42). Kramer shear press values for the same sample indicate significant difference (Table 42). Sensory panel results (Table 18) for the same samples indicate no significant difference. More extensive studies, as those prepared in Appendix, Test 13, may result in development of an objec- tive measure of cherry texture using the Instron, which will correlate with sensory evaluation to a greater ex- tent than the Kramer Shear Press values (Table 27). SUMMARY AND CONCLUS IONS Red tart cherries from four orchards in Michigan were frozen unpitted and pitted using either air at -10°F or by direct immersion in "Freon" refrigerant (dichloro- difluoromethane) at -25 to -35°F. Thawing of unpitted frozen cherries was accomplished by immersion in either 40% (by weight) aqueous ethylene glycol or 20 to 25% (by weight) aqueous propylene glycol thawing solutions. Temperature of the thawing solution affected % weight loss of cherries during pitting and during a 62 minute holding period after pitting. Immersion of un— pitted air-frozen cherries in thawing solution at 20 or 25°F resulted in lower % weight loss (2 min. after pit- ting) as compared with cherries thawed at 30 or 40°F. This was attributed to the partially thawed condition of cherries thawed and pitted at 20 and 25°F as compared to complete thawing of cherries at 30 or 40°F. ' As holding time after pitting increased, weight loss increased more rapidly for cherries thawed at 20 and 25°F as compared with those thawed at 30 and 40°F. This was attributed to greater tissue damage for cherries thawed at 20 to 25°F as a result of greater recrystalli- zation during thawing, mechanical damage during pitting, 98 :n Ilq 0 I. A 99 and to the formation of smooth channels during pit removal in partially thawed fruit which allows for more rapid juice loss as compared to juice lost during pitting of completely thawed cherries. "Freon"-freezing of unpitted cherries resulted in less % weight loss during pitting and during a 62 minute holding period after pitting, when compared with unpitted air-frozen cherries. This was attributed to less tissue damage caused by smaller ice crystal formation when cherries were rapidly frozen by immersion in "Freon" refrigerant. Immersion of unpitted frozen cherries in thawing solution for periods of 5 to 90 minutes did not greatly affect % weight loss during or after pitting for a one hour period. Variations in % weight loss between differ- ent lots were attributed to possible variations in clima- tic conditions, field conditions, and/or harvest maturity. Percent of pit removal was greater for unpitted air- and "Freon"-frozen cherries thawed at 20 or 25°F as compared to 30 or 40°F. This was attributed to pits being held firmly in place due to the firmer tissue structure of partially frozen cherries. Air- and "Freon"-frozen cherries, whether pitted before or after freezing, were processed as canned pie filling and evaluated for textural quality by sensory panels and Kramer shear press measurements. Percent 1...; 100 weight loss during processing was calculated from washed drained weight measurements. Thawing unpitted air- and "Freon"-frozen cherries at 20 or 25°F before pitting, resulted in higher % weight loss during further processing of cherries as canned pie filling when compared to 30 or 40°F thawing temperatures. It was shown, however, that total % of weight loss, for both air— and "Freon"—frozen I» .v‘ "nan.“ i l unpitted cherries, calculated as the sum of % weight loss .;. during pitting plus % weight loss during further process— ing, was comparable for any thawing temperature used. Total % weight loss of unpitted "Freon"-frozen samples was less for each thawing temperature used, as compared to air-frozen cherries. 0n the basis of total % weight loss during pitting and further processing, partially thawing unpitted frozen cherries at 20 or 25°F was advantageous. Juice was held in the cherry during pitting and lost in the final product during processing. Unpitted air- and "Freon"-frozen cherries were comparable in total % weight loss during pitting and further processing to cherries pitted prior to freezing and not thawed prior to further processing as canned pie filling. Results of texture evaluation by sensory panels were not consistent for all lots tested. This was attri- buted to use of untrained panel members and possible 101 variations in lots due to geographical location of harvest and harvest maturity. Generally, based on sensory panel evaluations, either unpitted air- or "Freon"—frozen cherries