'SUBSTITUTION OF FOAM SPRAY-DRE!) ACID WHEY SOUDS FOR BUTTERMILK SOLIDS IN CHOCOLATE CAKE Thesis for the Degree of M. S. MICHIGAN STATE UNiVERSiTY Mary Stelson Parks 1966 mesxs LIBRAR Y Michigan Stan: University 8003i USE GIéLY -‘ '22-7 'I-Inl ' b ABSTRACT SUBSTITUTION OF FOAM SPRAY-DRIED ACID WHEY SOLIDS FOR BUTTERMILK SOLIDS IN CHOCOLATE CAKE by Mary Stelson Parks This investigation was initiated to determine the effect of substituting various quantities of foam spray— dried acid whey solids for buttermilk solids on the quality characteristics of a standard quick-mix chocolate cake. The original buttermilk solids in the cake formula were replaced with 25%, 50%, 75%, and 100% foam Spray— dried acid whey solids. To determine the amount of substi- tution consistent with good quality, the cakes in which foam Spray-dried acid whey solids were substituted were compared by subjective evaluation and objective measurement with those prepared with 100% buttermilk solids. Five replications of each of the four variables and the control were tested and collected data were statistically analyzed by a computer. The results of this research suggested that foam Spray—dried acid whey solids may be feasibly substituted for buttermilk solids under certain conditions. When increasing percentages of foam spray—dried acid whey solids Mary Stelson Parks were substituted for buttermilk solids, batters became significantly less viscous and cake volumes became signifi- cantly smaller. It is suggested that a probable relation— ship exists between batter viscosity and cake volume and that dissimilarity in these physical properties are attri- buted primarily to differences in composition between foam spray—dried acid whey solids and buttermilk solids. Statistical analyses indicated that there were no significant differences between cake samples for the objective measurements of pH of the batter and cake, specific gravity of the batter, and volume, tenderness, compressi- bility, tensile strength, and color of the cakes. No significant differences existed between cake samples for subjective evaluations of outside attributes and inside characteristics of the cake. The fact that so few cake characteristics were altered by this substitution indi- cates that foam Spray-dried acid whey solids are a feasible substitute for buttermilk solids. In addition to retaining many of the original cake characteristics, the use of foam spray-dried acid whey solids would offer considerable savings in ingredient cost to the food manufacturer. Although this investigation has indicated that foam Spray-dried acid whey solids may easily and more economically be substituted for buttermilk solids, inquiry in the following areas might also be useful: (1) a search for procedures or substances to be incorporated with foam Mary Stelson Parks spray-dried acid whey solids in cake formulas to increase batter viscosity and cake volume: (2) an investigation of additional ingredients such as other acid or milk products for which foam spray-dried acid whey solids could be effectively substituted; and (3) a study of the advantages and limitations of substituting foam spray—dried acid whey solids for buttermilk solids in other products. SUBSTITUTION OF FOAM SPRAY-DRIED ACID WHEY SOLIDS FOR BUTTERMILK SOLIDS IN CHOCOLATE CAKE BY Mary Stelson Parks A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Foods and Nutrition 1966 ACKNOWLEDGMENTS The author wishes to express her sincere appreciation for help given in this study by many persons. Mrs. Mary Ellen Zabik provided generous encouragement, guidance, and time throughout this study. Miss Mary Morr gave special advice and assistance. Dr. Charles Stine of the Michigan State University Food Science Department stimulated interest in this study and provided necessary research funds to carry out the investigation. Dr. Clifford Bedford extended technical assistance with the Gardner Color Difference Meter. Grateful acknowledgment is expressed to Dr. Pearl Aldrich, Miss Simin Bolourchi, Miss Jacqueline Caul, Miss Katherine Germann, Mrs. Rosie Gilbert, Dr. Theodore Irmiter, Mrs. Jacqueline Meyers, Miss Rachelle Schemmel, Miss Donna Scott, Miss Jenny Lou Taylor, and Mrs. Mary Ellen Zabik for serving as panel members. A special thanks is extended to my husband and parents for their unfailing interest and encouragement. ii TABLE OF CONTENTS INTRODUCTION . . . . . . . . . . . . . . . . . REVIEW OF LITERATURE . . . . . . . . . . . . . Milk By-products-—Whey and Buttermilk Whey Buttermilk Spray—drying of buttermilk and whey Compositional differences between foam spray-dried acid whey solids and sweet cream buttermilk solids Types and Uses of Dried Whey Solids Regular or sweet whey Fortified or modified whey Acid whey Shortened Cakes Functioning of ingredients Cake batter viscosity pH of the batter and cake Specific gravity of batter Textural characteristics Chocolate Cakes pH of chocolate cakes Color of chocolate cakes iii 10 11 12 12 14 15 17 17 18 19 20 Page Objective Measurements 21 General methods of color measurement 21 Tristimulus filter colorimeter (Gardner Color Meter) 22 Problems of color measurement 23 Shear press 25 Shear press measurement of cake tenderness, compressibility, and tensile strength 25 Subjective Evaluation 27 EXPERIMENTAL PROCEDURE . . . . . . . . . . . . . . . . 30 Design of Experiment 30 Chocolate Cake Formula 31 Ingredient Procurement 31 Basic formula ingredients 31 Processing the whey 33 Concentrating the whey 33 Foam spray-drying 34 Method of Preparation 34 Baking and Storing Procedure 35 Preparation of Samples 35 Objective Measurements 37 pH of batter 38 Specific gravity of batter 38 Viscosity of batter 38 Volume of the cake 39 pH of the cake I 39 iv Page Color measurement 40 Tenderness of cake 40 Compressibility of the cake 41 Tensile strength of the cake 42 Subjective Evaluation 43 Outside attributes . 43 Inside characteristics 44 Analysis of Data 44 RESULTS AND DISCUSSION . . . . . . . . . . . . . . . . 45 Objective Measurements 45 Viscosity and volume 45 The pH of the batter, pH of the cake, and specific gravity of the batter 51 Gardner color difference measurements 52 Kramer shear press measurements 54 Subjective Evaluations 54 Outside attributes 56 Taste panel evaluation 56 Correlations for Objective and Subjective Measurements of Chocolate Cakes 56 Correlations for objective measurements 59 Correlations for subjective evaluations 62 Correlations between objective and subjective measurements 62 Page SUMMARY AND CONCLUSIONS . . . . . . . . . . . . . . . 65 LITERATURE CITED . . . . . . . . . . . . . . . . . . . 68 APPENDIX . . . . . . . . . . . . . . . . . . . . . . . 72 vi Table 10. 11. 12. 13. LIST OF TABLES Average composition of dried sweet cream buttermilk solids and foam spray-dried acid whey solids . . . . . . . . . . . . The pH of a chocolate cake as related to color . . . . . . . . . . . . . . . . . Average composition of Chef-lac sweet cream buttermilk solids . . . . . . . . The composition of foam spray-dried acid cottage cheese whey solids . . . . . . . Viscosity, pH, and Specific gravity of chocolate cake batter; pH and volume of chocolate cake . . . . . . . . . . . . . Analysis of variance for viscosity of the chocolate cake batter . . . . . . . . . Analysis of variance for volume of the chocolate cake . . . . . . . . . . . Gardner color difference measurements of chocolate cakes . . . . . . . . . . . . Kramer shear press measurements of chocolate cakes based on maximum force and area- under-the—curve index . . . . . . . . . Subjective evaluation of outside attributes of chocolate cake based on a 5-point scale . . . . . . . . . . . . . . . . . Taste panel evaluation of chocolate cakes based on a 7—point scale . . . . . . . . Significant correlation coefficients of objective measurements of chocolate cakes. Significant correlation coefficients of subjective measurements related to chocolate cakes . . . . . . . . . . . . vii Page 19 32 33 46 48 49 53 55 57 58 6O 63 Figure 1. LIST OF FIGURES Page Typical whey composition . . . . . . . . . . . 5 Typical composition of sweet cream buttermilk. 5 Sequence for cutting and testing the slices of chocolate cake for objective measurement . . . . . . . . . . . . . . . 36 Sequence for cutting and testing the slices of chocolate cake for taste panel evaluation . . . . . . . . . . . . . . . . 