OVERDUE FINES: 25¢ per du per itc- RETUMIKS LIBRARY MATERIALS: Place in book return to rmve charge fro- circulation records THE USE OF DETERGENT FRACTIONATED, EDIBLE BEEF TALLOW IN FOOD SYSTEMS By Cynthia Lynn DeFouw A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Food Science and Human Nutrition 1981 ABSTRACT THE USE OF DETERGENT FRACTIONATED, EDIBLE BEEF TALLOW IN FOOD SYSTEMS By Cynthia Lynn DeFouw Edible beef tallow fractionated by detergent (SDS) at controlled temperatures was compared as a deep-fat frying medium with 1) unfrac- tionated tallow, 2) tallow-vegetable oil blends, and 3) a commercial frying oil. Twenty consecutive batches of French fry potatoes were evaluated and oil samples were tested physically and chemically. Results showed a darkening of oil color and progressive increases in viscosity, peroxide value, and refractive indes. No significant differ- ence (p<:0.05) in general acceptability of the fries resulted from variation in frying medium, but quality of the fries from all media decreased after 20 fryings. A comparison was also made between cookies containing vegetable shortening and comparable batches in which edible tallow had been sub- stituted for the shortening. Results obtained with a 450 member panel showed a slight flavor preference for the vegetable shortening cookie, however about 70% of the respondents liked to some degree the cookie prepared with tallow. To Mom and Bill with love 11 ACKNOWLEDGEMENTS I'd like to give special thanks to Dr. Mary E. Zabik for her help and guidance throughout my graduate program. I am especially thankful for her assistance in the preparation of this manuscript. I'd also like to express appreciation to my committee members, Dr. Ian Gray, Ms. Jean McFadden, and Dr. John Allen for their review of this thesis. The consumer study would never have been realized were it not for the help of Mary Zehner. Her enthusiam and willingness to assist in this project are appreciated. Kathy Bundy's help was also appreciated. I am grateful for the work done by Dr. Gray, Tom Ryan and Diane Bussey in the fractionation of tallow. Their willingness to answer my questions throughout the course of this research were valued. I am also appreciative of all the people in the Department who both wittingly and unwittingly helped me obtain my goal: Margaret, our secretary; fellow graduate students; and professors. This work was made possible by a grant from the Fats and Proteins Foundation, Chicago, Illinois. Finally, and most importantly, I want to thank my family and Harold. The love and support of both Mom and Bill were always there when I needed it the most. Tom and his great sense of humor were also appreciated more than ever during these past two years. I am also very grateful to Harold for his constant encouragement and willingness to listen to my ideas. His assistance in the preparation of this manu- script was also valued. Thanks to all of you I have been able to see this accomplishment realized. iii TABLE OF CONTENTS Page INTRODUCTION . . . . . . . . . . . . . . 1 REVIEW OF LITERATURE . . . . . . . . . . . 3 Tallow . . . . . . . . . . . . . . 3 Tallow Production . . . . . . . . . . . 3 Edible vs. Inedible Tallow . . . . . . . . . 4 Rendering . . . . . . . . . . . . S Utilization of Tallow . . . . . . . . . . 5 Inedible tallow . . . . . . . . . . . 5 Edible tallow . . . . . . . . . . . 5 Fat Fractionation Technology . . . . . . . . . 6 Dry Fractionation . . . . . . . . . . . 7 Solvent Fractionation . . . L . . . . . 8 Detergent (Aqueous) Fractionation . . . . . . . 8 Deep-Fat Frying . . . . . . . . . . . . 9 Changes in Frying Fats . . . . . . . . . . 10 Hydrolysis . . . . . . . . . . . . 10 Smoke point . . . . . . . . . . . . ll Oxidation . . . . . . . . . . . . . 11 Antioxidants . . . . . . . . . . 13 Nutritive Considerations of Heated Oils . . . . . . 15 The Care of Frying Fat . . . . . . . . . . 15 EXPERIMENTAL PROCEDURE . . . . . . . . . . . 17 Deep-Fat Frying Study . . . . . . . . . . . 17 Materials . . . . . . . . . . . . . 17 Deep-Fat Frying . . . . . . . . . . . . 18 Oil Analyses . . . . . . . . . . . . 21 Color . . . . . . . . . . . . . 21 Viscosity . . . . . . . . . . . . 21 Refractive index . . . . . . . . . . . 22 Peroxide value . . . . . . . . . . . 22 Fatty acid analysis . . . . . . . . . . 22 French Fry Analyses . . . . . . . . . . . 23 Color . . . . . . . . . . . . . 23 Texture . . . . . . . . . . . . . 23 Moisture content . . . . . . . . . . . 23 Fat content . . . . . . . . . . . . 24 i. Table of Contents (cont'd.) Peroxide value . . . . . . . Fatty acid analysis . . . . . Sensory evaluation . . . . . . Analyses of Data . . . Consumer Acceptability Study . . . . . Materials . . . . . . . Cookie Preparation . . . . . . . Cookie Evaluation . . . . . . . . Analyses of Data .' . . . . . . . RESULTS AND DISCUSSION . . . . . . . . Frying Oils . . . . . . . . . . Color . . . . . . . Viscosity and Refractive Index . . . . Peroxide Values . . Fatty Acid Determination by Gas Chromatography French Fries . . . . . . . Sensory Evaluation . . . . . Objective Evaluation of French fries . . . Color . . . . . . . . . . Texture . . . . . . . . . Chemical Analyses . . . . . . . . Consumer Aeceptability of Chocolate Chip Cookies SUMMARY AND CONCLUSIONS . . . . . . . PROPOSALS FOR.FURTHER RESEARCH . . . . . LIST OF REFERENCES . . . . . APPENDICES O I O O O O O O O O O I. U.S. Per Capita Consumption of Total Food Fats, Vegetable Oils and Animal Fats 1960-77 (USDA, 1977) . II. French Fry Scorecard . . . . . IIIa. Cookie Questionnaire for Adults . IIIb. Cookie Questionnaire for Children . . Page 24 25 25 25 26 26 26 28 29 30 30 31 40 50 54 54 6O 60 66 70 77 88 93 95 99 99 100 101 103 Table of Contents (cont'd.) Page IV. VI. VII. VIII. XI. Mean Color (Lightness) Values for Original Tallow (OT), Tallow Fractions, Tallow Blends (T-CO; T-SBO), and a Commercial Frying Oil (CFO) . . . . . . . . 104 Mean Peroxide Value of Original Tallow (OT), Tallow Fractions, Tallow Blends (T-CO; T-SBO), and a Commercial Frying Oil (CFO). . . . . . . . . . . 105 Chromatogram Used for Determining Fatty Acid Profiles by Gas Chromatography . . . . . . . . . 106 Organoleptic Color of French Fries Prepared in Original Tallow (OT), Tallow Fractions, Tallow Blends (T-CO; T-SBO), and a Commercial Frying Oil After Every Fifth Successive Frying . . . . . . . . . . . . 107 Organoleptic Texture of French Fries Prepared in Original Tallow (OT), Tallow Fractions, Tallow Blends (T-SBO; T-CO), and a Commercial Frying Oil After Every Fifth Successive Frying . . . . . . . . . . . . . 108 Mean Fat Content (Solids Basis) of French Fries Prepared in Original Tallow (OT), Tallow Fractions, Tallow Blends (T-SBO; T-CO), and a Commercial Frying Oil ‘. . . . 109 Mean Peroxide Values of Fat Extracted From French Fries Prepared in Original Tallow (OT), Tallow Fractions, Tallow Blends (T—SBO; T-CO), and a Commercial Frying Oil (CFO) . 110 Demographic Characteristics of Adults Responding to Consumer Panel for Chocolate Chip Cookies Prepared with and Without Tallow (N-208) . . . . . . . . . 111 vi Table 10 11 12 13 LIST OF TABLES Type of reactions during the frying process (Roth and Rock, 1972). . . . . . . . . . . . Distribution of eight variables and their replicates among four fryers . . . . . . . . . . Formulation for chocolate chip cookies . . . . Means and standard deviations for color values of original tallow, tallow fractions, tallow blends and a commercial fry oil . . . . . . . . . . Analyses of variance of color values of original tallow, tallow fractions, tallow blends and a commercial frying oil. . . . . . . . . . . . . Means and standard deviations for viscosities and refractive indices of original tallow, tallow fractions, tallow blends and a commercial frying oil . . . . Analysis of variance of viscosities of original tallow, tallow fractions and tallow blends . . . . . . Analysis of variance of refractive indices of original tallow, tallow fractions, tallow blends and a commercial frying oil . . . . . . . . . . . Means and standard deviations for peroxide values of original tallow, tallow fractions, tallow blends and a commercial frying oil . . . . . . . . . Analysis of variance of peroxide values of original tallow, tallow fractions, tallow blends and a commercial frying oil . . . . . . . . . . . . Mean relative percentage of fatty acids present in frying oils over a period of 20 successive fryings. . . . Change in fatty acid composition of frying oils over a period of 20 fryings. . . . . . . . . Means and standard deviations for sensory characteristics of French fries prepared in tallow, tallow fractions, tallow blends or a commercial frying oil . . m Page 12 20 27 32 33 41 42 42 46 47 51 53 55 List of Tables (cont'd.) Table 14 15 16 17 18 19 20 21 22 23 24 25 26 Page Analyses of variance of French fries prepared in original tallow, tallow fractions, tallow blends or a commercial frying oil . . . . . . . . . . . . . 56 Means and standard deviations for color values of French fries prepared in original tallow, tallow fractions, tallow blends and a commercial frying oil . . . . . . . 61 Analyses of variance of color values of French fries prepared in original tallow, tallow fractions, tallow blends and a commercial frying oil . . . . . . . . . . 62 Means and standard deviations for texture (crispness) of French fries prepared in original tallow, tallow fractions, tallow blends, and a commercial frying oil . . . . . 67 Analysis of variance of texture (crispness) of French fries prepared in original tallow, tallow blends and a commercial frying oil . . . . . . . . . . . . . 68 Means and standard deviations of chemical analyses of French fries prepared in original tallow, tallow fractions, tallow blends and a commercial frying oil . . . . . . . 71 Analyses of variance of chemical analyses of French fries prepared in original tallow, tallow fractions, tallow blends and a commercial frying oil. . . . . . . . . 72 Percent moisture and fat of French fries prepared in original tallow, tallow fractions, tallow blends and a commercial frying oil after 1, 6, ll, 16, and 20 fryings . . . . 73 Mean relative percentages of fatty acids present in fat extracted from French fries over a period of 20 successive fryings . . . . . . . . . . . . . 75 Change in fatty acid composition of fat extracted from French fries over a period of 20 fryings . . . . . . . 76 Adult respondents' opinion of chocolate chip cookies prepared with tallow and vegetable shortening . . . . . . 78 Child respondents' opinion of chocolate chip cookies prepared with tallow and vegetable shortening . . . . . . 79 Percent of total respondents' preference for chocolate chip cookies prepared with tallow or vegetable shortening . . 79 viii List of Tables (cont'd.) Table 27 28 29 30 31 Page Chi-square cross tabulation results for cookie preference vs. opinion of control cookie -— Adult questionnaire . . 81 Chi-square cross tabulation results for cookie preference vs. opinion of control cookie —- Childrens' questionnaire 82 Chi-square cross tabulation results for cookie preference vs. opinion of tallow cookie -- Adult questionnaire . . 83 Chi-square cross tabulation results for cookie preference vs. opinion of tallow cookie -- Childrens' questionnaire . 84 Chi-square cross tabulation results for adult cookie preference vs. frequency of buying cookies . . . . 86 Figure 4a 4b 5a 5b 6a 6b 9a 9b LIST OF FIGURES Chemical reaction of fat hydrolysis . . . The stages of oxidation of a fat (Perkins, 1967). Detergent (SDS) fractionation of edible beef tallow . Change in color (lightness) of tallow fractions over 20 successive fryings . . . . . . . . . Change in color (lightness) of original tallow, tallow blends and a commercial frying oil after 20 successive fryings . . . . . . . . . . . . Change in color (greenness) of tallow fractions over 20 successive fryings . . . . . . . . . Change in color (greenness) of original tallow, tallow blends and a commercial frying oil over 20 successive ftYings O O O O O O O O O O O 0 Change in color (yellowness) of tallow fractions over 20 successive fryings . . . . . . . . . Change in color (yellowness) of original tallow, tallow blends and a commercial frying oil over 20 successive fiwhms. . . . . . . . . . . . Change in viscosity of original tallow (OT), tallow fractions, tallow blends (T-SBO; T-CO), and a commercial frying oil over a period of 20 consecutive fryings . Change in refractive indices of original tallow, tallow fractions, tallow blends and a commercial frying oil over a period of 20 successive fryings . . . Change in peroxide values of tallow fractions over 20 successive fryings . . . . . . . . . Change in peroxide values of original tallow, tallow fractions, tallow blends and a commercial frying oil over a period of 20 successive fryings . . . . X Page 11 14 19 34 35 36 37 38 39 43 44 48 49 List of Figures (cont'd.) Figure 10 11 12 13 14 15 16 Page Presence of off—flavors in French fries fried in original tallow, tallow fractions, tallow blends and a commercial frying oil after every fifth successive frying . . . 57 Greasiness of French fries fried in original tallow, tallow fractions, tallow blends and a commercial frying oil after every fifth successive frying. . . . . 58 Overall acceptability of French fries fried in original tallow, tallow fractions, tallow blends and a commercial frying oil after every fifth successive frying . . . 59 Change in lightness (Hunter L value) of fries fried in original tallow, tallow fractions, tallow blends and a commercial frying oil over 20 frying periods . . . . 63 Change in redness/greenness (Hunter value) of fries fried in original tallow, tallow frac ions, tallow blends and a commercial frying oil over 20 frying periods . . 64 Change in yellowness (Hunter b value) of fries fried in original tallow, tallow fractions, tallow blends and a commercial frying oil over 20 frying periods. . . . 65 Change in crispness of French fries prepared in original tallow, tallow fractions, tallow blends and a commercial frying oil over a period of 20 fryings . . . . . 