thawed and pitted at 30 or 40°F were significantly firmer than those thawed and pitted at 20°F, or there was no statisti— cally significant difference between cherries thawed at any temperature. Unpitted air- and "Freon"—frozen cher- ries, thawed and pitted at 30 or 40°F, were significantly firmer than those pitted prior to freezing and not thawed prior to further processing. Generally, unpitted and pitted "Freon"—frozen cherries were significantly firmer as compared to unpitted and pitted air- frozen cherries. This was attributed to less tissue damage as a result of rapid freezing. Panelists did not always prefer the cherries they judged firmest in texture. Unpitted air— frozen cherries, thawed and pitted at 30 or 40°F were generally preferred over those thawed and pitted at 20°F. There was no general preference for unpitted "Freon"— frozen cherries, thawed at 30 or 40°F, over those thawed at 20°F. Unpitted and pitted "Freon"-frozen cherries were preferred by a larger % of panelists over unpitted and pitted air- frozen cherries. Objective measurements for texture, using the Kramer Shear Press, could not be correlated with thawing temperatures used for unpitted air- and "Freon"—frozen 102 cherries. Shear press results did not correlate with sensory panel results. Variability among cherries within each lot was thought to interfere with accurate physical measurement of texture. Cherry skin interfered with accurate measurement of flesh firmness. An attempt was made to develop a procedure for measuring compression of cherries using the Instron Universal Testing Instrument. Limited sample prevented thorough investigation of the feasibility of this procedure. Relationship between re— sults of sensory panel evaluation of texture and % weight loss during processing of canned pie filling could not be established. Unpitted air— and "Freon"-frozen cherries were thawed at 20, 25, 30 and 40°F, refrozen and processed further as baked pie. Results of sensory panels were similar to those obtained for cherries from canned pie filling. Unpitted air-frozen cherries, thawed and pitted at 40°F were significantly firmer than those thawed and pitted at 20°F. "Freon"-frozen cherries were signifi- cantly firmer than air-frozen cherries, regardless of whether they were pitted before or after freezing and thawing. Total % weight loss for unpitted air— and "Freon"-frozen cherries, thawed at 20, 30 and 40°F, was higher for cherries processed as baked pie, as compared to cherries from canned pie filling. The greater % weight loss was attributed to additional tissue damage during :I' 311p 103 refreezing of frozen and thawed cherries prior to baking, use of dry mix instead of prepared slurry, and the baking operation itself. Considering that total % weight loss during pitting and further processing was comparable for all thawing tem- peratures used for unpitted air- and "Freon"-frozen cherries, it is the conclusion of the author, based upon sensory panel results, that thawing unpitted air- or "Freon"— frozen cherries at temperatures of 30 to 40°F is a feasible process which assures quality of final product comparable VA (7-.“ '-..“'k "‘ 6' to that obtained for cherries pitted prior to freezing. “*7 Furthermore, freezing unpitted cherries by immersion in "Freon"12 results in lower % weight loss during processing and firmer texture of final product, as compared with freezing unpitted or pitted cherries in air. However, this does not suggest that all of the possible freezing methods which might be used to freeze cherries at a slower rate than that obtained by "Freon“12 immersion would give results similar to those found in this study. REFERENCES 10. 11. REFERENCES Amerine, M. A., R. M. Pangborn and E. B. Roessler. 1965. Principles of sensory evaluation of food. Academic Press, New York. pp. 275-336; 360-354. Anon. 1969. DuPont demonstrates new freezing I system. Canning Trade. 91(18)8:22. Bartlett, L. H., and H. E. Brown. 1941. A new QUiCk freezing system. Refrigerating Engineer- 3 ing. 42:83-87. , 1 Bedford, C. L. 1970. Personal communication. k . Bedford, C. L. 1971. Personal communication. Bedford, C. L., and W. F. Robertson. 1955. The effect of various factors on the drained weight of canned red cherries. Food Technology. 9:321- 323. Bedford, C. L., and W. F. Robertson. 1957. Effect of handling and processing methods on the firm- ness and quality of canned and frozen red cherries. Mich. 