The effect of adding flaxseed as an egg replacer in chocolate chip cookies NUTR 453 Research Project Fall 2012 Chooing Lim Lindsay Turner
Abstract: Egg allergy is pretty common among kids. Usually it will disappear before the children grow into adolescence. However, in rare case, this allergy will carry into adulthood. The symptoms of egg allergy include skin rashes, hives, nasal inflammation and vomiting or other digestive problems. Besides that, some people may wish to avoid eggs due to their cholesterol content or dietary preferences such as vegan. Eggs are widely used in baking industry because of its binding properties. Due to the allergy problem and other reasons stated above, in this experiment, eggs are being substituted with flaxseed due to its functional value and binding properties. Flaxseed contains high level concentration of lignins, dietary fibers, and α-linolenic acids which can lower the risk of cardiovascular disease. Moreover, the antioxidant properties of flaxseed lignins are found to be useful in preventing various kinds of cancer. This experiment is designed to test and compare the texture, ph, and water activity between the variables. A chocolate chip cookies recipe is obtained from allrecipes.com and being modified to fit into the project. The independent variables in this experiment are the control (without flaxseed), cookies with 14.23 grams of whole flaxseed, and 14.23 grams of ground flaxseed. The dependent variables from this experiment are the texture, water activity, and color. The texture, color and, water activity of the cookies are objectively measured by knife probe texture analyzer, Hunter colorimeter, and water activity machine. This experiment is designed for 3 trials. Finally, the subjective measures such as flavor, palatability, and texture are being investigated by using the 9-scale hedonic sensory scoring sheet. This experiment demonstrated that replacing eggs with ground flaxseed showed a significant difference in texture. However, the replacement of eggs with flaxseed did not show a significant difference in color and water activity when compared to the control, 765. In the sensory evaluation, most of the panelists preferred the flavor and palatability of the control (765) but the texture of 518, the cookies with whole flaxseed. Through the experiment, ground flaxseeds can serve as a good binding agent in replacing eggs besides providing nutrients such as lignins, dietary fibers, and α-linolenic acids. Although from the sensory evaluation, most of the panelists prefer the control cookies which contain egg and high in fat. Hence, more researches should be done in this field in order to improve the texture, flavor, and palatability of egg replaced products. Introduction: According to Pub Med Health (2012), a food allergy is an exaggerated immune response triggered by allergens such as eggs, peanuts, milk, or some other specific food. An allergic response can range from mild symptoms such as bloating, nausea, diarrhea, and dizziness to more serious responses including fatality. One of the most common food allergens are eggs. An allergic response to eggs can show symptoms anywhere from a few minutes to a few hours after the consumption of eggs or egg-containing products (Mayo Clinic 2012). According to Mayo Clinic (2012), the signs and symptoms toward egg allergy include skin rashes, hives, nasal inflammation and vomiting or other digestive problems. It is very uncommon that an allergic response to eggs will leads to anaphylaxis, a life-threatening reaction (Mayo Clinic 2012).
