SENSORY AND OBJECT WE COMPARISON OF FRGZEN, EQF, DREEE AND CANNED MQNTMOEENCY CHERRIES EN PIES “lost: {or The Degree of M. 5. MICHIGAN STATE UNIVERSITY Onoiee DeGroEf Franks 1968 u Iall mu; my”! fill fl mm 111“ will; ml A ' Michigan Scam University ABSTRACT SENSORY AND OBJECTIVE COMPARISON OF FROZEN, IQF, DRIED, AND CANNED MONTMORENCY CHERRIES IN PIES by Onolee DeGroff Franks This investigation was initiated to determine the effect of canning, freezing, individual quick freezing and drying on the color, viscosity, and palatability of cherry pie fillings. The study, also, included determination of the following: the effect of use of commer- cial red food coloring on acceptability of dried cherries in pies; the effect of sodium bisulfite treatments on the color and quality of dried cherries; and the effect of freezing on the quality of dried cherries in pies. Subjective and objective measurements were utilized to evalu- ate the cherry pie fillings. Six replications of each of the variables were tested and collected data were statistically analyzed by a com- puter. Sensory evaluation of cherry pie fillings indicated that the colorand appearance of frozen and IQF cherry pie fillings received significantly higher scores than those of canned and dehydrated cherry Onolee DeGroff Franks pie fillings; the tenderness of cherry skin of frozen, IQF, and dehy- drated cherries were not significantly different; the nonsodium bisulfite-treated- and sodium bisulfite-treated-dried cherries scored significantly lower for color, flavor, and acceptability than the other cherry variables. The Hunter color-difference meter was utilized to determine the lightness, redness, and yellowness values of cherry pie fillings. However, only the redness values significantly correlated with those obtained by the sensory panel for cherry color. The redness values of IQF cherry fillings were significantly higher and the sodium bisulfite-treated- and nonsodium bisulfite-treated-dried cherry fill- ings were significantly lower than the other cherry variables. The Kramer shear press used to determine cherry tender- ness indicated that greater force was needed to shear IQF cherries than all other types of processed cherries. There were no significant differences among the force readings of frozen and dried cherry variables. Also, there was no significant correlation between shear press measurements and sensory evaluation of tenderness of cherry skin. Frozen pies prepared with dried cherries were subjected to sensory and objective measurements and the results were compared Onolee DeGroff Franks with those pie fillings freshly prepared with dried cherries. Although no significant differences were found between the two products, both products received low acceptability scores. Although this investigation has indicated that frozen, IQF, canned, and dried-with-coloring-added Montmorency cherries pro- duced acceptable pies, additional research is needed in the following areas: (1) an investigation to determine the effect of pretreatment with higher concentrations of sodium bisulfite on color retention in dehydrated cherries; (2) an investigation to determine use and accept- ability of dried cherries in other baked products; and (3) a study to determine the effect of storage time on color and palatability of frozen, IQF, canned and dehydrated cherries. SENSORY AND OBJECTIVE COMPARISON OF FROZEN, IQF, DRIED, AND CANNED MONTMORENCY CHERRIES IN PIES By Onolee DeGroff Franks A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Foods and Nutrition 1968 ‘F‘x URL U‘I‘J 1‘) U) “W ACKNOWLEDGMENTS The author is greatly indebted to Mrs. Mary Ellen Zabik who provided continuing encouragement, guidance, and time throughout this study. Grateful acknowledgment is expressed to Dr. Clifford Bedford of the Michigan State University Food Science Department for process- ing of the cherries and providing necessary research funds to carry out this investigation. Sincere appreciations are also expressed to Dr. Kaye Funk for her interest and assistance in this study and to Therese Dolecek for her assistance with the taste panel. Appreciations are expressed to Anne Adkins, Evelyn Catli, Eleanor Haag, Nancy Tschirhart, and Ethel Williams for serving as panel members. The writer acknowledges with deep gratitude the continuing aid and unfailing encouragements of her husband and parents. ii TABLE OF CONTENTS Page INTRODUCTION . . . . . . . . . . . . . . . . . . . . . 1 REVIEW OF LITERATURE . . . . . . . . . . . . . . . . 4 Composition of Cherries . . . . . . . . . . . . . . . 4 Water . . . . . . . . . . . . . . . . . . . . . . 4 Organic acids . . . . . . . . . . . . . . . . . . 5 Carbohydrates . . . . . . . . . . . . . . . . . . 6 Ash . . . . . . . . . . . . . . . . . . . . . . . 6 Vitamins . . . . . . . . . . . . . . . . . . . . 7 Color of Cherries . . . . . . . . . . . . . . . . . . 7 Anthocyanin pigments . . . . . . . . . . . . . . . 7 Factors affecting color in cherries . . . . . . . . . 9 Care during harvesting . . . . . . . . . . . . 9 Presence of metallic ions . . . . . . . . . . . 10 Presence of enzymes . . . . . . . . . . . . . 10 Presence of sugar . . . . . . . . . . . . . . 11 Presence of ascorbic acid . . . . . . . . . . . 12 Presence of sulfur dioxide. . . . . . . . . . . 12 iii pH Storage Preservation of Cherries Canned cherries Frozen cherries Processing Color . Texture . Palatability Individual quick frozen cherries Dehydrated cherries Color . Appearance Utilization of Sour Cherries . Frozen pies Objective Measurements Allo-Kramer shear press . Color measurements EXPERIMENTAL PROCEDURE Design of Experiment Ingredient Procurement . iv Page 14 14 15 15 17 17 18 19 20 20 21 22 22 22 23 24 24 25 27 27 28 Pastry formula ingredients Processing of cherries Canning . Freezing IQF . Dehydrated Packaging and storage Cherry filling ingredients . Commercial food coloring source Basic Formula . Method of Preparation Preparation of cherry filling Assembling of the pie and baking procedure . Frozen dried cherry pie procedure . Preparation of Samples . Subjective Evaluation . Objective Measurements pH of cherry filling . Color measurements Tenderness of the cherries Analysis of Data Page 28 29 29 29 30 30 30 31 31 32 34 34 35 36 36 37 38 39 39 39 41 RESULTS AND DISCUSSION . Subjective Evaluation of Cherry Pie Fillings Color . Appearance Viscosity of sauce Tenderness of cherry skin Texture of cherry flesh . Flavor Acceptability Correlation between cherry pie filling attributes . Analysis of taste panel member data Objective Measurements Hunter color-difference meter Correlation among the objective and subjective measurement of color Kramer shear press measurements Correlation between shear press and subjective evaluation of cherries Frozen Dried Cherry Pies Comparison of sensory evaluation of frozen and nonfrozen dried cherry pie fillings . Comparison of objective measurements of frozen dried cherry pie fillings vi Page 42 42 43 51 52 52 52 53 54 54 55 57 57 6O 6O 62 63 63 65 Page SUMMARY AND CONCLUSIONS . . . . . . . . . . . . . . 66 IJTERATURECHTED. .. . .. .. .. .. .. .. .. . 71 APPENDIX.......................77 Vii Table 10. 11. LIST OF TABLES Production and utilization of sour cherries in United States Composition of fresh, canned, and frozen sour cherries Formula used in the preparation of cherry pie fillings Analysis of variance for determining the effect of cherry process on the subjective evaluation of cherry pie filling attributes . Studentized multiple range test for sensory attributes Significant correlation coefficients for cherry filling attributes evaluated by subjective evaluation . Analysis of variance for determining significant differences among judges Analysis of variance for determining the effect of cherry process on the Hunter color-difference meter measurement of cherry pie filling Studentized multiple range test for Hunter color- difference meter measurement Analysis of variance for determining the effect of cherry process on shear press measurement of tenderness of cherries in pie filling Studentized multiple range test for shear press measurements . viii Page 32 44 45 48 56 58 59 61 62 Table 12. 13. 14. 15. 16. 17. 18. 19. Analysis of variance for determining the effect of freezing on the subjective evaluation of sodium bisulfite-treated-dried cherry pie fillings Analysis of variance for determining the effect of freezing on the objective evaluation of dried cherry pie filling Replicate averages, cherry process means, and standard deviations for sensory evaluation of cherry attributes (7-point scale; 8 judges) Replicate averages, cherry process means, and standard deviations for shear press measurements of cherry pie filling Replicate averages, cherry process means, and standard deviations for Hunter colormeter measurement of color Replicate averages, cherry process means, and standard deviations for sensory evaluation of frozen dried and nonfrozen dried cherry pie fillings Replicate averages, cherry process means, and standard deviations for shear press measure- ments and Hunter colormeter measurements of frozen dried and nonfrozen dried cherry pie fillings Replicate averages for pH of cherry pie fillings ix Page 64 65 80 82 83 84 86 88 Figure LIST OF FIGU RES Sequence for cutting and testing the slices of cherry pies for taste panel evaluation The color and appearance of five types of processed cherries prior to pie preparation The color and appearance of cherry pie fillings prepared with frozen, IQF, canned, and dried cherries General instructions for taste panel members Score sheet for sensory evaluation of cherry pie fillings Page 37 50 50 78 79 INTRODUCTION Michigan is the leading state in the production of red tart (sour) cherries. Montmorency variety is processed because of the excellent quality, the firmness in flesh, the size of the fruit, the long harvest season, and because it is a dependable producer of a good crop (Marshall, 1954). The average annual tart cherry production in the United States during 1958-66 was 137, 000 tons. In a normal year, when the cherry industry does not sustain losses from the late Spring frost or other adverse weather conditions, production has reached 224, 044 tons (Table 1). However, the processor capacity and storage space are sufficient to handle only about 110, 000 tons (Larsen _e_t_a_l. , 1966). Therefore new processing techniques for handling surplus cherries in normal years are needed in order to reduce profit loss and provide additional cherries for low production periods. Presently canning and freezing are the only methods of preservation being used extensively on a commercial basis; however, newer processes, dehydration and individual quick freezing, are in the experimental stage. Both of these techniques offer the economical advantage of reduced weight in transport, through removal of water in the dehydration process and elimination of sugar in the individual quick freezing process. The dehydration technique also offers the advantage of economical packaging, storage at room temperature, and handling surplus cherries in normal years. Of these two, the individual quick freezing process is less economical due to the higher cost of frozen storage, the utilization of more space, and insufficient freezer capacity and storage space to handle surplus cherries. Table 1. Production and utilization of sour cherries in United States. Year Fresh Canned Frozen Brined Total Sales tons tons tons tons tons 1958 6,398 47,739 46,588 765 101,490 1959 5,826 71,225 58,320 1,000 136,371 1960 5, 087 44, 332 64, 168 1, 100 114, 687 1961 6, 840 62, 723 93, 870 400 163, 833 1962 6,036 84, 293 73, 676 1, 670 165, 675 1963 4, 092 30, 860 44, 350 700 80, 002 1964 7,679 99,641 115,884 840 224,044 1965 4, 903 68, 193 85,001 1,725 159,822 1966 4, 747 37, 988 46, 166 4 88, 901 Source: The Almanac of the Canning, Freezing, Preservation Indus- tries. At the present time the sale potential of tart cherries is about 1. 