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The effect of nitrogen, potassium and SADH on yield, quality and vegeta— tive growth of sour cherries (Prunus cerasus, L. var. Montmorency). PhD. Thesis, Michigan State University. Dow Chemical Company, 1965. Dowfrost heat transfer fluid-effective down to -28°F. Form No. 176—560-69, p. 14. Downing, D. L., W. G. Huehn and R. L. LaBelle. 1971. Handling of red tart cherries for processing--a review. New York Food and Life Sciences Bulletin. ' N. Y. State Agr. Expt. Sta. 11:4. t-; - - _. a.” mu".- Fennema, 0., and W. D. Powrie. 1964. Fundamentals of low-temperature food preservation. In "Advances in Food Research, Volume 13," C. 0. Chichester, E. M. Mrak and G. F. Steward (eds.). 'Academic Press. New York, pp. 219-330. Finkle, B. J., E. Sa B. Pereira and M. S. Brown. 1971. Prevention of freeze damage to vegetable and fruit tissues by ultra-slow cooling. Int. Inst. of Refrigeration Bull. Annexe. In Press. Finney, E. E., Jr. 1969. Objective measurement for texture in foods. 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Published by the author. 5th ed., p. 94-97. 55. 56. 57. 58. 59. 60. 109 Sterling, C. 1959. Drained weight behavior in canned fruit: an interpretation of the role of the cell wall. Food Technology. 13:629-634. Tennes, B. R., R. G. Diener, J. H. Levin and R. T. Whittenberger. 1967. Firmness and pitter loss studies on tart cherries. Amer. Soc. Agr. Engr., 60th Ann. Mtg., Paper No. 333, pp. 4-6. Weil, K. 0., T. W. Moeller, C. L. Bedford and W. M. Urbain. 1970. Microwave thawing of individually quick frozen red tart cherries prior to pitting. Journal of Microwave Power. 5(3):188. Whittenberger, R. T. 1952. Factors which affect the drained weight and other characteristics of heat-processed red cherries. Food Research. 17:299. Whittenberger, R. T., and R. E. Marshall. 1950. Measuring the firmness of red tart cherries. Food Technology. 4(7):311-312. Whittenberger, R. T., H. P. Gaston and J. H. Levin. 1964. Effect of recurrent bruising on the pro- cessing of red tart cherries. Res. Rpt., Mich. Agr. Expt. Sta. 4:4. APPENDIX cell:- l‘ APPENDIX Preliminary Studies: To develop a feasible thawing procedure for unpit- ted frozen cherries the following factors were investigated: 1) Type of thawing media and equipment to use 2) Time and temperature conditions 3) Size of experimental samples 4) Method of evaluating effects of thawing procedure. Test 1: Effect g£_Agueous Ethyle2§_Glycol Solution at Various Temperatures on ThaWifig of Unpitted Frozen Cherries. 50 grams of unpitted air-frozen cherries from lot AW were thawed at temperatures ranging from 18 to 50°F in 40% (by wt.) ethylene glycol for periods of 10 to 30 minutes. Afterwards, they were hand-pitted using a No. 50 Standard Corporation Hand Pitter. Thawing procedure was the same as described in section III. Results of Test 1 are given in Table 30. Test 2: Length of TimeINecessary_for Frozen Cherries to Reach Thawing Solution Temperature. ~« 200 or 250 gram samples of unpitted air-frozen cherries from lot AW were thawed at 20 and 30°F in 40% (by wt.) ethylene glycol. Thermocouples, which had been 110 111 .wcoauapcoo o>onm co mfiau GOaMHmEEa mo poommm oc “muam o“ mcaHMSUm Ammam on on “00a accuouca oc ammOa moasn «o #:5086 mmuma om “unappam moansp saxm paw smoam mo mcaumou unmaam oa om om . .mcoauaccoo m>onm co mfiau coam IHmEEa mo pommmm oc “muam 0p mcanoncm smmam on on “moa amcumpca oc «mmoa moasn mo unsOEm aamfim mum> om umcaupam mcanoc caxm cam smmam Ho mcaumou unqaam oa mm om .mcoauaocoo m>onm co oEau coamnoEEa mo uommmw oc “ova accuopca no 025066 unmaam om “mmoa coach on “yam sua3 pm>ofimu smwam “mcau om luau mcaHSU moannono mo mcaxomuo mmma paunmaam oa mm om .mcoauaccoo o>onm :0 08a» coamumfifia mo uoommo on “ova accuouca manm om Iumoamcoo «mmoa moasm on “Mad nua3 cm>oEmn Smeam om “mcauuam mcamsc moanumco mo ocaxomno m>ammmoxm oa ma om A.casv oEaB Ahoy.mEmB Amficumv mucoEEou GOamuoEEa measmce moannmnu .uB .mofiau coamuoEEa com mmusucuomamu mooaum> pm aoomam ocmamnum msomnvm ca moauumno omuuamss mca3msu mo uommmm .om manna 112 inserted into the cherries prior to freezing, were attached to the Multi/Riter Recorder (Texas Instrument Corp.) and thawing rate was determined as the time necessary for temperature of the frozen cherries to reach thawing solu- tion temperature. Thawing procedure used was the same as described in Section III. Results of Test 2 are given in Table 31. Test 3: Effect of Immersion Time on Drained Weight of Pitted Fruit 200 gram samples of unpitted air-frozen cherries from lot AW were immersed in 40% (by wt.) ethylene glycol solution at 30°F, for the time necessary to reach thawing solution temperature (Table 31) plus 1, 5, 10, 15, and 30 minutes. Samples were pitted and drained weights re- corded after 2 minutes holding and at 5 minute intervals, thereafter, for 1 hour. Thawing and drained weight pro- cedures were the same as described in Section III. Results of Test 3 are shown in Table 32. Test 4: Effect of Thawing Temperature on Drained Weight of Pitted Fruit. 