Non-Allergenic Egg Substitutes in Muffins ABSTRACT Most egg substitutes on the market are those derived from egg products. While these are acceptable for consumers merely wanting to avoid the cholesterol in eggs, they are not feasible for use by consumers with egg allergies or consumers who are vegan and therefore do not consume eggs by choice. A pumpkin muffin recipe was chosen for testing as a control and with three different non-allergenic egg replacers: potato starch, flax meal, and silken tofu. The muffins were then assessed using a hedonic rating scale, the texture analyzer, and the water activity analyzer. While scores of each variation were not staggeringly different from one another, there were still clear results. Of all of the substitutes, the tofu yielded the best results, even surpassing the control recipe in measures of texture and consumer rating for tenderness. Flax meal yielded the least desirable product on all measures. Although the tofu yielded the best results out of all of the egg replacers, it is important to recognize that it still fell below the control muffin made with egg, indicating that some qualities of the egg are not being replaced adequately. The control muffin surpassed the tofu egg replacer with regard to consumer rating of appearance and flavor. INTRODUCTION The purpose of this project was to explore the use of several non-egg based egg substitutes in baked goods. Most egg substitutes are those derived from egg proteins, but lacking the fat and cholesterol of the yolk. These are great substitutes for many people, considering the prevalence of cardiovascular disease in our population today (Totheroh and Ries 1994). However, there are yet other populations who will be interested in a different type of egg replacer which is not derived from eggs. Such a replacement is desirable for persons who have an allergy to eggs or those who choose not to include eggs in their diet, such as vegans. Although vegan diets are still a minority, eggs rate as one of the top most allergenic foods, especially for children (Kilshaw 1981). Although the simple solution here would be to just leave the eggs absent from foods, the eggs themselves contribute many important qualities which desire replacement. The white of the egg adds structure and helps to bind the product, while the yolk often adds tenderness due to the fat present. In addition, eggs add an element of moisture to baked goods (Bradshaw 1969). With at least some ingredient of substitution, past research has shown that quality losses will be minimized (Totheroh and Ries 1994). For experimentation, three non-allergenic egg substitutes were chosen as independent variables to replace the egg in a pumpkin muffin recipe: potato starch, ground flax meal, and soft silken tofu (Coughlin 1999). The resulting products were assessed regarding several dependent variables: texture, water activity, tenderness, appearance, flavor, and consumer preference. Because of the original function of egg (tenderizer, moisturizer) the best means of objectively measuring the outcome were the texture analyzer and the water activity analyzer. Other dependent variables were assessed using a subjective consumer rating scale.
METHODS Procedure 1. Measure out ingredients, mix muffin batter, and bake as directed in original recipe below. Each muffin cup should be filled with ¼ cup of batter to control muffin size. 2. Repeat Step One three more times, each time choosing one egg substitute listed below and replacing the eggs in the original recipe. 3. After all variations have been baked, assign a three digit number to each variation. 4. Place each batch of muffins on plate with variation number labeled. Set out and allow for others to rate with hedonic rating scale (attached). 5. Take one muffin of each type, and perform three trials on the texture analyzer using the cone attachment and the muffin setting. 6. Use small piece taken from the top center of each muffin as a sample in the water activity analyzer. Analyze each muffin once to determine water activity. Control Recipe Used for Testing: Pumpkin Muffins Make 12 Muffins (Source: www.allrecipes.com) (150 g) 3/4 cup white sugar (60 ml) 1/4 cup vegetable oil (100 g) 2 eggs (180 g) 3/4 cup canned pumpkin (59 ml)1/4 cup water (172.5 g)1 1/2 cups all-purpose flour (2.85 g) 3/4 teaspoon baking powder (2 g) 1/2 teaspoon baking soda (.5 g) 1/4 teaspoon ground cloves (2 g) 1 teaspoon ground cinnamon (1.6 g) 1/4 teaspoon salt (.5 g) 1/4 teaspoon ground nutmeg 1. Preheat the oven to 400 degrees F (200 degrees C). Place paper liners in muffin pan. 2. Mix sugar, oil, eggs. Add pumpkin and water. In separate bowl mix together the baking flour, baking soda, baking powder, spices and salt. Combine with wet mixture. 3. Fill muffin cups 2/3 full with batter. Bake in preheated oven for 20 to 25 minutes.
Egg Substitute s: 1. (25.6 g) 4 T. flax + (88.5 g) 6 T. water 2. (113.9 g) 4 oz. soft silken tofu (blended with wet ingredients) 3. (10.4 g) 4 T. potato starch RESULTS Table 1: Average Hedonic Rating of Muffins Category Tenderness 6.9 7.2 6.0 6.3 Texture 6.3 7.0 6.2 6.2 Flavor 6.3 5.9 5.9 5.4 Appearance 7.2 7.0 6.8 5.2 Hedonic Rating 1 8.0 6.0 4.0 2.0 Control Tofu Potato Starch Figure 1: Tenderness of Muffins Flax Meal Note: Based on a scale of 1 to 9, w ith 1 being the w orst and 9 being the best. Lines on each bar represent the standar deviation. Hedonic Rating 1 8.0 6.0 4.0 2.0 Control Tofu Potato Starch Figure 2: Texture of Muffins Flax Meal Note: Based on a scale of 1 to 9, w ith 1 being the w orst and 9 being the best. Lines on each bar represent the standar deviation.