37 Chocolate cake score card . . . . . . . . . . 73 General instructions to panel members . . . . 74 Cake score card . . . . . . . . . . . . . . . 75 viii INTRODUCTION Acid whey is an acceptable food product, but problems arising from past processing techniques and its inherent composition have previously limited its incorporation into food products. Cottage cheese companies are concerned with disposing of whey as a waste product or with finding uses for the whey because increased cottage cheese production has resulted in increased quantities of acid whey by- product. The United States Department of Agriculture reported that in 1964, 623 million pounds of cottage cheese curd were produced in the United States. From the production of this quantity of cottage cheese, nearly 216 million pounds of dried acid whey solids could have been processed if there had been outlets for its use. In the past, excess whey was disposed of by empty— ing it into natural water ways, a practice which has become unlawful in many states (Alesch, 1958). Emptying fluid whey into sewage disposal systems is expensive and many companies will be forced to discontinue cottage cheese production unless cheaper means of disposal or new methods of utilization of the acid whey by—product are developed. Although acid whey has been Spray—dried for years, its high lactic acid content causes whey to dry less readily than sweet whey and to form lumps in the Spray— drying equipment (Hanrahan and Webb, 1961). In 1961, Hanrahan and Webb developed a more efficient method of foam spray-drying cottage cheese whey. However, without feasible outlets for the product, there is no reason to produce quantities of dried whey. Research is needed to discover new possibilities for utilizing this by-product. Some research has been directed toward utilizing sweet whey, but the inherent compositional differences between sweet and acid whey may preclude effective utili— zation of the latter by similar techniques. The effect of the addition of sweet whey to a basic cake is to produce a cake with improved flavor, browning, and keeping qualities and a cake crumb which is more moist and tender (Hanning and de Goumois, 1952). Due to the acidity and the distinctive flavor and odor, uses of acid whey may be substantially different and more limited than those of sweet whey. Recently the suitability of using foam spray—dried acid whey solids as a source of serum solids in fruit sherbets was demonstrated by Blakely (1964). However, research concerning the use of foam spray-dried acid whey solids in other products for human consumption has been limited. Because of some similarities in composition, foam spray-dried acid whey solids may approximate the functional properties of buttermilk solids. Moreover, Habighurst and Singleton (1965) have found that the use of acid whey at normal levels greatly accentuated the flavor of chocolate. Substitution of foam spray-dried acid whey solids for buttermilk solids would offer economy in the manufacture of certain foods since currently buttermilk solids cost approximately 15¢ per pound, and foam spray- dried acid whey solids sell for about 9—1/2¢ per pound (Stine, 1965). The baking industry is a large consumer of milk products. In bakery foods ordinarily prepared with buttermilk solids, the substitution of foam spray- dried acid whey solids might make possible retaining product quality at reduced cost. This investigation was initiated to add dimensions to the knowledge about the feasibility of substituting foam Spray-dried acid whey solids for buttermilk solids in a quick—mix chocolate cake formula. REVIEW OF LITERATURE Milk By—products——Whey and Buttermilk Whey and buttermilk are residual by—products from the manufacture of cheese and butter, respectively. As by-products derived from milk, both are good sources of high quality protein. Although these products are similar in composition, important differences exist. Whey (Whittier and Webb, 1950) Whey is the residual fluid remaining after ccagulated curd is removed from skim or whole milk. Cottage cheese may be rennin or acid coagulated; differences in composition of the resulting whey are due in part to the method of casein coagulation. If the casein is coagulated by rennin, calcium and phosphorus remain in the curd. When the coagu— lating agent is acid, added per fig or developed by fermen- tation of the lactose, part of the phosphorus and most of the calcium remain in the whey. During the fermentation process, lactic acid is formed by bacterial action from lactose; but, due to the simultaneous formation of gases and volatile acids, the increase in lactic acid is not equal to the decrease in lactose content. The typical composition of whey is found in Figure 1. Cheese Whey I T I 93.0% 7.0% Water Total Solids I F I —F T l 4.90% 0.90% 0.60% 0.30% 0.20% Lactose Nitrogenous Matter Ash Fat Lactic Acid 1 . r 1 0.50% 0.40% Heat-coagulable Non-heat-coagulable Protein Nitrogenous Matter Figure 1. Typical whey composition (Whittier and Webb, 1950). Buttermilk (Whittier and Webb, 1950) Buttermilk, a by-product of butter production, is generally classified as sweet cream or sour cream buttermilk. Sour cream buttermilk contains an average of 0.5 per cent lactic acid and less lactose than sweet cream buttermilk. Figure 2 shows the typical composition of sweet cream butter- milk. Sweet Cream Buttermilk F7 I 91.00% 9.00% Water Total Solids I F_’ l I ‘7 4.50% 3.40% 0.70% 0.40% Lactose Nitrogenous Matter Ash Fat Figure 2. Typical composition of sweet cream buttermilk. (Whittier and Webb, 1950). Spray-drying of buttermilk and whey Sweet cream buttermilk is condensed and spray- dried without further treatment unless it is to be used for bakery products. Fluid buttermilk intended for use in bakery products is processed through an additional supple- mentary heat treatment (Coulter and Jenness,l964). If whey is condensed and Spray—dried in the same manner as the buttermilk, the resulting product is not completely satis- factory for commercial use: upon exposure to air, the dried whey absorbs moisture and the lactose component crystallizes, causing the powder to cake. Various procedures and equipment have been designed and patented for producing a free—flowing dry whey (Coulter and Jenness, 1964). These methods generally involve crystallization of the lactose. As early as 1933, Eldredge patented the process of mixing the spray—dried whey with 8 per cent water, allowing the mixture to stand for 2—3 hours to form a cake, and then grinding the cake to form small particles. Today, Cheddar cheese whey is generally condensed to 50-55 per cent solids and spray-dried so that the powder contains approximately 10 per cent moisture. Lactose is then allowed to crystallize for a period of time and the powder is redried to not more than 5 per cent moisture to meet top (extra) grade requirements. If cottage cheese whey is dried in the same manner as the Cheddar cheese whey, the resulting product is sticky and clings to the walls of the drier. A method for pro- ducing free—flowing acid whey solids was developed by Hanrahan and Webb (1961). Briefly, this process involves pumping a nontoxic gas, such as nitrogen, at high pressure into the whey just before it reaches the Spray nozzle. As soon as the whey is atomized, it loses the increased pressure brought about by nitrogen injection, and this expansion of the gas forms particles of foam. Whey dried in this manner is very porous, has increased surface area, is only slightly hygroscopic, and can be more easily handled. Compositional differences between foam Spray—dried acid whey solids and sweet cream buttermilk solids Both foam spray—dried acid whey solids and sweet cream buttermilk solids contain similar components, but the proportion of the components differ. Foam spray-dried acid whey solids contain less fat and protein and more lactose, lactic acid,and ash (Table 1) than do sweet cream buttermilk solids. The by—products differ substantially in the nitrogenous matter, particularly the type of protein present. In the manufacture of cottage cheese, the lactalbumin and lactoglobulin remain in the fluid whey, whereas the casein is coagulated and precipitated in the curd (Whittier and Webb, 1950). Increased