200 gram samples of unpitted air-frozen cherries from lot AW were immersed in 40% (by wt.) ethylene glycol and water at 20 and 30°F for the time necessary to reach thawing solution temperature (Table 31) plus 10 minutes. Samples were pitted and drained weights recorded 2 minutes 113 Table 31. Effect of thawing temperature and sample weight on immersion time. := Wt. Cherries* Thawing Solution Storage Temp.** Immersion (grams) Temperature(°F) (°F) Time(min.)*** 200 20 4 - 6 4 250 20 4 - 6 4 200 30 4 - 6 25 250 30 4 - 6 25 *Frozen weight. **Temperature after removal from -10°F freezer and prior to immersion in thawing solution. ***Time necessary for sample to reach thawing solu- tion temperature: average of 5 replications. later and at 10 minute intervals, thereafter, for 1 hour. Thawing and drained weight procedures were the same as described in Section III. Results of Test 4 are shown in Table 33. Test 5: Effect of Sample Size on Drained Weight After Pitting. 200 or 300 gram samples of unpitted frozen cherries from Lot PM were immersed in 40% (by wt.) ethylene glycol at 40°F for the time necessary to reach thawing solution temperature, as measured by inserting thermo- couples into cherries after partial thawing, plus 10 minutes. Samples were pitted and drained weight recorded 114 Table 32. Effect of immersion time on drained weight of pitted fruit. Time Drained Weight (grams)* After “ Pitting Immersion Time in Aqueous Ethylene Glycol** (min.) 10 Min. 14 Min. 19 Min. 24 Min. 39 Min. 2 167.0 167.3 169.6 167.3 171.6 7 162.6 164.3 165.3 164.0 167.0 12 161.0 160.6 163.0 162.0 165.3 17 158.0 158.6 16.13 160.6 162.3 22 157.0 158.0 160.3 158.6 160.0 27 156.0 157.0 158.3 158.3 158.3 32 155.6 155.3 158.0 156.3 157.6 37 154.3 155.0 156.6 154.3 157.0 42 152.3 152.3 154.6 153.3 156.3 47 150.0 151.3 153.6 152.6 155.3 52 150.0 150.6 153.3 152.3 154.0 57 149.3 150.3 153.0 152.3 153.6 62 149.0 149.6 152.6 152.0 153.3 0 .I'J "I *Average of 3 replications based on 200 gram frozen weight of sample prior to pitting. **Time includes 25 min. period necessary to raise sample temperature to thawing solution temperature of 30°F. 115 Table 33. Effect of thawing temperature on drained weight of pitted fruit. Time After Drained Weight (grams)* Pitting (min.) Thawing Solution Temperature** 20°F . _ 30°F 2 183.4 167.6 12 182.2 161.0 22 177.4 158.3 32 168.0 155.0 42 158.8 153.3 52 153.8 151.3 62 149.2 150.0 *Average of 3 replications based on 200 grams frozen weight of sample prior to pitting. **Aqueous ethylene glycol (40% by wt.). Table 34. Effect of sample size on drained weight of pitted fruit. Sample Size (Frozen Wt.) Time Piitigg 200. grams 300 grams (min.) Drained Wt.* % Wt. Drained Wt.* % Wt. (grams) Loss (grams) Loss 2 176 12 254 15 12 171 15 247 18 22 168 16 243 19 32 166 17 240 20 42 165 18 238 21 52 164 18 236 22 62 ‘ 162 19 234 22 *Average of 3 replications. 116 2 minutes later and at 10 minute intervals, thereafter, for 1 hour. The % weight loss was calculated as follows: Equation 4. Frozen Wt. of Cherries -2 Min. Dr. Wt. X 100 Frozen Wt. of Cherries % Wt. Loss = Equation 4 includes pit loss. Thawing and drained weight procedures used were the same as those described in Sec- tions III and IV A. Results of Test 5 are given in Table 34. Test 6: Immersion Time Necessary to Raise Temperature of Unpitted Frozen Cherries to Thawing Solution Temperature. Each 200 gram sample was thawed by immersing it in 20% (by wt.) aqueous propylene glycol. Time necessary to reach each thawing solution temperature (20, 25, 30, and 40°F) was determined for each of the lots (AW, E0, PM, and RB) by inserting thermocouples into cherries after partial thawing and recording temperature increases using the Multi/Riter Recorder (Texas Instrument Corp.). Three thermocouples were inserted into 3 cherries per 200 gram sample from each lot. Thawing and drained weight proce- dures used were the same as described in Section III and IV A. Results are shown in Table 35. As shown in Table 35, it took longer for internal cherry temperature to reach 30°F as compared to 20, 25 and 40°F. This might be explained by considering the length IT i 1‘ 117 Table 35. Time necessary for frozen cherries to reach thawing solution temperature Lot Thawing Solution Time Necessary to Temperature (°F)* Reach Temp. (m1n.)