3 pounds per capita (Larsen et al. , 1966). It is felt that this will remain rather stable unless the cherry industry (1) learns to alleviate or live with the wide production fluctuation or related fac- tors, and (2) develops new products or new utilization methods for cherries. However, before the cherry processors will produce new or modified cherry products, the quality and acceptability of the product must be determined. Therefore, this investigation was initiated to compare sensory and objective quality characteristics of two new types, dried and individual quick frozen (IQF), with the two standard and accepted methods of processing, frozen and canned. Since red tart cherry pie is the most popular dish prepared from this fruit, it was used as the testing medium. The primary purpose of this investigation was then to deter- mine the effect of canning, freezing, individual quick' freezing (IQF) and drying of cherries on the color, texture, and palatability of pie fillings. Secondary objectives included comparison of quality char- acteristics of frozen and nonfrozen pies, both prepared with dried cherries; to determine the effect of the addition of commercial red food coloring on the acceptability of dried cherries in pies; and to determine the effect of sodium bisulfite treatments on the color and quality of dried cherries. REVIEW OF LITERATURE Composition of Cherries Only a few research groups have studied the chemical compo- sition of cherries (Marshall, 1954). All of these analyses, based on chemical composition of the pit-free portions of the fruit, vary due to difference among studies in one or more of several factors: variety, degree of maturity at time of harvesting, environmental factors and methods employed in analyses (Marshall, 1954). Water Canning and freezing processes alter the original moisture content of cherries (Table 2). Drained canned cherries have a higher moisture content than fresh cherries due to the migration of water medium into the cherry flesh. However, there is a decrease in the moisture content of frozen cherries preserved with dry sugar, due to osmosis. In this process there is diffusion of water molecules from a region of low sugar concentration (fruit) to a region of high concen- tration (dry sugar) until a state of dynamic equilibrium is established. Table 2. Composition of fresh, canned, and frozen sour cherries. a Constituents Fresh (watgrligfgked) (sug::—O::cr:lked) Water (‘70) 83. 7 88.0 70. 6 Protein (g) 1. 2 .8 1.0 Fat (g) .3 .2 .4 Carbohydrates (g) 14. 3 10. 8 28.0 Ash (g) . 5 . 3 . 2 Vitamin A (IU) 1000 680 480 Thiamine (mg) . 05 . 03 . 03 Riboflavin (mg) . 06 . 02 . 06 Niacin (mg) . 4 . 2 . 3 Ascorbic Acid (mg) 10 5 6 aBased on constituents in 100 grams of cherries. Source: Watt and Merrill. 1963. Organic Acids There is a progressive increase in active acidity from the time the youngest fruits were obtainable until the cherries had reached full size (Marshall, 1954). The acidity of red tart cherries has gen— erally been reported either as total titratable acidity or as malic acid (Das, 1964). Acids such as citric, tartaric, and succinic were reported to occur only in traces (Marshall, 1954). In 1964, Das re- ported the presence of 20 non-volatile organic acids and one volatile inorganic acid in red tart cherries. The following acids were identi- fied: glutamic, aspartic, lactic, shikimic, quinic, galaturonic, glyceric, glycolic, tartaric, malonic, citric, neochlorogenic, iso- chlorogenic, fumaric, chlorogenic, and phosphoric. The dominate acid isolated in this study was malic acid (1259 mg/100 g fruit). Carbohydrates Approximately 50-60 per cent of the total dry matter of the edible portion of red sour cherries is composed of carbohydrates (Constantinides et_a_l_. , 1964). Ninety-nine per cent or more of this total contain fructose and glucose sugars (Constantinides 3131. , 1964). Five reducing oligosaccharides, which were not identified, were reported to be present in minute quantities (Constantinides 3311. , 1964). Ash The ash of cherries includes minute quantities of many mineral salts including: calcium, phOSphorous, iron, sodium, and potassium, with potassium being the highest mineral constituent present (Marshall, 1954). Cherries rank intermediate among the commonly grown fruits in respect to total ash constituent. Vitamins Sour cherries contain vitamin A, thiamine, riboflavin, niacin, and ascorbic acid (Table 2). In comparison to other fruits, the cherry is one of the best sources of riboflavin. Ascorbic acid is higher in cherries than in other deciduous tree fruits, but is only 12-25 per cent of that found in citrus fruits (Marshall, 1954). Color of Cherries Many fresh fruits owe a considerable part of their attractive- ness and consequent popularity to the bright red and purple colors of the anthocyanin pigments (Culpepper _e_t_a_l. , 1927). In 1956, two anthocyanin pigments of red tart cherries, antirrhinin and mecocyanin, were isolated and identified by Li et al. , 1956. Anthocyanin Pigments The anthocyanin pigment occurs in plant cells as glucosides which are ethers of monosaccharides, sometime with one monosac— charide moeity and sometime two (Meyer, 1960). When the glucoside is hydrolyzed with acid, alkali, or enzyme, the sugar and sugar-free residue is obtained (Lowe, 1955). This residue is known as anthocyanidin and alteration of its structure changes the color of the anthocyanin . anthocyanin % anthocyanidin + monosaccharide Glidden (1953) reported only three general types of antho- cyanidin have been isolated: I II III +C1_ +Cl HO O Q OH HO 00 COR OH RHO 00 OR OH / OH QR! OH OH pelargonidin chloride cyanidin chloride delphinidin chloride The numerous variations of anthocyanin pigment have been found to be methyl ethers of these three general types (Robinson, 1933a; Robinson et a1. , 1932b). The anthocyanins and the anthocyanidins are amphoteric in nature and yield salts of both acids and bases. The acid salts are red in color while the basic salts are blue (Glidden, 1953). An example of a basic reaction was reported in Meyer (1960). O + HOOQ .C: oHK HOOD _COH —OK HW=O / OC61—11105OH 0C6H1105OH OC6Hllo5 OC61—11105 OC6Hl 105 OC6H1105 Cyanin color base salt red at pH 3. 0 or less violet pH 8. 5 blue pH 11.0 Factors Affecting Color in Cherries In cherries the anthocyanin pigments occur in the cells of the skin, but not in the flesh. Processing the fruit distributes the antho- cyanin throughout the tissue (Griswold, 1962). The variation in color of the anthocyanin pigments of cherries is influenced by many factors: care during harvesting, presence of metal cations, enzymes, sugar, ascorbic acid, sulfur dioxide treatments, pH, and storage conditions. Care during harvesting. Rough handling of cherries during harvesting and transporting to the processing plant bruises the fruit flesh. If the cherries are bruised before soaking, loss of red pig- ments from the injured tissues becomes apparent within two or three. hours. This occurs since the water soluble pigments can diffuse readily and eventually all are leached from the fruit (Van Buren gt_a_l. , 1959). This study further showed enzymatic action in the presence of air or O contributes to this conversion of pigment to a colorless 2 form. However, the enzyme is relatively inactive in unbruised fruit 10 because the pigments are separated in the fruit cells from the enzymes that can destroy them. Wittenberger et_a_l_. (1956) thus concluded bruising of cherries is the primary cause of surface dis- coloration. Presence of metallic ions. Culpepper et al. (1927) reported when processing was carried out in glass, the original color was preserved except for lessening in intensity due to partial conversion of the anthocyanin into the colorless form by heat. In tin cans, a greater loss of color occurs, accompanied by the conversion of some pigments to violet and consequent shifting of the color of the product toward purple. This alteration in color resulted from the anthocyanin forming a complex salt with the metal. Griswold (1944), also, reported cherries canned in plain tin were very poor, and those canned in enameled tin compared unfavorably in color and palatability with those canned in glass. Cruess (1948) stated that prolonged heat as Well as metallic ions injures the anthocyanin color of canned fruits. Presence of enzymes. Anthocyanin pigments are phenolic compounds and are readily oxidized or reduced with the loss of red color (Mayak, 1965). Relatively greater enzyme—decolorizing ability was found in those tissues which accumulate the greatest amount of anthocyanin. Thus, the oxidizing activity of the decolorizing enzyme in the skin is greater than that of the less-pigmented flesh (Van Buren 11 fl. , 1960). Pung 913.1. (1963) using mushroom tyrosinase found that in the absence of catechol the reaction was very slow, but in the presence of catechol the rate of mecocyanin discoloration increased rapidly. Thus, they concluded that anthocyanins themselves are poor phenolase substrates; but are readily discolorized by phenolase in the presence of a better substrate, such as catechol, a normal constituent of cherries. Therefore, unless the polyphenoloxidases are inactivated, the catechol will be oxidized to produce O-benzoquinones, which may polymerize to form simple melanins (Mayak, 1965). The preservation of cherries and other small fruits by a preliminary heat blanching will destroy the enzyme. However, frozen and dried fruits still contain the decolorizing enzyme and continual color loss will occur during storage unless oxygen is excluded or an oxygen inhibitor added. Presence of sugar. Sugar was found to preserve the bright- ness of cherry color. Griswold (1944) pr0posed the theory that sugar either depresses the decomposition of anthocyanin to anthocyanidin plus monosaccharides or protects the pigment from oxidation. Cher- ries frozen without the addition of sugar or sugar sirup are exposed to air and thus, the anthocyanin pigment will be oxidized and the cherries will darken and discolor. 12 Presence of ascorbic acid. Loutfi (1951), Grommeck et a1. (1964), and Stein 31:31. (1954) stated that ascorbic acid has protective action on the color of frozen cherries. The presence of oxygen was shown to be detrimental to the color of frozen cherries. Ascorbic acid, an anti-oxidant, maintains the phenolic substrate in the reduced form and thus prevents browning. A schematical presentation of this reaction was given by Mayak (1965). phenol tyrosinase > dehydrophenol tyrosinase 09 >quinone I \ dehydroascorbic acid ascorbic acid Loutfi (1951) recommended the use of 175 mg of ascorbic acid per pound package to maintain the fresh flavor and bright color of red sour cherries. Presence of sulfur dioxide. Sulfur dioxide has been used extensively in the fruit and vegetable industry, chiefly as an inhibitor of microbial growth and of enzymatic and nonenzymatic browning (Goodman 3331. , 1965). Phenolase oxidase has been shown to catalyze the oxidation of anthocyanin pigments in the presence of the ' proper phenolic substrate. Sulfur dioxide would be expected to inhibit this degradation of anthocyanin by combining with the enzymatically 13 produced O-quinone, and stopping their condensation to melanins. However, sulfur dioxide is also known to bleach reversibly, the anthocyanin pigments. The bleaching of anthocyanin by sulfur dioxide is a revers- ible process that does not involve hydrolysis of the 3—glycoside group, reduction of the pigment, or the addition of bisulfite to a ketone, chalcone derivative (Jurd, 1964). In sulfite discoloration the reactive species is the antho carbonium ion. The experimental evidence indi- cated that this simply reacts with a bisulfite ion to form a colorless chromen 2(or 4)-su1fonic acid (R—SO H), similar in structure and 3 properties to an antho carbinol base (R-OH) (Jurd, 1964). SOBH - 0+ 0 ———>.