69 xi INTRODUCTION Animal fats (tallow and grease) are the second largest source of fats and oils in the United States (Anon., 1978) and until re- cently the primary domestic uses of tallow were in the manufacture of candles, soaps and animal feeds. Using improved fractionation procedures, under-utilized, less costly fats and oils are being modified to compete with more expensive fats and oils. The utiliza- tion of fractionated, edible beef tallow as a substitute for various food fats and oils has many economic advantages (Taylor at 31., 1976). The United States is the world's largest producer of beef tallow, supplying nearly 5.6 billion pounds annually (Kramer, 1971). Of this total, at least half is exported while only 10% of the total is used domestically for edible products (Taylor e£_al,, 1976; Burnham, 1978). The current abundance of tallow may be attributed to the success of the beef industry, as tallow also is a renewable resource. Considering its current availability, there is a potential for more extensive use of tallow as a food fat. Morris 35 31. (1956) stated that much of the edible grade tallow was divert- ed to inedible channels due to the lack of a market in the edible field. Both the demand and cost for imported oils such as cocoa butter, palm oil, coconut oil and palm kernel oil have been steadily increasing (Taylor 35 31., 1976). Consequently, fractionated tallow has been considered as an abundant, less expensive substitute for the more costly fats and oils typically used in the food and confectionery industries. Within the past decade there's been a 202 increase in per capita consumption of food fats in the United States (USDA, 1977). Bartholomew (1980) reported that consumption has reached 58 lb/year within this country. This trend can be attributed to the increase in consumption of oils from vegetable sources, as there's been a steady decline in animal fat consumption (Appendix I). Fractionated fats which are less saturated than their original source may be more competitive with vegetable oils with regard to their nutritional status. Luddy 35 El' (1973) reported that tallow could be successfully fractionated with a solvent (acetone) to obtain fractions with quite different physical properties. The USDA's Eastern Regional Research Center obtained three fractions from the solvent fractionation of tallow: a solid, semi-solid, and liquid or oil fraction (Anon., 1977), however disadvantages associated with this method have prompted investi- gation into alternative methods for the fractionation of tallow. Bussey at El. (1981) recently fractionated tallow using an aqueous fractionation procedure. The purpose of this study was to compare the olein portions of aqueous (detergent) fractionated tallow, original unfractionated tallow and tallow-vegetable oil blends to a typical commercial frying oil as deep-fat frying media. Additional research was conducted to determine consumer response to cookies prepared with tallow as a replacement for shortening. REVIEW OF LITERATURE This review of literature is comprised of three sections. The first two summarize both the utilization and processing of tallow and also the fractionation procedures which have been applied to tallow. Since the major focus of this research was to evaluate fractionated tallow as a deep-fat frying medium, the last portion of this review is devoted to the practice of deep- fat frying. Tallow Tallow has been defined as the solid fat deposits of animals; its pure form is white and odorless. It is used to make soap, candles and butter substitutes (Burnham, 1978). When considering the current applications of tallow and tallow fractions, this definition appears outdated. Tallow Production The volume output of tallow ranks second only to soybean oil (Kramer, 1971). Although government figures estimated nearly 6 billion pounds of tallow are produced annually, the National Renderers Association indicated a figure closure to 8.1 billion pounds per year (Kramer, 1971). Bartholomew (1980) attributed the increase in the annual production of tallow to two elements: 1) government support programs to the beef industry and 2) the expansion of beef cattle feed— ing in this country. A.major problem associated with increased produc- tion has been finding markets for the increasing surplus of tallow above domestic requirements. Exports have absorbed much of the excess and' represented nearly one-half of the total output in 1971 (Kramer, 1971). However, larger production of foreign-produced oils has recently pro- vided competition for U.S. tallow exports (Anon., 1976). Edible vs. Inedible Tallow Not all tallaw is considered food grade. Kramer (1965) differen- tiated between inedible and edible tallow relating the difference to standards set by the USDA. He stated that "by law, the raw fat avail- able for edible rendering must come from federally inspected cattle and be handled and processed under government regulations." Rendering plants must be operated under the same inspection and processing stan- dards set by the USDA as for the processing of table meats (Burnham, 1978). Although total tallow production is up 63% (Bartholomew, 1980) only a small portion of this amount is comprised of edible tallaw (Burnham, 1978; Kramer, 1965). “There is the potential however, that if demand for edible tallow increased, as much as 70% of tallaw produc- tion could be handled to meet edible classification standards (Anon., 1977). Rendering The rendering process differs very little for inedible and edible tallow. Kramer (1971) described the rendering process as that utilized to obtain tallow and other by-products (primarily meat meal) from.the fat, skin, meat, bones and offal of an animal. The main objective is to separate any residual moisture in the raw material from.the fat and solids (Burnham, 1978). The primary difference in the rendering of edible vs. inedible tallow is the use of lower and higher temperatures, respectively (Burnham, 1978). Utilization of Tallow Inedible tallow. Traditionally tallow was used as a major compo- nent in candles, however with time and technological advancements, tal— low has been used in soaps, as a source of glycerine, fatty acids, and in other industrial products (Burnham, 1978). The major domestic use of tallow has been in animal feeds (Kramer, 1971; Anon., 1978); as much as 402 is utilized for this purpose (Anon., 1976). Twenty-five percent of this country's tallow production is used to produce fatty acids for industrial purposes (Anon., 1976; Anon., 1978). Even though the change to petro-based detergents reduced the demand for tallow in soap production, the third largest domestic use for tallow is in soaps (Anon., 1978). Edible tallaw? One of the earliest applications of tallow'was as an ingredient in shortenings (Morris at 31., 1956; Kramer, 1965). 1For the remainder of this review of literature, edible tallow will be referred to as simply "tallow" unless otherwise specified. Morris 25 a1, (1956) studied beef tallow in shortening preparations in an attempt to optimize the plastic range of a tallow shortening. Tallow has also been used for frying by restaurants because of its desirable flavor (Baeuerlen gt El°’ 1968). An increased consumer awareness with regard to nutrition could have negative implications for beef tallow consumption as evidenced by decreased consumption of fats from animal sources (USDA, 1977) (Appendix I). A recent study which was sponsored by the American Soybean Association revealed that most consumers were aware that animal fats are higher in saturated fats whilevegetableoils are associated with polyunsaturates (Andres, 1980). Tauber (1980) reported that nutrition and the avoidance of fat, cholesterol, sugar, etc. ranked third in level of concern for consumers. "There is little doubt that the production of edible beef tallow would increase substantially if a more profitable market for the product could be anticipated (Luddy £2 31., 1973)." Fractionation can yield a product comprised of over 652 unsaturates (Luddy at al., 1973; Bussy 35 31., 1981) thus there is a potential for increased tallow utilization as a result of fractionation (Anon., 1977). Fat Fractionation Technology In order to separate the saturated fatty acids from the unsaturated fatty acids in a fat, low temperature crystallization was employed (Schwitzer, 1959). This method involved chilling the fat with subse- quent pressing to squeeze out the unsaturates. Later in time, fraction- al crystallization was used primarily for the isolation of pure individ- ual glycerides (Riemenschneider gt_al,, 1946; Swern, 1964). More recently, Luddy £5 31. (1973) employed a solvent fractionation technique to obtain liquid, solid and semisolid components with many potential uses. Although tallows contain too high a percentage of solids to be used effectively as shortening agents (Hoerr, 1960), excess solids can be partially removed by fractional crystallization. Bussey EEJEL' (1981) summarized the advantages and disadvantages of the three estab- lished methods of fractionation: dry fractionation, solvent fraction- ation and detergent (aqueous) fractionation. Dry Fractionation As described by Haraldsson (1974), dry fractionation is "the crystallization of the oil (normally after refining) followed by straight separation of the fractions by means of filtration or press- ing." Riemenschneider at El. (1946) investigated the use of low temperature fractionation as a step in determining glyceride composi- tions of fats and oils. Another application of low temperature, dry fractionation was in the separation of butterfat into fractions, each with unique melting points (Baker, 1970). Baker (1970) suggested that the liquid butterfat fraction had potential as a deep-fat frying medium and the hard butterfat fraction as an ingredient in the manu— facture of chocolate. Although dry fractionation is the simplest and longest established method, filtering can become difficult at low temperatures or when small crystals are formed (Bussey 25 31., 1981). Solvent Fractionation Solvent fractionation has an advantage over dry fractionation in that is is a more efficient means of separation (Bussey g£_al,, 1981). Luddy 35 a1. (1973, 1977) demonstrated that tallow could be success- fully fractionated by acetone crystallization. Three distinct portions were obtained: A solid with applications as a hardening agent in margarines and shortenings; a semi-solid with characteristics comparable to cocoa butter; and a liquid oil with applications as an all—purpose cooking oil. Holsinger st 31. (1978) successfully substituted the oil fraction from solvent fractionated beef tallow for soybean oil in a whey-soy drink mix. The primary disadvantages of solvent fractionation are the need for flame-proof equipment, the high cost of solvents and the difficulty of removing trace solvent residues (Bussey st 21., 1981). Detergent (Aqueous) Fractionation The third method of fractionation is aqueous fractionation, developed by Haraldsson (1974) for use with palm oil. The basic princi- ple of detergent fractionation involves the dispersion of a partly crystallized oil in water which contains a surfactive agent. By means of centrifugation to separate the oil and water phases, fatty acid crystals can be separated from the oil (Bussey 33 31., 1981; Haraldsson, 1974). Bussey £5 a1. (1981) investigated ways to optimize the detergent fractionation process in their work with beef tallow. Detergent fraction- ation of tallow yielded many fractions including an oil, a hard*white solid and a softer yellow solid. The application of detergent fractionated tallow as a shortening agent in baked products has been recently studied. Hoojat and Zabik (1979) found that the substitution of tallow fractions for shortening produced acceptable sugar snap cookies. Bundy e£_al. (1981) used tallow fractions in white layer cakes and indicated that acceptable cakes could be produced if additional emulsifiers were added to the batters. Deep-Fat Frying Foods prepared by deep-fat frying play major roles in our diets and are products of a multi-billion dollar industry. Often associated with the fast-food segment of the food service industry, foods such as doughnuts, potato chips, French fried foods, chicken and seafood often rely on deep-fat frying as a method of cookery. Fats utilized as deep- fat frying media serve dual roles: functioning as a means for heat transfer and contributing to the nutrition and flavor of fried products (Bates, 1952). Baeuerlen 35 El’ (1968) enumerated the characteristics of an optimum frying fat: 1) a light or fairly light color; 2) a surface free from foam and smoke; 3) a clean, clear appearance free of burnt particles; and 4) flavor, or blandness, which enhances the eating quality of the fried food. Thompson etual. (1967) demonstrated that the degree of deterioration of a fat was dependent on how it had been used. Twenty one sets of fat or oil samples were collected from commercial deep-frying operations. One sample in the set was fresh, unused oil; the other was the same batch of oil after it was used and ready to be discarded. Samples were obtained from restaurants, hospi- tals, food manufactureres and armed services. Results were based on 10 comparative iodine values, peroxide values, free fatty acid analysis, viscosity and gas chromatography. Investigators found that some food processors adequately maintained their frying oils while others abused and damaged theirs. Robertson (1967) reviewed the changes which occurred in foods during deep-fat frying. The amount of fat absorbed in a food is depend- ent on: 1) length of cooking; 2) total surface area of the fat; 3) the smoke point of the fat; and 4) the composition and nature of the food (Lowe, 1955). Bates (1952) also related fat absorption to viscosity of the frying fat, frying temperature used, and formulation of the product being fried. Changes in Frying Fats The major changes which affect the quality of a frying fat are: hydrolysis, polymerization, oxidation and discoloration. As a result of an increased interest in changes which occur to a fat in deep-fat frying, numerous studies were reported during the 1950's. Hydrolysis. In 1932, Porter egflal. reported that the deterioration of a fat was mainly due to hydrolysis which yielded glycerol and acids. Later, Carlin at El’ (1954), Baeuerlen at 31. (1968), and Roth and Rock (1972) acknowledged that hydrolysis (Figure l) was the major chemical reaction affecting a fat however it was of secondary importance to that of oxidation. Roth and Rock (1972) classified three conditions in the frying process: storage, standby, and frying (Table 1). They associated hydrolysis with the "frying period" when the fat was exposed to air, 11 t' 9 H u-c-o-c-n u—é-ou ' 9 ' 9 H-c-o-c-n +3H20—bu-c-0H + 3IH:-0l| I '0' ' H-c-o-c-n IH;-0l-I u u TRIGLYCERIDE +WATER -’ GLYCEROL + FATTY ACIDS Figure 1. Chemical reaction of fat hydrolysis. water vapor, and the food being fried. Fatty acids are the main products of fat hydrolysis. Smoke point. In 1940, Lowe at 31. reported that the free fatty acid content of a frying fat was inversely