** AW 40 12 AW 30 28 AW 25 9 AW 20 4 PM 40 19 PM 30 30 PM 25 11 PM 20 8 E0 40 15 E0 30 25 E0 25 9 E0 20 4 RB 4O 14 RB 30 23 RB 25 10 RB 20 7 *Aqueous propylene glycol (20% by wt.). **Average time of 3 replicates, initial temperature 4-6°F. 118 of time necessary to traverse the zone of maximum ice crystal formation (freezing point approximately 28.5°F) of cherries. When immersing frozen cherries in a 30°F thawing solution a smaller temperature differential exists between cherries and thawing medium when compared to im- mersing cherries in a 40°F thawing solution. Time to "1 traverse the zone of maximum ice crystal formation is 1 less when the temperature differential is greater. There- fore, using a higher thawing temperature (above the freez- -.. .nw 431." E'IYH ing point of cherries) results in shorter thawing time. " k- Test 7: Effect of Ambient Temperature and Relative Humidity on Drained Weight. Drained weight measurements were made in Room No. 124, Food Science Building. Relative humidity in this room ranged from 50 to 65% during drained weight measure- ments, as measured using the Electric Hygrometer Indicator (Model 15-3001) with Violet Colored Hygrosensor. Ambient temperature averaged 80°F (14°F) during drained weight measurements. Test 7 was designed to measure ambient temperature and R. H. effects on drained weight in the above ranges. 200 gram samples of unpitted air-frozen cherries from lot AW were immersed in 40% (by wt.) ethy- lene glycol and water at 40°F for 22 minutes. Samples were pitted and drained weight measured 2 and 62 minutes 119 later (see Section III and IV A for thawing and drained weight procedures). Results are given in Table 36. Table 36. Effect of ambient temperature and relative humidity on drained weight. . . % Wt. Loss L Thawing Immigr 31°“ M‘blent After Pitting g: ot a Time % R.H. Temp. Temp.( F) (min ) (OF) ' 2 62 min. min. I AW 30 5 64 84 12 23 ! AW 30 5 60 84 12 23 I L AW 30 5 51 84 14 23 AW 30 5 ** 76 15 22 AW 30 5 ** 80 12 21 *Average of 3 replicates calculated from drained weight measurements after pitting. **Value not recorded. Test 8: Effect of Freezing Method on Texture of Processed Cherries-:Propylene Glycol as a Substitute for Ethylene Glycol. A 3-gallon solution of Dowfrost Inhibited Propylene Glycol (Dow Chemical Co.) and water was prepared (20% by weight--according to specifications in From No. 176-560-69, Dow Chemical Co., and calculations by Pearson Square pro- cedure, Sommer, 1949). The solution of aqueous propylene glycol was poured into two 30 lb. tin cans (1 1/2 ga1./can) which was immersed in 40% (by wt.) aqueous ethylene glycol 120 in the Constant Temperature Bath (American Instrument Co.). 285 grams of unpitted air- and "Freon"-frozen cherries from lot EO were immersed in the aqueous propylene glycol at 25°F for 36 minutes, then pitted and processed as baked pie. Pies were prepared by mixing the following ingre- dients and adding them to a 9" frozen pie shell: Ingredient Quantity (grams) Cherries 256 to 260 Sugar 121 Starch 17 Salt 0.5 Water 121 Top crusts were prepared from Pillsbury Pie Crust Mix. The pies were baked for 40 minutes at 400°F in a Market Forge Air Convection Oven. Cherries pitted prior to freezing were thawed in air at 78°F for 30 minutes and processed as cherry pie. All cherries, after baking, were evaluated for general appearance, flavor and texture by 5 judges, who scored each quality characteristic by assigning a number from 1 to 5 (l=excellent; 5=poor). Results were as follows: Pie I Cherries pitted prior to freezing at -lO°F; thawed for 30 minutes in a single layer at ambient temperature (78°F). Pie II Cherries unpitted prior to air freezing at -10°F; thawed by immersion in 20% (by wt.) propylene glycol and water solution. Pie III Cherries unpitted prior to "Freon"-freezing; thawed by immersion in 20% (by weight) propylene glycol and water. 