__ 0 H503 + O / 0 / O bisulfite Antho Carbonium Chromen sulfonic acid ion ion Stradman (1948) stated sulfur dioxide has proven to be by far the most effective inhibitor tried, and is widely used commercially. Sulfur dioxide treatment is eSpecially beneficial in maintaining normal color of dried fruits; since this type of fruit deteriorates primarily in color and flavor from the browning reaction. However, if fruit does not receive sufficient amount of treatment, quinone formation during l4 storage, in excess of those bound with 802’ will result in increasing discoloration rates (Embs 111. , 1965). EH: In a study by Grommeck ia—I. (1964) the results indi- cated the anthocyanins tested are degraded faster by peroxidases at pH 4. 5-5. 5 than at other pH levels. They stated the structure of anthocyanin is known to change with pH and this perhaps explains the effect of pH on their oxidation rate by peroxidase. As mentioned earlier, the presence of metallic ions, also, alters the pH of the anthocyanin pigment and results in color deterioration. Storage. Prolonged storage of fruits with red or red violet pigments is accompanied by bleaching of some pigments and the development of a red-brown and finally a brown color (Meyer, 1960). Glidden (1953) found the greatest factor in the deterioration of color of the pigment appeared to be the temperature of storage. Grommeck 3:31. (1964) also reported that the temperature definitely affects the reaction rate, with the rate increasing rapidly as the temperature is raised until a maximum rate is reached between 60-70° F. Kertesz _e_t_a_l_. (1948) and Meschter (1953), and Daravingas 13.—1. (1965) found the effect of increasing storage temperature and/or as well as dura- tion of storage significantly reduced the anthocyanin pigments of strawberry preserves and canned raspberries. 15 Preservation of Cherries Canned Cherries The exact beginning of the cherry industry is unknown. Marshall (1954) reported that in 1909 approximately 2, 200 tons of red cherries were canned; and this was probably the earliest in com- mercial canning of substantial portions. The limiting factor in the canning of red cherries was, and still is the factory capacity. Cher- ries ripen and are harvested in a given area in about two weeks, and if the plant could not handle the crOp in this time, part of the cherries were wasted. Red cherries that are to be canned are picked without stems to facilitate both harvesting and handling at the factory (Marshall, 1954). They are soaked in tanks containing cold water during trans- port from the orchard to the factory where they are pitted and canned. The generally accepted practice of soaking red cherries in tanks prior to pitting was developed by W. R. Kappler in 1918 (Marshall, 1954). This process made it possible to keep the cherries from Spoiling for a longer time and caused them to become more turgid so that they pitted without much flesh clinging to the pit. However, the exact effect depends on the quality of the fruit. Marshall (1954) reported unbruised cherries soaked in water for various lengths of 16 time increased in both weight and firmness and decreased in both soluble solids and acid content. Bruised cherries, however, did not gain sufficiently in weight and lost substantial quantities of soluble solids and acids. A study by Bedford _e_t_a_l. (1957) indicated the firm- ness and quality of the canned product could be improved by soaking the cherries in a calcium salt solution and by canning with added calcium salt. Even though cherries that are packed for dessert purposes are canned in sirup, the cherries packed as pie stock are canned in water, thus most of the pitted red cherries are water-packed (Mar- shall, 1954). Weckel fl. (1959) found processing red sour pitted cherries in sirup rather than in water enhances certain qualities such as color, flavor, and firmness of fruit. Bedford et al. (1957) reported results from taste panel evaluation of pies indicated canning with 0.5, 1.0, 1. 5 and 2.0 ounces of sugar or 10, 15, 20 and 25 per cent sugar sirup to each No. 2 can of sour cherries made the product more acceptable. Griswold (1944), also, found Montmorency cherries packed in water compared unfavorably with those packed in 50 per cent sirup in respect to palatability, brightness of color and texture. Even the addition of 0.5 -1. 0 ounce (2. 5-5 per cent) of sugar to each No. 2 can of cherries increased the firmness and brightness and im- proved the palatability over cherries packed in water (Marshall, 1954). 17 Frozen Cherries The first freezing of cherries was done by pie bakers at market centers, in the original fresh fruit crate (Rogers, 1940). In 1921, cherries were first frozen in barrels. At first no sugar was used but, gradually, it was learned that a combination of five parts of cherries to one of sugar improved the color, flavor, and texture (Rog— ers, 1940). However, additional sugar and a prolonged period of freezing resulted in excessive juice. Tressler (1944) found if the pr0portion of fruit to sugar is greater than 5 to 1, the color and quality may not be protected. Today most frozen cherries are packed in thirty pound tins. Bakers and preservers are still the chief sales outlet for the frozen cherry although sales to frozen pie processors are gaining steadily (Great Lakes Report, 1954). Processing. Handling of cherries is of even greater impor- tance for cherries that are to be frozen than to be canned. Bruised cherries and cherries broken up by faulty pitting are readily detected in the frozen pack (Marshall, 1954). Pitting of cherries aggravates the oxidation problem and thus makes it essential to reduce the time from the initial factory handling to freezing to a minimum (Marshall, 1954). 18 Although the sirup pack has been shown to have many advan- tages over a dry sugar pack, the dry sugar pack is still generally preferred because most frozen cherries are intended for the baking trade where a product with a maximum drain weight, or a minimum juice is desired (Marshall, 1954). In contrast, Bedford 3t_al. (1962) reported freezing cherries in sirup resulted in higher drained weights than the dry sugar pack. In this study the drain weights increased as the sirup concentration increased, reaching a maximum with 35-40 per cent sirup solutions. There is some difference of opinion, how- ever, as to the best concentration of sirup for cherries frozen for dessert purposes. Joslyn (1934) found 40 per cent sirup to be satis- factory, while Loutfi (1951) and Diehl ia_l. (1930) recommended 55- 60 per cent concentration. At the present time packers are using a 50° Brix sirup. During freezing and thawing, cherries are subjected to browning or oxidation, thus resulting in a produce of poorer flavor and color. In the following paragraphs the effect of freezing on color, texture, and palatability will be reviewed. C_ol_9£. Gudagni et al. (1958) found the most readily visible change in cherries stored at 20° F was discoloration or browning of the fruit exposed to the headspace atmosphere. The degree of sever- ity of this enzymatic discoloration was found to depend on the amount 19 of sirup coverage, storage temperature, and length of storage. Dur— ing storage there is an actual loss inred anthocyanin pigments as well as oxidation of other tannin-like phenolic compounds which are con- verted to melanins (Gudagni fl. , 1958). However, the small amount of surface browning does not appear to be of practical importance when the entire can content is mixed and prepared for pies in the usual manner (Gudagni 9131. , 1963). In contrast, Loutfi (1951) found there was an increase in the color intensity of the frozen product rather than a disColoration. He hypothesized that during the freezing procedure, in the presence of sugar, leucoanthocyanin were converted to the red anthocyanin pigment. Texture. Gudagni Lal. (1963) and Gee $31. (1957) found toughening of frozen Montmorency cherries was greatly influenced by storage time and temperature. They reported firmness of frozen cherries stored at 10-30° F increased rapidly with time, but was stable at -10° F. Toughening (increased firmness) did not appear to be related to sugartreatment of cherries. Siruped and untreated con- trol samples gave the same tenderometer values after storage at -10° F (Gee El. , 1957). Therefore, the changes in texture were attributed to pectinesterase action of pectin diesterfication and the formation of a calcium pectinate gel, from calcium present in the fruit tissue combining with carbonyl groups, when cherries are not frozen solid as they are at -10° F (Gee et al. , 1957). 20 Palatability. In a study by Guadagni et al. (1958) the most detectable organoleptic change was an increase in firmness. The flavor quality factor closely paralleled firmness changes. The color curve indicated little or no difference between controlled and the stored samples up to six to eight weeks of storage at 20° F. Therefore, cher- ries can be held for at least oneyear at 0° F and about six months at 10° F without significant changes in color or flavor scores in pies (Guadagni et al. , 1963). Individual Quick Frozen Cherries Rogers (1940) stated individual quick frozen cherries (IQF), frozen by cold air, Spray, or immersion, were unquestionably supe- rior to frozen cherries for providing a greater yield as a pie filler. He also stated, however, that IQF cherries do not retain their original bright red natural color as well as cherries packed in either the bar- rel or thirty pound tin and therefore the idea of quick freezing individ- ual cherries was abandoned. In a study of the color of cherries by Labelle 131. (1966) the combined browning and loss of redness was very noticeable in IQF processed cherries. Mayak (1965) reported the most readily observable changes in pitted red cherries, IQF processed without any pretreatments or packing medium, were the loss of red color and 21 browning of the flesh. However, when the cherries were pretreated with 802’ color loss decreased. In his study cherries treated with 1000 ppm SO showed the least color loss, followed by those treated 2 with 500 ppm SO Therefore, sulfur dioxide treatments could be 2. used to prevent enzymatic and oxidative color destruction and brown- ing during freezing, frozen storage and subsequent thawing (Bedford, 1967). However, additional research is needed on the color, texture, and palatability characteristics of the cherries before the process can be used for commercial application. Dehydrated Cherries The cherry industry was interested in other methods of pres- ervation which would provide wider distribution and consumption of its product. Therefore, preliminary investigations on cherry dehydra— tion were initiated by the Michigan Agricultural Experimental Station in 1943 and continued in 1944. The investigation of 1943 indicated the chief objections to dehydrated cherries were inability to rehydrate sufficiently and color deterioration following any considerable length of storage (Alderman fl. , 1945). In addition, dehydration has not been able to compete economically with preservation by canning and freezing (Marshall, 1954). Although sun drying is cheaper, it is less desirable than heat dehydration; for heat dehydration enables 22 more rapid and controlled drying and the production of a product of much higher quality (Mrak et al. , 1943). Color. Red tart cherries tend to turn brown or become oxidized on exposure of the flesh to the air. The application of heat, in the process of dehydration, causes further discoloration and results in an unattractive reddish-brown product (Alderman et al. , 1945). Appearance. Dehydrated cherries may attain a slight raisin-like taste and appearance (Mrak §t_a_l. , 1943). In Alderman .e_t_a_l. (1945), study of the appearance of dehydrated cherries did not compare favorably with the appearance of fresh, canned or frozen cherries. However, they reported that dehydrated cherries do com- pare favorably with products prepared with other types of dried fruits, such as raisins, dates, or figs. The dried cherries were compared in the following products: muffins, coffee cakes, tea scones, cookies, and cakes. In all cases the cherries had better color and flavor scores if cut in halves or thirds and rehydrated in a double