amounts of protein remain in the buttermilk by-product because casein is not precipitated in the production of butter. Table 1. Average composition of dried sweet cream buttermilk solids and foam spray-dried acid whey solids. Sweet Cream Buttermilka Acid Wheyb % % Moisture 3.0 3.0 Fat 5.0 1.0 Protein 36.0 11.9 Lactose 46.7 63.7 Lactic Acid 1.4 8.4 Ash 7.9 11.02 aWebb and Johnson, 1965. bStine and Sargent, 1963. Types and Uses of Dried Whey Solids Dried whey solids are usually classified according to three types: (1) regular or sweet; (2) fortified or modified; (3) acid. Each type contributes certain distinct characteristics and advantages to food products in which they are incorporated. Regular or sweet whey Regular or sweet whey is the residual by-product from the manufacture of Parmesan, Swiss and Cheddar type cheeses (Habighurst and Singleton, 1965). This type of whey has been used successfully for years, because its low acid content allows the fluid whey to atomize readily and to dry without the formation of lumps in the spray-drying equipment (Hanrahan and Webb, 1961). Properly processed, the dried powder resists moisture pickup but readily absorbs water when reconstituted (Habighurst and Singleton, 1965). Regular or sweet dried whey solids are versatile and improve quality characteristics of many products at a reduced cost to the food manufacturer. Sweet whey can be easily and profitably incorporated into baked products. Heat coagulable proteins, lactalbumin and lactoglobulin, contribute to product structure during baking: lactose promotes desirable browning (Alesch, 1958). Incorporating 15% dried sweet whey in cakes containing 20-40% fat and 100% sugar, based on the weight of flour, gave the cakes improved crumb characteristics as well as promoted more desirable flavor, browning, and keeping quality (Hanning and de Goumois, 1952). Cakes containing whey were larger in volume and scored higher for texture, tenderness, and flavor at all fat levels. Taste panel evaluation indi- cated a reduction in fat content of cakes from 40 to 30%, 30 to 25% or from 25 to 20% could be adequately compensated for by the addition of 15% whey to the cakes of lower fat content. More recently, proteins and lactose of Cheddar cheese whey have been separated and individually added to baked goods in an effort to determine the separate contributions of these two main components of whey to the quality characteristics of baked products. Hofstrand gt al., (1965) found whey proteins and lactose to have opposite 10 effects on cake doughnut quality. Added whey proteins re— sulted in a more elastic dough, a firmer crumb, and de— creased fat absorption, compressibility, and general eating quality. Addition of the lactose component of whey decreased dough elasticity and increased compressi- bility and fat absorption. The volume was markedly de— creased when whey proteins were used but little affected when additional lactose was used. The researchers postu- lated that the reduced volume with increased amounts of protein was the result of lowered initial coagulation temperature, causing the protein to coagulate before the doughnut had expanded to maximum volume. Fortified or modified whey Fortified or modified whey is produced by adding protein such as milk protein (casein), NFDM, or soya protein to regular or sweet whey (Singleton et__l., 1965). With the addition of these hydrophilic substances, the water binding capacity of the products in which they are incorporated is increased. Addition of this type of whey to the bread formula produces a dough which is more elastic and easier to handle in the equipment, and which has less chance of being overmixed. Fortified or modified whey can be used in place of NFDM at a savings in production cost. From the nutritional standpoint fortified whey exceeds NFDM in thiamine, riboflavin, calcium, sodium, ll lactose, Vitamin A, panothenic acid, and choline; and because of the increased amounts of whey proteins, lactalbumin and lactoglobulin, it is richer in lysine and tryptophan. Bread in which this type of whey is incor- porated has the added advantages of softer crumb, improved texture, even crust color, and more flavor. Acid whey, The latest type of dried whey solids with important potential application for the food industry is the acid type (Singleton et_§l., 1965). Acid whey is the fluid remaining after the coagulated curd of cottage or cream cheese is removed. Since initiation of the new processing technique, commonly known as "gas injection" spray—drying, possible uses for dried acid whey have become much more extensive. Acid whey solids, substituted for normally used milk solids, add desirable properties to sherbets and pro- duce high quality products (Potter and Williams, 1949). These investigators found that when cottage cheese whey was used in place of milk solids in sherbets, it was un- necessary to add citric acid to sherbet mixes. By using acid whey solids instead of milk solids the manufacturer could realize a saving in ingredient cost of 10 cents per 100 pounds of sherbet base. Recent research by Blakely (1964) indicated that good quality sherbets with smooth 12 texture were obtained when foam spray-dried acid whey solids replaced 25, 50, 75 and 94.5 per cent of the serum solids in orange, lemon, and raspberry sherbets. Shortened Cakes Cakes are classified according to two types: those made without fat or chemical leavening agents, commonly known as angel food or Sponge cakes, and those made with fat and generally a chemical leavening agent included, called butter or shortened cakes (Griswold, 1962). Cake batter structure of a shortened cake is considered to be a dispersion of air in fat which is distributed in a flour—liquid medium (Carlin, 1944). This foam structure and its relation to batter viscosity is of crucial impor- tance in the production of a high quality cake. In addition to batter viscosity, some other indices related to cake quality are pH of the batter and cake, specific gravity of the batter, and textural characteristics of the cake. Production of a cake which is sufficiently tender yet rigid and one which has good body, texture, and flavor, requires the attainment of a delicate balance of ingredients. Some of the ingredients which promote this balance are flour, milk, egg, fat, and sugar. Functioning of ingredients Gluten developed in the flour and the proteins of milk and egg are constituents which contribute to batter l3 elasticity and allow the batter to stretch around gas bubbles and entrap them in the batter. Because only a minimal amount of gluten development is desirable in cake batters, soft flour with high starch and low protein content is usually chosen (Meyer, 1960). Carlin (1944) observed that very few, if any, new bubbles were formed from the chemical leavener, baking powder, but that dif- fusing carbon dioxide merged into the gas bubbles previously formed during the creaming of shortening and sugar or entrapped in the sifted flour. Because protein elasticity allows for retention of gas bubbles and the carbon dioxide tends to move into already existing air bubbles rather than forming new ones, overmixing and rough handling should be avoided so as to prevent loss of the bubbles formed in the batter. During baking, lightening of the batter is due to the release of carbon dioxide and expansion of the carbon dioxide and air within the bubbles, and a semi—rigid cake structure is formed by the gelatinization of the starch and the coagulation of the egg and milk proteins (Meyer, 1960). Fat and sugar in cake recipes increase tenderness, but decrease elasticity of cake batters. By retarding the development of gluten, sugar aids in promoting cake tender- ness. The emulsifying agents contained in the fat help retain gas bubbles in the batter and distribute fat more evenly throughout the batter. Fats containing added emulsi- fiers produce batters with less tendency to curdle and l4 permit the incorporation of larger proportions of sugar and liquid in the cake formula. This results in a sweeter, more moist cake (Meyer, 1960). Carlin (1944) found that cake batters made with fats containing monoglycerides were less viscous than batters made from the same fat without the monoglycerides and that the emulsified fat produced a better cake. A study of the bubble mechanics in cakes by Handleman £E.2£~r (1961) indicated that when unemul- sified shortening was used in the cake formula, bubble—to- bubble diffusion was slow; therefore, since leavening gas evolved only into a relatively small number of the bubbles, these bubbles attained buoyancy, rose to the top and were lost from the batter. These authors theorized that the reduced volume observed in cakes containing unemulsified shortening resulted from the loss of gas by this bubble- to-bubble diffusion mechanism. Cake batter viscosity A relationship exists between the viscosity of the cake batter and the batter structure. Collins (1940) added fat soluble dyes to plain cake batters in order to study batter structure more easily. She found that thin batters contained a few large sized gas bubbles dispersed irregularly throughout the batter. Thin batters were not viscous enough to hold the air incorporated during the mixing procedure or the gas liberated by the baking powder. 