121 General Appearance Flavor Texture Pie I 5.0 4.0 4.5 Pie II 2.5 3.0 4.0 Pie III 1.0 2.5 2.5 When processed as baked pie, unpitted "Freon"- frozen cherries, thawed in 20% (by wt.) propylene glycol and water solution at 25°F for 36 minutes were found to be firmer in texture and more acceptable in flavor and av— general appearance than unpitted air-frozen cherries, thawed by the same procedure. Both unpitted "Freon"- and “wwn—l air-frozen cherries were judged firmer in texture and more acceptable in flavor and general appearance than cherries pitted prior to freezing and thawed in air at 78°F for 30 minutes. There was no detectable off—flavor attributed to propylene glycol. Test 9: Temperature Correction for Thawing Large Qauntities of Cherries. Samples of unpitted air- and "Freon"-frozen cherries, in 2700, 3000, 4200 and 4400 gram quantities, were thawed at 20, 30, 40 and 45°F. Thermocouples (copper, 0.18" diam.; constantan, 0.19" diam.) were inserted into a representative sample (approximately 3 cherries per quantity) after partial thawing and internal cherry temperature recorded 10, 15, 20, and 25 minutes after immersion in thawing solution. 122 At thawing solution temperatures of 20 or 30°F, cherries reached thawing solution temperature within the period specified for each lot in Table 35. As shown in Table 37, cherries thawed in quantities of 2700 grams or greater did not reach a thawing solution temperature of 40°F within the period specified for each lot in Table 35. Setting thawing solution temperature at 45°F resulted in cherries (quantities greater than 2700 grams) reaching 40°F within specified immersion time (Table 35). Test 10: Comparison of Methods for Measuring % Weight Loss. During processing of canned pie filling as described in Section IV B., measurements were made of % weight loss (juice) during pitting by collecting the juice from pitted cherries after draining for approximately 1 to 5 minutes on 1/4" mesh wire "drained weight" screens. Juice was weighed directly and % weight loss during pitting calculated using the following equation: Equation 5. Juice Weight Initial (Piozen) Sample Wt. X 100 % Wt. Loss = These results represented direct measurement of juice loss during pitting stage of the processing operation for canned pie filling. The values used in Tables 12 and 15 for % weight loss during pitting were calculated from drained weight data (Tables 10 and 13) according to methods 123 Table 37. Effect of sample size on thawing temperature. . Internal Sample Thaw1ng Soak Lot fizifigg Size* Temp. Time ngggy (grams) (°F) (min.)** (6F)*;* RB Air 2700 40 15 38 RB Air 2700 40 20 38 RB Air 2700 40 25 40 AW Air 3000 40 20 37 AW Air 3000 40 22 38 AW Air 3000 40 25 39 PM Air; R-12 4200 40 25 35 AW PM Air 4400 45 10 38 E0 AW PM Air 4400 45 15 40 E0 AW PM Air 4400 45 25 40 E0 PM R-12 3900 45 10 38 PM R-12 3900 45 15 40 PM R-12 3900 45 25 40 *Based on frozen weight of sample. **Total immersion time in thawing solution. ***Measured by inserting thermocouples in 5 cherries. 124 described in Sections III and IV A. and Equation 1, page 22. These indirect measurements of % weight loss were used in Tables 12 and 15 because they represented both juice and flesh loss. Also, values were calculated more accurately (exactly 2 min. after pitting for 3 replicates at each thawing temperature used) during the "special study" (Section IV A) as compared to actual processing. A comparison of % weight loss, measured directly (Equation 5) and indirectly (Equation 1, Section IV A) is shown in Table 38. The % pit loss was calculated during actual processing (Section IV B). These values are compared to those calculated in Section IV A (Table 39). Test 11: Effect of Processing Procedures on Texture of Cherries from Canned Pie Filling. Two processing methods were used to prepare canned pie filling from lot E0. Processing Method I is described in Section IV B. Processing Method II was similar to Method I with the following modifications: I l) Smaller quantities of cherries (300 grams) were used. Total quantity thawed, pitted and canned was approximately 1200 grams. 2) Time between removal of cherries from thaw- ing solution and filling was reduced. The effect of time and size of sample (Process I and II) during processing on texture of final product is shown in 125 Table 38. Comparison of values for % weight loss obtained during special study and actual processing. Special Study* Actual Processing** Thawing Lot Tfmp' Sample Wt. % Wt. Sample Wt. % Wt. ( F) (grams) Loss (grams) Loss E0 20 200 2.4 3600 0.0 E0 30 200 14.9 4200 13.7 E0 40 200 13.1 4400 12.1 AW 20 200 3.0 3000 0.0 AW 30 200 13.0 4200 10.7 AW 40 200 13.0 4400 12.1 PM 20 200 4.7 3000 0.0 PM 30 200 8.6 4200 9.7 PM 40 200 10.3 4400 13.4 RB 20 200 2.5 3000 0.0 RB 30 200 7.6 4200 11.5 RB 40 200 10.1 4400 12.6 PM*** 20 200 4.2 3600 0.0 PM*** 30 200 3.4 3900 3.2 PM*** 40 200 3.5 3900 6.0 RB*** 20 200 2.0 3600 0.0 RB*** 30 200 4.0 3900 5.3 RB*** 40 200 4.9 3700 6.0 *Average % Wt. Loss of 3 replicates based upon frozen wt. prior to thawing and pitting; measured indirectly and includes juice and flesh loss (see Appendix, Test 10, and Section IV A of Methods and Materials). **Percent Wt. Loss based upon total amount of juice collected during pitting; measured directly as juice loss (see Appendix, Test 10 and Section IV B of Methods and Materials). ***Indicates R-12 Frozen sample, otherwise Air- Frozen. 