Besides being allergic, some people may wish to avoid consuming eggs due to their cholesterol content or dietary preferences such as with veganism. Eggs contain high level of cholesterol and limiting the consumption of eggs can reduce the risk of cardiovascular diseases. Not only do eggs provide flavor in baked goods, they also have a multitude of other uses. Eggs are widely used in the baking industry because they contribute to structure, incorporate air when beaten, provide liquid, fat, and protein, and emulsify fat with liquid ingredients (Baking Management 2005). Although yolks contribute a high level of cholesterol, eliminating or reducing egg yolks in a recipe can result in less tenderness. In this research project, the binding properties of eggs in baking industry is highlighted and eggs are being replaced with flaxseed in the making of chocolate chip cookies due to its functional value besides providing the same binding properties as eggs. At present times, flaxseed has new prospects in food because of the growing consumer s interest for functional food with health benefits (Blecker 2011). Flaxseed contains high level concentration of lignins, dietary fibers, and α-linolenic acids which can lower the risk of cardiovascular disease. Touré and Xu (2010) reported that among the reported potential health benefits associated with flaxseed or flaxseed meal are decreased risk of cardiovascular disease (Craig 1999;Jenkins and others 1999), decreased risk of cancer, particularly of the mammary and prostate cancer gland (Craig 1999), anti-inflammatory activity (Ranich and others 2001), laxative effect, and alleviation of menopause symptoms and osteoporosis (Kurzer and Xu 1997). For instance, flaxseed lignins provide highly active antioxidants which are found to be useful in preventing breast cancer, prostate cancer and colon cancer (Touré and Xu 2010). Moreover, the high fiber content on the flaxseed also can reduce blood cholesterol, regulate blood glucose, and preventing constipation and providing protection against colon cancer (Rodrigues and others 2012). By using flaxseed as an egg replacer, it will not only be beneficial because of their multiple health benefits, but it serves as a good alternative, for those who are unable to or wish not to consume eggs. The reason flaxseed is being used as a binding agent is because of its physical properties and it has also been said that the binding properties of flaxseed are similar to those of eggs making them a good substitute. This is said to be because flaxseed is high in mucilage that can increase the water absorption. The high moisture absorption has a positive effect on the texture mainly elasticity and softness of food products during their handling and cooking (Oomah 2001). This is because when the mucilage mixes with water it becomes very sticky. Flaxseed has been researched for its health benefits, but there are not many studies done on its effects on food. Most studies done on flaxseed have to do more with utilizing as flour in recipes; there are no recipes on the effects of flaxseed on foods when used as an egg replacer. In an article about baking with flaxseed based breads they observed the breads retain moisture and softness more efficiently than the control flaxseed-free bread. The presence of mucilage probably improves moisture holding, and contributed to these properties. Sensory analysis, however, mentioned an increase of the elasticity and a loss of the crispness of breads with high concentration in flaxseed meal. (Touré and Xueming 2010) In addition, from the journal article title Eating Quality of Banana Nut Muffins and Oatmeal Cookies Made with Ground Flaxseed, the palatability and overall acceptability of cookies prepared with ground flaxseed are being evaluated. From the result, the control cookie
looked pale compared with the 33% and 50% ground flaxseed cookies. The 33% ground flaxseed cookies were rated near optimum in color, tenderness, and flavor. Hence, the acceptability of 33% ground flaxseed cookies is higher among the panelists (Alpers and Sawyer-Morse 1996). Hence, with the prior knowledge that obtained from the article, this research project is designed to test and compare the texture, ph, and water activity between the variables. A chocolate chip cookies recipe is being obtained from allrecipes.com and being modified to fit the project. The independent variables in this experiment are the control 765(without flaxseed), cookies with 14.23 grams of whole flaxseed (518), and 14.23 grams of ground flaxseed (433). The dependent variables from this experiment are the texture (which is going to be measured by knife-probe texture analyzer), water activity (measure using water activity system), and color (by using Hunter colorimeter). Finally, the subjective measures such as flavor, palatability, and texture are being investigated by using the sensory scoring sheet. Methods: Recipe: (for 12 servings) Ingredients 115 g butter 100 g white sugar 110 g packed brown sugar 1 egg 5 ml vanilla extract 190 g all-purpose flour 2 g baking soda 5 ml of hot water 2 g salt 170 g semisweet chocolate chips *Chopped walnuts are omitted from the above *For the variables 433 and 518, substitute 1 egg by combining 14.23g flaxseed with 1.5 ounces water before adding it to the mixture The original recipe for the chocolate chip cookies will set as the control for the experiment. The recipe is obtained from allrecipes.com. Flaxseed meal and whole flaxseed at the amount of 14.23g are added to the cookies in order to replace eggs (by providing binding properties) besides providing nutritional properties. Procedures: Preheat oven to 350 degrees F (175 degrees C). Then, in a medium bowl, cream together 115g of butter,110g of brown sugar and 100g of white sugar. Mix in the egg and 5ml vanilla. Combine 190g flour, 2g baking soda and 2g of salt; stir into the batter until moistened. Mix in the 170g chocolate chips. Then, scoop 2 inch size balls onto baking sheet. Finally, bake for approximately 10 minutes in the preheated oven, until the edges are light brown. Before the