Hedonic Rating 1 8.0 6.0 4.0 2.0 Control Tofu Potato Starch Figure 3: Flavor of Muffins Flax Meal Note: Based on a scale of 1 to 9, w ith 1 being the w orst and 9 being the best. Lines on each bar represent the standar deviation. Hedonic Rating 1 8.0 6.0 4.0 2.0 Control Tofu Potato Starch Figure 4: Appearance of Muffins Flax Meal Note: Based on a scale of 1 to 9, w ith 1 being the w orst and 9 being the best. Lines on each bar represent the standar deviation. Table 2: Overall Muffin Preference* Average 2.1 2.3 2.6 3.0 Std. Dev. 1.0 1.0 1.2 1.1 *Based on rating scale with 1 being the most preferred and 4 being the least preferred Table 3: Water Activity Average 0.811 0.787 0.72 0.781 Std. Dev. 7 3 6 6
Water Activity 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Figure 5: Water Activity of Muffins Note: Lines on the bars represent the standard deviation. Table 4: Muffin Texture According To the Texture Analyzer Average 70.4 48.6 121.3 57.7 Std. Dev. 13.9 12.2 57.2 22.8 20 18 16 14 12 10 8 6 4 2 Figure 6: Muffin Texture According to the Texture Analyzer Note: Lines on the bars represent the standard deviation. Force (g) DISCUSSION The results of using various egg substitutes in a muffin recipe were not extremely obvious. For tenderness, each egg substitute variation was ranked fairly similarly with scores ranging just from 6.3 for flax meal to 7.2 for tofu. For texture, values were again similar, ranging from flax meal and potato starch at 6.2 to tofu at 7.0. For flavor, scores ranged from 5.4 for flax meal to 6.3 for the control. Finally, for appearance, scores
ranged from 5.2 for flax meal to 7.2 for the control, the largest variation in scores across all categories of interest. These scores can be viewed in Table 1, and Figures 1-4. Overall, it appears that the flax meal variation consistently scored the worst on all measures. This is consistent with findings from Ramcharitar et al., who found that in comparison of a flax seed muffin with a control containing no flax, tasters found significant differences in regard to color, flavor, texture, and overall acceptability. On the other hand, the tofu variation was scored well pretty consistently, coming in as best for both tenderness and texture, and following closely behind the control for flavor and appearance. These individualized ratings are consistent with the overall ranking preference for each muffin. As seen in Table 2, the control was the most preferred, followed by the tofu variation, the potato starch variation, and the flax meal variation. For objective values, water activity and texture were measured. Similar to the hedonic ranking of each muffin type, the water activity did not differ much between variations. As seen in Table 3 and Figure 5, the control had the most water activity, followed by the tofu variation, the flax variation, and the potato starch variation. The potato starch was somewhat expected to show a lower water activity, based on the it s function as a starch and gelling agent. It binds much more water closely to the starch, making the overall quality of the muffin appear drier (Almasi 1979). Objective values of texture differed slightly from the hedonic ratings of texture. According to the Texture Analyzer and as seen in Table 4 and Figure 6, the most tender texture was found to be the muffin using tofu as the substitute. The flax meal variation was the next most tender, followed by the control, and finally the potato starch variation. Although results were not strikingly different among the different muffins, it appears that the tofu variation is the best egg substitute of all three tested. It seemed to come in first or second in many categories of ranking, as well as in objective measures. Though it is the best of all three substitutes, it is apparent that it is not quite as well received by tasters as the control muffins made with regular eggs. While using tofu as an egg replacer appears to improve texture and tenderness, the flavor and appearance of the final product may be slightly negatively affected. This is to be expected based on the fact that egg contributes to maillard browning, an improver of appearance (Beatreme Foods 1991). Further research should be done on this subject. It may be important to observe the effects of the same substitutes in a more basic recipe to assess the tenderness and texture. Canned pumpkin is an obvious contributor of moisture in the recipe used, and could have unrealistically caused the results to turn out better than a regular recipe may. Other sources of error during experimentation could be due to a faulty pumpkin measurement in the first trial, however, these results were still included because they did not appear to differ drastically from the rest. Different baking pans could have also caused variations and possible error in the results.
Hedonic Rating Scale Rate texture, flavor, and appearance of muffin samples on a 9-point scale with 9 = most tender, finest texture, most flavorful, best appearance and 1= extremely tough, coarse texture, least flavorful, worst appearance. Sample 542 Tenderness Texture Flavor Appearance Sample 299 Sample 712 Sample 361 Overall Preference Ranking Please rank the samples in order of your overall preference, with 1 being the sample you like the best and 4 being the sample that you like the least. Sample 542: Sample 299: Sample 712: Sample 361:
References All Recipes. 2006. Pumpkin Muffins. Retrieved Friday September 22, 2006. http://allrecipes.com/ Almasia E. 1979. Dependence of the amount of bound water of foods on temperature. Acta-Alimentaria 8:41-56. Beatreme Foods. 1991. Whipping agent replaces egg white. Prepared foods 160:62. Bradshaw CA. 1969. Baking ingredients and their functions. Food Product Development 3:108-112. Kilshaw PJ.1981. Food Allergy. British Nutrition Foundation Nutrition Bulletin 6:84-92. Ramcharitar A, Badrie N, Mattfeldt-Beman M, Matsuo H, Ridley C. 2005. Consumer acceptability of muffins with flaxseed. Journal of Food Science 70:504-507. Totheroh B, Ries C. 1994. Palatability of peanut butter and sugar cookies made with egg substitutes. Journal of the American Dietetic Association 94:321-322.