126 Table 39. Comparison of values for % pit loss obtained during special study and actual processing. Thawing Special Study* Actual Processing** LOt $f?§' Sample Wt. % Pit Sample Wt. % Pit (grams) Loss (grams) Loss E0 20 200 4.6 3600 5.1 E0 30 200 4.1 4200 4.0 E0 40 200 4.4 4400 4.3 AW 20 200 5.1 3000 5.6 AW 30 200 4.7 4200 4.4 AW 40 200 4.7 4400 4.7 PM 20 200 5.0 3000 4.5 PM 30 200 4.7 4200 3.9 PM 40 200 4.5 4400 4.7 RB 20 200 4.5 3000 4.6 RB 30 200 4.1 4200 4.0 RB 40 200 4.2 4400 2.5 PM*** 20 -- -- 3600 4.5 PM*** 30 -- -- 3900 4.1 PM*** 40 -- -- 3900 4.6 RB*** 20 -- -— 3600 5.0 RB*** 30 -- -- 3900 -- RB*** 40 -- -- 3700 5.1 *Average % Pit Loss of 3 replicates based upon frozen wt. prior to thawing and pitting (see Sec. IV A). **Percentage Pit Loss based upon total weight of pits collected during pitting (see Section IV B). ***Indicates R-lZ-Frozen sample, otherwise Air— Frozen. 127 Table 40. The effect of processing method on % weight loss at various thawing temperatures is shown in Table 41. Test 12: Formulation of Cherry Pie A major problem in preparing frozen pies, using dry mix instead of slurry, was that during baking the starch and sugar settled to the bottom of the pie shell and the consistency of the slurry was very "soupy." Various starch/sugar ratios were tried: 1:7; 1:9; 1:10; 1:11; 1:15; and the 1:10 ratio resulted in better consis- tency as compared to that obtained with commercial sample (Chef Pierre Hi-Pie). Using 1:1; 1:2; and 1:2.4 ratios of cherries to dry mix, the 1:2.4 ratio resulted in fill- ing comparable to commercial pie. Various baking times were used--60 min.; 65 min.; 70 min.; 80 min.; 90 min.; and 100 min. at various oven temperatures of 400°F, 425°F, and 450°F in different ovens (Fish, A. J. Fish Co., Market Forge, Model 186 C—2, General Electric). Pies baked in the Fish Oven at 400°F for 65 minutes had con- sistency comparable to commercial pies. Test 13: Compression Measurement Using Instron Universal Testinngnstrument. An attempt was made to develop a procedure for measuring compression of processed cherries under a con- stant force, which would serve as an objective measure of 128 Table 40. Sensory evaluation by rating and ranking methods for effect of processing method on texture of air-frozen cherries (Lot EO) thawed at various temperatures. ‘3‘ ' Thaw Rating Thaw Rankin Temp. nga2** Signif.*** Temp. 333$ Signiffl+ (°F) r 5% 1% (°F) 5% 1% Process I* 40 6.6 40 25 30 6.2 P+++ 37 25 5.4 30 39 20 4.5 20 64 40 5.8 P+++ 5.1 N.S. Process II* 40 6.0 4O 17 30 5.6 P+++ 23 35 5.4 30 39 20 5.3 20 41 40 5.5 P+++ . ‘ 20 4.8 *See Appendix, Test 11 and Sec. IV A & B. **Mean score of 22 panelists using a 9-point rating scale (higher score = firmer texture). ***Mean scores not connected by line show significant differences at the 1 or 5% level. +Rank sum of 14 panelists using the Kramer procedure for ranking (Kramer, 1963) (lower rank value indicates firmer texture). ++Rank scores not connected by line show significant differences at the l or 5%‘1evel. +++P-sample pitted prior to freezing and received no thaw prior to processing. N.S. indicates no significant difference between any of the mean or rank scores. 1'1". 129 Table 41. Effect of processing method on % weight loss ! for air-frozen cherries (Lot E0) thawed at various temperatures. % Weight Loss* P;::::§iflg Thawing Temperature (°F) 20 30 40 P*** ,I I 37.6 34.8 29.3 27.9 II 37.6 28.1 26.5 28.9 *Average value of 3 replicates (Process I) and 5 replicates (Process II), based upon 256 gram put-in weight, ; calculated from drained weight of cherries after process- —mfi ing. **Described in Appendix, Test 11. ***P-sample pitted prior to freezing and received no thaw prior to processing as canned pie filling. firmness. Cherries were placed in a standard compression cell (5 3/4 cm. diameter; 7 7/10 cm. depth--designed for use with the Allo-Kramer Shear Press) in quantities of 75, 100 and 125 grams. A special probe (5 cm. diameter; 7 3/10 cm. length designed for Allo-Kramer Shear Press) was attached to the crosshead of the Instron. Various loads were applied (300; 5,000;£L000; and 10,000 grams) by