experiment, whole flaxseed will be soaked in advance for about 1 hour so that the flaxseed can congeal. Design of the experiment: Control: (765) Variable A: (433) with whole flaxseed Variable B: (518) ---with ground flaxseed Variable 765 (Original Recipe) 115 g butter 100 g white sugar 110 g packed brown sugar 1 egg 5 ml vanilla extract 190 g all-purpose flour 2 g baking soda 5 ml of hot water 2 g salt 170 g semisweet chocolate chips Variable 433 115 g butter 100 g white sugar 110 g packed brown sugar 14.23 grams of flaxseed meal with 3.5 ml of water 5 ml vanilla extract 190 g all-purpose flour 2 g baking soda 5 ml of hot water 2 g salt 170 g semisweet chocolate chips *The egg is substituted by flaxseed meal. Variable 518 115 g butter 100 g white sugar 110 g packed brown sugar 14.23 grams of whole flaxseed with 3.5 ml of water 5 ml vanilla extract 190 g all-purpose flour 2 g baking soda 5 ml of hot water
2 g salt 170 g semisweet chocolate chips *The egg is substituted by whole flaxseed. Before the experiment, whole flaxseed is being soaked in advance for about 1hour so that the flaxseed can congeal. The end products are tested on their texture (using knife-probe texture analyzer), water activity (water activity system), and color (Hunter colorimeter). The force of the texture analyzer is set at grams. Each of the trials is run 3 times per variable under each instrument and the readings are being averaged. The sequence of the test is texture analyzer using knife probe, color, and then water activity. The arrangement is as such because whole piece of cookie is needed to run under the texture analyzer. Then, the broken pieces of cookie are being run under Hunter colorimeter and then the smaller debris of the cookies is being test in the water activity system. 2 to 3 pieces of fresh cookies are set up in the plate (the plates are labeled with variable numbers such as 765, 433, and 518) and placed in front of the counter for the testing of the panelists. Sensory scoring sheet is prepared for the panelists. The sensory scoring sheet is as below: Flaxseed as Egg Replacer in Chocolate Chip Cookies Sensory scoring sheet using a 9 points hedonic scale to rate 1-least desirable flavor, palatability, texture 5-Neither desirable/undesirable flavor, palatability, texture 9-Most desirable flavor, palatability, texture Cookie Variable Flavor Palatability Texture 765 433 518 The processes will need to be replicated 3 times for each variable. For each trial, 3 types of cookies are being baked (765, 433, and 518) and tests are run 3 times on each variable. Discussion: The results of this experiment demonstrate that there is a greater difference replacing whole flaxseeds than ground flaxseed for eggs on the final product. The difference between variables objective measurements were reported on texture, water activity and color. As well as subjective testing utilize the 9-point hedonic scale. To test the texture of the variables a knife-probe texture analyzer was used. This measured the force in grams in order to break the cookie in half. Three trials each including three tests were ran for each variable. Averages for each trial as well as overall averages for each variable can be seen in Table 1. Variable 765 was the softest with a texture of 2411.66, followed by 518 with a texture of 4557.88g then 433 with a texture of 14245.2g. There is no significant difference between variables765 and 518 as well as no difference between variables 433 and 518
(Table 2). However the texture of variable 433 was drastically higher than the others (Figure 1). Variable 433 used ground flaxseed so it can be determined that opposed to eggs and whole flaxseeds its binding capabilities are much large. With that said sources of error may have largely contributed to these differences in texture. Trial 1 was held in the refrigerator for days prior to obtaining the measurement. Also, the degree to which each cookie was cooled varied between variables. Warmer cookies will need less force to be broken. The next objective measure to determine that water activity of each cookie was measured using the water activity machine. Again three trials each consisting of three tests were ran for each variable. Averages for each trial as well as overall averages for each variable can be seen in Table 3. Variable 518 was significantly different from 765 and 433 with a lower average of 0.4171 compared to 0.5803 and 0.5496 respectively (Table 2). Variable 765 had a slightly higher water activity than variable 433, but not significant. From figure 2 it can be