15 Conversely, gas bubbles were small, numerous, and evenly distributed in thick batters. Thin batters were darker and more intense in color whereas the thicker batters appeared lighter in color. The amount of air held in the batters may have, in part, determined the intensity of the color as large numbers of gas bubbles increase the dispersion of the dye particles which, in turn, results in a batter of lighter color. Less viscous batters were associated with oil-in—water emulsions while more viscous batters were found to be water—in-oil emulsions. Batter viscosity correlates with cake quality. In cake batters where the proportion of ingredients is balanced, thin, runny batters produced inferior cakes and viscous batters produced more desirable cakes (Lowe, 1955). A relationship between batter viscosity and cake volume was noted by Swickard (1941), who observed that as batter viscosity increased from thin to thick, corresponding increases in volume were noted. Cakes made from more viscous batters received higher ratings by taste panel members for tenderness, texture, moistness, and flavor. ,pH of the batter and cake AS pH of the cake is varied from the alkaline to the acid range, a corresponding change in cake attributes is noted (Cathcart, 1951). If the pH of the batter or cake is alkaline, there is a tendency for the color of the cake to become darker, have a coarse, open grain, and poorer l6 keeping qualities. A lighter colored, denser cake with better keeping qualities is produced when the pH of the cake is acid. Because many factors influence the pH of the batter and cake, determining optimum range of pH values for cakes is very difficult. The functioning of the baking powder as the principal leavening agent in cakes involves the reaction between the acid salt, such as monocalcium phosphate, and the alkaline baking powder base, sodium bicarbonate (Maselli and Pomper, 1960). AS a result of this interaction, salts such as sodium phosphate form and the leavening gas, carbon dioxide, evolves. Because of the loss of some carbon dioxide, and consequently of acid, during mixing and baking, the pH values of the batter during the early stages of mixing tend to be lower than pH of the batter at the end of the mixing process or the final pH of the cake. Protein-containing materials such as flour, milk, and eggs tend to buffer the effect of the baking powder and minimize changes in batter and cake pH. The pH of other ingredients used in cake production have been recorded by Cathcart and can be found in the article by Maselli and Pomper (1960). Because all ingredients used in the cake formula in some way influence total pH values for cakes, ingredient pH should be considered in arriving at optimum pH ranges for cakes. 17 Specific gravity of batter The Specific gravity of cake batter is the ratio of the weight of a designated volume of batter to the weight of an equal volume of water (Cook, 1963). This measure can be used as‘a quality control factor since it indicates the amount of batter aeration. Desirable specific gravity values for certain cake batters are sponge cakes. 0.50, and layer cakes, 0.65 to 0.75. Values lower than the optimum range indicate overaerated cakes. Higher values indicate denser batter which results in cakes with lower volume and more compact texture. With changes in mixing procedure or quantity or quality of ingredients used, specific gravity readings should be taken and alter- ations made to obtain optimum range values since cake characteristics such as grain, texture, tenderness, and volume are readily affected by the Specific gravity of the batter (Ellinger and Shappeck, 1963). Textural characteristics Texture of batter products refers to the Size of the gas bubbles, grain, thinness or thickness of the cell walls, and sometimes includes tenderness measurements (Meyer, 1964). Measurement of tenderness is complicated because its meaning varies in relation to the type of food being evaluated (Griswold, 1962). Objective measure- ment of tenderness must imitate and reproduce the cutting, 18 grinding, and squeezing action normally made by teeth. In addition to tenderness measurements, objective evalua- tion of cake textural characteristics may be made by measuring the resistance to compression. Compressibility relates to the softness or firmness of the product, and is measured by determining the distance a known force or weight depresses the cake crumb or the amount of weight or force necessary to depress the cake crumb a certain distance. Compressibility is a measure of cake aeration and structural rigidity (Hunter et__l., 1950). Textural quality of cake may also be evaluated by determining tensile strength. Platt and Kratz (1933) developed the original method for obtaining tensile strength values for cakes. Tensile strength is an indi- cation of the amount of force necessary to pull a piece of cake apart. In this measurement, an hourglass shaped piece of known dimensions is pulled apart by the weight of water flowing into a cup suspended from the bottom of the piece of cake. During the staling process of sponge cake, Platt and Kratz found that tensile strength was inversely related to compressibility: values for tensile strength increased when compressibility values decreased. Chocolate Cakes Chocolate cakes vary greatly in kind and quality. When cocoa or chocolate is added to a plain cake formula, the batter becomes more acid, thicker, and less sweet l9 (Griswold, 1962). Cocoa products may be added to a white or yellow cake formula without being detrimental to quality as long as the amount added ranges approximately from 10 to 15%, and the amount of flour is reduced by the weight of the cocoa less its fat content (DeGrood, 1959). Since the color of chocolate cake is related to pH, the proportion of ingredients affecting the pH level of the cake must be controlled to produce a cake which is acceptable both in taste and appearance. pH of chocolate cakes The color of chocolate cakes becomes a more desir- able brown or reddish-brown as the pH is made alkaline by the addition of soda and the flavor becomes less desirable as the pH increases (Lowe, 1955). Use of sufficient quantities of sodium bicarbonate in a chocolate cake formula to give the cake a pH higher than 8.0 will cause a detrimental effect to taste (Grewe, 1930). Chocolate as a color con- stituent and indicator in cakes is yellow at pH 5.0 and changes to red at pH 7.5. Changes in color with the corresponding change in pH are indicated in Table 2. Table 2. The pH of a chocolate cake as related to color (Cathcart, 1951) o pH Color 5 - 6 cinnamon 6 - 7 brown 7 - 7.5 mahogany 7.5 — 8 red—mahogany 20 Color of chocolate cakes A wide range of variation exists in the color of chocolate cakes and it is important to produce a cake which appeals to the consumer's eye. Using the Munsell system, Grewe (1930) found that as the milk acidity decreased, the color of the cakes became deeper, i.e., a dark chocolate cake was produced when sweet milk was used and a much lighter one was produced by strongly acid milk. This agrees with Lowe (1955), who stated that a deeper red or mahogany Shade chocolate cake is produced with sweet milk and soda than with sour milk and soda. The type of chemical leavener and the amount of time the batter sets before baking also influence the color of chocolate cake (Lowe, 1955). The color is always darkened with the use of Soda and lightened with the use of baking powder. The type of baking powder exerts some effect on color: phosphate and tartrate type baking powders produce a reddish color and the sulfate-phosphate type produces a relatively darker brown. A deeper mahogany color results when the batter sets 10 to 15 minutes after mixing than when baked immediately after mixing. Change in cake color may be due to one factor or to a combination of factors. 