setting the full scale load selector to the desired load. As crosshead, with probe attached, moved downward, the probe compressed the cherries in the compression cell until the desired load was achieved. The distance of 130 crosshead travel was measured on the Instron chart and the integrated area-under-curve obtained was calculated using the Instron Integrator attached to the recording device of the Instron Testing Instrument. Values obtained indicated the amount of compression resulting from a constant load and could be an indication of the firmness of cherries. The most reproducible results were obtained using a 125 gram sample of cherries; 5,000 gram load; 20 cm./min. crosshead travel speed; 20 cm./min. chart speed; and 7 cm. gauge length (see Instron Instruction Manual for explana- tion of various settings). Table 42 shows results obtained on a sample of cherries that were found to be significantly different using the Allo-Kramer Shear Press. Results ob- tained using both instruments were statistically analyzed using a "t" test (Sokal and Rohlf, 1969). Test 14: Effect of Refreezing and Use of Dry Mix for Pies to be Frozen Prior to Baking. A special test lot of pies was prepared and baked at the same time as pies described in Section IV C. The following pies were prepared: Pi§_l,--568 grams (frozen weight) of air-frozen cherries from Lot AW were thawed at 40°F by methods described in Section III, pitted and refrozen in air at -10°F. After 3 weeks storage at -10°F they were blended with a prepared slurry (described below) and poured into 131 Table 42. Comparison of values measuring firmness of ‘ cherries by compression and shear force. MethOd C??§§i§§i3’3 (31112:: $3222)“ Lot E0 E0 E0 E0 Thawing Temp. 20°F 40°F 20°F 40°F Replicate l 122 94 39 60 2 92 86 42 48 3 123 88 43 67 4 82 85 40 65 5 103 .21. .21. .19.. Mean 104.4 90.0 41.6 57.8 N.S.*** SIGN. 5% *Value measured as integrated area under force- distance curve with Instron Integrator. **Value measured as maximum peak of force-distance curve with Allo-Kramer Shear Press. ***Indicates no significant difference between mean scores. pie shells (Lloyd J. Harris), covered with top crust (Pillsbury), and refrozen in -10°F Chrysler-Koppin freezer. Pie II.—-568 grams (frozen weight) of cherries were processed as was Pie I with the following exceptions: a.) Pie was not refrozen-baked directly after blending frozen cherries with dry mix. 132 b.) Dry mix (described in Section III C) was used in place of prepared slurry. Pie III.—-Same as Pie I with the following excep- tion: a.) Pie was not refrozen-baked directly after blending frozen cherries with prepared slurry. Pie IV.--Same as Pie I with the following excep- tion: a.) Dry mix (described in Section III C) was used in place of prepared slurry (described below). Prepared slurry The following ingredients were used: Ingredient Weight (Grams) Sugar 242 Starch 34 Salt 2 Water 242 Preparation was as follows (Bedford, 1970-- Personal Communication): 1.) "Thoroughly disperse the starch in cold water, using about 1 quarter of the water." (For single batches in the above study, approximately l/3 of the total water was used per batch). 2.) "Heat the remainder of the water with about 1/3 of the sugar to 170 - 175°F". (For single batches in above study a Mirro 8" X 4" sauce pan was used to heat sugar solution). 1— 133 3.) "Add the starch slurry in a thin stream with constant and thorough agitation. Heat the mixture to 170 - 175°F. It should be clear." 4.) "Add the remainder of the sugar, mixing in thoroughly." 5.) "Cool to 140 - 145°F before adding to the cherries in the shells.“ a The slurry was added to 568 grams of frozen cherries in 10" pie shells (Lloyd J. Harris #279, Institutional Size) and covered with top crust from, and Ff. according to, directions on package of Pillsbury Pie Crust Mix. Cherries from the above pies were evaluated for general appearance by the author, and for firmness by a 20 member sensory panel using same rating procedures as described in Section IV C. Statistical analysis was by analysis of variance (Kramer and Twigg, 1966; Le Clerg, 1957) for differences between mean scores and by Duncan‘s Multiple Range Test (Le Clerg, 1957) to identify the significantly different samples. Results are shown below: Sensory Evaluation (Firmness) Significant Difference Pie # Mean 5% 1% I 6.1 I IV 6.0 I III 5.3 I II 3.1 General Appearance Pie # I IV III II 134 Very Very Very Good Comments good appearance shriveled appearance shriveled appearance appearance "I7'11?11111411414144