Tofu is a high protein food made from soybeans that are usually sold as a block of

Abstract Tofu is a high protein food made from soybeans that are usually sold as a block of wet cake. Tofu is the result of the process of coagulating proteins in soymilk with calcium or magnesium salt from a hot water extracted protein-oil emulsion. Due to the many health benefits of tofu/soybeans, tofu was used as a replacement in a typical full fat cream cheese recipe. The purpose of this experiment was to create a healthier version of a full-fat cheesecake using silken tofu, with the intent of creating a product with similar taste, color and appearance as well as texture as a standard full-fat cheesecake. Three different variables of ingredients were used. One variable was cheesecake made with fullfat cream cheese. The second variable was a cheesecake made with half full-fat cream cheese and half silken tofu and the last variable was a cheesecake made with all silken tofu. The full-fat cream cheese product provided the best overall taste while the half cream cheese and half tofu product produced the best appearance and color. The values from the Hunter Colorimeter, measuring lightness/darkness, showed the ½ cream cheese and ½ tofu cheesecake variation produced the darkest product. Also the full fat cream cheese cheesecake had the highest force per grams producing the hardest texture. Introduction Tofu is a high protein food made from soybeans that are usually sold as a block of wet cake. Tofu is the result of the process of coagulating proteins in soymilk with calcium or magnesium salt from a hot water extracted protein-oil emulsion. The resulting protein-lipid coagulated mixture is placed into a molding box to form the soy curd, or tofu. As Beddows and Wong tell us, overall there are three main types of tofu available in

American grocery stores. Firm tofu is dense and solid and holds up well in stir- fry dishes, soups, or on the grill. Firm tofu also is higher in protein, fat and calcium compared to other forms of tofu. Next we have soft tofu. Soft tofu is a good choice for recipes that call for blended tofu, or in Oriental soups. The third choice of tofu is silken tofu. Silken tofu is formed from a slightly different process that results in a creamy, custard-like product. Silken tofu works well in pureed or blended dishes. Typically cheesecakes are made with full-fat cream cheese as one of their main ingredients. However full-fat cream cheese alone in cheesecakes is very unhealthy. For example, one ounce of cream cheese typically has 100 calories, 9 grams of fat, and 6 grams of saturated fat and 40 mg of cholesterol. Whereas one ounce of silken tofu has 18 calories, 1.04 grams of fat,.150 grams of saturated fat, and 0 mg of cholesterol. Therefore the purpose of this experiment is to create a healthier version of a full-fat cheesecake using silken tofu, which will have similar taste, color and appearance as well as texture as a standard full-fat cheesecake. Tofu was used in this recipe because of the huge health advantages tofu, made from soybeans, has compared to cream cheese, a type of saturated fat. Several studies from Sirtori and Evans (1993) have demonstrated some of the many health benefits of soybean consumption. For example, soybeans have shown to have some effect in individuals with cholesterol and heart disease, severe menopause symptoms, as well as cancer. For example these studies have shown that adding soy protein to the diet or replacing animal protein in the diet with soy, lowers blood cholesterol. Soy has also shown a link of soy consumption to a reduce risk of some cancers, especially breast

cancer. Carrol ( 1991) reports findings from a study among Asian- American women and the correlation with breast cancer. In her studies, Carrol states studies have shown Asian women, who typically eat a soy-based diet, have a much lower incidence of breast cancer than Western women. The average soy intake necessary to elicit these beneficial effects is approximately 50 grams per day, which shows a need for consumer acceptable foods that contain high levels of soy. Consumers need a wider variety of foods that contain soy or tofu to increase the consumption of soy in the U.S. The challenge for food scientist is to produce acceptable foods fortified with soy. Three different trails were performed in order to determine taste, appearance, color, and texture of the cheesecakes. Three different variables of ingredients were also used. One variable was cheesecake made with full-fat cream cheese. The second variable was a cheesecake made with half full-fat cream cheese and half silken tofu and the last variable was a cheesecake made with all silken tofu. Two objective methods and one subjective method were conducted in this experiment. The objective methods included the use of the texture analyzer to measure texture and the use of the hunter colorimeter to determine color values. The subject method in this experiment was a consumer preference and hedonic ranking test. This measured how much the panelist liked each sample based on overall taste, as well as color and appearance. The dependent variables in this experiment are appearance and color of each of the cheesecakes as well as the panelists taste. The independent variables are how much cream cheese and tofu is used in