21 Objective Measurements Objective measurements are used to determine dif- ferences between food products because they are more re- producible and less subject to error than subjective methods. Data from any instrument used for objective testing should generally be in agreement with data from sensory evaluation. Color, tenderness, compressibility, and tensile strength are the characteristics of baked products most commonly evaluated by objective measurements. General methods of color measurement The color of food is often evaluated subjectively by panelists. Although vast numbers of different Shades of color can be differentiated by the human eye, color perception differs with each individual. Keeping in mind a color standard from one scoring session to the next is also difficult for the panelist. Precise, objective, and reproducible measurements are needed for determining color differences (Mackinney and Chichester, 1954). Many methods and instruments are available for color measurement. Although some are more reliable than others, they may also present many problems. The Munsell charts, containing 982 colors, and the Maerz and Paul Dictionary of Color, containing 7056 colors, are quick and fairly satisfactory methods for determining color of a food by matching the sample with a color in a book. 22 Color is also determined with the Maxwell discs, using the Munsell system of notation. In this method discs are slit and slipped together, spun at a rate of speed sufficient to give the appearance of a solid color, and adjusted until the spinning color matches the sample color. All of these methods, however, depend on a visual estimation of color (Triebold and Aurand, 1963). The basic instrument, recognized by the American Standards Association as fundamental to the standardization of color, is the spectrophotometer. This instrument measures the amount of light reflected by the object in each part of the spectrum (Judd and Wyszecki, 1963). Intensity of the light is plotted on a graph against wave length. This instrument has the advantage of being precise and objective, but it is expensive and interpretation of the data requires much time and Skill (Mackinney and Chichester, 1954). Tristimulus filter colorimeter (Gardner Color Meter) The Gardner Color Meter determines color differences on the bases of three scales (L, a and bL in comparison L' with the color of a standard plate (Endres, 1965). A light source from the instrument strikes the sample at a 450 angle and is, in turn, diffused perpendicularly from the sample back into the machine. This reflected light then passes through each of three filter photocells which in turn create a current by which the light's intensity can be measured. 23 For a machine reading to correlate well with the visual estimate made by the eye, color should be determined on more than one coordinate (Francis, 1963). The Gardner Color Meter measures lightness of an object by the L scale so that the median point between black and white has the value 50 (Endres, 1965). Perpendicular to this white- black axis are the color solid rectangular coordinates, a and bL' A negative value on the a scale indicates L' L greenness and a positive value redness; a negative value on the bL scale indicates blueness and a positive value yellowness. Values determined by this instrument can be converted to any of the other standard systems of color measurement (Mackinney and Chichester, 1954). Problems of color measurement The accuracy of the tristimulus filter colorimeters depends on the accuracy of the response achieved by the combination of the filter, photocell and the light source. Difficulty in measuring occurs when a white reference point is used because a large color difference between the measured sample and the reference point usually results. As the difference between the standard and the observed color increases, the uncertainty and discrepancy in the measurement increases (Mackinney and Chichester, 1954). Accurate color measurement is difficult with white and black. White reflects almost all of the light striking the surface, and black absorbs most of the energy falling 24 on its surface. Black and white are nonselective in their reflectance because they do not reflect one part of the color Spectrum more than another (Judd and Wyszecki, 1963). Uncertainty in distinguishing different colors with the Gardner Color Meter increases as the extremes of black and white are approached, because the current decreases as the radiant energy falling upon the photocell decreases. Obtaining accurate readings at low intensities is impossible (Mackinney and Chichester, 1954). The non-homogeneous character of food samples pre- sents another problem with color measurement. Many foods are not homogeneous; consequently, a composite reading from a heterogeneous sample must be made. This can be done by using a suitable instrument or by actual physical manipulation. The Purdue Color-Ratio Meter has a series of photocells located in a circle and the reading is a composite of responses from all of the cells. With the Hunter color-difference meter, arithmetic means of several spot readings must be computed unless a specially adapted attachment is procured which Spins or rotates the sample and gives one average reading. In a study on the methods of presenting raspberry and strawberry samples to the Hunter color-difference meter (Tinsley et al., 1956), a high correlation was observed between the means of Spot and rotation values. Although there was a high correlation between blended samples and the rotation and spot values, the L, a and bL values were considerably lower in the LI case of the blended samples. 25 Shear_press Kramer EE.§L- (1951) developed an instrument, the shear press, to measure the tenderness of lima beans. After his initial adaptation of the shear press to food products, researchers expanded its use to include other vegetables, meats, and baked products (Kramer, 1961). The basic component of the shear press is a hydraulic system which moves a piston with an even application of force at a pre-determined rate of Speed. Resistance by a food product being tested to the force exerted is recorded on an electronic recording attachment. Proving rings, with ranges from 100 pounds for measuring soft materials to 5000 pounds for hard products, eliminate frictional error which might give inaccurate readings. The recorded time-force curves may be read as the maximum force, which is the peak shear value or as the total work, which is determined by measurement of the area-under-the—curve (Endres, 1965). Shear press measurement of cake tenderness, compressibility, and tensile strength Procedures for measurement of compressibility, ten- derness, and tensile strength of angel cakes were developed by Funk 2E.