boiler for 15 minutes. Utilization of Sour Cherries There has been a slight decrease in the proportions of total commercial crops that were utilized by canning, and an increase in those utilized by the freezing industry (Table 1). In the years of 1962 23 to 1966, an average of 44 per cent of the total tart cherry sales was utilized by the canning industries and 51 per cent by the freezing industry (Table 1). The canned cherries may be packed in sirup for dessert purposes or in water for pie stock. Frozen cherries are mainly packed for institutional use; however, the use of frozen cher- ries in unbaked frozen fruit pies for retail sale has been increasing. Cherries are, also, utilized for such other processing as the market- ing of wines, juices, preserves, and candied cherries (Marshall, 1954). Frozen Pies Commercially produced, unbaked fruit pies have met wide consumer acceptance and their retail sales have shown a rapid in- crease. Recently studies have‘been conducted on the storage temper- ature and time, and effect of defrosting on the quality of frozen pies. Kulp 3t_a_l. (1962) reported a freezing time up to twenty-eight hours had no effect on the quality of crust or filling. Pratt (1955) and Kulp e_t_al_. (1962) found that frozen pies should be held at 0° F or below. Gudagni _e_t_a_l. (1963) stated, temperatures above 10° F were more detrimental to the quality of the fruit filling than the pastry. Also, temperature fluctuation should be minimal during transportation and storage, in order to maintain the highest quality possible. Pratt 24 (1955), Kulp et al. (1962), and Fanelli et a1. (1961) recommended baking frozen pies without defrosting, for defrosting of any degree adversely affects the quality of the pies. Objective Measurements Objective evaluation offers a means of precise measurement of quality characteristics and reproduceability of results under con- ditions which might affect the reliability of taste panel members. However, the usefulness of objective measurement is, to some extent, contingent upon reasonable agreement with sensory evaluation (Funk 3E1. , 1965). Thus, it is of primary importance that objective meth- ods be developed which will provide a true measurement of the par- ticular quality factor under study (Funk et al. , 1965). Allo-K ramer Shear Press The Allo—Kramer shear press has been used to measure textural quality of meat, poultry, jellies, fruits, vegetables, and baked products. The operational principles of the shear press were reviewed and discussed by Brown (1964), Endres (1965), Parks (1966) and Wolfe (1967). In a study by Kramer _e_til. (1951) and Kramer (1952) high coefficient of correlation between shear press measurements and 25 sensory evaluation of canned lima beans and sweet corn were obtained. Kramer Lad. (1953), also, reported shear press measurements of raw peas correlated significantly with panel scores on canned peas. Shallenberger 921. (1963) and Wiley e_t_a_l_. (1960) found a high corre- lation of panel scores for firmness of canned slice apples with shear values. Sweeney gt_a_l. (1962), also, reported that shear press values for grapefruit, pineapple, raspberries, and strawberries agreed with panel texture scores. However, shear values for peaches were lower than expected on the basis of the panel texture score. Kramer et al. (1954) found the measurement of maturity of raw, canned, and frozen lima beans by the shear press more reliable than taste panel evalua- tion. However, Sather et al. (1963) reported that there was no corre- lation with shear resistance and appearance scores of pears. Color'Measurements The Hunter color and Gardner color-difference meter have been used with food products to obtain instrumental color measure- ments which will correlate with a visual estimate of color. Use of the instrument was reviewed by Endres (1965), Parks (1966), and Wolfe (1967). Tinsley e_t__a_l. (1956) and Robinson (1961) found good correla— tion between Hunter color-difference meter measurements and 26 subjective color evaluation. Tinsley reported that with sensory grad- ing of color it is difficult to eliminate effect of factors other than color. In his study the appearance of raspberry samples determined whether the sample scored high or low within a grade. Sweeny sat—al. (1962) reported high correlations with taste panel scores and Gardner color measurements. The bright red to extremely dark red range of color in strawberries and raspberries were shown by both the wide ranges in color-difference meter L and a values and in panel scores. L Gudagni et al. (1957) and Livingston (1959) reported significant cor- relations between Hunter and Gardner aL values and the subjective estimation of color difference in strawberries. The relative redness values measured by the Hunter meter were very similar to changes which enable visual observers to detect color differences in frozen strawberries (Gudagni e_t_&l., 1957). Sather L211. (1963), also, found significant correlation with appearance and Hunter a readings of L canned pears. EXPERIMENTAL PROCEDURE This research was initiated to determine the differences in quality characteristics, if any, among frozen, canned, individual quick frozen (IQF) and dried Montmorency cherries. The cherries were harvested from the same trees to minimize factors known to affect quality (climate, fertilizer, etc. ). Design of Experiment This study was designed to determine the effect of canning, freezing, individual quick freezing, and drying of cherries on the color, texture, and palatability of pie fillings. The investigation was also designed to determine the effect of the addition of commercial red food coloring on acceptability of dried cherries in pies; to deter- mine the effect of sodium bisulfite treatments on the color and quality of dried cherries; and to compare the quality of dried cherries in pies which have been frozen and stored at -23. 3° C, for two weeks, with freshly prepared pies made with dried cherries. Six replications of each variable were prepared and sub- mitted to sensory evaluation and objective measurement of quality 27 28 characteristics. All data was subjected to the appropriate statis- tical analyses. Ingredient Procurement Pastry Formula Ingredients Common lots of cake flour, bread flour, salt, and shortening were obtained from the Michigan State University Food Stores. The flours, salt, and shortening were weighed to the nearest gram on a Toledo torsion balance, 5-Kilogram capacity. The pastry was made in seven batches, each consisting of 4536 grams cake flour, 1734 grams bread flour, 3525 grams shorten- ing, 136 grams salt, and 1320 milliliters of water. The flour and salt were placed in the 12-quart bowl of the Hobart mixer, model A-2 00, and blended with a paddle attachment for 2 minutes. A mixing period of 2 minutes at 70 rpm was used to blend the shortening with the flour. Water was mixed into the Shortening-flour mass for 2 minutes at 70 rpm. The pastry was placed on a moderately floured board and folded 50 times. Rolling was done by hand with an 14-1/2-inch rolling pin, on a 24 X 18-inch board provided with cleats 3/16-inch high. Cake flour was used to flour the board and rolling pin. The rolled crust was cut with a 9-inch pie cutter. Twenty-four single crusts, each separated 29 with freezing paper, were placed in 11-3/4 X 11—3/4 X 7-inch card- board boxes, and frozen and stored at ~23. 3° C until used during the following three week cherry pie evaluation period. The boxes were used to protect the pastry against crushing and breaking during storage. Processing of Cherries Montmorency cherries grown and harvested commercially with a mechanical harvester from southwest Michigan were used. The cherries were tranSported in an ice box by truck to the Michigan State University Food Science laboratory, and on arrival were weighed and placed in soaking tanks with running water at 13. 9° C. The cherries were delivered to the laboratory Within 2 hours after harvest and were soaked for 4 hours prior to processing. The cher- ries were pitted in a Dunkley cherry pitter of pilot plant capacity. Canning. Twelve ounces of pitted fruit were put into No. 303 cherry enamel cans, covered with boiling water, exhausted 6 minutes, sealed, processed in boiling water for 8 minutes, cooled and stored at 4° C. Freezing. Sixty-four ounces of pitted fruit were placed in a plastic bag, 13 ounces of dry sugar added, and bags sealed and rotated to mix fruit and sugar and then frozen and stored at -20. 6° C. 30 133. Pitted cherries were transferred into a 0.2% NaHSO3 solution in a 10-gallon stainless steel kettle and held for 1 minute. The treated fruit was transferred to a perforated dehydrater tray, about 2 cherries deep, drained 5 minutes and frozen in an air blast at -20. 6° C. The frozen fruit was placed in 30 pound tins and stored at -20. 6° C. Dehydrated. The cherries to be dehydrated were processed two ways; untreated or pretreated with a 0. 5% NaHSO solution dip. 3 Untreated. Pitted cherries were placed one layer deep on a perforated dehydrater tray and dried. 802 treated. Pitted cherries were dipped into a 0.5% NaHSO3 solution for 1 minute, transferred to perforated dehydrater tray and dried. The cherries were dried in a Proctor Schwartz dehydrater, with partial through air flow. A programmed air temperature drop was used. Initial dry bulb temperature was 93° C. The cherries were dried for 1 hour at this temperature, followed by 1 hour at 88° C, 1 hour at 77° C, and finished at 68. 3° C. The drying time was about 10 hours to reduce the moisture content to about 25%. Packaging and storage. The processed cherries were trans- ferred to the Home Economic Research laboratory prior to initiation of the investigation. Upon arrival, the dried cherries were portioned 31 into appropriate amounts, heat sealed in heat sealable polyester pouches, and stored at 4-5° C until used. The canned cherries were stored at room temperature, and the IQF and frozen cherries, left in original containers, were held at -23° C until used. Cherry filling ingredients. To eliminate any possible varia- tion in ingredients, the sugar, salt, and starch were each obtained from common lots. The waxy-maize starch (Polar Gel 5) was fur- nished by the American Maize-Products Company and the sugar and salt were purchased from a local distributor. The sugar and starch were weighed to the nearest gram on a Toledo torsion balance, 5-Kilogram capacity, and salt was weighed to the nearest 0. 1 gram on an BOO-gram capacity torsion balance. Pre- weighed sugar, salt, and starch were then packaged in closed poly- ethylene bags, and stored at room temperature. Commercial food coloring source. Two commercial certified FD&C colors, Red #2 (Amaranth) and Red #4 (Ponceau Sx) were used as coloring agents. Three grams of each dye, weighed to the nearest 0. 1 gram on the torsion balance, BOO-gram capacity, were added to two 100-milliliter volumetric flasks, and dissolved in 90 ml of dis— tilled water on a steam bath. The dyes were cooled, brought to volume, stoppered, and held at room temperature until used. 32 Basic Formula The formula used in this study was developed in the labora- tory prior to the investigation. Pie fillings were prepared according to the formulas given in Table 3. Table 3. Formula used in the preparation of cherry pie fillings. Type of cherry Ingredients Dried cherry variable Frozen IQF Canned a No 802 SO2 Color added g g g g g g Sugar 40 400 400 400 400 400 Starchd 66 66 66 66 66 66 Salt 4 4 4 4 4 4 Cherries 2160 1800 1800 318 337 337 Distilled water 1482 1463 1461 FDC Red #Zb soln. 1.0 m1 FDC Red #4° soln. 1. 0 ml aSame formula was used for the frozen dried cherry pies variable. A bAmaranth (3%), National Analine Division, 40 Rector Street, New York 6, N. Y. cPonceau Sx (3%), National Analine Division, 40 Rector Street, New York 6, N.Y. dPolar Gel 5, American Maize-Products Company, Roby, Indiana. 