each product. This directly relates to the products overall taste, texture, appearance, and color. Methods There were three formulas created, one control, one with control and silken tofu, and one with silken tofu. The control was Philadelphia Full- fat Cream Cheese. The following procedures were used for each formula Control 1) Mix cream cheese, sugar, and vanilla with electric mixer on medium speed for 5 minutes until well blended. Add eggs; mix on medium speed for 5 minutes until blended. Stir in melted chocolate. Stir for 15 strokes. 2) Pour into crust 3) Bake at 210 C for 40 minutes or until center is almost set. In order to do so check the center of the cheesecake with a toothpick. Stick a toothpick in the center of the cheesecake and then check for food on the toothpick. If there is food on the toothpick, continue to let cheesecake bake until toothpick test passes. Cool. Refrigerate 3 hours or overnight. ½ Control and ½ silken tofu 1) Mix cream cheese and silken tofu, sugar, and vanilla with electric mixer on medium speed for 5 minutes until well blended. Add eggs; mix on medium speed for 5 minutes until blended. Stir in melted chocolate. Stir for 15 strokes. 2) Pour into crust 3) Bake at 210 C for 40 minutes or until center is almost set. In order to do so check the center of the cheesecake with a toothpick. Stick a toothpick in the center of the cheesecake and then check for food on the toothpick. If there is food on the toothpick, continue to let cheesecake bake until toothpick test passes. Cool. Refrigerate 3 hours or overnight. Silken Tofu 1) Mix silken tofu, sugar, and vanilla with electric mixer on medium speed for 5 minutes until well blended. Add eggs; mix on medium speed for 5 minutes until blended. Stir in melted chocolate. Stir for 15 strokes.

2) Pour into crust 3) Bake at 210 C for 40 minutes or until center is almost set. In order to do so Check the center of the cheesecake with a toothpick. Stick a toothpick in the center of the cheesecake and then check for food on the toothpick. If there is food on the toothpick, continue to let cheesecake bake until toothpick test passes. Cool. Refrigerate 3 hours or overnight. Control Recipe-Chocolate Cheesecake (U.S. Department of Agriculture, 2004). 226 grams of Philadelphia Cream Cheese 100 grams of granulated sugar 6 ml of vanilla 2 eggs 4 Squares of Baker s Semi-Sweet Baking Chocolate 1 Oreo Pie Crust- 170 grams ½ cream cheese and ½ tofu recipe-chocolate Cheesecake 113 grams of Philadelphia Cream Cheese 113 grams of Silken Tofu 6 ml of vanilla 2 eggs 4 Squares of Baker s Semi-Sweet Baking Chocolate 1 Oreo Pie Crust- 170 grams Tofu Cheesecake recipe-chocolate Cheesecake 226 grams of Silken Tofu 6 ml of vanilla 2 eggs 4 Squares of Baker s Semi-Sweet Baking Chocolate 1 Oreo Pie Crust- 170 grams Each of the recipes listed above were tested following the same procedure. The independent variables were the amount of silken tofu added to each recipe. The addition of this ingredient to a chocolate cheesecake could affect tenderness, color, flavor, and overall acceptability. Therefore these attributes were tested.

Sensory Evaluation A sensory hedonic line scale was used to subjectively evaluate the experimental cheesecakes. Three- digit random numbers were used for each of the three treatments. The order in which the treatments were tasted by each of the panelist was also randomized. A total of 9 subjects were used to evaluate the appearance and color as well as the taste of each cheesecake in all three trials. Each subject was asked to rate the appearance and color on a scale set from like extremely to dislike moderately. Subjects were also asked to rate the taste and overall desirability using the same scale set. Hunter Colorimeter The hunter colorimeter was used to measure the color in the treatments of the chocolate cheesecake. This instrument can be used to measure the color of a variety of products. Its unique geometry sees color the way the human eye sees color, and it can report color in a variety of ways, including the common L, a, b Hunter parameters ( Weaver, C., 2003). The L- values represent measurements of lightness and darkness, the a-value measures redness to greenness, and the b-value measures blueness to yellowness. The Colorimeter was generated for each of the three trials. Texture Analyzer The texture analyzer was used to objectively measure the texture and hardness of each sample. The Texture Analyzer consists of a moving crosshead that compresses or extends a food sample, a load cell that measures force, various probes for testing food texture, and a digital readout or computer (Weaver, C., 2003). The cone probe set on the