§L- (1965). Cakes designated according to three degrees of toughness, based on the amount of flour added to a basic cake mix, were subjectively evaluated by a 26 taste panel for tenderness, moistness, and texture. The same cakes were objectively evaluated by the Kramer shear press for tenderness, compressibility, and tensile strength. High correlations were found between the Kramer maximum- force shear press values of tenderness, compressibility, and tensile strength and the panel evaluations of tender- ness, cell wall thickness, cell size and moisture. From this investigation, the authors concluded that the quality characteristics of angel cakes could be evaluated with sufficient precision using the Kramer shear press. Brown (1964) evaluated the functional properties of albumen by comparing angel cakes prepared from five types of albumen. She concluded that significant dif- ferences in compressibility of angel cakes resulted when the cakes were prepared with the different types of albumen. No Significant differences, however, were found between the cakes for tenderness and tensile strength values. It is conceivable that because of the lack of use of an optimum range in these measurements, existing differences may not have been recorded. She also concluded that, while her findings were in conflict with those of Funk _t.gl., (1965) the differences in her cakes may not have been gross enough to have been recorded by the shear press. Butter cakes differ considerably in textural characteristics from foam cakes. Gruber and Zabik (1966) investigated the feasibility and limitations of using the Kramer shear press as an objective indicator of tenderness, 27 compressibility, and tensile strength of butter cakes. Results obtained from the study showed tenderness to be the best of the methods tested for determining textural characteristics of butter cakes; differences in compres- sibility and tensile strength were detected only between very tough and tender cakes. Highly significant correlations between sensory evaluations and shear press measurements indicated to these researchers that objective measurement of butter cake characteristics by the Kramer shear press could be used in lieu of sensory evaluations. Subjective Evaluation In food research, recognizing and identifying differences in quality characteristics of food products is necessary (Boggs and Hanson, 1949). Estimation of differences in food samples can be effectively made by a small panel of judges. Numerical scoring of product characteristics by panel members is useful for obtaining a basis by which product quality can be controlled and changes caused by methods and ingredients can be evaluated (Meyer, 1960). Qualities commonly evaluated in baked products are: appearance, symmetry, color of crust and crumb, texture, aroma, moistness, tenderness, flavor, and general eating quality. Boggs and Hanson (1949) reported that application of particular procedural methodology will help obtain more accurate experimental results. Higher accuracy can be 28 obtained when there is a minimum of within-sample variation: a limited number of samples and characteristics are to be judged; all samples for which comparative data are desired are submitted at one time: and a sufficient number of replicates are included in the investigation so that trends can be repeated and so that the data can be statistically analyzed. Past experiences condition human beings to non— objective reSponseS, a limiting factor in food evaluation. In an experiment to estimate the extent to which memory taste affected actual taste, Dunker (1939) gave white chocolate'UDpanelists to be evaluated for flavor. No flavor difference from regular brown chocolate was reported when panelists were blindfolded; when the blindfold was - removed, the white chocolate was thought to taste less like the customary brown product. In this experiment, panelists found it difficult to isolate and examine just the aspect of flavor without being influenced by the pre- vious visual concept of how they expected chocolate to look. Panel evaluation is usually desirable, not as an entity in itself for evaluating food acceptability, but as a basis for correlation with chemical and physical measurements (Boggs and Hanson, 1949). Use of particular objective measurements, however, Should be contingent upon agreement with sensory evaluations, and these objective tests should provide a true measurement of the quality 29 factor being studied (Funk et_al., 1965). If objective measurements could be developed that would correlate very highly with sensory evaluations, these researchers proposed that the need for sensory evaluation might be consequently eliminated in future studies. EXPERI MENTAL P ROCEDURE This research was initiated to determine whether foam spray—dried acid cottage cheese whey solids could be satisfactorily substituted for buttermilk solids in a chocolate cake formula. Results of preliminary experiments substituting foam spray—dried acid whey solids for butter— milk solids in a standard chocolate cake recipe indicated that an acceptable cake can be produced when foam Spray- dried acid whey solids are used in part, if not completely, for buttermilk solids. To ascertain what effect substitu- tion would have, all other factors known to affect quality of the cakes were carefully controlled. Design of Experiment A standard chocolate cake formula which included 90.8 g of buttermilk solids was the control cake, and sub- sequent variables included partial to complete replacement of the buttermilk solids by the foam spray-dried acid whey solids in the same formula according to the following schedule: Variable Buttermilk solids Whey solids 1 (control) 100% 0% 2 75% 25% 3 50% 50% 4 25% 75% 5 0% 100% 30 31 Five replications of each variable were prepared and submitted to subjective evaluation and objective measurement of quality characteristics to determine maximum substitution of whey for buttermilk solids consistent with good quality. Chocolate Cake Formula The formula selected for use in this study was adapted from a standard quick-mix chocolate cake recipe (KitchenAid Recipes).l Cakes were made according to the following formula: Amount % of Flour Cake flour 672.0 9 100.0 Baking Powder 10.8 g 1.6 Soda 8.0 g 1.2 Salt 18.0 g 2.6 Sugar 800.0 9 119.0 Shortening 282.0 g 41.9 Vanilla 15 ml 2.2 Egg 288.0 g 42.8 Chocolate 170.1 g 25.3 Distilled water 900.0 g 133.9 Hulk solids (buttermilk and/or whey) 90.8 g 13.5 Ingredient Procurement Basic formula ingredients Common lots of cake flour, baking powder, soda, salt, sugar, shortening, vanilla, chocolate, and buttermilk solids were obtained from the Michigan State University lKitchenAid Recipes, Hobart Manufacturing Co., Troy, Ohio (1962), p. 11. 32 Food Stores. Composition of buttermilk solids is listed in Table 3 (Van Winkle, 1966). Cake flour and sugar were weighed to the nearest gram on a 5-kilogram torsion balance and salt was weighed to the nearest 0.1 gram on a trip balance. Cake flour, salt, and sugar were then mixed, packaged in closed polyethylene bags, and stored at room temperature. Shortening was weighed to the nearest gram in plastic bowls, packaged in polyethylene bags and stored at 4-50C. Vanilla, baking powder, and Soda were stored at room temperature in closed containers and measured on the day they were used. Table 3. Average composition of Chef-lac sweet cream buttermilk solids (Van Winkle, 1966). Protein 34.0% Butterfat 5.0% (min.) Moisture 3.0% (min.) Titratable acidity l.75%(min.) Sodium content 0.54% The Michigan State University Poultry Department furnished a common lot of eggs which were broken, thorough- 1y blended, and portioned into plastic—lined cardboard freezer containers. The eggs were then blast frozen at —40°C and stored at —23OC. Before using, these frozen eggs were thawed at 4—50C for 24 hours and warmed to 250C before use in the cakes. 33 Processing the whey The whey was dried and concentrated for ease in handling as the water content of cottage cheese whey is approximately 93.5% (Hanrahan and Webb, 1961). The Michigan State University Dairy Plant furnished the cottage cheese whey and the Food Science Department processed the whey according to the procedure designed by Hanrahan and Webb (1961). The average composition of the foam spray- dried acid whey solids used in this experiment is indicated in Table 4. Table 4. The composition of foam Spray—dried acid cottage cheese whey solids (Stine and Sargent, 1963). Percent Protein 11.94 Fat 1.02 Moisture 3.00 Acidity 8.39 Lactose 63.70 Ash 11.02 Concentrating the whey. Whey was concentrated by the procedure outlined by Blakely (1964). In order to remove particles of curd, all cottage cheese whey used in this experiment was filtered through a single gauze faced 6 l/2—inch Rapid-Flo filter disk. Prior to foam Spray-drying, whey preheated to 460C was concentrated to approximately 50% total solids in a 16-inch Rogers vacuum pan. 34 Foam sprayedrying. Between the main pumping tank and the spray dryer, nitrogen under a pressure of 1050 1bs./sq.in. was injected into the main line at a rate of 2.0 cu. ft./ga1. and mixed with the whey. This served to expand the spray droplet and make it less dense. In a Rogers co-current horizontal inverted tear-drop dryer, equipped with