proportional to the smoke point. Vail and Hilton (1943) later studied the smoke points of 27 fats and oils and they too found an inverse relationship to the smoke point and the percentage of free fatty acids. Monoglycerides were shown to lower the smoke point of continuous processed lard, however fat absorp- tion was unaffected by monoglyceride presence (Bennion and Banning, 1956). Lowe at 31. (1958) determined the smoke points of some commer- cially available fats which contained emulsifiers. Factors which reduced smoke points were: increased fatty acid content, increased fat surface area exposed to air, and accumulated bits of food. Oxidation. During the process of deep-fat frying the oil is continuously or repeatedly used at elevated temperatures in the presence of oxygen (Thompson, 1967). Perkins (1967) discussed the chemical 12 Table 1. Type of reactions during the frying process (Roth and Rock, 1972). PERIOD REACTIONS REACTIVE PRODUCTS RATE a) Storage 1. Autoxidation Slow Hydroperoxides Carbonyls b) Standby l. Autoxidation Fast Carbonyls 2. Isomerization Fast Long and short chain acids 3. Pyrolysis Slow Esters 4. Polymerization Slow Alcohols Glycols Trans isomers Hydrogen Carbon dioxide Carbon monoxide Water Ethers Epoxides Branched chain fatty acids c) Frying 1. Same as standby Same as standby 2. Hydrolysis Fast Fatty acids Mono— and diglycerides Glycerine 13 reactions which occur during the autoxidation of a frying fat or oil (Figure 2). During the induction period no detectable reactions occur; however, soon after the peroxide content rises rapidly to a maximmn, it declines as the percentage of oxygen in the oil gradually increases. As polymerization increases so does viscosity. Volatile compOunds (aldehydes, ketones, acids, alcohols and hydrocarbons) are formed during degradation. Perkins and Van Akkeren (1965) studied intermittent heating and cooling cycles of cottonseed oil and found increased deteri- oration as a result. They attributed the results to an increased build- up of peroxides and carbonyls which were destroyed by subsequent heating. These compounds could then propagate the formation of additional free radicals. Catalytic agents such as copper, cobalt and iron can increase the rate of oxidative reactions in a fat (Tilgner, 1978). Antioxidants. Antioxidants extend the shelf life of a fat by reacting with free radicals formed during the initiation and propagation stages of oxidation. One of the greatest challenges to the effective use of antioxidants is in deep-fat frying because of the relatively high temperatures involved and the large quantities of moisture usually driven off (Sherwin, 1972). Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are steam distillable and propyl gallate decomposes at high temperatures (Sherwin, 1972). Magoffin and Bentz (1949) reported three ways that an antioxidant is removed from a frying oil: by steam distillation, by absorption into the fried product, and by its consumption in its role as an antioxidant. After 5,000 pounds of potatoes were fried in a vegetable shortening, the amount of anti- oxidant in the fat decreased from .026 to .0042 (Magoffin and Bentz, 1949). l4 .Aaeoa .mcaxcmav one m mo couumvuxo mo mmwmum was .N muawse A NE..— EmoomSIv mwo_xO¢wu R 4.0 2. 2m U>x0 e 2 commons: zmo>xo 20_w¢m>w¢ ZO_._._mOS_OOmD ZO:.._Om mnszmmm mQXOmmu 2030302. 15 Sair and Hall (1951) discussed the addition of antioxidant-salt products after the frying process and their success in increasing the storage life of potato chips and other deep fried food products. With certain types of nuts, antioxidants are combined with the dressing oil used for glazing purposes. Nutritive Considerations of Heated Oils The possibility of a health danger due to the mishandling of frying oils is a topic of current interest. Rice 35 il' (1960) reviewed studies indicating that the conditions needed for the nutritional damage of fat were much more severe than were possible in home or commercial cooking operations. Melnick (1957) has emphasized the fact that conditions observed in the laboratory resulting from thermally damaged fat are extreme and therefore irrelevant to commercial operations. Johnson at 31, (1957) however, have reported enlarged livers in rats fed diets containing corn oil which has been thermally oxidized by bubbling air through oil held at 180°C for 24 hours. Chang £5 31. (1978) used infrared and mass spectrometry to identify 220 volatile decomposition products produced during deep-fat frying, many of which had known toxic properties. The Care of Frying Fat The method of care of a frying fat is an important factor in determining its frying life. Rust and Harrison (1960) studied the effect of four methods of care on the length of frying life and deteriorations in the fat. They found that filtering and refrigeration of the fat and l6 cleaning of the fryer between frying periods prolonged the frying life. Jacobson (1967) suggested using the lowest possible temperature commen- surate with product quality in the frying of foods as a means of main- taining fat quality. Freeman (1969) reported that an oil "kept busy with food will last longer than one standing idle at frying temperatures." He attributed this to the steam which is liberated from the fried food, acting as a "blanket" to protect the oil from oxygen. Both Fritsch gt_al, (1979) and Graziano (1979) investigated the use of changes in dielectric constant of oils as a measure of oil deterioration. This type of test provides a quick, on-site way for determining the degree of degradation in a frying fat without depending on physical changes alone. EXPERIMENTAL PROCEDURE This research was initiated to determine whether detergent frac- tionated edible beef tallow is suitable for use in various food systems. The olein fraction of tallow obtained by detergent fractionation and tallow-vegetable oil blends were investigated as media for deep-fat frying. Additional research was conducted to determine consumer accep- ability of chocolate chip cookies prepared with tallow as a replacement for shortening. These cookies were sampled by 449 people in Port Huron, Michigan and information was obtained regarding the acceptability of the cookies as well as some demographic information about the partici- pants. Deep-Fat Frying Study Materials Edible tallow obtained from the AIW. Stadler Company in Cleveland, Ohio was fractionated using the detergent fractionation procedure described by Bussey st 31. (1981). Softened tallow was mixed with 0.6% sodium dodecyl sulfate (SDS) (by weight of tallow) and allowed to crystallize for 18 hours at 45°C. A 5% aqueous solution (based on the 'volume of water) of electrolyte (sodium sulfate) was added and dispersed 17 18 for one hour. Centrifugation at 2700 rpm for 15 minutes at room temper- ature followed immediately and the olein portion was retained for deep- frying. Subsequent fractions at 40°C, 35°C, and 25°C were obtained by decreasing the temperature and centrifuging as already described. Figure 3 summarizes the fractionation procedure. For use as deep-fat frying media the following fats were used: four olein fractions (25°C, 35°C, 40°C and 45°C fractionation tempera- tures); 502 blends of unfractionated tallow with soybean oil (T-SBO) and with corn oil (T-CO); original, unfractionated tallow (OT); and a partially hydrogenated soybean commercial frying oil (CFO) ("Newe-Frye", Humko Products, Kraft Inc., Memphis, TN.). The commercial frying oil was used as a standard for comparison purposes and was purchased from Michigan State University Food Stores. The vegetable oils used in the tallow blends were obtained from a local food retailer. BHA was added to all tallow fractions, tallOvaegetable oil blends and original tallow so that all variables contained the legal allowable limit of antioxidant which is 0.02% BHA based on weight of fat. Product specifications for the commercial frying oil indicated TBHQ had been added to preserve freshness. Commercially frozen straight-cut, extra fancy "shoestring" style French fry potatoes were obtained from.Michigan State University Food Stores. Deep-Fat Frying Four Sears (model #34-6425) deep-fat fryers with alumdnum.interiors and a 1.4 liter capacity were used for the deep-fat frying of French fries. Each variable and its replicate were randomly distributed among 19 Tallow + 0.6% SDS (45°C) +5.0Z Na SO 2 4 (Centrifugation) Solids Olein (40°C) (Centrifugation) Solids Olein (35°C) (Centrifugation) Solids > (25°C) (Centrifugation) Solids Olein Figure 3. Detergent (SDS) fractionation of edible beef tallaw. 20 four groups and then were arranged so as to avoid using the same fryer for both a variable and its replicate. For each group of variables, the entire deep-frying portion of the experiment was completed before progressing to the next group of variables. The distribution of the variables among fryers is found in Table 2. Table 2. Distribution of eight variables and their replicates1 among four fryers. Fryer Number Group Number 1 2 3 4 1 CFO 35°C T-SBO T-CO 2 T-CO2 25°C 40°C T-SBO2 3 45°C CFO2 OT OT2 O O O O 4 25 C2 45 C2 35 C2 40 C2 1Replicates are denoted by a subscript Initially, 1323 g of oil were preheated to 185°C (approximately 15 minutes) and loads of the frozen French fries weighing 150 g were fried for seven minutes at this initial temperature. At the end of the frying period, fries were drained on a double thickness of paper toweling and either presented to a panel for sensory scoring or packaged and held at -23°C until needed for further analyses. Seventy m1 of oil were retained from each fryer for oil analyses after each of 20 consecutive fryings. In order to evaluate the oils under the most severe conditions of use, the «quantity of oil was never restored to the original volume of 1323 g after any of the fryings. After every fifth frying, oils were filtered through 21 a double thickness of cheesecloth and throughout the experiment both the oils and fryers were stored at 4°C overnight. Approximately four fryings were completed each day. Oil Analyses 9212:. Before the first frying and after every frying thereafter, the color of the oil was measured using a model D-25 Hunter color difference meter with an inverted head. A yellow tile (L=78.4, aL=-l.9, bL=+25.0) was used to standardize the instrument. Approximately 70 ml of warm oil were placed in a optical glass cylinder cup (7.4 x 1.9 cm), and covered with an inverted, white-lined can to provide a standard optical background before taking a reading. After the first reading was taken, the sample was rotated 90°, a second reading obtained, and the average value reported. Viscosity. Oil viscosities were determined prior to the initial frying and after each consecutive frying. A Nametre model 7.006 Direct Readout Viscometer was used in conjunction with an Exacal 100 controlled temperature circulating water bath at 50°C : .OIOC. Approximately 40 m1 of warm oil obtained from each fryer were placed in glass beakers (3.5 cm x 7.7 cm) and the beakers were then lowered into the circulating water bath. Samples were allowed to temper for 15 minutes before lowering the viscometer head into the sample. Once the head was immersed in the oil, the sample was allowed to equilibrate an additional 15 minutes before a reading was taken. After color and viscosity were determined for each sample, enough oil for determining refractive index, peroxide value and GLC analysis 22 o . was retained and stored at -23 C in culture tubes with screw-on tops. Refractive index. After frying was completed for all variables and their replicates, refractive indices were determined on the stored, frozen 011 samples. Indices were determined for the unused oils and after each consecutive frying. A Bausch and Laumb, Abbe-3L refractometer equipped with a 400 i .0100 circulating water bath was used. Samples were allowed to equilibrate on the prism of the refractometer for one minute before readings were taken. The values reported were the average of two readings. Peroxide value. Oil samples obtained after the first, fourth, sixth, ninth, eleventh, fourteenth, sixteenth, eighteenth, and twentieth fryings as well as unused oil samples were used for determining peroxide values. AOAC Method 28.023 (AOAC, 1975) was used and the procedure was repeated for each sample, reported values being an average value. Fatty_acid analysis. Oil samples obtained from the unused oil and after the first, sixth; eleventh, sixteenth and twentieth fryings were analyzed for their fatty acid profiles. Fatty acid methyl esters were prepared for GLC analysis using the boron trifluoride-methanol procedure described by Morrison and Smith (1964). The methyl esters were analyzed with a 5830A Hewlett Packard gas chromatograph equipped with a flame ionizing detector. A glass column, 6 ft. x 1/4 in. inside diameter, packed with 15% diethylene glycol succinate (DECS) on 80/100 Chromosorb was used. The column was operated isothermally at 190°C with a nitrogen flow rate of 30 ml/min. The temperature of the injector and detector was maintained at 210°C and 350°C respectively. Fatty acid percentages were calculated for C14, C16’ C16zl’ Cl8’ C18:1’ C18:2’ and 618:3 fatty acids ‘using a 18850A Hewlett Packard microprocessing integrater. 23 French Fry Analyses French fries from the first, sixth, eleventh, sixteenth, and twentieth fryings were used for both physical/chemical and sensory analyses. Immediately after frying, French fries were drained and a portion was presented to panelists for sensory evaluation. The remain- ing fries were used for bath color and texture measurements, after which fries were ground in a Waring blender until homogeneous, packaged in individual polyethylene bags with whirl closures and held at -23°C until needed for further analyses. On the fryings when no analyses were per- formed, fries were packaged, without grinding, in polyethylene bags with zip tops and stored at -23°C. 9212;, Color readings for the fries prepared in the eight oils were obtained using the same equipment and procedure described for determina- tion of oil color. The instrument was again standardized to a yellow tile. Texture. An Alla-Kramer shear press equipped with a TR-3 recorder was used to evaluate texture of the French fries. A 100 pound transducer and range of 10 were used, with a single blade cell to measure the force required to shear a single fry. A randomly selected French fry was plac- ed perpendicular to the blade and the value reported was an average of three separate fries. Moisture content. Five gram samples of thawed, ground French fries were accurately weighed to the nearest 0.0001 g and dried at 90°C over- 'night under a vacuum of 27 inches of Hg in a Hotpack vacuum oven, model 633 (AOAC Method 14.003). The samples were cooled in a desiccator tnafare being reweighed. The percentage moisture in the cooked French 24 fries was calculated according to the formula: % moisture 3 original sample wt (g) - dried sample wt (g) X 100 original sample wt (g) Duplicate measurements were made on each frying and the average was reported as the percent moisture. Fat content. Fat was extracted from duplicate 8 g samples, accurate- 1y weighed to the nearest 0.0001 g, of thawed, ground fries using the chloroformrmethanol method of extraction described by Bligh and Dyer (1959). The majority of the chloroform.was evaporated from the chloroform-lipid extract by means of a stream of nitrogen while samples were held in a 35°C water bath. The remaining traces of chloroform were removed by placing flasks containing the samples in a Hotpack vacuum oven (model 633) set at 40°C, with a vacuum of 27 in of Hg, overnight. Percentage fat was determined using the following equation: wt of extracted lipid (g) A fat = original sample wt (g) X 100 Fat content was expressed as a percentage of total solids. Conversions were made by the formula: 0 . . 