cream cheese setting was used with the texture profile analysis software to generate force, gradient, and area. For each sample, pretest speed was set at 2.0 mn/s, test speed was set at 1.0 mn/s, post- test speed set at 5.0 mm/s, and distance was set at 5.0 mn. Results Texture Analyzer Variation Trial 1(g) Average (g) Trial 2 (g) Averages (g) Trial 3 overall Average(g) average(g) All cream cheese 39.7,27.4,29 32 17.5,19.9,17.0 18.1 14.2,18.0,21.2 17.8 22.6 1/2 cream cheese + 1/2 tofu 19.1,19.4,20 19.5 9.3,12.7,12.9 17.6 11.8,18.0,21.0 16.9 18 All tofu 17.0,12.6,21.1 16.9 13.2,11.2,16.0 13.4 18.3,18.5,18.6 18.4 16.2 Table 1: Grams of force (Hardness) for the three cheesecake variations Cream Cheese half and half tofu 39.7 19.1 17 27.4 19.4 12.6 29 20 21.1 17.5 9.3 13.2 19.9 12.7 11.2 17 12.9 16 14.2 11.8 18.3 18 18 18.5 21.2 21 18.6 STDEV 8.021 4.319 3.299 mean 22.6 18 16.2 mean+stdev 30.621 22.319 19.499 mean-stdev 14.579 13.681 12.901 Table 2: Standard Deviation and Mean from the Texture Analyzer.

Hunter Colorimeter Variation Trial 1 Averages Trail 2 Averages Trail 3 Averages L- 22.56,21.95 Overall average All cream cheese L -21.1,21.07 a-6.14,6.15 b-5.80,5.83 L- 21.08 a--6.14 b-5.81 a- 6.45,6.54 b- 5.81,5.86 L- -22.25 a- -6.49 b- 5.83 L-20.9,21.2 a- 6.01,6.21 b- 5.71,5.75 L- 21.05 a- 6.11 b- 5.73 L- 21.46 a- 6.24 b- 5.79 1/2 cream cheese+ 1/2 tofu L--23.9, 23.99 a- 7.05,7.07 b- 7.42,7.43 L- 23.94 a- 7.06 b- - 7.42 L- 22.56,21.95 a- 6.45, 6.54 b- 5.81,5.86 L- 22.26 a- -6.49 b- 5.83 L- 22.3, 22.56 a- 7.10,7.02 b- 7.42,7.40 L- 22.43 a--7.06 b- 7.41 L- 22.87 a -6.87 b- -6.86 All tofu L-17.84,17.79 a-4.57, 4.60 b--5.14,5.14 L-17.8 a-4.58 b-5.14 L- 18.5.18.1 a- 4.68, 4.74 b- 5.21,5.25 L- 18.3 a- 4.71 b- 5.23 L- 17.81,17.52 a- 4.56,4.55 b- 5.20,5.19 Table 3: Hunter Colorimeter values for the three cheesecake variations L- -17.66 a- -4.55 b- 5.19 L- -17.92 a- -4.61 b- 5.18 Sensory Evaluation Like extremely Like very much taste Likes Moderately Like slightly Neither like or dislike Dislike Dislike slightly moderately All cream Cheese 12 3 3 3 3 0 3 1/2 cream cheese+ 1/2 tofu 0 6 12 9 0 0 0 All tofu 0 0 3 0 3 9 12 Table 4: Sensory evaluation of taste of the three cheesecake variations Sensory Evaluation Like extremely Like very much Appearance and color Likes Moderately Like slightly Neither like or dislike Dislike Dislike slightly moderately All cream Cheese 6 9 6 0 0 0 1

1/2 cream cheese+ 1/2 tofu 3 3 9 9 0 6 All tofu 0 0 0 3 0 6 15 Table 5: Sensory Evaluations for appearance and color of the three cheesecake variations Sensory Evaluation for taste 12 Number of panelist 10 8 6 4 2 0 Like extremely Like very much Likes Moderately Like slightly Neiter like or dislike dislike slightly dislike moderately panelist taste descriptions All cream cheese 1/2 cream cheese+ 1/2 tofu All tofu Figure 1 Taste descriptions of the three cheesecake variations

12 Number of panelist 10 8 6 4 2 0 Like extremely Like very much Likes Moderately Like slightly Neiter like or dislike dislike slightly dislike moderately panelist taste descriptions Sensory Evaluation for appearance & color All cream cheese 1/2 cream cheese+ 1/2 tofu All tofu Figure 2: Appearance and color of the three cheesecake variations

Grams of force 35 30 25 20 15 10 5 0 Trial 1 averages (g) Trials Trial 2 Averages (g) Trial 3 Averages(g) Grams of force using The TA for cheesecake variations All cream cheese 1/2 cream cheese + 1/2 tofu All tofu Figure 3: Average grams of force for the three cheesecake variations