a Spraying Systems type SPC 6 nozzle with a 0.040 inch orifice diameter, the expanded whey droplet was dried and collected for storage in polyethylene bags. During spray-drying, average inlet and outlet temperatures were 1270C and 850C reSpectively. This foam Spray-dried acid whey was refrigerated at 4-50C until time of use. Method of Preparation To insure even distribution of the dry ingredients, the previously weighed cake flour, salt, sugar, and milk solids (buttermilk and/or whey depending on the variable) were dry-blended using a paddle attachment in a 12 quart bowl Hobart model A—200 for 5 minutes. Shortening, vanilla, and 450 g of distilled water were added to the dry ingre- dients and mixed using speed 2 (90 rpm) for 1 minute and 45 seconds. The bowl and paddle attachment were scraped. Soda and baking powder were weighed to the nearest 0.1 g, added to the mixture, and blended using speed 3 (162 rpm) for 15 seconds. The bowl and paddle were again scraped, and the chocolate, egg, and remaining portion of distilled water were mixed into the batter for 35 2 minutes using speed 2 (90 rpm). Baking and Storing Procedure Using a 5-kilogram capacity torsion balance, 1400 grams of batter were weighed into each of two 14 1/2 x 4 x 4-inch oblong aluminum loaf pans. The number of large air bubbles were reduced by cutting through the batter with a metal Spatula. The 2 pans were placed side by side, approximately 4 inches apart, on the middle Shelf of an Etco forced convection oven, model 1860 A, and baked for 55 minutes at 1770C. After baking, the cakes were allowed to cool on racks at room temperature for an hour. When volume measurements were obtained, the cakes were removed from pans and put on cardboard bases, then placed in polyethylene bags, labeled with predetermined coded numbers, tied and immediately frozen at -23OC. Preparation of Samples The two frozen coded cakes from each replication of each variable were allowed to thaw for 18 hours. Then the contour, surface, and surface color were subjectively evaluated by four judges. One of the two cakes of each replication was used for objective evaluation and the other for taste panel evaluation. To obtain identical slice thickness of cake samples for objective measurements, one of the partially thawed cakes was sliced using a Hobart electric slicer, model 410, set at 60. Shear press samples 36 were cut with appropriately shaped cutters for shear press evaluation. All samples were tightly wrapped in Saran to prevent dehydration. The first replication of the control and each variable were cut and tested according to the pre- determined sequence presented in Figure 3. To assure randomized samples, subsequent replications were subjected to the rotational pattern described by Funk et 1., (1963). ..C.‘ .C.‘ .C: .C! x +1 u JJ m +) m +1 0‘ U1 0‘ 4J 0‘ 4J H c c c H c -H H m m m H m H H H u H H u -H :n o u u m 4J o u a) .Q m m H m m cu m H m m T4 m m m m m m m a) c m m m c a) m m C a) c B B H a) H ,H H r1 m Pi H m $4 m m m H :4 -H m 44 m m T4 H H «4 m L4 m D :3 0 CL 0 m LI :0 H o a) (L o m U (L 'o m m c E r4 C +J c H c: c E F4 c c £5 a O U m (D O O (D X (D X (D G) O 0 CI) (1) O (D Q: B U U 5* [11 E1 III B B U U B B U E! H nu rn q M) KO t\ m ox <3 H o: «n e U» \o l\ m H ~+ .4 H 44 r4 H r4 ,4 Figure 3. Sequence for cutting and testing the slices of chocolate cake for objective measurement. Since the slicer had a tendency to mask the texture, the cakes for taste panel evaluation were cut with a serrated edge cake knife to the approximate thickness of the slices made by the Hobart slicer. Again, cakes were cut according to a predetermined sequence of slicing (Figure 4). Cake slices designated for taste panel members were rotated according to the pattern used by Funk et al., (1965). 37 CRUST H ea (n w u» \o t\ m F4 cu tn w H) (o [\ m H L4 H H L4 H H >4 H H :4 H H L4 H H 333333333322230’3 E E £5 E E £5 E E £5 E E E £3 E '2 E m m a) m m a) m m a) w m a) m m a) m E E E E E5 £2 E E E E E £5 £5 E E E a H r4 H r4 H r4 H r4 H r4 H r4 H r4 H r4 D m m a) w m a) m m a) m m a) m w a) m m CQCCGCQCCCCCCCGGU m m ru m m to m m to m r0 m m to m m mmmmmmmmmmmmmmmm Hoim<§661wH ucmo mom H.o pm ucmoHMHcmHm¥¥% .wuHHHQmQOHQ mo Hm>mH ucmo Mom H um pamoHMHcmHmks .quHHQmQOHQ mo Hm>mH name you m um ucmoHMHcmHm« Op pmpmHmH mucmEmHSmmmE m>HuomeSm mo mucmHUHmmmoo COHDMHOHHOU uchHMHcmHm 404. «mm. 6am. «we. assess ** ¥ **k SSS IMDQOOOH Hmv. mmw. mow. Ho>mHm *3.» k. .1 wmm. mmv. 5mm. mom. mmm. mmmcumocme * « «% ats k on. hmm. mmw. 0mm. musumHoz «(1* eff .41... u.» «mo. mow. mom. mhv. mmw. endpxme 88* 8 SEE *8 * 0mm. mmw. HOHOO , « woflmcH mmm. HOHOU « mommusm mmm. momwusm **8 mmm. Hsoucou 88* I as S «u S v. E L w L D u D n n o W n 0.3 T e o e ofls o 1 1 u a q 1.3 e u I. x TLI. T.J .3 3 m Er; 1.8 A P s .4 o D. o e e o e 3.8 1.0 o e 3 n 1.8 713 o n unuo 1.4 1 1 n 1 e e 1 1.1.+ A e u 1 e S 8.! _ e e _ A s e S .mmxmo SDMHOUOQU .MH mHQmB 64 Theories may be advanced for the lack of these significant correlations. Taste panelists may not have been using the same criteria as the shear press for determining cake tenderness quality. Also ranges of difference in cake samples may not have been great enough to expect significant correlations, even when all of the buttermilk solids in the recipe were replaced by the foam spray—dried acid whey solids. SUMMARY AND CONCLUSIONS The purpose of this investigation was to determine the effect of substituting various quantities of foam Spray- dried acid whey solids for buttermilk solids on the quality of chocolate cake. To examine the amount of substitution consistent with good quality, 25%, 50%, 75%,and 100% of the original buttermilk solids were replaced with the foam Spray—dried acid whey solids. These cakes were compared with the control prepared with 100% buttermilk solids. Five replications of each of the five variables were examined. Chocolate cakes were prepared by the standard quick- mix method and submitted to a series of objective measure- ments and subjective evaluations. Physical properties of the batter were studied by obtaining measurements of pH, viscosity, and Specific gravity. After the cakes were baked, the volume, tenderness, compressibility, tensile strength, color, and cake pH measurements were obtained. A four—member panel evaluated cakes for outside characteristics of surface, contour, and color; an eight-member taste panel evaluated cake characteristics for inside color, texture, moisture content, tenderness, flavor, and general acceptability. Results indicated that the substitution of foam Spray- dried acid whey solids for buttermilk solids brought about highly significant changes in cake batter viscosity and 65 66 cake volume. Batters were progressively less viscous and cake volumes became progressively smaller with increasing substitutions of foam spray-dried acid whey solids for butter- milk solids. It was concluded that a probable relationship existed between the viscosity of the batter and the cake volume and that compositional differences between the two by-products were the primary causes for these physical changes. The foam Spray-dried acid whey solids used in this investigation contained substantially less protein and lecithin and more acid and lactose than did the buttermilk solids. These differences in composition could have caused the thinner batters which were found when foam spray-dried acid whey solids were substituted for buttermilk solids. The thinner batters apparently were unable to retain gas as well as the thicker batters: and this reduction of gas may have, in turn, caused smaller cake volumes. The addition of protein or lecithin to the cake formula containing foam spray-dried acid whey solids might help remedy the thinner batter. All other objective measurements and subjective evaluations showed no Significant differences due to this substitution. In all other respects, then, foam Spray— dried acid whey solids could be successfully substituted for buttermilk solids in a quick-mix chocolate cake formula without causing any significant changes in cake properties. The particular appeal of using foam spray-dried acid whey solids as a substitute for buttermilk solids is that solids 67 changes so few batter and cake characteristics and in addition would provide considerable savings in ingredient cost to the food manufacturer. Although the results of this project suggested that foam Spray-dried acid whey solids are a feasible substitute for buttermilk solids under certain conditions, it is also evident that further research is needed in the following areas: (1) investigation of procedures or substances which would increase batter viscosity and subsequent cake volume with the use of foam Spray—dried acid whey solids: (2) comparison of these results using the conventional mixing method and/or another basic chocolate cake formula: (3) an investigation of the effect of using cocoa instead of chocolate on cake characteristics; (4) studies to deter- mine what additional ingredients such as other acid or milk products could be effectively substituted for by foam spray-dried whey solids; and (5) an investigation of the feasibility and limitations of Substituting foam spray— dried acid whey solids into other products containing buttermilk solids. LITERATURE CITED Alesch, E. A. 1958. Utilization of whey solids in food products. J. Dairy Sci. 41, 699—700. Blakely, L. E. 1964. Foam Spray-dried cottage cheese whey as a source of solids in sherbets. M.S. Thesis. Michigan State University Library, East Lansing. Boggs, M. M., and H. L. Hanson. 