3 % fat (wet basis) A fat (solids ba31s) (100 - % moisture of sample) X .01 Approximately 15 drops of lipid obtained from the extraction were retained in 10 ml glass vials with plastic tops and stored at -23°C until needed for GLC analysis. The remaining lipid extract was used in the determination of peroxide value of the extracted fat. Peroxide value. AOAC Method 28.023 (AOAC, 1975) was used for deter- Inining peroxide values of the fat extracted from the French fry samples. IDuplicate determinations were made and the average was reported as 25 peroxide value. Fatty acid analysis. The same method of sample preparation and GLC analyses as described for oil samples was used in the determination of fatty acid profiles for the fat extracted from French fries. The conditions used previously (temperature and flow rates) were also used for the fat samples extracted from the fries. Sensory evaluation. After the first, sixth, eleventh, sixteenth, and twentieth fryings taste panels were conducted using a trained, 10— member panel. Fries were presented to the panelists while hot and were unsalted so that any off-flavors wouldrunzbe masked by the salt. For each variable, small paper packages similar to those used by fast-food outlets for French fries were labeled with a random number specific for that variable. Three fries fried in each of the oils were packaged into bags and the bags were placed in pre-heated, covered institutional-type serving trays. A reference sample from a local fast-food restaurant was included with the samples as a color reference. The fries were then presented to taste panelists in individual booths lit with fluorescent lights simulating daylight. Characteristics evaluated were: texture, greasiness, off-flavors (rancidity), color and overall acceptability using a linear, 100 mm scale (see Appendices for scorecard). Analyses of data Data were analyzed for variance using the STAT package with the Michigan State University CDC CYBER 170, Model 750 computer. When signi- ficant differences were found between the two extreme means, Duncan's Multiple Range Test (Duncan, 1957) was used to pinpoint differences among means 0 26 Consumer Acceptability Study One thousand chocolate chip cookies, five hundred made with vegetable shortening and five hundred with tallow, were prepared for subjective evaluation by consumers in Port Huron, Michigan. Materials Common lots of granulated sugar, flour and miniature chocolate baking chips were obtained from Michigan State University Food Stores. Common lots of brown sugar, eggs, vanilla, salt and baking soda were purchased from a local food retailer. Half of the cookies were prepared with a hydrogenated vegetable shortening containing mono- and diglycerides (CrischO obtained from Michigan State University Food Stores, while the other half of the cookies were prepared with edible tallow as the shorten- ing agent. Tallow was obtained from the A.W. Stadler Co., Cleveland, Ohio. Cookie Preparation The same formulation was used for both the cookies prepared with vegetable shortening (control) and the cookies prepared with tallow with the type of fat being the only difference (Table 3). The method of prep- aration and baking time was identical for both variables. Preparation began with the creaming of the fat, granulated sugar and brown sugar for three minutes at medium speed (90 rpm) using the paddle attachment in a Kitchen Aid mixer, model K5-A. The bowl was scraped «down after one minute of mixing. The egg and vanilla were added to the 27 Table 3. Formulation for chocolate chip cookies. Control Tallow Ingredient Cookie Cookie Vegetable shortening, g 170.0 Tallow, g 170.0 Granulated sugar, g 114.0 114.0 Brown sugar, g 114.0 114.0 Whole egg, g 96.0 96.0 Vanilla, ml 5.0 5.0 Flour, g 284.0 284.0 Salt, g 6.0 6.0 Baking soda, g 3.7 3.7 Chocolate chips, g 250.0 250.0 creamed mixture and were mixed for two minutes at medium speed. The dry ingredients (flour, salt and baking soda) were sifted once, added to the previous mixture and mixed for one mdnute at low speed (60 rpm). The bowl was scraped down after 30 seconds of mixing. The chocolate chips were then added and mixed for 30 seconds at medium speed. The dough was shaped into balls weighing approximately 15 g and placed on stainless steel baking sheets, 17 x 10 x 1/8 inches (42.50 x 25 x 0.31 cm). Baking sheets were lightly greased with vegetable shortening, approximately one gram per sheet. Before baking, the dough balls were flattened slightly with the bottom of a beaker which had been lightly floured. The cookies were baked for 12 minutes at 375°F (190°C) in a 12 1-lb loaf size JNational Reel Type Test Baking Oven. The cookies were removed from the laaking sheets after baking, cooled on wire racks and packaged 28 in individual, transparent polyethylene bags with whirl closures. The bags were labeled with either a "#" representing the control cookie or a "%" representing the tallow cookie. A11 cookies were stored at -23°C until evaluated. (Total storage time was less than 3 weeks.) Cookie Evaluation As part of a taste-panel exhibit representing the Agricultural Economics Consumer Marketing Information Program, cookies were evaluated by 208 adults and 241 children at the "Fun and Facts Fair" in Port Huron, Michigan in April, 1980. Two separate questionnaires were used: one for children under 16 and another for 16 years and older (see Appendices for sample questionnaires). The children were asked to evaluate both cookies, state their preference and their frequency of eating cookies. A space for comments was provided. The adults were also asked to evaluate both cookies, state their preference and the reason for preference, and their willingness to buy a similar type of cookie. Also asked were: frequency of eating and buying cookies, type of cookies most frequently purchased, and ages of household members who would like this type of cookie. Demographic information obtained from only the adults included: sex and age of respondent, number living in household, age of children under 18 living at home and total family income for 1979 before taxes. Both the questionnaires for children and adults used a hedonic scale for evaluating the cookies; the childrens' having a 5-point facial hedonic scale and the adults' having a 7-point descriptive hedonic scale. Throughout the taste panel the order of tasting was alternated ‘to eliminate the possibility of bias, with half the participants receiving tfhe tallow cookie first and half receiving the control cookie first. 29 Analyses of Data Chi square (Snedecor and Cochran, 1967) was used to analyze data obtained from the consumer taste panel. From the childrens' survey, cross tabulations were done for preference vs. opinion of each cookie and for frequency of eating cookies vs. opinion of each cookie and preference. From the adults' survey, cross tabulations were done for demographic data and preference vs. opinion of each cookie, preference, willingness to buy, and frequency of eating and buying cookies. Cross tabulations were also done for willingness to buy vs. frequency of eating and buying cookies. RESULTS AND DISCUSSION This study was designed to determine the feasibility of using detergent fractionated beef tallow as well as unfractionated tallow blended with vegetable oils, as deep-fat frying media for French fry potatoes. Objective and subjective data were examined to determine the effect of fractionation on the functionality of tallow, tallow fractions, and tallow blends. In addition, chocolate chip cookies prepared with tallow as a substitute for shortening were presented to consumers for sensory evaluation. Frying Oils Tallow, tallow fractions and tallow blends were studied as deep- fat frying media partially because of the increased use of deep frying in restaurants and fast—food outlets. Also it was desired that these oils be studied under the stressful conditions which are inherent to this type of cookery. The common practice of adding fresh oil to maintain a constant volume in the cooker wasn't followed so as to allow the maximum.rate and extent of oil destruction. 30 31 Color Means and standard deviations for Hunter color values are presented in Table 4 and the analyses of variance for these data are summarized in Table 5. Duncan's Multiple Range Test revealed the two tallow-vegetable oil blends were significantly darker then the original tallow (OT) or tallow fractions (p<:0.05). Additionally they were found to be signifi- cantly more yellow (larger b values) than the OT or 40°C tallow L fraction (p<:0.05). This is probably a result of carotene pigments present in the vegetable oils. Freeman (1969) suggested that it was the tocopherols and other components of an oil which produced colored components upon oxidation which increased the general color of the oil. Figures 4ar6b illustrate the changes in oil color over the period of 20 fryings. As expected, all oils became darker and more yellow after each successive frying which contributed to the high standard deviations for oil averages. Lowe at 31. (1940) attributed the darkening of frying oils to two factors: breaking down of the fat and the accumulation of small food particles. Jacobson (1967) correlated color changes of a fat to an increase in free fatty acid content. Since free fatty acids discolor readily, they alter the color of a fat as their concentrations increase (Bates, 1952). The development of yellows (increased bL values) occurred in all oils over a period of fryings and was also reported by Bennion and Hanning (1956) in their study of lard decomposition during the frying of French fries. Although L and b values changed noticable over the frying L period, aL values (greenness) remained somewhat constant; all oils exhibiting a slight green tinge (Figures 6a and 6b). 32 Table 4. Means and standard deviations1 for color values of original tallow, tallow fractions, tallow blends and a commercial fry oil. Hunter Color Values Type 2 3 4 of Oil L aL bL Original Tallow 41.6 : 0.6C1 -4.7 i 0.3"1 +11.9 i 1.5"”1 Tallow Fractions: 25°C 41.4 i 1.0bc -4.8 i 0.5abc +12.s i 2.3C 35°C 41.7 : 1.6a -4.9 i 0.5Cd +12.4 : 2.3c 40°C 41.4 : 0.6b -4.8 i 0.6ab +12.1 i 2.1"“'13 45°C 41.4 : 0.9b -4.8 i 0.3"3de +12.4 i 1.9bc Tallow Blends: w/Soybean 011 40.9 i 0.8d -4.9 i 0.5de +14.0 i 1.9° w/Corn 011 40.4 i: e -4.9 : 0.4Cl +16.1 i 1.4'E Commercial Frying c d d 011 41.2 i 0.7 -5.0 i 0.4 +13.3 + 1.9 1Mean and standard deviation of the mean based on duplicate determina- tions after each of 20 fryings. 2Lightness (100 = white, 0 8 black) 3 Greenness 4Yellawness abc Column means with the same superscript are not significantly different at p< 0.05 (Duncan, 1957). 33 Table 5. Analyses of variance of color values of original tallow, tallow fractions, tallow blends and a commercial frying oil. Mean Squares Source df L aL bL Total 335 ** ** ** Variable 7 7.89 0.50 83.57 ** ** ** Fry Sequence 20 9.49 1.19 47.73 ** Interaction 140 0.61 0.17 1.55 Within 168 0.12 0.13 0.37 ** ' Significant at the 1% level of probability. !m.awar'r. - _ 34 .mwowhum o>fimmoooam om uo>o waowuomuw sedan» mo Ammoaunwfiav uoHoo ca owcmno wait...— ..3 mumsaz Oomv finnfi oeov o--o Comm #4.? $20. 5.04;“. 30-... (h .9» ouawfim u 12. 3011M 'l 35 .owoahuw o>ammoaosm 0N youwo Hwo waahum Howouoaaoo a one moaoHo aoaaou .3oaaou Hooflwfiuo mo Ammoauswwav uoaoo ca owoono .oq ouawum wait: .3 mums-.2 5.3.23.5 all. :0 caooxomith DiED __osoo.;o__£ xvi-k. :0 Eu _a_o._oEEoO ole NV 1 301VA 36 7:. 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Illa mZOCOo weaken doom you 000: Hao waahum Hmwouoaaoo m can .moooan BoHHmu .3oHHou Hocfimwuo mo Aooam> an wouasmv mmoczoaaoh ca owcoco 9.02;": no mums—.2 on o. 2 0 . 1 . _ . 1 _ .ee seamen NI. 39 3+ 3+ \\ ------- \\ Bozo... 353.0 I Q \-\-¥ .1 :0 533m .223 U ----- .0 {A :Oc..00 .30zah {7 ------ ¥ 1 2+ :0 3“. 30.0.2800 To 3MVA 1q 40 Viscosity and Refractive Index Means and standard deviations of the means for oil viscosities and refractive indices are presented in Table 6. The analyses of variance for these data are given in Tables 7 and 8. Mean viscosities for the oils ranged from 27.3 centipoise x g/cm3 for tallow~corn oil (T-CO) to 45.5 centipoise x g/cm3 for the commercial frying oil (CFO) (Table 12). Figure 7 shows the viscosity of the oil samples over the course of 20 fryings. Although product specifications for the CFO indicated that it was a clear liquid above 35°C, the CFO was not included in this figure or in the analysis of variance because polymorphic crystal structure at 50°C made an accurate viscosity reading impossible. Polyunsaturated fatty acids tend to polymerize when fats or oils are submitted to strong heat treatment (Grob EE.