L-value 25 20 15 10 5 0 All cream cheese 1/2 cream cheese + 1/2 tofu all tofu Cheesecake variations L-value averages for cheesecake variations using the Hunter colorimeter Figure 4: Average L-values for the three cheesecake variations L-values

a-values 8 7 6 5 4 3 2 1 0 cream cheese 1/2 cream cheese + 1/2 tofu tofu cheesecake variations a-values averages for cheesecake variations using the Hunter colorimeter Figure 5: Average a-values for the three cheesecake variations a- values b-values 8 6 4 2 0 b-values cream cheese 1/2 cream cheese + tofu 1/2 tofu cheesecake variations b-value averages for cheesecake variations using the Hunter Colorimeter Figure 6: b values for the three cheesecake variations

Discussion According to the results obtained from the three trials performed, the subjective data showed varying results and the objective data showed consistent results. From the sensory evaluation the full-fat cream cheese product provided the best overall taste with a majority of the panelist also liking the ½ cream cheese + ½ tofu product. For example, from Figure 1, twelve panelists said they extremely liked the full-fat cheesecakes and twelve panelists said they moderately liked the ½ cream cheese and ½ tofu product. However when appearance and color was evaluated, the ½ cream cheese and ½ tofu product was the most acceptable to the panelist. Figure 2 shows 18 people liked the appearance and color of the cream cheese product whereas 24 people like the appearance and color of the ½ cream cheese and ½ tofu product. From the objective data, the texture analyzer was used to measure texture and the Hunter Colorimeter was used to measure color. The values from the Hunter Colorimeter showed the ½ cream cheese + ½ tofu cheesecake variation produced the darkest product. For example, Figure 4 shows the average L- values. L-values determine the lightness/ darkness of the product. The L-value for the three cheesecakes showed the following; the average L-value for the full-fat cheesecakes was 21.46, 22.87 for the ½ cream cheese + ½ tofu variation and 17.92 for the all tofu variation. The ½ cream cheese and ½ tofu cheesecake also showed the highest a-value as well as the highest b-value. The L-value, a-value, and b-values were slightly lower for the full cream cheese and full tofu variations. From the texture analyzer the all cream cheese variation had the highest force. The all cream cheese variation produced the highest force (hardness). Figure 3 shows the average force for the all cream cheese product in all three trials was 22.6 grams. The ½

cream cheese + ½ tofu variation resulted in an average of 18 grams of force and the tofu product resulted in an average of 16.2 grams of force. The addition of soy causes the binding of more water therefore making the cheesecake made with soy/tofu less hard (Damodaran,1996). This explains why the all cream cheese product was the hardest. Potential Sources of error: When using any type of instrument such as the Texture Analyzer or Hunter Colorimeter, there is always the possibility of error. For example much of the data between trials seemed accurate and consistent however some of the data was contrary to previous data. Improper computer settings, improper cone settings or the improper covering of the sample in the Hunter Colorimeter are some examples. One of the main sources of error in this experiment could have been due to improper heating time, baking time, as well as cooling time. If all the cheesecakes were not cooked and cooled for the same amount of time, the resulting product could vary greatly. Future Recommendations: For future recommendations, proper cooking and cooling time is key for this experiment in order to determine accurate texture for the three variations. The amount of silken tofu could also be increased or decreased in order to affect the color, taste, appearance, and texture. Plus the overall color could be greatly improved by the addition of less chocolate producing a lighter and possible less rich product.

References Beddows, C.G. and Wong, J. 1987a. Optimization of yield and properties of silken tofu from soybeans. III. Coagulant concentration, mixing and filtration pressure. International Journal of Food Science and Technology 22:29-34. Carrol, K (1991). Journal of American Dietetic Association. Review of Clinical Studies on cholesterol-lowering response to soy protein, 91,820-826. Damodaran, S (1996). Amino Acids, Peptides, and Proteins. Chapter 6, Food Chemistry, Owen R. Fennema (Ed.), 397-398. MarcelDekker, Inc., New York. U.S. Department of Agriculuture ( 2004). UDSA National Nutrient Database for Standard Reference. Retrieved September 25, 2005 from, Agriculture Research Service Web Site: http://www.nal.usda.gov/fnic/foodcomp Sirtori, C.R., & Evan R. (1993). Soy bean protein diet & plasma cholesterol from therapy to molecular mechanisms. Journal of American Dietetics Association, 676, 188-198. Weaver, C. (1996). The Food Chemistry Laboratory. CRC Press, New York.

The Effect of Tofu in Baked goods By: Kaitlin Scherrer Dr. Daniels F & N 453 11-20-05

Hedonic Ranking Scale 1) Taste each sample (Sample # s 314, 543, and 875) 2) Please taste each sample and rinse with water in between 3) Place the sample # where the sample best describes your preference. Appearance and color Like extremely Like very much Like Moderately Like slightly Neither like nor dislike Dislike slightly Dislike Moderately Taste Like extremely Like very much Like Moderately Like slightly Neither like nor dislike Dislike slightly Dislike Moderately