1949. Analysis of foods by sensory difference tests. Advances in Food Research 2, 219-258. Brown, S. L. 1964. Effect of heat treatment on the physical and functional properties of liquid and spray—dried albumen. M.S. Thesis. Michigan State University Library, East Lansing. Carlin, G. T. 1944. A microscopic study of the behavior of fats in cake batters. Cereal Chem. 21, 189-199. Cathcart, W. H. 1951. Baking and bakery products in ”The Chemistry and Technology of Food and Food Products, Vol. II." M.B. Jacobs, Ed. Interscience Publishers, Inc., New York. 1162-1211. Collins, 0. D. 1940. The viscosity of cake batter as related to batter structure. M.S. Thesis. Purdue University Library, Lafayette, Ind. Cook, W. C. 1963. Specific gravity in the control of cake quality. Baker's Dig. §Z_(2), 105-106. Coulter, S. T., and R. Jenness. 1964. Dry milk products in ”Food Dehydration, vol. II-—Products and Techno- logy." W. B. vanArSdel and M. J. Copley, Eds. The AVI Publishing Company, Inc., Westport, Conn. 591-651. DeGrood, J. 1959. Chocolate and cocoa in cookie and cake production. Baker's Dig. 33, (2) 36-40. Duncan, D. B. 1955. Multiple ranges and multiple F tests. Biometrics 11, 1—8. Dunker, K. 1939. The influence of past experience upon perceptual properties. Am. J. Psychol. 52, 255-265. 68 69 Ellinger, R. H., and F. J. Shappeck. 1963. The relation of batter specific gravity to cake quality. Baker's Dig. 21 (6), 52-58. Endres, J. A. 1965. The effect of drying processes on the color and gel strength of baked whole egg and milk slurries. M.S. Thesis. Michigan State University Library, East Lansing. Francis. F. J. 1963. Color control. Food Technol. 21 (5), 38-45. Funk, K., M. Zabik, and D. Downs. 1965. Comparison of shear press measurements and sensory evaluation of angel cakes. J. of Food Sci. 29, 729-736. Grewe, E. 1930. Effect of variation in ingredients on color of chocolate cake. Cereal Chem. 2, 59-66. Griswold, R. M. 1962. "The Experimental Study of Foods." Houghton Mifflin Co., Boston. Gruber, S. M., and M. E. Zabik. 1966. Comparison of sensory evaluation and shear press measurements of butter cakes. Food Technol. (in press). Habighurst, A., and A. Singleton. 1965. Improve your products with whey solids. Food Proc. 26 (8), 74-78. Handleman, A. R., J. F. Conn, and J. W. Lyons. 1961. Bubble mechanics in thick foams and their effects on cake quality. Cereal Chem. 22, 294-305. Hanning, F., and J. de Goumois. 1952. The influence of dried whey on cake quality. Cereal Chem. 22, 176-189. Hanrahan, F. P., and B. H. Webb. 1961. USDA develops foam— Spray drying. Food Eng. 22 (8), 37-38. Hofstrand, J. T., M. V. Zaehringer, and R. A. Hibbs. 1965. Functional properties of two components of Cheddar cheese in bakery products: 1. Cake doughnuts. Cereal Sci. Today 29, 212-214, 233. Hunter, M. B., A. M. Briant, and C. J. Personius. 1950. Cake quality and batter structure. Cornell Univ. Agr. Ext. Sta. Bull. No. 860. Judd, D. B., and G. Wyszecki. 1963. "Color in Business, Science, and Industry.“ 2nd Ed. John Wiley and Sons, Inc., New York. 7O Kramer, A. 1961. The shear press, a basic tool for the food technologist. The Food Scientist 2, 7—16. Kramer, A., R. B. Guyer, and H. P. Rodgers, Jr. 1951. New shear press predicts quality of canned lima beans. Food Eng. 22, 112. Lowe, B. 1955. "Experimental Cookery." 4th ed. John Wiley and Sons, Inc., New York. Mackinney, G., and C. O. Chichester. 1954. The color problem in foods. Advances in Food Research 2, 302—351. Maselli, J. A., and S. Pomper. 1960. The significance of pH in baking. Baker's Dig. 24 (5), 66-69, 87—88. Meyer, L. H. 1960. "Food Chemistry." Reinhold Publishing Corporation, New York. Platt, W., and P. D. Kratz. 1933. Measuring and recording some charachteristics of test sponge cakes. Cereal Chem. 29, 73-90. Potter, F. E., and D. H. Williams. 1949. Use of whey in sherbets. Ice Cream Trade J. 22 (9), 54-55. Singleton, A. D., H. N. Haney, and A. B. Habighurst. 1965. Adapting dried whey products to present—day bakery operations. Cereal Sci. Today 29, 53-55, 62. Stine, C. M. 1965. Private communication. Department of Food Science. Michigan State University. Stine, C. M., and J. S. E. Sargent. 1963. Analysis of Spray dried cottage cheese whey. Mich. State Univ. Agr. Exp. Sta. Quart. Bull. 42, 159-161. Swickard, M. T. 1941. The viscosity of cake batters in relation to some indices of cake quality. M.S. Thesis. Purdue University Library, Lafayette, Ind. Tinsley, I. J., A. P. Sidwell, and R. F. Cain. 1956. Methods of presenting raSpberry and strawberry samples to the Hunter color and color-difference meter. Food Technol. 29, 339-344. Triebold, H. 0., and L. W. Aurand. 1963. "Food Composition and Analysis." D. Van Nostrand Company, Inc., Princeton, New Jersey. U. S. Department of Agriculture. 1959. "Food, The Yearbook of Agriculture 1959." U.S. Department of Agriculture, Washington. 71 U.S. Department of Agriculture. Statistical Reporting Service, Crop Reporting Board. 1965. Production of manufactured dairy products, 1964. Washington, D.C. Van Winkle, Webster. 1966. Private communication. Webster Van Winkle Corporation. Summit, New Jersey. Webb, B. H., and A. H. Johnson. 1965. "Fundamentals of Dairy Chemistry." The AVI Publishing Company, Westport, Conn. Whittier, E. O., and B. H. Webb. 1950. "Byproducts from Milk." Reinhold Publishing Corporation. New York. APPENDIX Chocolate Cake Score Card Name Date Code number Instructions: Check the phrase which most nearly describes the contour, surface and color. Contour slight cracking, small even hump. slight cracking, moderate humping. moderate amount of cracking and humping, slight number of cross slits. moderate cracking, extreme humping, moderate number of cross slits. extreme humping, extreme cracking, extreme number of cross slits. Surface 2 no pinholing 1/4 of surface covered by pinholes 1/2 of surface covered by pinholes 3/4 of surface covered by pinholes extreme pinholing Surface color rich even brown or reddish—brown deep brown but Slightly streaked moderate brown medium light brown burned spots Comments: Figure 5. Chocolate cake score card. 73 74 GENERAL INSTRUCTIONS TO PANEL MEMBERS Please do not give any facial or vocal reactions as you evaluate your sample. The samples are coded with random numbers and are pre— sented in a randomized order. Please start with the sample in the lower left corner of the tray and pro— ceed toward the right. The upper row should be evaluated in the same order. Using a red pencil please mark the .numerical score which most nearly fits your evaluation of each quality characteristic of the sample in the box at the right hand side of the score card. Score each sample indepen— dently of others. BE SURE THE PLATE CODE MATCHES THE SCORE CARD CODE. Each sample will have its own Score card. You may rinse your mouth between sample evaluations with the water provided. Please make sure you have five numbers written on the score card and have answered the question at the end. Figure 6. General instructions to panel members. 75 . 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