§1°’ 1980). As polymeri- zation occurs, viscosity increases (Perkins, 1967). The increase in viscosity for all oil samples in this present study has been attributed to fatty acid polymerization. Carlin EE.El° (1954) also reported that increased viscosity was evidence of thermal decomposition of frying fats. Refractive indices were largest for the tallow fractions which Bussey gt il’ (1981) reported as having the least saturated fatty acid profiles. This was also confirmed by subsequent GLC analyses for all of the oil samples (Table 11). Increased refractive indices are indica- tive of thermal decomposition and polymer formation of a fat or oil (Carlin gt al., 1954). Figure 8 shows the increase in refractive indices which occurred over 20 frying periods for each of the variables. Lowe 23.2l' (1940) found that refractive indices of lard and other fats not only increased with continued use, but also as frying temperatures 41 Table 6 . Means and standard deviations1 for viscosities and refractive indices of original tallow, tallow fractions, tallow blends and a commercial frying oil . Type of Viscosity 3 Refractive Oil (Centipoise x g/cm ) Index Original Tallow 29.7 : 2.1Md 1.4588 : .0004“l Tallow Fractions: 25°C 29.0 : 1.8b 1.4593 1‘. .0003° 35°C 30.5 i 3.4d 1.4591 : .0006b 40°C 29.1 : 1.7b 1.4590 i .0004b 45°C 30.1 : 2.0Cd 1.4588 1 .0004‘“:l Tallow Blends: w/Soybean 011 29.3 i 3.6bc 1.4524 : .0005d w/Corn 011 27.3 i 2.93 1.4639 : .0004e Commercial Frying f 011 45.5 i 18.5 1.4653 + .0003 1Mean and standard deviation of the mean based on duplicate determina- tions after each of 20 fryings. 2The commercial frying oil was omitted from the analysis of variance for viscosity due to extreme standard deviation. abcColumn means with the same superscript are not significantly differ- ent at p<0.05 (Duncan, 1957). 42 Table 7. Analysis of variance of viscosities of original tallow, tallow fractions and tallow blendsl. Source df Mean Squares Total 293 ** Variable 6 42.66 ** Fry Sequence 20 63.66 Interaction 120 2.19 Within 147 2.83 . 1The commercial frying oil was omitted from the analysis of variance due to extreme standard deviation. ** Significant at the 1% level of probability. Table 53. Analysis of variance of refractive indices of original tallow, tallow fractions, tallow blends and a commercial frying oil. Source df Mean Squares Total 335 ** Variable 7 .0003 ** Fry Sequence 20 .0000 Interaction 140 .0000 Within 168 .0000 ** Significant at the 1% level of probability. 43 3‘ TALLOW FRACTIONS 33 o—ozs:c " I------I 35°C / 32 A——A4OC I,I\‘ ‘ 3 ¥———4 45°C ‘~~--./ 30 x ” ,...— ,0 / 29 /’/A/ , ‘90 //, £55 128 “L’__-___4r/fl/ Q 27 . = 30 25 x UNUSED FRY 1 FRY 6 FRY ll FRY 16 FRY 20 :7; 1101113211 or rnvmcs O a. ,2: I'- 34 o—o ORIGINAL TALLOW / z 33 *— —*TALLOW-SOYBEAN OIL / I-I-I fi------=¢(TALLOW-CORN OIL / U 32 ,/ 31 1,59: 30 29 23 - 27 26 25 , 24 {I ________ fi. 23 - UNUSED FRYl FRYG FRYll FRYIG FRYZO NUMBER OF PRYINGS Figure 7. Change in viscosity of original tallow, tallow fractions, tallow blends, and a commercial frying oil over a period of 20 consecutive fryings. 44 O ....... A ”640— ’,.—" """"""" k _ ....... A A— ————————— Au" _ ”I “"0— o—--— ”’0’ / 14620 — __ __ -—O I / _ O—-*‘" C -— d x In 21.4600— _I In 2 t3 III-I a _ é a: 8" MI 0. 4... O 11 16 2O FRY NUMBER Figure 9a. Change in peroxide values of tallow fractions over a period of 20 successive fryings. d O PEROXIDE VALUE 49 ¥ __-_ 4 4 ----- 4 COMMERCIAL FRY OIL ” D ----- D TALLOW-CORN OIL o——o TALLOW-SOYBEAN OIL H ORIGINAL TALLOW I l I I I I 4 0 1 6 ' 11 16 20 FRY NUMBER Figure 9b. Change in peroxide values of original tallow, tallow blends, and a commercial frying oil used for deep frying over a period of 20 fryings. 50 single batch of fries before being allowed to cool, intermittent heat- ing may have contrituted to the variation in peroxide values. Beef tallow contains only negligable tocopherols to provide natural antioxidant properties; 0.001% compared to soybean Oil with 0.168% (Schwitzer, 1956). Although the legal limit of antioxidant (0.022 BHA) was added to all oil systems, peroxide values generally doubled after only one frying. Roth and Rock (1972) discussed the lack of antioxidant effectiveness during deep-fat frying. An extreme rate of hydroperoxide formation and decomposition occurs during heat- ing and storage of the oil followed by rapid decomposition into free radicals. The reaction rate is such that antioxidants present in levels allowable in food cannot inhibit the large number of free radicals present. Carlin e£_313 (1954) suggested that unless constantly replen- ished, antioxidants may be quickily lost at frying temperatures. BHA is steam distillable thus easily lost as moisture is driven off in deep frying (Sherwin, 1972). It has been postulated, therefore, that the antioxidant present in each of the experimental oils was ineffective in inhibiting peroxide formation. Fatty Acid Determination by Gas Chromatography Relative percentages of fatty acids as determined by gas chromatographic (GC) analyses of methyl esters of all frying oils are presented in Table 11. A sample chromatogram is found in the Appendices. As the temperature at which tallow was fractionated decreased, the percentage of saturated fatty acids present in olein fractions tended to decrease. Linoleic acid was present in only trace amounts for both original and fractionated tallow samples. 51 Table 11. Mean relative percentage of fatty acids present in frying 0113 over a period of 20 successive fryings. Percent Fatty Acids Frying Oils C14 C16 C16:1 C18 C18:1 C18:2 C18:3 Original Tallow 3.50 27.49 3.45 17.45 48.12 tr. —-— 25°C 3.46 25.38 5.37 13.58 51.44 tr. --— 35°C 3.99 27.32 3.86 14.62 49.51 tr. --- 40°C 3.73 25.85 5.51 13.86 51.02 tr. --- 45°C 3.43 26.18 4.47 16.20 49.69 tr. --- Tall°w' . 1.85 20.11 1.31 10.31 46.68 18.75 0.42 Soybean 011 Ta11°w7 1.74 20.28 1.90 9.42 36.33 30.31 tr. Corn 011 . C°mmer°ial 0.07 12 99 -- 6 49 47 06 32 36 0 9o Frying Oil ' ° ' ' ° 1Data based on 2 replications. 52 Perkins (1967) explained that many popular frying fats are based on beef tallow because of the lower percentages of linoleic acid present, thus reducing the potential for oxidation. Table 12 summarizes the change in fatty acid content of each Oil over the course of 20 fryings. There were slight losses of linoleic acid for the T—SBO, T-CO, and CFO. Chang 33 31, (1952) and Kilgore (1964) also reported losses of linoleic acid in vegetable Oil after heating. Grob (1980) analyzed, by gas chromatography, tallow based frying oils before and after heat treatment and reported an increased proportion of saturated peaks at the cost of unsaturated peaks after heating. Results from fatty acid determination in this study were somewhat erratic and were attributed to both small variations within samples and to the condition of the column. It is recommended for future studies that the column be repacked after approximately every 20 samples rather than 45 samples to maintain peak separation efficiency. 53 Table 12. Change in fatty acid composition of frying oils over a period of 20 fryingsl. Percent Fatty Acids Frying °115 c14 C16 C16:1 c18 c18:1 18:2 18:3 Original Tallow Unused 3.70 29.16 4.56 17.83 44.75 tr. -- Fry 1 3.71 27.81 3.53 17.20 47.77 tr. - Fry 6 3.51 26.90 4.69 17.19 47.72 tr. .- Fry 11 3.55 27.51 2.56 17.72 48.66 tr. -- Fry 16 3.25 26.58 3.02 17.23 49.93 tr. - Fry 20 3.29 26.98 2.35 17.50 49.88 tr. -- 25°C Fraction Unused 3.37 24.53 6.04 12.81 51.67 tr. - Fry 1 3.47 24.43 6.01 13.34 52.68 tr. -- Fry 6 3.42 24.88 5.87 13.53 52.31 tr. -— Fry 11 3.20 24.07 6.95 13.39 51.15 tr. -- Fry 16 3.54 26.72 3.95 14.37 49.63 tr. -- Fry 20 3.75 27.64 3.38 14.03 51.21 tr. -- 35°C Fraction Unused 4.34 29.90 3.26 14.23 48.28 tr. - Fry 1 3.69 25.80 5.62 14.50 50.35 tr. - Fry 6 3.74 26.51 3.23 15.08 50.09 tr. -- Fry 11 3.91 26.47 3.30 14.80 50.18 tr. —- Fry 16 4.09 26.98 4.43 14.38 48.60 tr. - Fry 20 4.15 28.25 3.33 14.74 49.54 tr. - 40°C Fraction Unused 3.46 22.65 8.09 11.28 54.39 tr. - Fry 1 3.79 25.54 6.13 13.51 50.95 tr. -- Fry 6 3.82 27.37 4.55 14.70 49.47 tr. -- Fry 11 3.68 26.21 4.43 14.44 51.21 tr. - Fry 16 3.69 26.60 5.55 14.02 50.30 tr. -— Fry 20 3.95 26.75 4.29 15.22 49.79 tr. - 45°C Fraction Unused 3.51 25.94 5.61 15.24 49.57 tr. -- Fry 1 3.56 25.97 5.49 15.97 48.92 tr. -- Fry 6 3.32 26.94 2.74 17.06 49.95 tr. - Fry 11 3.36 26.01 5.27 16.35 49.02 tr. - Fry 16 3.50 26.59 2.69 16.41 50.82 tr. - Fry 20 3.33 25.62 5.04 16.16 49.84 tr. - TallowbSoy 011 Unused 2.03 21.39 2.06 11.00 45.61 17.49 0.43 Fry 1 1.81 18.89 1.67 9.50 46.60 21.18 0.36 Fry 6 1.83 20.16 1.79 10.54 46.34 18.85 0.50 Fry 11 1.82 19.75 1.89 10.13 46.64 19.33 0.50 Fry 16 1.81 20.17 1.91 9.76 47.25 18.86 0.25 Fry 20 1.81 20.28 2.11 10.91 47.61 16.81 0.48 Tallowaorn 011 Unused 1.79 21.15 2.14 9.80 35.29 29.83 tr. Fry 1 1.70 19.44 2.14 9.40 34.89 32.32 tr. Fry 6 1.72 19.61 1.62 9.09 36.00 31.95 tr. Fry 11 1.78 20.34 1.45 9.24 36.34 30.86 tr. Fry 16 1.71 20.47 2.60 9.54 36.97 28.71 tr. Fry 20 1.74 20.68 1.46 9.44 38.50 28.17 tr. Commercial 011 Unused 0.04 12.53 -- 6.24 45.06 34.89 1.23 Fry 1 0.03 11.97 -— 6.52 45.28 34.54 1.66 Fry 6 0.05 13.72 - 6.01 46.71 32.70 0.81 Fry 11 0.10 12.19 - 6.51 46.53 32.97 1.70 Fry 16 0.10 13.77 -- 6.26 48.28 30.01 tr. Fry 20 0.07 13.77 - 7.37 50.49 28.17 tr. 54 French Fries French fry potatoes were chosen for deep-fat frying because of their inherent blandness which would therefore allow any flavor differ- ences imparted by the oils to be recognized more easily. Means and standard deviations as well as analyses of variance for sensory and Objective evaluations accompany this discussion. Sensory Evaluation Means and standard deviations of the means for sensory character- istics are presented in Table 13 and a summary of the analyses of vari- ance for these qualities is presented in Table 14. Color and general acceptability were not significantly (p<10.05) affected by the type of frying oil. French fries fried in the OT were slightly more crisp and less greasy than those fried in the tallow fractions separated at 25°C, 35°C, or 40°C. Fries prepared in the T-CO blend had the least presence of off flavors, however all fries were scored equal to or better than the fries prepared in the CFO. All fries became progressively lighter after the first frying and were more greasy, less crisp by fry eleven. These changes in sensory scores were also reflected in high standard deviations for oil averages. Changes in sensory scores for color and texture of French fries after every fifth frying are presented in Appendices VII and VIII. Results obtained by sensory analyses for these two parameters paralleled those obtained by objective analyses and will therefore be discussed with Objective data. Figure 10 illustrates the changes in off-flavors after every fifth .Ammma .omoosnv mo.ouvm.um unnuOMMHv hausmoamaowam no: one umHuOmquam mama on» nufia momma :EOHOUOAO .AOHnmuamuumv OOH ou AOHamuemoomonv 0 mo OHmOm 55 o .Ano>mam1mmo mamuuxmv ooa ou Auo>mam1wwo oov O HO manomm .Ahmmmuw >uo>v OOH ou Ammmofimmouw oov o no manomq .Aemwuo >uo>v 00H ou Aeaaav o «o manomm .Axumu %um>v ooa ou Annmaa hum>v o «o manomm .ON a .ea .HH .o .H mum aoum moauw acumen mo oowumaam>o no woman some ecu mo coaumfi>0m vnmvomum mom ammza ma.ma + H.Nq no.5H + o.w¢ amm.HH + m.mq amm.HH + N.om m¢.HH + w.mm HHO Hafiouoaaoo 66.: H 9% 68.2 H «.3 page H 23 Nazi H 6;: 68.2 H Nam :8 88? mm.~H + o.~¢ on~.qa + w.mq pmN.OH + o.cq amm.HH + «.58 mq.ma + «.mm HHO omonuom\3 "mmooam 3OHHmH mm.m H 5.3 unmoé H ~.wm now.m .1... Hé.‘ nmaé H «6.» amt: H m.mm can.» mod H “.3 nm~.m .1... m.mm 9%: H mém AN.NH H «.mq mm.mH .._I. m.~m vooq mod Wade onwmé H n.mm no.3 H w.mm no.3 H 04.» «HA: .1... mém 06mm ma.n + o.m¢ now.~ + m.qm nm.m + w.mm no.m + H.mm mm.¢ + N.Hm comw "moowuomum 3OHHmH mm.c + o.~m nmq.oa + m.om m~.mH + ¢.o¢ pm.0H + m.nm mm.HH + o.mm soHHmH Hmeswfioo omuflafinmueooo< Hmuoooo muo>mam commoammmuu mousuxma Nuoaoo HHO mo mama mOHumHuouomumsu whomoom .HHO wofimuw HOHOHOEEOO n no muoman 3OHHmu .m:oauomum aoHHmu .Soaamu ow mounemue mOHum noomum mo mOHumHuOuomumso huomcmm How HOOOHumH>Om vumwsmum new name: .MH manna 56 suoaenmnoua «6 Hm>6H Nm men 06 namosenamsmg sunfisnmnoua no Hm>mH NH 6:0 um nemunnoemamra Ho.Nw em.¢HH HH.om mn.m~a mm.OHH on ofinufis mq.mm 00.0HH Hm.om mm. mm annoy hufiafinmummoo< Hmuoooo uo>mHm mmmofimmmuu Ousuxoa uoaoo we mounom mommavm one: .HHO weaken HMHOHOEEOO n no Commas 3OHHmu .mfioauomuw Boaamu .BOHHmu Hmofiwauo :H nonmamne mmfiuw zuaouh mo moflmwum> mo momhamo< .qa OHan 57 Otirnel Tel on 4 5': A» O 000000000000 0.0...LOIICOCIICCUCUIIOOIIOCIIIIIOIOOUOICCICIJ W OI....0.I00......IO.C.-0.0UIOOCODCOIUOIOIICIOOI0.00UCCIOUL U [r o o .0 o o . [ 0 Tallow - Soybean Oil 4 0°C 0......IUUOUCOUOIUUCUCICOCO-DC...CU..0...’..I...I'.......A IN 1's llow - Corn 011 35‘: .CCCOOCOOICUIOUCL 25°C Commercial Fry Oil . IIJIIIIIIIP u» n u ”an “r... 8808 2...... 3.38 3.323 2.... . 2.2:... 3.30... Eamzmm W w W 5 5 4 3 2 100 Presence of off-flavors in French fries fried in original tallow, tallow fractions, tallow blends and a commercial frying oil after every fifth successive frying. Figure 10. 58 O O GIEASV _, o o VkRY 70 50 SENSORY SCORES a O H O N EAL o NO GREASINESI Comment“ Tallow. Tallow- Orlgtnal "Y 011 Corn Oll Soybean 011 Tallow O O causv _, U a VERY 70 40 SENSORY SCORES NO 6 REMINE.‘ N O 1:. .8 II a O H II 0 . O 0 b (I 6'. Figure 11. Greasiness of French fries fried in original tallow, tallow fractions, tallow blends and a commercial frying oil after every fifth successive frying. 59 45%: A 0......OCOIOOOCOCOIOO'OOCOOOOD0......OOOCOOOOIOIOOIOOOOOOL A0 W :w: 7 O 5 O 3 2 33...... 3.33 2.323 .3323" 40°C 35°C 25°C 1’1 .100 9 ROI...IDIOOOOOOOOOCOOOOOOOOOOOOCOOOOOOOOOOOOOOOOIIOOOOOO; Tallow- Soybean Oil Tallow- Corn Oil Commercial Fry i m m ‘ 0.3a.eeuo< o o o o o 3 w 7 e m 4 3 9. 0 3:00» 3323 straw" Original Tallow OH Overall acceptability of French fries fried in original Figure 12. tallow, tallow fractions, tallow blends and a commercial frying oil after every fifth successive frying. 60 frying from the first through the twentieth frying. There were no sig- nificant changes (p<:0.05) in flavor of fries over the 20 fryings but it is interesting to note that for the 25°C, 35°C and 40°C tallow fractions, off-flavors decreased after the first frying and increased again after the sixth frying. Rust and Harrison (1960) reported that a taste panel preferred potatoes cooked in fat that had been used a short time to those cooked in fresh fat. It is possible that the moisture present in the French fries naturally steam deodorized the oils as the fries were frying. Melnick 35 31. (1958) found that the volatiliz- ation of water from potato chips during frying essentially steam deodor- ized and refined the frying oil throughout its use. Other researchers have also reported the protective effect of steam and its ability to distill decomposition products from a frying Oil (Perkins and Van Akkeren, 1965; Fuller 25 31., 1971). Changes in greasiness and general acceptability over the period of 20 fryings are presented in Figures 11 and 12, respectively. Fries became significantly (p‘<0.05) more greasy after the eleventh frying however general acceptability was not affected significantly (p<:0.05) until the sixteenth frying. It has been reported in the literature (Anon., 1977) that consumers preferred snack foods fried in the claim ("beef Oil") portion of solvent fractionated tallow to those fried in vegetable oils. Objective Evaluation of French Fries Color. Means and standard deviations of the means for Hunter color values appear in Table 15. Analyses of variance of these data 61 Table 15. Means and standard deviations1 for color values of French fries prepared in original tallow, tallow fractions, tallow blends and a commercial frying oil. Type of Hunter Color Values . 