33 The formula was varied according to the type of processed cherries used, to compensate for differences in moisture of cherries, for the addition of sugar to frozen cherries, and liquid coloring to the dried cherry variables. The exact amount of moisture was determined for each type of cherry by using the AOAC vacuum oven method (1955). The following moisture percentages were based on an average of four readings: S02 No 802 Frozen Canned* IQF Dried Dried 76.44% 88.51% 85.33% 15.17% 19.76% *After draining for 5 minutes. The moisture content of the canned cherries remained fairly constant, regardless of the length of drainage time, after 5 minutes. This is due to water bound within the tissues. Therefore, the moisture content of the canned cherry pies was higher than the other pie variables investigated in this study. The amount of water added to the dried cherries was sufficient to make them equivalent to the moisture content of the IQF cherries. The IQF moisture content was used as the standard since this type of processed cherry had neither the addition of water nor sugar. The moisture content of the frozen cherries was similar to IQF when corrected for sugar solids. 34 Method of P reparation A day prior to preparation, the IQF cherries were weighed, to the nearest gram on a Toledo torsion balance, 5-Kilogram capacity, into a 3-quart bowl and covered with Saran. The pre—weighed frozen and IQF cherries were then thawed overnight at 4-5° C. The canned cherries were drained in a mesh strainer (24 wires per inch) for 5 minutes and weighed to the nearest gram on a Toledo torsion balance, 5-Kilogram capacity, prior to pie preparation. Preparation of Cherry Filling To insure even distribution of dry ingredients, the previously weighed starch, sugar, and salt were dry-blended using a paddle attachment in a 5—quart bowl, Hobart model K-5, for two minutes at 56 rpm. The cherries, cherry juice or distilled water and dry ingre- dients were blended with a wooden spoon in a 3-quart aluminum sauce— pan. The mixture was cooked to 40° C on a 7-1/2—inch surface burner set on high. To avoid scorching the heat was then reduced to medium and the mixture was cooked until it thickened and boiled for 15 seconds. Stirring was controlled so that the cherry filling received 6 stirs every five minutes until it began to thicken, then it received three stirs every minute to the end of the cooking period. The thickened mixture was immediately removed from the source of heat. In the 35 preparation of the artificially colored dried cherry filling, each of the coloring agents was measured with a one milliliter volumetric pipette and blended into the cherry mixture at this time. The filling was transferred immediately to a 5—quart Hobart mixing bowl, covered with Saran wrap and then stored at refrigerator temperature 4-5° C for 18—24 hours. Assembling of the Pie and Baking Procedure Pre-rolled pastry was removed from the freezer, thawed, and placed in 9 X 1-1/4-inch aluminum pie pans. The cherry fillings were removed from the refrigerator and the pH was recorded. Using a 5—Kilogram capacity Toledo torsion balance, 950 grams of cherry filling were weighed into each of two pastry lined aluminum pie pans. The filling was covered with a top crust and the edges were turned under and crimped. A 4—inch Slit was cut in the center of the sealed crust to permit the escape of air and steam. Three variables (6 pies) were baked at the same time. The pies for sensory evaluation and objective measurements were baked on separate shelves. The posi— tion of the pies in the oven was randomized by successive rotation between the two shelves every baking period. The pies were baked in an ECTO forced convection oven, model 186-A, for 40 minutes at 232°C. 36 Frozen Dried Cherry Pie Procedure The frozen dried cherry pie filling was prepared in the same manner as previously described. The filling was stored in a 5-quart Hobart mixing bowl at 4-5° C until it cooled to 25° C. The pH was recorded and the pies were assembled. The pies were immediately frozen at -30. 6° C, which took approximately two hours. After freez- ing, the pies were individually wrapped in freezing paper and held at -23. 3° C until baked. When the frozen pies were removed from the freezer, a 4-inch slit was made in the sealed crust, and the pies were baked in an ECTO forced air oven, model 186-A, at 232° C for 60 minutes. Preparation of Samples The two coded pies from each replication of each variable were allowed to cool for two hours before cutting for evaluation. One of the two pies of each replication was used for objective evaluation and the other for taste panel evaluation. The top crust was carefully removed from the pie to be used for objective measurements and discarded. The pie was divided into thirds and cherry filling from each of the sections was spooned into three 70-min diameter X 50-mm high pyrex crystallizing dishes for color measurements. The same cherry filling was then used for shear press measurements. 37 To obtain identical slice size and randomization for sensory evaluation eight equal sections were marked on the pie pans and the sections were numbered 1 through 8 prior to the investigation. Pie slices designated for taste panel members were rotated according to a similar pattern used by Funk et al. (1965), as shown in Figure 1. H N 00 fl" L0 to 1‘ (I) w H N 00 fl" L0 (0 b- 2. :4 n :4 :4 L. s. :4 :4 L: L. :4 s4 s4 :4 L. o a) a) a) a) a) a) o m o a) o o m a) cv .o .0 .o .o .0 .o .0 .0 .0 .o .o n .0 .n .o .o 8 8 E E E E E E S 8 E E E 8 E 8 cu m o o a) a) a) cu m o a) o a) a) cu m S 8 8 E S S S E E E E S E E E E H H r-i r-i l—‘ H r-4 H F" 0—0 H H r-l H H H cu m a) o a) cu m cu m o a) o a) o m o c: c: c: c: c: c: c: c: c: c: c: c: c: c: c: :2: c6 c6 :6 c6 c6 c6 c8 c6 c8 c6 c6 c6 c6 c6 c6 c6 D-u EL. 04 D4 Q. 04 Cl. IL 04 D-q IL 04 04 £14 D—u 04 1st Replication 293 Replication Figure 1. Sequence for cutting and testing the slices of cherry pies for taste panel evaluation. Subjective Evaluation An eight member taste panel was utilized to determine the acceptability of the color, appearance of cherry, viscosity of sauce, tenderness of skin, texture of flesh and flavor of cherries processed by various methods. All attributes were scored on a 7-point rating scale. Judgment as to whether the product was acceptable or not was 38 indicated and additional comments were noted. The cherry pie score card appears in the appendix. Three training sessions prior to evaluation of the pies were held in order to check the suitability of the terms used on the score card, to acquaint the panel members with the product, and to allow them to ask questions. Directions for taste panel members appear in the appendix. In addition, the panel members were directed to remove the top crust before evaluation. All samples were coded according to predetermined randomized numbers. Sectors for each pie were placed on 7-1/2-inch randomly numbered white plates. Each plate was tightly wrapped with Saran to prevent dehydration until evaluation by the panel members approximately 1-1/2 hours later. There were fourteen test periods with three samples presented and evaluated individually each period. All evaluations were carried out under 15- watt cool fluorescent lighting. Objective Measurements Objective tests were used to evaluate pH, color, and tender- ness of the various processed cherries. Prior to baking, pH deter- minations were made on the cherry fillings. Baked pies were evalu— ated for cherry color and tenderness. 39 pH of Cherry Filling The pH determinations were made on the cherry filling with a Beckman Zeromatic pH meter equipped with Calomel and glass electrodes. The filling was placed in conventional pyrex 5-ounce baking cups prior to assembling the pies and pH was recorded. Color Measurements Color of the baked cherry filling was measured using a Hunter Color-difference meter, model D-25. The instrument was +15. 6) covered standardized with a red tile (L, 25.0; a +27. 8; b L’ L’ with an optical lens in preparation for determination of L (lightness), a (redness) and b L+ L+ (yellowness) values of the cherry samples. Samples were taken from three sections of the pie and each sample was placed in a separate 70-mm diameter X 50-mm high pyrex crystallizing dish. The top of the crystallizing dishes were-leveled off and the flat surfaces were covered with special optical lens (3 in. X 4 in. X 1/8 in. ). The assembly was placed under the viewing area and readings were recorded. Each value reported represents an average of three readings. Tenderness of the Cherries Tenderness was measured using the standard shear-compression cell of the Allo-Kramer shear press, model SP-12, equipped with an 40 electronic recorder, model E-2 EZ. The 3000—pound proving ring, 10-pound range, 25-pound pressure and 30—second downstroke were used for this measurement. After color measurements were recorded, 1/2 inch of the top layers of cherries was removed from the crystallizing dishes; and 100-gram samples were weighed to nearest gram, from each dish, into conventional custard cups on an 800-gram capacity Torsion balance. Also during weighing, the cherry pieces were examined for pits by injecting a No. 9 sewing needle into the fruit flesh; any sample containing a pit was not used. The weighed samples were removed from the cups with a rubber spatula, and placed in the lower assembly of the cell. The values for tenderness were recorded on the chart paper as the upper assembly cell sheared through the cherry pieces. The sections of the cell assembly were thoroughly rinsed with luke- warm water between each evaluation. Tenderness of the cherries was determined using two factors, maximum force and area-under-the-curve. Maximum force needed to shear through the cherry samples was calculated as Maximum graph reading X ranége (‘70) X ring sample weight 41 Each maximum force value was based on an average of three trials. To compute area, the graph curve was carefully cut out and weighed on a Mettler balance, Model H—15. The area was computed by multi- plying the weight of the graph by a determined conversion factor 174. 2 as discussed by Funk $31. (1965). An average of three samples was recorded for each replication. Analysis of Data Subjective and objective data were summarized and evaluated by the CDC 3600 computer at Michigan State University. The Rand Routine was used to calculate analysis of variance for types of cher- ries, judges, and comparison of frozen dried vs. dried cherry pies. The BAStat Routine with a transformation subroutine was employed to determine standard deviations of the means and simple correlation coefficient. Significant differences among types of cherries, indi- vidual treatment combination and mean sensory scores and judges were evaluated through the use of the Studentized range test (Duncan, 1957). RESULTS AND DISCUSSION The purpose of this investigation was to determine the effect of four different types of processing methods—~freezing, canning, individual quick freezing, and dehydration-~on the quality character- istics of Montmorency cherries in pies. In addition, studies were made with dried cherries to determine the effect of artificial coloring on their acceptability in pie filling; the effect of sodium bisulfite treatment on color and quality; and the suitability of dried cherries in frozen pies. Objective and sensory data were examined to ascertain the quality of the cherries used in each variable. Methods were deveIOped in the laboratory to control all other variables which might affect the quality of the product. Subjective Evaluation of Cherry Pie Fillings The color, appearance, viscosity of sauce, tenderness of cherry skin, texture of cherry flesh, flavor, and acceptability of cherry pie fillings were evaluated by an eight member taste panel. A 7-point rating scale was used, with 7 being the most desirable score. Replicate averages, cherry process means, and standard 42 43 deviations for sensory evaluation of cherry processes are included in the Appendix. The data analyzed for variance indicated very highly significant differences among cherry pie filling attributes of the sensory test (Table 4). Therefore, the data were further subjected to a Studentized range test to determine significant differences among cherry process means (Table 5). Simple correlation coefficients for the seven cherry filling attributes were derived (Table 6). Color Analysis of cherry process means (Table 5) indicated that the colors of frozen and IQF cherry pie fillings were scored significantly higher than the colors of all other variables. The dried cherry pie filling to which red food coloring (FDC #2 8n #4) had been added scored significantly higher for color than the other dried cherry pie variables and obtained similar color scores to those for canned cherry pie fill- ings (0. 