2 3 4 011 L aL bL Original Tallow 55.5 i 2.68 +0.6 i 2.23 19.9 : 0.8a Tallow Fractions: 25°C 55.8 i 1.481 +0.8 i 1.5a 20.6 i 0.9“1 35°C 54.9 i 2.98 -0.2 i 1.8a 20.3 : 1.5a 40°C 57.8 _-i_-_ 4.0a +0.2 i 2.7"”1 20.4 i 1.1a 45°C 55.6 i 1.8“1 -0.1 i 1.3al 20.5 i 0.7a Tallow Blends: w/Soybean Oil 54.9 i 2.2at +0.8 _-i_-_ 1.8a 19.8 i 0.83 w/Corn 011 54.8 i 3.08 +0 : 2.33 19.9 i 1.0a Commercial a a a Frying 011 53.5 i 3.7 +0.5 1 2.5 19.3 _+_- 0.6 1Mean and standard deviation of the mean based on duplicate measure- ments of French fries from fry 1, 6, ll, 16 and 20. 2Lightness (100 8 white, 0 = black). -a 8 greenness, +a = redness. 4 yellowness abccolumn means with the same superscript are not significantly differ- ent at p<0.05 (Duncan, 1957). 62 Table 16. Analyses of variance of color values Of French fries prepared in original tallow, tallow fractions, tallow blends and a commercial frying oil. Mean Squares Source df L aL L Total 79 Variable 7 ~ 5.59 1.36 1.83 ** ** Fry Sequence 4 55.06 31.71 0.37 Interaction 28 5.74 2.81 0.74 Within 40 4.73 2.54 1.09 ** Significant at the 1% level of probability. 63 .mvowumn wofihum ON uo>o HHO woa%hm HOHOHOaEOO m can nomads BOHHmu .3oaawu anoamauo .mooauomum soaamu OH moaum mafium mo Amsam> A umuosmv monounwaa ca owoono .mH ouowfim maz;~: ac mum—‘32 ON 0— S o p - ON 0— = o p _ . _ q . h. _ a. . _ . INN .1... n... .1... 26.35 ._1- :5 .. do 253093935010 ... 1 Wow" 00.1.8. a _l- r a 0 I. O .1 4—0 zmoo ZOJl—(g—u \ Uomm ‘l‘ ~s :0 >5. 5505.25.00 «11¢ .. M 0.2 «11* ... A -9. 1 mzofiofiz 2.035 ... -9. W n n 3 3 64 .OOOHHOQ 955.3 cm uo>o HHO woahum Hmwouméaou m use accede aoHHOu .3936”. HmonHuo .moofieomum 3033 a.“ v3.3 mOHHm mo Amend; do mousse mmooooouw\mmoovou a.“ omomsu .3 83me muz_>¢.._ no zumEaz ca 3 = o a w. - a. In. .- B B 1. _l A - c w a M n m n... 3 Id... 3 N... - N... m+ I m... .. 0.3 a ..... a. 25.35 22.0.50 1.. O _.... 4+ 0.3 0.5.... - 4+ :0 2538.30.12» D I I D . Comm ] 362592.935 #54. 0.2. x ..... x do 5: 55052200 055.0 mZOZU<¢u >>O._._E 2652.200 I 0.2 I m2030fiuoommaoo on mo voauom o uo>o HHo wowhum Hofioumaaoo m use madman aoHHou .mooauooum acaaou .3oHHmu Hmcawauo ca umpmmoum mofium nocmum mo mmmammfiuo ca mwamnu .oa ouowam .315: “S Emzmz as 3 = = c u _ 332» 22.25: 3 m. as 2553 .332» a 55 N as 38-332» ? I o 5:... ._<_2m2281 a." 2 ... m.- .. w... W W 3 w 3 w niu n)v m6 mi e.m I ed 03 I , ma 0...: o ..... o . 3 Ohm IIIII- o.3 I as 3. 2255.... 332» 70 fried in the T-SBO or the CFO. French fried potatoes also became significantly less crisp (p<:0.05) after the eleventh frying (Figure 16) as evidenced by a decrease in pounds force required to shear through a single fry. A possible explanation for decreased crispness is the decreased oil to French fry ratio mentioned previously. As oil quantities decreased toward the final fryings, frozen fries cooled the oil to the point where fries temporarily "sat" in the oil and were essentially undercooked (less crisp) at the end of the constant 7 min- ute frying time. Chemical Analyses French fries fried in all oils were analyzed for moisture and fat; in addition peroxide values were determined for the extracted fat. Means and standard deviations of the means are presented in Table 19. Analyses of variance of the data are presented in Table 20. No significant differences were found in moisture contents among the French fries fried in any of the oils. Moisture content did generally increase over the 20 fry periods with significant (p‘<0.05) differences after fry 16 (Table 21). It is postulated that as the oil temperatures dropped with the addition of frozen fries, less dehydration of the fries occurred. Consequently more moisture was retained in the French fry. Fat was extracted from French fries and the percentage fat was calculated on a solids basis. The fries prepared in both the T-CO and CFO contained significantly (p<:0.0S) less fat than those prepared in the other oils while fries prepared in the 25°C tallow fraction had 71 Table 19. Means and standard deviations1 of chemical analyses of French fries prepared in original tallow, tallow fractions, tallow blends and a commercial frying oil. Type Percent Percent Fat Peroxide Value of Oil Moisture (Solids Basis) (meq/lOOOg) a bc 3 Original Tallow 32.0 i 3.4 30.7 i 1.2 5.5 i 2.2 Tallow Fractions: 25°C 34.3 i 4.7"1 34.6 i 4.3(1 5.9 i 1.6"?1 35°C 35.4 : 2.7a 31.8 i 3.9‘2 5.5 _+_- 2.251 40°C 35.5 i 5.03 31.6 i 3.18 5.6 i 1.761 45°C 31.3 : 2.9a 31.7 i 3.6c 6.0 i 3.0al Tallow Blends: w/Soybean 011 35.3 _4; 5.1"”1 28.9 : 2.5b 8.7 i 3.0b w/Corn 011 35.1 35 5.63 19.8 i 4.2al 9.6 i 3.1b Commercial a a a Frying 011 33.7 i 4.4 19.7 i 3.0 5.8 + 2.8 1Mean and standard deviation of the mean based on duplicate readings of French fries from fry 1, 6, 11, 16, and 20. abcColumn means with the same superscript are not significantly differ- ent at p<0.05 (Duncan, 1957). 72 Table 20. Analyses of variance of chemical analyses of French fries prepared in original tallow, tallow fractions, tallow blends and a commercial frying oil. Mean Squares Source df Moisture Fat Peroxide Value Total 79 ** ** Variable 7 26.79 324.07 26.16 ** ** ** Fry Sequence 4 94.73 73.54 35.97 Replication l 1.07 22.36 15.19 Interaction 28 11.20 6.75 4.91 Within 39 17.01 7.76 4.03 ** Significant at the 1% level of probability. 73 .mfimmn mwaaow m :o pmmmmumxm w» you unmouom N .mcowumafiauoumm oumoaamop no pummma No.¢H mc.mm om.mH HH.mm Hm.om mm.om om.om ow.qm oN.NN m¢.~m HHO mafi2um Hmaoumaaoo oo.oH mm.mm «o.ma ao.mm m¢.m~ mN.qm mo.H~ qw.mm Ho.mm mw.mm HHO auoo\3 om.m~ mH.mm mm.m~ om.~q mm.mN mm.qm wH.mN oo.mm Nm.om wo.m~ Hao ommn>om\3 “mvcoam .3oHHmH NH.Hm co.qm mo.om mH.Hm m~.Hm mo.n~ mm.~m mm.Hm oa.mm om.Hm come No.Hm 0N.H¢ mm.o~ 2N.am om.¢m oa.qm mm.mm o~.Nm oq.~m N¢.om oooq oa.~m n~.em oa.c~ mm.mm co.~m o¢.qm mm.Hm mm.om mq.om mm.qm comm om.om HH.mm mN.Nm mm.»m w~.om mm.om mo.mm om.~m ©¢.mm Ho.~m comm "moofiuomum BoHHmH mn.om mo.m~ mo.Hm mm.mm mm.om o~.»~ mH.om mw.am mH.Hm om.~m aoaame Hmofiwfiuo umm muoumaoz umm unnumfioz umm muaumfioz umm musumfioz umm ouaumwo: ago no mama N N N N N N N N NN N cN sum 0H Noe NH sum 8 as» see .mwcfihum ON cam .oH .HH .0 .H umumm HHo wowmum Hmaoumaaoo m pom mwaman 3oHHmu .maONuomum Boaamu .3oHHmu Hmofiwauo ca cmumawua mmwum noooumfwo umfi pom muaumfioa osmoumm .HN manna 74 the highest fat content (significant at p<:0.05) (see Appendix IX). Bates (1952) reported no significant differences in fat absorption resulting from the use of various fats ranging from hard fat flakes through shortening to salad oils. Fries from the first, sixth, and eleventh frying contained signifi- cantly (p‘30.05) more fat than those from the sixteenth and twentieth frying and those fried during the sixteenth frying were found to have the lowest fat content (p<:0.05). Table 21 gives the mean fat contents of fries fried in each oil over a period of 20 fryings. These results were unexpected since fat content was expected to increase as break- down products were formed in the oils. Perhaps with the slower rate of cooking which occurred toward later fryings, greater starch gelatiniza- tion within the potato took place thereby causing a barrier to fat absorption. Peroxide value determinations were made on the fat extracted from the fries. The peroxide values of the French fries prepared in the tallow blends were significantly higher (p‘<0.05) than the other oils, indicative of greater oxidative products present in the tallow blends. The high percentage of unsaturated fatty acids present in the soy and corn oil may have contributed to the increased oxidation of these samples. A figure representing these results appears in the Appendices. Subsequent fatty acid analysis of the extracted oils revealed a higher linoleic acid content in these blends than was present in either the tallow fractions or original tallow. Results from fatty acid determinations by gas chromatography of extracted oils are located in Tables 22 and 23. Fatty acid profiles from the oil extracts generally followed the same trend as did the 75 Table 22. Mean relative percentages of fatty acids present in fat extracted from French fries over a period of 20 successive fryingsl. Percent Fatty Acids Frying 0113 C14 C16 C16:1 C18 C18:1 C18:2 C18:3 Original Tallow 2.92 25.34 3.69 20.35 45.63 1.83 tr. 25°C 3.35 25.09 6.40 12.98 48.61 3.60 tr. 35°C 3.57 25.83 5.93 13.43 51.23 tr. -- 40°C 3.38 24.91 4.18 16.61 47.55 3.37 tr. 45°C 3.52 26.17 3.76 18.75 43.78 4.02 tr. Tallow- Soybean Oil 1.74 19.71 2.60 9.24 47.78 18.76 0.46 Tallow Corn Oil 1.81 20.71 2.63 8.07 36.61 30.17 tr. Commercial Frying Oil 0.13 11.59 0.22 7.90 46.21 31.14 2.80 ji— 1Data based on 2 replications. 76 Table 23. Change in fatty acid composition of fat extracted from French fries over a period of 20 fryings. Percent Fatty Acids Frying 05“ C14 c16 c16:1 c18 C18:1 c18:2 18:3 Original Tallow Fry 1 3.19 26.35 3.94 21.12 42.91 1.25 tr. Fry 6 3.05 25.44 3.74 20.39 25.38 2.10 tr. Fry 11 2.89 26.10 4.15 19.95 45.30 1.62 tr. Fry 16 2.86 25.14 3.39 20.05 46.11 2.45 tr. Fry 20 2.63 23.67 3.32 20.24 48.44 1.71 tr. 25°C Fraction Fry 1 3.35 23.84 7.47 12.64 4.55 4.15 tr. Fry 6 3.44 25.67 5.51 12.94 48.98 3.46 tr. Fry 11 3.32 24.76 7.14 12.88 48.42 3.49 tr. Fry 16 3.31 24.79 6.91 12.69 48.05 4.28 tr. Fry 20 6 3.31 26.41 4.97 13.76 49.06 2.61 tr. 35°C Fracgion Fry 1 3.81 26.58 5.96 12.52 51.13 tr. - Fry 6 3.56 24.87 6.22 13.70 50.15 tr. -- Fry 11 3.55 25.69 5.97 14.00 50.80 tr. -- Fry 16 3.43 25.31 5.87 13.39 52.00 tr. -- Fry 20 3.52 26.71 5.65 13.54 50.50 tr. —- 40°C Fraction Fry 1 3.52 25.13 4.10 16.86 46.82 3.57 tr. Fry 6 3.61 25.64 4.39 17.01 56.83 2.52 tr. Fry 11 3.59 25.35 4.24 17.28 46.30 3.24 tr. Fry 16 3.21 24.03 3.94 15.85 48.39 4.59 tr. Fry 20 2.96 24.41 4.23 16.05 49.41 2.95 tr. 45‘C Fraction Fry 1 3.53 25.31 3.72 17.79 42.28 7.37 tr. Fry 6 3.52 26.22 4.10 18.99 44.61 2.56 tr. Fry 11 3.65 26.23 3.50 19.03 43.54 4.06 tr. Fry 16 3.47 25.58 3.77 18.43 45.30 3.45 tr. Fry 20 3.41 27.53 3.70 19.52 43.18 2.66 tr. TallowbSoy Oil Fry 1 1.88 19.85 2.40 8.89 45.67 20.81 0.51 Fry 6 1.64 18.94 3.01 9.38 47.11 19.44 0.49 Fry 11 1.81 19.91 2.22 9.43 49.14 17.22 0.54 Fry 16 1.63 18.99 2.30 9.39 49.21 18.06 0.42 Fry 20 1.76 20.88 3.05 9.09 47.74 18.30 0.36 Tallowaorn Oil Fry 1 1.93 21.51 1.81 7.99 34.88 31.89 tr. Fry 6 1.80 20.39 2.60 7.74 35.60 31.88 tr. Fry 11 1.81 20.10 3.71 7.95 35.97 30.47 tr. Fry 16 1.66 20.07 2.68 8.22 38.17 29.19 tr. Fry 20 1.83 21.49 2.38 8.42 38.45 27.43 tr. Comercial Oil Fry 1 0.11 10.94 0.16 6.92 44.16 34.59 3.12 Fry 6 0.15 11.44 0.13 7.70 46.50 31.53 2.55 Fry 11 0.12 11.39 0.28 8.41 45.23 32.24 2.33 Fry 16 0.14 11.74 0.12 7.92 47.44 29.44 3.21 Fry 20 0.15 12.46 0.41 8.56 47.71 47.91 2.79 77 frying oils however due to the greater column sensitivity, the presence of linoleic acid was detected for the tallow fractions whereas it was only detected in trace amounts in the frying oils. Kilgore (1964) reported that the fatty acid content of fat extracted from potatoes was the same as the fat used to fry them. It was reported however that after 10 hours of frying, the fat extracted from the potatoes had a lower linoleic acid content than the frying fats. This was also found to be generally true for the tallow-vegetable oil blends in this study, since the total elapsed heating time after 20 fryings was approximately 10 hours. Consumer Acceptability of Chocolate Chip Cookies Chocolate chip cookies were chosen for the consumer acceptability study with the thought that any off-flavors contributed by the tallow might be masked by the chocolate. Hoojat and Zabik (1979) found that tallow could be successfully incorporated into a control sugar-snap cookie with minimal differences from a sugar-snap cookie prepared with vegetable shortening. As part of an exhibit representing Michigan State University's Extension Consumer Marketing Program in Port Huron, Michigan, a consumer acceptability panel was conducted to determine acceptability and preference for a cookie made with tallow and one made with a vegetable shortening agent. A breakdown of demographic characteristics of the adult partici- pants appears in the Appendices. A total of 241 children (ages 16 and below) also responded (total N=449), however no demographic informa— tion was obtained from them. 78 Tables 24, 25 and 26 summarize the adults' opinion of both choco- late chip cookies, the childrens' opinion of both cookies and the cookie preference, respectively. All respondents tended to like, to some degree, vs. dislike both the cookie made with tallow and the control cookie. Although a greater percentage of total respondents preferred the control cookie to that prepared with tallow, approximately one-third of the children responding indicated that they liked both cookies equally, while 17% of the adults said they preferred neither one nor the other. I! Table 24. Adult respondents' opinion of chocolate chip cookies pre- pared with tallow and vegetable shorteningl. Percent Response Degree of Liking Control Cookie Tallow Cookie Like very much 36 24 Like moderately 38 36 Like slightly 17 19 Neither like nor dislike 5 Dislike slightly 10 3 2 Dislike moderately 0 Dislike very much 2 1Data based on 208 responses. 79 Table 25. Child respondents' opinion of chocolate chip cookies pre- pared with tallow and vegetable shorteningl. Percent Response Degree of Liking Control Cookie Tallow Cookie Like very much 48 35 Like moderately 37 31 I.“ Neither like nor dislike 9 20 } Dislike moderately 4 9 r Dislike very much 2 5 I“ -: - lData based on 241 responses. Table 26. Percent of total respondents' preference for chocolate chip cookies prepared with tallow or vegetable shortening. Prefer Prefer Prefer Both Prefer Neither Respondents Control Tallow Equally Cookie Adultl 57% 26% * 172 Children2 44% 23% 31% 2% lData based on 208 respondents. 2Data based on 241 respondents. * Not present on adult questionnaires as a response. 80 Chi—square analyses were conducted and are reported in Tables 27- 30. A significant interaction (p<:0.01) was found between preference and degree of liking for each cookie for both adult and children respon- dents. As expected, a greater percentage of respondents, both adults and children, preferring the control cookie said they liked it to some degree vs. disliking it. This same trend held true for respondents preferring the tallow cookie. It is interesting to note that for the adults who liked both cookies equally, a greater percentage rated both the control and tallow cookie as "liked very much" than those who preferred either the control or the tallow cookie. The adults who preferred the control cookie listed flavor and texture as the major reasons for their preference. Some participants detected an off-flavor in the tallow cookie which left an aftertaste and therefore preferred the control cookie. The presence of higher, less sharp melting point fatty acids may contribute to the aftertaste by lingering in one's mouth longer than would a lower, sharper melting point fat. Baeuerlen EELEl' (1968), in their discussion of the selec- tion of a frying fat, reported tallow has a higher melting point than lard and therefore does not impart a good mouthfeel. Of the children who stated a reason for preferring the control cookie, approximately 15% mentioned the off-flavor or aftertaste of the tallow cookie. Adults preferring the tallow cookie also listed flavor and texture as their primary reasons for preference. Apparently the flavor of the tallow, while objectionable to some, was also preferred by some of the participants. Morris et 31. (1956) attributed the limited use of tallow in shortenings to its tendency to develop reverted flavors. Baeuerlen SE 31. (1968) however, have reported that tallow has wONuZm .8.on u... unonchmHmN .mcma .cmunooo can uoompocm H ANo.ooHv mom AN~.m V »H aNm.»Hv on ANo.»mv w» ANo.»mv N» Hmuoe ANm.eH v mm ANm.N V H HN3.HHV s ANo.oev 3H ANN.mNV 6H Hmacm anon ANN.6N v mm ANN.HNV NH ANN.NmV NH me.mNV NH HNo.oNc HH 36HH6» AN».sm V mHH ANN.m v N ANa.HHV 3H ANN.qu on ANN.NNV on Houucoo Hmuoa mxfiamwn no 2Hu5waam mamumumvoz nos: hum> oucmuwmwum oxHHmHa no: mxHH uanHmz mxHH mxHH mxHH meooo AN mcmv mmcommmm mo hoamsvmum II meooo Houucou mo cofiafimo . muwmcaoflumosv uH=n< II maxooo Houucoo mo :oHCHmo .m> mocmumwmua maxooo How NmuHSmmp soHumH:AMu mmouo Hmumawmlano .NN nanny 82 .mmumsmcmas mucoHMMmum mo :ofiummsv puma muomvcoammu 0H “Hemuz m .Hcdva u... namoHchmHmN .nema .omusooo can uoompmfimH mANo.o0HV Hmm AN.H0 v «a AN~.m v ma ANw.me mm ANm.w¢v mad Hmuoa AN©.Hm V m» aNn.N v N ANH.¢ v m ANm.q~v ma ANm.wov on Hmswm nuom ANq.m~ v «m ANm.mHv 0H ANq.omv HH ANo.omv mm ANH.HHV o 3oHHmH ANo.mq v «OH ANo.H v N ANw.q v m ANm.me oq aNm.¢mv mm Houucoo Hmuoe nos: >nm> hamumumvoz uo mxfifimfio you mxflq moamu8wmum mxwamfin xauzmfiflm oxfiamwn oxfla nonuamz maxooo AN vamv mmsoammm mo hocosvmum II owxooo Houuaoo mo cowowmo .muwmacofiummav .mcmuuawsu II mwxooo Houucoo mo cowcfiao .m> mocmuowmum maxooo you Nmuasmmu coaumfianmu mmouo Hmumavmlfino .wN manna .wONuz 83 m .85 v6 a. namUHmHamHmN .Ncma .cmunooo can uoomwmomH Awo.ooHV woN ANN.ONV mq ANN.mHV oq ANm.omV on aNo.MNV ma HmuoH ANm.oH V mm ANm.N V H ANN.m V N Ano.qu 8H AN¢.HmV ma Hmnvm zoom ANq.oN V mm ANo.o V o ANm.¢HV m ANN.mmV HN aNm.N¢V 0N soHHmH aNN.om V mHH ANo.mmV N2 Amq.mNV om ANN.¢mV H2 ANN.q V m Honusoo HmuoH mxfiamwa no haunwwam hamumumvoz £052 >um> moamuwmmum mxHHmHn Hos oxHA Monufloz mxfiu mxHA meA aN vamV mmcoammm Mo hoamsumum II wwxooo 3oaama mo aofiafimo .moHHmS:ONumm=v oasm< II mfixooo 3oaamu mo coacamo .m> moamumwmum owxooo How Nmuaammu cowumasnmu mmouo Hmumscmlasu .mN manna .mmum3mamaa moamummoua mo cofiummav ume muamuaommmu OH .Hanz 84 m .Ho.ova u... namuEHamHmN .neoa .amunoou mam uooovmomH mANo.ooHV HmN ANo.MHV om ANm.mHV we ANN.omV Hm ANm.omV mm annoy ANo.Hm V mm ANH.8 V m ANH.< V m Ano.NmV NN ANw.qu o8 Hmscm :uom ANq.mN V «n ANo.o V o AN2.N V q Aum.NNV mH ANw.coV mm soHHmH ANo.m¢ V «OH Ano.oNV nN ANm.omV mm ANm.NNV mN Awo.m V oa Houucoo Hmuoa nos: hum> hamumumvoz no meHmNa no: mxHA moamumwmum mxHHmHa NHuewHHm mxHHmHo 63H; “mauHmz meooo AN mcmV oncommmm mo hocmovmum II mwxooo 30HHmH mo cowcwmo .muamccoaummsv .mamuwafino II waooo 3oHHmu mo aoficfiao .m> mocmumwmum mfixooo How NmuHSmmu GONumaonmu mmouo Hmumaumlwno .om manna 85 superior resistance to oxidation. The texture of the tallow cookie was slightly crunchier than the control cookie which was found to be a characteristic undesirable to some but equally desirable to others. The control cookie was prepared with a vegetable shortening containing mono- and diglycerides and the tallow cookie had no added emulsifier. It was probably due to this Fu- fact that the control cookie was slightly softer. Morris gt a1, (1956) discussed the advantage of using tallow-vegetable oil blends as shortening agents in order to increase the plastic range and facilitate VII. the manufacture of more uniform products. Table 31 shows Chi-square cross tabulation results for adult cookie preference vs. frequency of buying cookies. A significant (p<:0.05) interaction was found between adult preference and frequency of buying cookies. A greater percentage of those people preferring the control cookie tended to only buy cookies monthly or less, than did those either preferring the tallow cookie or having no preference. Respondents with no preference tended to buy cookies bi-weekly or more. Remaining data obtained from the adult questionnaires tended to confirm expectations. There was a significant (p1<0.01) interaction between willingness to buy vs. frequency of buying cookies. Adult respondents were asked whether they would be willing to purchase this type of cookie if it were available for $1.19 per 13 oz. package which was the average retail price of similar cookies at the time of this study. As might be expected, the people who purchased cookies weekly, biweekly or even monthly were more willing to buy than those who purchased cookies less than once a month. Those who purchased less 86 OONuZm .3.on um paSHchmeN .NOOH .omunooo Ono uoommocmH AN0.00HV OON ANO.me mm ANO.me ON AN0.0NV on Ann.OHV «m Hmuoa AN0.0H V mm ANN.mNV O AN0.0 V m HNH.NmV NH “N0.0NV OH Hmsvm :uom AN<.ON V mm AN<.OmV ON Ann.¢HV w ANN.NmV OH aN¢.OHV O aoHHmH ANN.Om V OHH Auq.N¢V Om ANN.mNV ON ANN.HNV mN AuN.NHV nH Houuaoo Hmuoa >Hnucoz mHaucoz thmosIHm thmoS monouomoum coca mmmu meooO AN OamV mmdoammm mo hammocmum II monooo waHhsm mo hocoavoum .anonoo onmsc mo mocosvmuw .m> mocmuomoua meooo uHsmm Mom muHsmmu aoHumHnnmu mmouo oumoumIHno .Hm oHan N H 87 frequently tended to think the suggested price was too high. Since they purchased cookies infrequently, this may have been their opinion of the price of all cookies. Results relating stage of the family life cycle to cookie buying frequency were typical of what was expected: a higher percentage of weekly cookie buyers had children under 13 years old living at home while the least heavy cookie purchasers (less than monthly) had no children at home. This was attributed to children being the heaviest cookie eaters. Age of the respondent and stage of the family life cycle were related to preference for the control or cookie made with tallow only at the 10% level of probability. Significant at the p‘IO.lO level, were age of adult respondent vs. preference and stage of the family life cycle vs. preference. Respondents who preferred the control cookie tended to be 25-44 years old, those who preferred the tallow cookie tended to be over 45 years old, and those with no preference tended to be under 25 years old. Respondents who preferred the control cookie were generally those with either no children or only children 12 years old and younger. Those who preferred the tallow cookie tended to have teen-age children between the ages of 13 and 17, while those with no preference between cookies tended to have both children less than 13 years old and teen-agers living at home. SUMMARY AND CONCLUSIONS Four different olein fractions were obtained by detergent (SDS) fractionation of tallow and the purpose of this study was to determine the acceptability of these fractions plus two tallow—vegetable oil blends as deep-fat frying media. Consumer response to cookies prepared using tallow as a replacement for shortening was also determined. The olein fractions obtained by detergent fractionation of four tallow samples at controlled temperatures (25°C, 35°C, 40°C, and 45°C) were compared to original, unfractionated tallow (OT). Additionally, a 50% tallowbcorn oil (T-CO) and a 50% tallow-soybean oil (T-SBO) blend were also compared. A commercial frying oil (CFO) was used as a standard for comparison. Commercially frozen French fry potatoes were fried in each of the eight oils over a period of 20 fryings and both the oils and the fries prepared in the oils were analyzed throughout the study. Objective analyses of the oil consisted of: color determina- tion, viscosity, refractive index, peroxide value, and fatty acid determination by gas chromatography. French fries were evaluated for texture; color; moisture; fat content; peroxide value and fatty acid determination of the extracted fat; and by a trained sensory panel. Objective measurements of oil quality indicated that all oils became darker and more yellow over the period of frying. Mean color values showed the two tallow-vegetable oil blends to be significantly darker than the other variables. Viscosity, refractive indices, and peroxide values increased for all oils over 20 frying periods, indicative 88 89 of oil breakdown. The T—CO was significantly less viscous than other oils. The CFO underwent polymorphic crystal changes at the temperature used for determining viscosity and therefore accurate readings were not obtained for this sample. Refractive indices corresponded well with fatty acid profiles obtained by GLC analyses. Values were largest for the oils with the least saturated fatty acid profiles. Peroxide values were significantly higher for the OT, T-SBO, and T-CO than the tallow fractions or the CFO, indicating a greater degree of oxidation in these oils. There were no significant differences in color or moisture of the French fries fried in any of the oils. Shear press results indicated that all fries became less crisp over the 20 frying periods. Fries prepared in the T-CO and CFO contained significantly less fat than did those prepared in the other oils; fries prepared in the 25°C fraction had the highest percentage of fat (expressed on a solids basis). Peroxide values of the fat extracted from the fries prepared in the tallow blends were significantly higher than the other oils. Organoleptic evaluation of the fries prepared in all variables indicated that color and general acceptability were not significantly affected by the type of frying oil. Fries fried in the OT were slightly more crisp and less greasy than those fried in the tallow fractions separated at 25°C, 35°C or 40°C. All fries were scored equal to, or better than those fried in the CFO. In general, all French fries became lighter, less crisp, and more greasy over the course of 20 fryings. Off-flavors decreased after the first frying and increased again after the sixth which was attributed to a natural steam deodoriza- tion effect as moisture from the fries bubbled through the hot oil. 90 The intention of this study was to evaluate the performance of tallow fractions and tallow blends under stressful c0nditions, thus fat was not replenished during the course of the experiment. The functional life of an oil used in deep-fat frying may be dependent on the turnover rate, or the rate of addition of fresh oil to the used oil (Perkins and Van Akkeren, 1965). Since there was no turnover of fat over the period of 20 fryings, it may be expected that simulation of commercial frying practices would improve results currently obtain- ed for tallow fractions and tallow blends. Results have indicated that fractionated beef tallow held up as well physically as a commercial frying oil and in addition the flavor rated more favorably with taste panel members. The T-CO blend showed very good potential as a deep-fat frying medium. Both the oil and fries prepared in it were rated higher than the other variables for all tests performed except peroxide value, in which case values for the T-CO blend were quite high. This was somewhat of a dichotomy since as peroxide values increased, flavor scores were expected to decrease, however taste panelists preferred fries fried in the T-CO. In the second portion of this research a consumer acceptability study was conducted in April, 1980 to test chocolate chip cookies prepared with tallow for preference as compared to cookies prepared with a commercial shortening. Cookies were evaluated by a total of 449 participants (208 adults and 241 children) using separate questionnaires for the adults and children. All respondents were asked to evaluate both cookies, state their preference, and state their frequency of eating cookies. Additionally, the adults were asked about their cookie-buying practices and for certain demographic 91 information. Although chocolate chip cookies prepared with tallow weren't scored as favorably as the control cookie made with vegetable shortening, tallow appeared to be an acceptable shortening agent in chocolate chip cookies. A greater percentage of children, and a slightly smaller percentage of adults, than preferred the control, had no preference for either cookie. Adults preferring the control cookie tended to list flavor and texture as the major reasons for their preference. The tallow contributed a slight off-flavor and aftertaste to the cookies. This was attributed to the higher melting point fatty acids present in tallow which lingered in the mouth. The texture of the tallow cookie was slightly harder believed to be a result of no emulsifiers present in this cookie. Chi-square cross tabulation results indicated a greater percentage of those people preferring the control cookie tended to only buy cookies monthly or less, than did those who preferred the tallow cookie or those who had no preference. There was a significant interaction between willingness to buy vs. frequency of buying cookies. Those respondents who purchased cookies frequently were more willing to pay $1.19 for a l3-ounce package (the current price for a comparable type cookie). Remaining cross tabulations tended to substantiate that which was expected. The largest number of cookie purchasers had children under 13 years old living at home while those who purchased cookies less than monthly had no children at home. Although not significant, families with the largest income tended to purchase cookies more fre- quently, however there was no relationship between income and cookie 92 preference. Tallow appeared to be an acceptable shortening agent in chocolate chip cookies. Although a slightly higher preference for an all vegetable shortening cookie was indicated, 79% of the adults and 66% of the children liked the cookie made with edible tallow. PROPOSALS FOR FURTHER RESEARCH Since adding back fresh fat to fryers in order to facilitate adequate fat turnover is the prevalent commercial practice, fractionated tallow and tallow blends should be evaluated as deep fat-frying media by simulating commercial practices. The effect of frying a batter system on the quality of fractionated tallow and tallow blends as frying media should be investigated. Since the consumer acceptance of fractionated tallow as a food fat depends upon its nutritive value, nutrition studies need to be conducted. Such investigations should include cholesterol studies and toxicity of thermally damaged tallow and tallow fractions. Although consumer acceptability of cookies made with tallow as a shortening agent was good, this study should be repeated using tallow fractions to determine their acceptance in a flavored cookie. While consumers reacted favorably to the cookie prepared with tallow, the current interest in cholesterol and unsaturated fats may pose marketing problems for this type of product. A 93 94 a consumer attitude survey may be useful in determining ways to position this type of product in the marketplace. LIST OF REFERENCES {15: '1. LIST OF REFERENCES Andres, C. 1980. Labeling of oil sourse may spur consumer awareness. Food Processing. 