1 per cent level). There were highly significant differences between the color of 0. 5 per cent sodium bisulfite- and nonsodium bisulfite-treated—dried cherry pie fillings. .However, they both received significantly lower color scores than the other pie filling variables (p _<_ O. 01). Kodachrome pictures were made of the fruit prior to pie preparation and of the pie filling after baking. Figure 2 shows the 44 523868 .8 H32 88 .88 H .o mfi 8 68223298... mm H.309 mod 26 mmd Sod 3.0 26 mm gonna oo .o so .o mm .o S .o mo .o S .o m cosmozamm 331.36 83.1.me 33%; .H *3”; A 3333 .m .3330 .2 m mmooofim 13.830 525m nmofi mo Exm modm £3.00.ko 0&3on mmoMMMM mimoomtr lawman?“ (H300 Snowmen.“ 62834.5 omnWoQ mo monsom mumswm smog .mofififlfim wsfldm ma hnnmno mo :ofimgm>o o>3ooflnsm 2: no mmooona mnpoao mo Soto one mcficwfinouov no.“ mosmEm> mo 293934 .6 3an 45 Table 5. Studentized multiple range test for sensory attributes. a Color Dried Coloring Dried Dried Frozen IQF added Canned SO2 treated No S02 0. 1% Level: 6.1 5.7 4.5 4.3 3.5 2.1 1% and 5% Level: 6.1 5.7 4.5 4.3 3.5 2.1 Appearance Dried Coloring Dried Dried Frozen IQF Canned added 802 treated No 802 0. 1% Level: 6.3 5.6 3.9 3.8 3.5 3.4 1% Level: 6.3 5.6 3.9 3.8 3.5 3.4 5% Level: 6.3 5.6 3.9 3.8 3.5 3.4 aMeans underscored by the same line are not significantly dif- ferent (Duncan, 195 7). 46 Table 5. Viscosity of Sauce Continued. Dried Coloring Dried Dried IQF added Canned Frozen SO2 treated No 802 0. 1% Level: 6.8 6.5 6.3 62 5.9 5.7 1% Level: 6.8 6.5 6.3 6.2 5.9 5.7 5% Level: 6.8 6.5 63 6.2 5.9 5.7 Tenderness of Skin Dried Dried Coloring Dried Canned Frozen IQF 802 treated added No 802 0. 1% Level: 6.6 6.2 6.0 5.6 5.3 5.2 1% Level: 6.6 6.2 6.0 5.6 5.3 5.2 5% Level: 6.6 6.2 6.0 5.6 5.3 5.2 aMeans underscored by the same line are not significantly dif- ferent (Duncan, 1 957). 47 Table 5. Continued. Texture of Flesh Dried Coloring Dried Dried Frozen IQF Canned added 802 treated No 302 0. 1% Level: 6.3 5.8 49 4.8 4.7 4.5 1% and 5% Level: 6.3 5.8 49 4.8 4.7 4.5 Flavor Dried Coloring Dried Dried Frozen IQF Canned added SO2 treated No SO:2 0. 1% Level: 6.0 6.0 5.5 5.5 4.8 4.1 1% and 5% Level: 6.0 6.0 5.5 5.5 4.8 4.1 Acceptability (%) Dried Coloring Dried Dried Frozen IQF added Canned SOZ treated No 802 0.1% and 1% Level: 98 97 78 75 37 20 5% Level: 98 97 78 75 37 20 aMeans underscored by the same line are not significantly dif- ferent (Duncan, 1 957). 48 523863 no 26>“: 88 6.8 a .o 2: 8 2638993; 523868 .8 663 ES .68 H 2: 8 88:899.... .mfifinmnona mo H923 ”Emu non m 33 am EmoEEwfima 3.8%. 33.88. 882. 3.8.83. $.33. 138%. 5233388. 53.8mm. 888mg. .336. fining. 888mg. “wing . no.8?“ Iguanas. 888mg. :33. :3. Sexism. 8844mm? swam mo 8.3885; 133mm. *4,an 8333‘. 883% . 843m. 23m .6 mmosnopcoH 1.332. 133.38. $3. .83. 33.88. 8:8 .6 .3888; 19.1.43 . 838$. 33.3w. 3&3. $2.. .3383. 8.86 .8 86883.4 twig. 3.3%. 3.83. .383. 3.38. 3.388. P88 26 sonoo 533w amen mo Exm moan mousflnflm 13800484 non/mam opame mo mmm: mimoomfir summaada poHoO 9:33 mnnmno Lennon. .Gofimgmkwm o>fiomhnsm E 663396 mmusnifim mafia 13.850 no.“ mwcowoflmooo :oSmHonnoo Emoflwnmwm .m 3an 49 relative differences in the color and appearance of the fruit from dif— ferent processing treatments prior to preparation of the pie fillings. The colors of the various cherry pie filling variables evaluated by the judges are shown in Figure 3. The color of the sodium bisulfite treated IQF cherries was highly acceptable. Mayak (1965) reported that the 802 pretreatment of pitted cherries prior to IQF processing decreased red color loss and browning of the fruit flesh whereas untreated fruit lost red color and browned as reported by LaBelle e_t_a_l. (1966). The panel members indicated that the color of canned cherry filling had less red color-intensity than the frozen and IQF cherries. It is apparent in Figures 2 and 3. The loss of the typical bright red cherry color during canning was reported by Culpepper Eat—al. (1927), Griswold (1944) and Whittenberger still. (1956). The low color scores given to the dehydrated cherries, by the panel, were due to the occur- rence of oxidative browning which produced a light, brownish-red to brown color in the cherries. This was more pronounced in the non- sulfited fruit. Therefore, since considerable browning did occur, the investigator concluded that the treated dried cherries did not receive a proper amount of sodium bisulfite to combine with the quinone and inhibit melanin formation. This color deterioration was described by Alterman et al. (1945) as being one of the chief objections to dehydrated 50 1. 2. 3. 4. 5. 1 Figure 2. The color and appearance of five types of pro- cessed cherries prior to pie preparation. 1. 2. 3. 4. 3 5. I 6. v V ‘V— A Figure 3. The color and appearance of cherry pie fillings prepared with frozen, IQF, canned, and dried cherries. Kg. Frozen IQF Canned D ried - SO 2 treated Dried - no 802 Key Frozen IQF Canned Dried- coloring added Dried— SOz treated Dried- no SO2 51 cherries. However, addition of commercial red coloring to the dried cherry pie filling improved the color score. The pie fillings of the other dried cherry variables were light, brownish—red in color as compared to the cherry red color of the colored pie fillings (Figure 3). Appearance The appearance of frozen cherry pie filling was scored sig- nificantly higher than IQF cherry pie filling, which in turn was scored significantly more desirable than those of the canned and dehydrated cherry fillings (p _<_ 0.001). There were no significant differences among the appearance of canned and dehydrated cherry pie fillings (0. 1 per cent level). The appearance of canned cherries scored significantly lower than frozen and IQF cherries, due to destruction of the typical, whole cherry character. This destruction occurred during prepara- tion of the pie filling. Therefore, the additional cooking and stirring was disadvantageous to the tender texture of the heat processed cherries. The taste panel members criticized the dried cherry variables for their moderately plump, wrinkled appearance (Figure 3). This is in agreement with the findings reported by Alderman et al. (1945). 52 Viscosity of Sauce Comparison of cherry processes (Table 5) revealed the vis- cosity of IQF, dried-colored, canned, and frozen cherry fillings were not significantly different (p _<_ 0.001). At the 5 per cent level the vis- cosities of sodium bisulfite—, and nonsodium bisulfite—treated-dried cherry sauces were scored significantly lower than IQF, dried-with- coloring-added, and canned cherry sauces. The lower viscosity scores of pie fillings made with dried cherries may be due to incomplete rehy- dration even though the dried cherry variable with red food coloring scored significantly higher (1 per cent level). Tenderness of Cherry Skin The tenderness of the skin of frozen, IQF, and dried cherry variables were not significantly different at the 0. 1 per cent level (Table 5). However, the skin of canned cherries was scored as being significantly more tender than those of the dried cherry variables (pf 0.01). Texture of Cherry Flesh The Studentized range test revealed that the flesh of frozen and IQF cherries were significantly more tender and heavier fleshed than the canned and dried cherry variables (1 per cent level). The 53 flesh texture of the dried cherries was described by the judges as being thin (or lacked fleshiness). This may be due to incomplete rehydration of the cherries during preparation. The flesh of canned cherries was described as being fleshy, but undesirably mushy. Flavor There were no significant differences for flavor (Table 5) among frozen, IQF, canned and dried-with-coloring-added cherry pie fillings (p _<_ 0.001). However, the flavor of sodium bisulfite-, and nonsodium bisulfite-treated-dried cherries were scored significantly different and significantly lower than the other cherry variables at the 1 per cent level. The dried cherries were often reported as being too tart or bitter and the sauce as being too sweet. Therefore, unlike the frozen, IQF, and canned cherries, sugar was not absorbed into the fruit tissues; and thus, there was a contrast between the concentrated tart flavor of the partially rehydrated fruit with the sweet flavor of the sauce. Although the dried cherry fillings with red coloring added were described as being too tart, they received significantly higher scores than the other dried cherry variables; and thus indicating an interrela- tionship between eye appeal and scoring for flavor. It, also, indicates that the presence of sodium bisulfite at the level used in this experiment did not affect the flavor scores. 54 Acceptability Judgment as to whether the product was acceptable or not was indicated by checking yes or no on the score sheet. To determine significant differences the responses were converted to a percentage by dividing the number of positive reSponses for each replication by the total number of judges (8) and multiplying the quotient by 100. The acceptability of frozen, IQF, dried-with-coloring—added, and canned cherry pie fillings were not significantly different at the 0. 1 per cent level of probability. However, the sodium bisulfite- and nonsodium bisulfite-treated-dried cherry fillings were only acceptable 1/3 and 1/5 of the time (p E 0. 001). Since the fillings made from dried cherries with color added were as acceptable as fillings made from canned or frozen cherries, the investigator concluded color was the major contributing factor to acceptability. The wrinkled, raisin-like appearance and browning were often reported by the panel members as undesirable characteristics of the noncolored dried cherry variables, and may be the reason for their lower acceptability scores. Correlation betv‘veen Cherry Pie Filling Attributes Significant correlation coefficients between cherry filling attributes are included in Table 6. A high positive correlation existed between most attributes (0. 1 per cent), with the exception of no 55 correlation between viscosity of sauce and tenderness of cherry skin. However, correlation between these two attributes would not be expected. Thus, sensory evaluations of cherry attributes and the acceptability of cherry pies were highly interrelated. Analysis of Taste Panel Member Data To determine variations among the scoring of judges, sensory data for cherry pie attributes were subjected to three-way analyses of variance (Table 7). The analyses indicated significant differences which could be attributed to cherry process and judges, as well as interaction between these factors. There were no significant differ- ences in replications and thus the judges were consistent in their scoring between replications. Although there were significant differ- ences among judges for all sensory attributes, the same general trend held true for significant differences among cherry processes as those indicated in Table 4, with the exception of acceptability. For this factor some of the judges scored IQF and frozen cherry pie fillings significantly different and more acceptable than canned and colored cherry pie fillings made with dried cherries. The highly significant interactions between cherry process and judge were examined. However, no consistent trend to cause this interaction could be determined. Moreover, the use of the 56 523203 no 32: ES .80.. H .o 3... a. Sauna??? mo .0 mm .o S .H 8 .o as .o 3 .o 8 .o mam 32m *..._.mm .o fag .m 3.3 .N 33.3 .m 3 .o *imm .N $3.3 .m mm 3.9:. x mo ***wm.H ***up.m *%*ow.mH ***Hw.HH *%*mm.w ***om.pm ***Ho.mm b owpzw S .o om .H 3 .o 2 .m E .o 8 .o 8 .o m nonsmoiom .363: .m $.15 .5 5.8 .mm 33.3 .3 its. s $1.5 .S .53.?” .mS m 380.5 0.86 SK 389 533m no>mfim smofl mo HOGWMM: mfimoomdw mocm uoHoU Sopmonm -3954 musfimH ugopcoh . . unmomnfiw mo mocwEm> moumom mo moasom mumsvm smog .mowpsfl wqofim moocopmmhp «38¢?me wfififinmpoc 50% oonwEmS mo mambwfim . N. 3an 57 interaction mean square as the error term in calculating F value for cherry process means still resulted in very highly significant values. Objective Measurements Objective evaluation of color of cherries was determined by the Hunter color-difference meter and cherry tenderness by the A110- Kramer shear press. Numerical data from these measurements were subjected to analyses of variance. Significant differences were derived by use of the Studentized multiple range test (Duncan, 1957) and corre— lation coefficients were calculated. Replicate averages for cherry processes, cherry process means, as well as standard deviations for the objective evaluations are included in the Appendix. Hunter Color-Difference Meter Analysis of variance for color differences measured by the L, aL, and bL values (Table 8) revealed highly significant differences which could be attributed to cherry processing. Comparison of the cherry process means (Table 9) indicated that canned cherries were lighter in color than IQF and sodium bisulfite-treated-dried cherries, which in turn were lighter than frozen, nonsodium bisulfite-treated— dried, and dried cherries with coloring added to the filling (0. 1 per cent level). The aL values indicated that the color of IQF cherry pie 58 fillings were very highly significantly more red than pies prepared with all other types of cherries. The sodium bisulfite- and nonsodium bisulfite-treated-dried cherries were the least red (p 5 0.001). Analysis of bL values indicated that canned cherries were the most yellow. The yellowness value of the IQF cherries was significantly lower than that of the canned cherries, but higher than the values of the other processed cherries (0. 1 per cent level). Table 8. Analysis of variance for determining the effect of cherry process on the Hunter color-difference meter measurement of cherry pie filling. Source of Degorf‘ees Mean squares variance freedom L Values aL Values bL Values Cherry process 5 52 . 20*** 92. 78’1"“< 16. 53*** Replication 5 1 . 39 0.46 0. 18 Error 25 0.56 0.42 0.23 Total 35 >.'<>'.<>::<>:<>:< Error 25 0.05 0.03 Total 35 ***Significant at the 0. l per cent level of probability. difference. Comparison of the cherry process means (Table 11) revealed that greater force was needed to shear IQF cherries than pie fillings prepared with all other types of cherries (p E 0. 001). Both the total force and area-under-the-curve values indicated that canned cherries were very highly significantly more tender than the other types of processed cherries. There were no significant dif- ferences among the force values of frozen and dried cherry vari- ables (0. 1 per cent level). 62 Table 11. Studentized multiple range test for shear press measure- ments. Shear Press Values Based on Maximum Force (lb/g) Dried Coloring Dried Dried IQF Frozen added No 802 SO2 treated Canned 0. 1%, 1% and 5% Level: 3.0 2.4 2.2 2.1 2.1 .93 . Shear Press Area-Under—the-Curve (cm2) Dried Coloring Dried Dried Frozen IQF added SO2 treated No SO2 Canned 0. 1% Level: 2.4 2.3 2.1 2.1 1.8 1.1 1% and 5% Level: 2.4 2.3 2.1 2.1 1.8 1.1 w aMeans underscored by the same line are not significantly dif- ferent (Duncan, 1957). Correlation between shear press and subjective evaluations of cherries. A very highly significant correlation (r = +0. 879) existed between the two shear press measurements. However, there was no significant correlation among shear press measurements and sensory 63 evaluation of tenderness of cherry skin. As mentioned previously, appearance and color of cherry samples may have influenced the judges' evaluation of tenderness in this study. Frozen Dried Cherry Pies Sodium bisulfite-treated-dried cherry pies were prepared and frozen two weeks prior to baking. These pies were subjected to sensory and objective measurements to determine if the results compared favorably with the test results of the freshly prepared pie fillings made with dried cherries. If an acceptable frozen cherry pie could be prepared from dried cherries, the process could serve as a means of utilizing dried cherries for retail sales and institu- tional use. Comparison of Sensory Evaluation of Frozen and Nonfrozen Dried Cherry Pie Fillings Replicate averages for cherry process, cherry process means, as well as standard deviations for the sensory evaluation of frozen and nonfrozen dried cherry pie fillings are included in the Appendix. Analyses of variance for sensory evaluation revealed no significant differences between the two products (Table 12). There- fore, freezing did not alter the sensory characteristics of dried 64 m 38% «ed rod mod :6 wed mod rod v posum 8.0 mod mod vmd no.0 $06 and v cofimoflaom mad mo; 3 .o mmd mod Had mm; H meooonm mahosv 335m smog mo Exm mocm Lawmoaw po>m¢m 92:.me umMoMMMM. mimoomzw unwoaadw noHoU Eoflwoum modding oopon mo oopsom ohmsvm smog .mwfizm ma mpnoso pozpupoummfinofifisfln Esfioom mo 6839595 mfiuooESm 55 co mfiuoob mo gumbo o5 9552233. .39 mocmfiums mo $9393. .2 3an 65 cherry pie fillings. However, since both products received low acceptability scores, dried cherries could not be utilized in com- mercial preparation of frozen pies without further improvements in processing. Comparison of Objective Measure- ments of Frozen and Nonfrozen Dried Cherry Pie Fillings Replicate averages for cherry process, cherry process means, as well as standard deviations for the objective measure- ments of frozen and nonfrozen dried cherry pie fillings are included in the Appendix. Analyses of variance for objective measurements (Table 13) indicated no significant differences between the two pro- ducts. Thus, freezing did not alter the color or tenderness of the dried cherry pie fillings. Table 13. Analysis of variance for determining the effect of freezing on the objective evaluation of dried cherry pie filling. Mean square S f Degrees ource O of Shear press Hunter variance freedom Force Area LValue aLValue bLValue Cherry process 1 0. 05 0. 06 2. 12 0.08 0.00 Replication 4 0. 17 0. 08 1. 05 0. 45 0. 07 Error 4 0.02 0.02 0.40 0.78 0.27 Total 9 SUMMARY AND CONCLUSIONS The primary purpose of this investigation was to determine the effect of canning, freezing, individual quick freezing and drying on the color, viscosity, and palatability of red cherry pie fillings. Secondary objectives included comparison of the quality character- istics of frozen dried cherry pies versus nonfrozen dried cherry pies; determination of the effect of commercial red food coloring on acceptability of cherry pies made with dried cherries; and determina- tion of the effect of sodium bisulfite treatments on the color and quality of dried cherries. All cherries used in this investigation came from a common lot; standardized procedures were utilized in the preparation, baking, and testing of pie fillings. All data reported are the average of six replications. Sensory evaluation of cherry attributes were evaluated by an eight member taste panel using a 7-point rating scale, with 7 being the most desirable score. The results of the sensory test indicated that the color of frozen and IQF cherry fillings were pre- ferred over canned and pie fillings made with dried cherries (0. 1 66 67 per cent level). The color of nonsodium bisulfite-treated-dried cherry fillings scored highly significantly lower than 0. 5 per cent sodium bisulfite—treated-dried cherry fillings. Both scored sig- nificantly lower than 0. 5 per cent sodium bisulfite—treated-dried cherry fillings with red coloring added (0. 1 per cent level). Sub- jective evaluation of appearance revealed that frozen was preferred over IQF cherry filling and both were preferred over the canned and pie fillings made with dried cherries (0. 1 per cent level). The viscosity of the sodium bisulfite-treated- and nonsodium bisulfite-treated-dried cherry fillings scored significantly lower than those of the IQF, dried-with-coloring—added, and canned cherry pie fillings (5 per cent level). There were no significant differences in tenderness of cherry skin of frozen, IQF, and the dried cherry variables (0. 1 per cent level). Canned cherries were scored sig- nificantly more tender than the dried cherry variables (1 per cent level). The sensory evaluation of texture of cherry flesh revealed that the flesh of frozen and IQF cherries were scored significantly higher than canned and dehydrated cherries (1 per cent level). There were no significant differences for flavor and acceptability among frozen, IQF, canned, and dried—with-coloring-added cherry pie fillings (1 per cent level). The sodium bisulfite-treated- and nonsodium bisulfite-treated-dried cherry pie fillings scored 68 significantly lower for flavor and acceptability than the other vari- ables (1 per cent level). The Hunter color-difference meter was utilized to determine differences in color of cherry fillings. Analysis of the color data indicated that canned cherries were lighter and more yellow than the other processed cherries (0. 1 per cent level). IQF cherry fillings had significantly higher redness values than pie fillings prepared with all other types of cherries. Analysis of the redness values also revealed that sodium bisulfite and nonsodium bisulfite-treated-dried cherries were less red than the other variables (0. 1 per cent level). Correlation coefficients were determined between sensory evaluation of color and the Hunter values. Positive correlations were found between Hunter a values and the sensory data for color. However, L there were no significant correlations among L, bL values and sensory test. The Kramer shear press was utilized to determine tender- ness of the various processed cherries. Analyses of data revealed that greater force was needed to shear IQF cherries than all other types of processed cherries (0. 1 per cent level). There were no significant differences among the force readings of frozen and dried cherry variables (0. 1 per cent level). Correlation coefficients were determined between sensory evaluation of texture and the shear 69 press. There were no significant correlations between the two measurements. Sodium bisulfite-treated-dried cherry pies were prepared and frozen two weeks prior to baking, The baked frozen pies were subjected to sensory and objective measurements and the results were compared with those of freshly prepared pie fillings made with dried cherries. Analyses of variance for both sensory and objective measurements revealed no significant differences (between the two products. However, since both products received low acceptability scores, dried cherries could not be utilized in commercial prepara- tion of frozen pies Without further improvements in processing. The results of this investigation indicated that frozen and IQF cherries produced the most desirable pie fillings. Sodium bisulfite-treated- and nonsodium bisulfite-treated-dried cherries were least desirable; however, the addition of commercial red food coloring significantly improved the sodium bisulfite-treated-dried cherry pie fillings. The findings in this study indicated a need for research in the following areas: (1) an investigation to improve dehydration techniques and to determine the effect of pretreatment with higher concentration of sodium bisulfite on color retention in dehydrated cherries; (2) a study to determine more effective methods of rehydrating dried cherries; (3) a study to determine the 70 effect of cherries in other baked products; (4) a study to determine the effect of commercial red food coloring on acceptability of frozen dried cherry pies; (5) to compare sensory attributes of IQF cherry pies with commercially prepared frozen sour cherry pies; and (6) a study to determine the effect of storage on color and palatability of frozen, IQF, canned and dehydrated cherries. LITERATURE CITED Alderman, D. C., and B. Newcombe. 