41(5):62-64. Anon., 1976. Fats and Oils Situation, Number 281. ERS. USDA, Feb., 1976, p. 17. Anon., 1977. Tallow -- New uses for an old product? JAOCS. 54:70Ae 71A. Anon., 1978. Tallow, as No. 2, is trying harder. JAOCS. 55:786Ae787A. AOAC. 1975. "Official Methods of Analysis", 12th Ed. Association of Official Analytical Chemists, Washington, DC. Baeuerlen, R., Brody, H., and Erickson, D. 1968. Frying fats and their uses. Baker's Dig. 42(6):51-55, 62. Baker, B.C. 1970. Use of butterfat fractions for special purposes. 18th International Dairy Congress. Sydney, Australia, p. 244. Bartholomew, D.M. 1980. Oilseed demand never saturated. JAOCS. 57(4):34OA~344A. Bates, R.W. 1952. Six-factor control assures quality deep-fat fried foods. Food Engineering. 24:82-83, 160, 162. Bennion, M. and Hanning, F. 1956. Decomposition of lard in the frying of French fried potatoes and of fritter-type batters. J. Home Economics. 48:184-188. Bligh, E.G. and Dyer, W.J. 1959. A rapid method of total lipid extraction and purification. Can. J. Biochem. Physiol. 37: 911—917. Burnham, F. 1978. "Rendering -- The Invisible Industry". Aero Publishers, Inc., Fallbrook, CA. Bundy, K.T., Zabik, M.E., and Gray, J.I. 1981. Edible beef tallow substitution in white layer cakes. Cereal Chem. In press. Bussey, D.M., Ryan, T.C., Gray, J.I., and Zabik, M.E. 1981. 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Graziano, V.J. 1979. Portable instrument rapidly measures quality of frying fat in food service operations. Food Tech. 33(9):50—52, 56-57. Grob, R., Neukom, H.P., and Battaglia, R. 1980. Triglyceride analysis with glass capillary gas chromatography. JAOCS. 57:282-286. Haraldsson, G. 1974. The LIPOFRAC system and fraction of palm products. Presented at the Society of Chemical Industry, London, Palm Oil Symposium, Dec. 2 and 3. Hoerr, C.W. 1960. Morphology of fats, oils and shortenings. JAOCS. 37:539-546. Holsinger, V.H., Luddy, F.E., Sutton, C.S., Vettel, H.E., and Allen, C. 1978. An oil fraction from edible beef tallow as a constituent of whey-soy drink mix. JAOCS. 55:473-477. Hoojat, P. and Zabik, M.E. 1979. unpublished data. Jacobson, G.A. 1967. Quality control of commercial deep-fat frying. Food Tech. 21:147-152. Johnson, O.C., Perkins, E., Sugai, M., and Kummerow, F.A. 1957. Studies on the nutritional and physiological effects of thermally oxidized oils. JAOCS. 34:594-597. Kilgore, L.J. 1964. Fatty acid components of fried foods and fats used for frying. JAOCS. 41:496-500. Kramer, C.W. 1965. Recent trends in U.S. production and consumption of edible meat fats. Fats and Oils Situation. No. 226, ERS, USDA, pp. 29-35. 97 Kromer, C.W. 1971. U.S. tallow and grease production and marketing trends. Fats and Oils Situation. No. 260. ERS, USDA. Nov. pp. 17-25. Lowe, B. 1955. "Experimental Cookery", 4th ed. p. 557. John Wiley and Sons, Inc. New York, NY. Lowe, 8., Nelson, P.M. and Buchanan, J.H. 1940. The physical and chemical characteristics of lards and other fats in relation to their culinary value. 111. For frying purposes. Iowa Agr. Exp. Station, Ames, Iowa. Research Bull. 279. Lowe, B., Pradham, S., and Kastelic, J. 1958. The free fatty acid content and the smoke point of some fats. J. Home Ec. 50:778-779. Luddy, F.E., Hampson, J.W., Herb, S.F. and Rothbart, H.L. 1973. Development of edible tallow fractions for specialty uses. JAOCS. 50:240-244. Luddy, F.E., Hampson, J.W. Herb, S.F. and Rothbart, H.L. 1977. Physiochemically designed fat compositions from tallow. U.S. Patent 4,049,839. Magoffin, J.E. and Bentz, R.W. 1949. The use of antioxidants in potato chipping. JAOCS. 27:687-690. Melnick, D. 1957. Nutritional quality of frying fats in commercial use. JAOCS. 34:578-582. Melnick, D., Luckmann, F.H. and Gooding, C.M. 1958. Composition and control of potato chip frying oils in continuing commercial use. JAOCS. 35:271-277. Morris, S.G., Magidman, P., Luddy, F.E., and Riemenschneider, R.W. 1956. Beef tallow in shortening preparations. JAOCS. 33:353-355. Morrison, W.R. and Smith, L.M. 1964. Preparation of fatty acid methyl esters and dimethylacetals from lipids with boron fluoride-methanol. J. Lipids Res. 5:600-608. Perkins, F.G. 1967. Formation of non-volatile decomposition products in heated fats and oils.Food.'Tech. 21:611-616. Perkins, F.G. and Van Akkeren, L.A. 1965. Heated fats, IV. 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Schwitzer, M.K. 1959. Processes involving changes in the characteristics of oils. "Continuous Processing of Fats". Chemical Publishing Co., Inc. New York, NY. Sherwin, E.R. 1972. Antioxidants for food fats and oils. JAOCS. 49(8): 468-471. Snedecor, C.W. and W. G. Cochran. 1967. "Statistical Methods". 6th ed. Ch. 11. The Iowa State University Press. Ames, IA. Swern, D., ed. 1964. "Bailey's Industrial Oil and Fat Products". 3rd ed. Interscience Publishers. New York, NY. Tauber, E. 1980. Translating consumer food values into solid R&D and marketing ideas. Food Prod. Develop. 14 (7):26-27. Taylor, H.E., Luddy, F.E., Hampson, J.W. and Rothbart, H.L. 1976. Substitutability of fractionated beef tallow for other fats and oils in the food and confectionery industries: An economic evaluation. JAOCS. 53:491-495. Thompson, J.A., Paulose, M.M., Reddy, B.R., Krishnamurthy, R.G. and Chang, 8.8. 1967. A limited survey of fats and oils commercially used for deep-fat frying. Food Tech. 21:87A-88A. Tilgner, D.J. 1978. Progress in the deep-fat frying process. Fleischwirtschaft. 58:1434-1437. USDA., "Food Consumption, Prices, and Expenditures". Agr. Econ. Report No. 138. Washington, D.C. 1977. Vail, G.E. and Hilton, R. 1943. Edible fats and oils, two chemical characteristics. J. Home Econ. 35:43-46. APPENDICES 60 POUNDS .5 0 08 O 20 10 U.S. PER CAPITA CONSUMPTION OF TOTAL FOOD FATS, VEGETABLE OILS AND (USDA, 1977) ’62 ’64 99 APPENDIX I ANIMAL FATS 1960 - 77 '66 '68 YEAR TOTAL FOOD FATS VEGETABLE OILS ANIMAL FATS ’70 '72 '74 ’76 100 APPENDIX II FRENCH FRY SCORECARD Sample No. Name Instructions: 1. Please check to make sure that the sample number on this sheet matches that on the sample being evaluated. 2. The reference French fry is NOT meant for tasting and is to be used as an aid in scoring COLOR only. 3. Place an "X" along the horizontal where your perception of each attri- bute is best represented. TEXTURE: 5 5 5 Limp Very Crisp GREASINESS !— ; 5 No Very . Greasiness Greasy OFF-FLAVORS : } 1' i (Rancidity) None Extreme DESCRIBE THE FLAVOR: COLOR: I 1 I l T 3 Lighter Darker 4. Rate the overall acceptability and include any comments: OVERALL ACCEPTABILITY I I Unacceptable AcceptableI q_ COMMENTS: THANKS! 101 APPENDIX IIIa COOKIE QUESTIONNAIRE FOR ADULTS Number (1) COOKIES - TASTE TEST MICHIGAN STATE UNIVERSITY Directions: Typewriter symbols (! and '.') are used to identify both sanples you will be tasting. ease taste one sample and record your Judgement before going on to the other samples. Cookies should be tasted one bite at a time. l. Please taste the sample marked 1L Now indicate below which statement best describes your opinion. Check one. [31 [32 [:13 El" [15 [36 U7 5 Dislike Dislike Dislike Neither Like Like Like VET! moder- slightly like nor slightly moder- very much ately dislike ately much 2. Next taste the samle marked #. Again. please indicate below the statement that best describes your opinion. Check one. Ell [32 [33 C] 4 Us [:16 C17 7 Dislike Dislike Dislike Neither Like Like Like very moder- slightly like nor slightly moder- very much ately dislike ately much 3. Hhich sample did you prefer? Check one. [I l [32 03 8 Sample # Sample I 'Liked both # and 2 equally Reason for preference 4. If this type of cookie were available for Sl.l9 per l3 oz. package. would you buy it? C15 C14 D3 El2 [31 9 '-Yes. would Yes. would Not sure. Probably Definitely definitely probably maybe some- wouldn't wouldn't buy it buy it time buy it buy it 5. How often do you or anyone else in your household eat cookies? Check one. DI [:2 D3 D4 [:15 - :16 -o Every- 3-4 times Once or Once or Less than Never day a week twice a twice a once a month week month 6. How often do you buy cookies? Check one. . [31 [:12 [33 04 [:15 ll Neekly Every 2 Monthly Less than Never buy. or weeks monthly only bake my own (Go to question 7) a. If you do buy cookies. what type or types of cookies do you buy most often? Check those that apply. [31 C]? D3 [34 Us [35 12 Packaged. Refrigerator Frozen, Cookie Packaged as Other (Explain) ready-to- slice a bake ready to mix from a bakery eat bake 102 APPENDIX IIIa (cont ' d) 2 7. Check the age groups of the people in your household who would like this type of cookie. Check all the age groups that apply. BI 52 [33 D4 [:15 [36 la Children Children Men 18 Women l8 Nobody in the Nobody 12 years 13-17 years 8 years and household would eats I under years older older like then cookies NOW HOULD YOU PLEASE ANSWER SOME QUESTIONS ABOUT YOURSELF AND YOUR FAMILY? 8. Please indicate your sex. Female DI NaleDZ 14 9. What is your age as of your last birthday? Please check one. [31 [32 [33 E14 [:15 l5 Under 18-24 25-44 45-64 65 and 18 years years years years over 10. Now many persons are currently living in your household (include yourself)? 16 ll. Check the age groups of the children under l8 living at home. Check one. [3‘ C12 [33 [34 l8 No children, or All children All children Some in both none under l8 years under l3 years between l3 1 l7 groups (under l3 and years between 13 8 l7) l2. Into which of the following groups would your 1979 total family income fall (before taxes were deducted)? Check only one. [3 l [j 2 [J 3 [34 19 5her s1o.mo - 320.000 - $30,000 Sl0,000 Sl9.999 $29,999 and over COMMENTS THANK YOU 103 APPENDIX IIIb COOKIE QUESTIONNAIRE FOR.CHILDREN Nmunr COOKIES - TASTE TEST MICHIGAN STATE UNIVERSITY Please taste the cookie marked . Check the box over the face which best describes how you like this cookie. Check one. [35 [31 Now. please taste the cookie marked . and again check the box over the face that best describes how you like this cookie. Check one. E31 63 “3 69 Check which of these cookies you liked well enough to ask your son or dad to buy. Check one. [32 (9. @- i (9. ® - [:12 Us [34 Sample Sample Both . Neither and . nor How often do you eat cookies? [31 Cl 2 D3 D 4 [15 Everyday A couple of Once or twice Less than one Never . times a week a month time a month COMMENTS THANK YOU 104 .:O .._O nut. 95 OO-h Oman—52.3 oOO 6mm omN ._.O 0.0 e e e I I eeeeeeeee _ I I I eeeeeeeeo . I I I . o e e e I I I .eeeeeeeee I I I .oeeeeeeee I I I e e e e e I I I .eeeeeeeeo I I I . o e o e I . I I e o e e o I I I . o e e e .eeeeoeeee I I I .eoeeeeeoo I I I e e e o e I I I . o e e e I I I e e e e o I I I . I I I I .eeeeeoeee I I I .eeooeoeee I I. I e e e e e I I I e o e e I I I e e e e e I I I e e o e eeeeeaeee I I I eeeeeeeee I I . I e e e e e I I I e e e e I I I . . O . . - . . . e e e o eeeooeeee I I I .eeeeeeeee I I I e e a e e I I I . e a e o I I I e e e e e I I I . e e e e .eeeeeeeeo I I I .eeeeeeeee I I I e e e e e I I I . e e e e I I I e e e o e I I I e e e o .eeeeoeeee I I I .eeeoeeeee I I I o e o e e I I I .oeeeoeeeo I I I eeeeeeeee II II I e o e e e e e e e I I I v I I I I . . e e o e e . e e o e I I I e e e e e I I e e e e I I I I I . - . e e e e o e e e e I I I. . . . . . H88 HHo 8sz.8 288228 2 $2 .HSm-H. moo-NV 888 382a . 8883; 3829 . 2.0V 8.58. 22820 m8 833» $82885 8.8 2.82 >H Van—2mm“: JOTVA 1 831N515! 105 H... .3 we: 98 8-» 8....» one 8 _ [ pom pom no .HomoV HHo quNmm H monommm 22m: > Van—.2934 (BOOM/bill") 2mm aaIxouad 106 APPENDIX VI CHROMATOGRAM USED FOR DETEIO‘IINING FATTY ACID PROFILES BY GAS CHROMATOGRAPHY PEAK FATTY ACID D'nmo Om) 9 Q 2. 3.58 4.21 6.27 7.21 8.91 12.00 Retention Time (min) 107 APPENDIX'VII f M \ HH“Haw“ N ................I..U..l.......'.........'I..ll..... CFC) 45%: \x as“ o/ o m v. V \ T-CO 40°C 35%: OIL AFTER EVERY FIFTH SUCCESSIVE FRYING T-SBO TILT o w 6 59.50 L“ . mire It 322.. ufJu .gza: 60 '- Ref. - 4O 20 - TALLOW FRACTIONS, TALLOW BLENDS (T-CO; T-SBO) , AND A COMMERCIAL FRYING Ref. - ORGANOLEPTIC COLOR OF FRENCH FRIES PREPARED IN ORIGINAL TALLOW (OT), H.330 108 APPENDIX VIII ORGANOLEPTIC TEXTURE OF FRENCH FRIES PREPARED IN ORIGINAL TALLOW (OT), TALLOW FRACTIONS, TALLOW BLENDS (T-SBO; T-CO), AND A COMMERCIAL FRYING OIL AFTER EVERY FIFTH SUCCESSIVE FRYING oIIIIIIIIIOIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIJ \ CFO T-CO ..I......I..I....l........"'..‘I....'.....A 0% \ ......'C......I....I...I'.......'.........l T-SBO 0 OT 45°C 40 35°C 25°C (\o’ob‘o P’p - n n P L 1 0 d m m w m 4 o 1%...0.) a8...— 0 “VI I...'.......'.I............l...l..'l...w A o\ o\ II......I..I..'......'I'.-....'.'.I..'Lv M T D'..'..........................I......A -|u _ 0a 0 "1.1. 4 0 1.5.0 .> as... 60- 50- 109 .2: he ws>h Eu 8-. 8m.- .me , mm (Slum) mamas 1w. 8.6V flo Saba gogoo < 92 A84. gamut mnzmam 33.23 £28533 sodas . 38 33.29 .2533 zH gamma mag 5sz no $33 2508 .5528 HE Em: NH NHszmmd 110 :o 3 we: 2» 8.» 8: .3 ,.S. .3 -.m~ & 2. -1‘ ¢ In N d 3 M [M u a i a A L“ «V! n 3 O LU \I I L. m. / I 0 III! I 0. .é ( a. [_2 Aomov AHo oszmm A uonommm z