1945. Dehydration of Mont- morency cherries. Mich. Agr. Expt. Sta. Quart. Bull. 28 (2):97. Almanac of the Canning, Freezing, Preservation Industries. 1967. Edward E. Judge and Son, Westminister, Maryland. AOAC. 1955. ”Official Methods of Analysis. " 8th ed. Assoc. Offic. Agr. Chemists. Washington, DC. Bedford, C. L. 1967. Private Communication. Department of Food Science. Michigan State University. Bedford, C. L., and W. F. Robertson. 1957. Effect of handling and processing methods on the firmness and quality of canned and frozen red cherries. Mich. Agr. Expt. Sta. Quart. Bull. 40 (1)251. Bedford, C. L., and W. F. Robertson. 1962. Processed Mont- morency cherries--a ten year summary. Mich. Agr. Expt. Sta. Quart. Bull. 45 (2)2334. Brown, S. L. 1964. Effect of heat treatment on the physical and functional prOperties of liquid and spray-dried albumen. M. S. Thesis. Michigan State University. Constantinides, S. M., and C. L. Bedford. 1964. Sugars in red tart cherries and their changes during maturation. J. Food Sci. 29:804. Cruess, W. V. 1948. "Commercial Fruit and Vegetable Products. " 3rd Ed. McGraW-Hill, New York. Culpepper, c. W., and J. s. Caldwell. 1927. Behavior of antho- cyan pigments in canning. J. Agr. Res. 35:107. 71 72 Das Seshremani Kreshna. 1964. Non-volatile acids of red tart cherries. Ph.D. Thesis. Michigan State University. Daravingas, G., and R. F. Cain. 1965. Changes in the anthocyanin pigments of raspberries during processing and storage. J. Food Sci. 30:400. Diehl, H. C., J. R. Mangers, C. R. Cross, and W. B. Bonney. 1930. The frozen pack method of preserving berries in the Pacific Northwest. U.S. Dept. of Agr. Tech. Bull. 148. Embs, R. J., and P. Markakis. 1965. The mechanism of sulfite inhibition of browning caused by polyphenol oxidase. J. Food Sci. 30:753. Endres, J. R. 1965. The effect of (drying processes on the color and gel strength of baked whole egg and milk slurries. M. S. Thesis. Michigan State University. Fanelli, M. J., and M. F. Gunderson. 1961. Defrost of prepared frozen foods. I. Defrost temperatures of frozen fruit pies, frozen meat pies, and frozen soup. Food Tech. 15 (10):419. Funk, K., M. E. Zabik, and D. M. Downs. 1965. Comparison of shear press measurements and sensory evaluation of angel cakes. J. Food Sci. 30:729. Gee, M., and R. M. McCready. 1957. Texture changes in frozen Montmorency cherries. Food Res. 22:300. Glidden, M. 1953. Isolation of the pigment of red cherries and factors influencing its color. M. S. Thesis. Michigan State University. Goodman, L. P. , and P. Markakis. 1965. Sulfur dioxide inhibition of anthocyanin degradation by phenolase. J. Food Sci. 30:135. Great Lakes Reports. 1954. What' 8 ahead for the cherry pack. Quick Frozen Foods. 17 (2):43. Griswold, R. M. 1944. Factors influencing the quality of home- canned Montmorency cherries. Mich. State Univ. Agr. Expt. Sta. Bull. 27:194. 73 Griswold, R. M. 1962. "The Experimental Study of Foods. ” Houghton Mifflin C0,, Boston. Grommeck, R. , and P. Markakis. 1964. The effect of peroxidase on anthocyanin pigments. J. Food Sci. 29:53. Guadagni, D. G., C. C. Nimmo, and E. F. Jansen. 1957. Time- temperature tolerance of frozen foods. VI. Retail pack- ages of frozen strawberries. Food Tech. 11 (7):389. Guadagni, D. G., C. C. Nimmo, and E. F. Jansen. 1958. Time- temperature tolerance of frozen foods. XI. Retail packs of frozen red sour pitted cherries. Food Tech. 12 (1):36. Guadagni, D. G., J. Harris, and K. M. Eremia. 1963. Factors affecting qualities of pies prepared from frozen bulk-pack red sour pitted cherries. Food Tech. 17 (3):221. Guadagni, D. G., J. Harris, and S. Okano. 1963. Stability of com- mercially prepared frozen fruit pies. Food Tech. 17 (7): 934. Joslyn, M. A. 1934. The present status of methods for improving the quality of frozen fruits and fruit products. Fruit Prod. J. 13:142. Jurd, L. 1964. Reactions involved in sulfite bleaching of antho- cyanins. J. Food Sci. 29:16. Kertesz, A. I., and E. Sondheimer. 1948. To reduce color losses in strawberry preserve. Food Ind. 20:1300. Kramer, A. 1952. A tri metric test for sweet corn quality. Pro- ceedings American Societal Horticultural Science. 59:405. Kramer, A., K. Aamlid, R. B. Guyer, and H. P. Roger, Jr. 1951. New shear press predicts quality of canned lima beans. Food Eng. 23:112. Kramer, A. , and K. Aamlid. 1953. The shear press an instrument for measuring the quality of foods. III. Application to peas. Proceeding American Societal Horticultural Science. 61:417. 74 Kramer, A., and W. J. Hart, Jr. 1954. Recommendations on pro- cedures for determining grades of raw, canned, and frozen lima beans. Food Tech. 8:55. Kulp, K., and W. G. Bechtel. 1962. Frozen fruit pies. Food Tech. 16 (7):104. LaBelle, R. L., and J. C. Moyer. 1966. Dehydrofreezing red tart cherries. Food Tech. 20 (10):1345. Larsen, R. P., M. Kelsey, P. Wooley and G. McManus, Jr. 1966. Project 80. Fruit Industries of Michigan in the Fruit and Vegetable Industries. Research Report 49. Farm Science. M.S.U. Agr. Expt. Sta. and Coop. Extension Service, East Lansing, Michigan. Li, K. C., and A. C. Wagenknecht. 1956. The anthocyanin pigments of sour cherries. J. Am. Chem. Soc. 78:779. Livingston, G. E., C. Tan, Z. I. Sabry. 1959. Colorimetry of strawberry preserves. Food Tech. 13 (6):303. Loutfi, S. M. 1951. Use of sugar, sugar syrup and ascorbic acid in frozen red cherries. M. S. Thesis. Michigan State Uni- versity. Lowe, B. 1955. ”Experimental Cookery." 4th ed. John Wiley and Sons, Inc. , New York. Marshall, R. E. 1954. "Cherries and Cherry Products." Inter- science Publishers, Inc. , New York. 'Mayak, S. 1965. The effect of various additives on color degrada- tion and browning of IQF tart cherries. M. S. Thesis. Michigan State University. Meschter, E. E 1953. Effect of carbohydrates and other factors on strawberry products. J. Agr. Food Chem. 1:574. Meyer, L. H. 1960. "Food Chemistry. " Reinhold Publishing Cor- poration. New York, New York. Mrak, E. M., H. J. Phaff, and H. Friar. 1943. Dehydration of cherries. Fruit Prod. J. 22 (7):198. 75 Parks, M. S. 1966. Substitution of foam spray-dried acid whey solids for buttermilk solids in chocolate cake. M. S. Thesis. Michigan State University. Pratt, D. B. 1955. Frozen pies. Proc., 31st An. Meeting Am. Soc. Bakery Engineers. 79. Pung, C. Y., and P. Markakis. 1963. Effect of phenolases on anthocyanins. Nature. 199:597. Robinson, R. 1933a. Natural coloring matters and their analogues. Chemistry and Industry. 11:737. Robinson, W. B., J. F. Ransford, and D. B. Hand. 1961. Mea- surement and control of color in the canning of tomato juice. Food Tech. 15 (6):314. Robinson, R. M., and R. Robinson. 1932b. Deve10pments in the chemistry of anthocyanins. Nature. 130221. Rogers, A. J. 1940. Cherries and how they are successfully quick frozen. Fruit Prod. J. 20:80. Sather, L. A., and L. D. Calvin. 1963. Relation between prefer- ence scores and objective and subjective quality measure- ments of canned corn and pears. Food Tech. 17 (7):97. Shallenberger, R. S., J. C. Moyer, R. L. LaBelle, W. B. Robin- son, and D. B. Hand. 1963. Firmness of canned apple slices as affected by maturity and steam-blanch tempera- tures. Food Tech. 17 (1):103. Stradman, E. R. 1948. Nonenzymatic browning in fruit products. Adv. in Food Res. 1:325. Stein, J. A., and K. G. Weckel. 1954. Factors affecting the color stability of frozen Montmorency cherries. Food Tech. 8 (10):445. Sweeney, J. P., V. J. Chapman, M. E. Martin, and E. H. Dawson. 1962. Quality of frozen fruit from retail markets. Food Tech. 16 (10):138. 76 Tinsley, I. J., A. P. Sidwell, and R. F. Cain. 1956. Method of presenting raspberry and strawberry samples to the Hunter color and color-difference meter. Food Tech. 10 (8):339. Tressler, D. K., and C. W. DuBois. 1944. No browning of cut fruit when treated by new process. Food Ind. 16:701. Van Buren, J. P., D. M. Scheiner, and A. C. Wagenknecht. 1960. An anthocyanin-discolorizing system in sour cherries. Nature. 185:165. Van Buren, J. P., D. M. Scheiner, and A. C. Wagenknecht. 1959. Color loss in small fruit. Farm Research. 25:15. Watt, B. K., and A. L. Merrill. 1963. Composition of foods. Agr. Handbook. No. 8. Agr. Research Service. U.S.D.A. Weckel, K. G., P. Buck, W. Beyer, and J. Birdsall. 1959. Con- sumer preference of sweetness in sirup packed vs. red sour pitted Montmorency cherries. Food Tech. 13 (6):300. Whittenberger, R. T., and C. H. Hills. 1956. Bruising causes cherry discoloration. The Canner and Freezer. 94:14. Wiley, R. C , and A. A. Thompson. 1960. Influence of variety, storage and maturity on the quality of canned apple slices. Proceedings American Society Horticultural Science. 75:61. Wolfe, N. J. 1967. A comparison of frozen, foam-spray dried, freeze-dried, and spray-dried eggs in baked custards. M. S. Thesis. Michigan State University. APPENDIX 78 GENERAL INSTRUCTIONS FOR CHERRY PIE EVALUATION 1. Please refrain from drinking coffee, eating, or smoking one-half hour before panel evaluation. 2. Please do not give any facial or vocal reactions as you evaluate your samples. 3. The samples will be presented one at a time. Using a red pencil please mark the block which most nearly fits your evaluation of each quality characteristic of the sample. 4. When you have completed the evaluation, turn your score card over and an assistant will replace it with a second sample. 5. Take your time in judging each sample. 6. Rinse your mouth between sample evaluation with the water pro- vided. 7. Three samples will be evaluated during each session. 8. You will be provided with a list of dates for taste paneling. Figure 4. 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Replicate averages, cherry process means, and standard deviations for sensory evaluation of frozen dried and nonfrozen dried cherry pie fillings. Cherry attribute Rep. Dried Dried nonfrozen frozen Color 1 3. 5 4. 4 2 4. O 4. 1 3 3. 1 4. 1 4 3. 0 3. 9 5 3. 0 3. 6 Mean/standard dev1at10n 3. 3 :l: 0. 43 4. 0 i: 0.29 for cherry processes Appearance 1 3. 5 3. 9 2 3. 8 3. 5 3 3. 4 3. 9 4 3. 6 3. 6 5 3. 1 3. 6 Mean/standard dev1at10n 3. 5 :I: O. 26 3. 7 d: 0. 19 for cherry processes Viscosity of sauce 1 5. 8 6. 0 2 5. 8 5. 9 3 5. 5 5. 8 4 5. 8 6. 1 5 6. 0 5. 6 Mean / standard deviation 5.8i0.18 5.9:I:O.19 for cherry processes Tenderness of cherry skin 1 6. 3 5. 4 2 5.6 5.3 3 5.3 5. 1 4 5.8 5.1 5 4.3 4.6 Mean/ standard deviation 5.5:t0.74 5.1:t0.31 for cherry processes Table 1 7 . Continued. 85 Cherry attribute Rep. Dried Dried nonfrozen frozen Texture of cherry flesh 1 4. 9 4. 4 2 4. 8 4. 3 3 4. 1 4. 6 4 4. 8 4. 3 5 4. 5 4. 3 Mean/standard dev1at10n 4. 6 i 0. 33 4. 4 :I: O. 13 for cherry processes Flavor 1 4. 3 5. 6 2 5. 0 5. 4 3 4. 9 5. 5 4 4. 5 4. 9 5 4. 8 5. 4 Mean/standard deV1ation 4.7 :1: 0.29 5.4 :t 0.27 for cherry processes . Acceptability (‘70) 1 13 75 2 38 5O 3 25 50 4 25 75 5 25 38 Mean/standard dev1at10n 28 :I: 0. 11 60 i- 0. 19 for cherry processes 86 Table 18. Replicate averages, cherry process means, and standard deviations for shear press measurements and Hunter colormeter measurements of frozen dried and nonfrozen dried cherry pie fillings. Cherry attribute Rep. Dr led Dried nonfrozen frozen Shear press 1 2. 06 1. 97 3 2. 04 2, 09 4 2. 17 2, 62 5 2. 53 2, 30 Mean / standard deviation 2.15:1: 0.22 2.30zt 0.38 for cherry processes Shear press 1 2. 21 1. 70 area-under-the-curve 2 1. 86 1. 80 (cm ) 3 1. 97 1. 96 4 2. 04 2. 02 5 2.45 2. 25 Mean / standard deviation 2.11 :1: 0.23 1.95: 0.21 for cherry processes Hunter L values 1 20. 8 18. 5 (lightness) 2 19. 0 17. 9 3 18. 1 18. 1 4 18. 7 17. 8 5 17. 9 17. 6 Mean/ standard deviation 18. 90:1: 1. 15 17. 981: 0.34 for cherry processes Table 18. Continued. 87 Cherry attribute Rep. 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