concluded that cookies using eggs have the highest water activity followed by ground then whole. Using whole flaxseed may absorb more water in the beginning but baking will decrease the amount of water in the cookie. This shows that whole flaxseed cannot make a very good binding agent as it is weak in water bounding capacity. Water activity can affect the flavor and palatability of a product. These results coincide with the findings from the sensory evaluation. On the basis of flavor and palatability variable 518 scored the lowest (Figure 4). The third objective measure utilized the Hunter Colorimeter. This measures the color of a product using L, a and b values. The L values is a measure on the basis of light and dark, with a value of 0 being black and a value of 100 being white white. Our measurements indicate that each variation of cookie baked to the same level of darkness. L-values for each variable are not statistically significant (Figure 3). The a-value is a measure of the colors red and green where a positive value indicating red a negative value indicating green and 0 being neutral. Our values are slightly above zero indicating that they are more red than green (Table 5). This can be expected since the cookies were slightly brown. The b-value is a measure of colors yellow and blue where a positive value indicates yellow, a negative value indicated blue and 0 being neutral. These values are greater than the a values which makes sense because the cookies were overall light, meaning there had to be more yellow than red to balance out the color. Variable 765 was the lightest and had the greatest yellow to red ratio; both 433 and 518 had no significant difference on this measurement. Overall the colors are very similar, which can be seen in appendix 1. The subjective measurement used was a sensory evaluation using the 9-point hedonic scale. Rankings were done from 1 indicating least desirable to 9 indicating the most desirable on the basis of flavor, palatability, and texture. For flavor variable 765 scored the highest and variable 518 scored the lowest. (Figure 4) However there was no significant difference between variables 765 and 433 as well as 433 and 518 (Table 8). The same findings are true for palatability among the three variables (Figure 4 & Table 8). As for texture, the inverse scores were given, 518 had the best followed by 433 and 765 (Figure 4). These results are to be expected, the overall favorite
was variable 765 which was the control and the least favorite was variable 518 which utilized whole flaxseeds. In conclusion, the results from are testing are helpful in determining the efficiency in using flaxseed in place of eggs. The substitution of ground flaxseed for eggs may serve as the effective alternative. There is no significant difference in water activity, color, and overall preference between the variables 765 and 433. Using whole flaxseeds may elicit a less desirable product. Also, according to the sensory evaluation, most of the panelists prefer the original recipe which contains egg and high in fat. However, by utilizing ground flaxseed people will be able to enjoy the same product they know and love with enhanced health benefits. For future work plan or experiment, other factors such as storing condition and temperature that can affect the properties of the cookies should be taken in account in order to minimize the error. In this experiment, the cookies in the first trial were kept in the refrigerator which then led to stone- hard cookies. This had greatly affected the measurement on the knife-probe texture analyzer. Besides that, according to the sensory evaluation, most of the panelists are more prefer the original recipe which contains egg and high in fat. Hence, more researches should be done in this field in order to improve the texture, flavor, and palatability of egg replaced products besides promoting health among the consumers. Results: Table 1: Texture Analyzer average values for trials 1-3, with the overall average and standard deviation for each variable calculated using all 9 tests in trials. Trial 1 4035.33 16135.13 10591.67 Trial 2 1838.33 25281.14 1668 Trial 3 1361.33 1319.33 1414 Average 2411.66 14245.2 4557.88 SD 1430.9 14810 4594.3 Table 2: Texture analyzer mean with statistical significance. Average 2411.66 a 14245.2 b 4557.88 ab Means within a row not bearing the same letter are statistically significantly different p < 0.05.
Texture Analyzer 35000 30000 25000 Force (g) 20000 15000 10000 Average 5000 0 5000 a Variable Figure 1: Average force (grams) measured using texture analyzer for each variable. Table 3: Water Activity average values for trials 1-3, with the overall average and standard deviation for each variable calculated using all 9 tests in trials. Trial 1 0.565 0.528 0.341 Trial 2 0.598 0.535 0.376 Trial 3 0.56 0.585 0.535 Average 0.5803 0.5496 0.4171 SD 0.06106 0.04106 0.1015 Table 4: Water activity mean with statistical significance Average 0.5803 a 0.5496 a 0.4171 b Means within a row not bearing the same letter are statistically significantly different p < 0.05.
Water Activity 0.7 0.6 0.5 Aw Values 0.4 0.3 0.2 Average 0.1 0 Variable Figure 2: Average water activity values for each variable. Table 5: Hunter Colorimeter average values for trials 1-3, with the overall average and standard deviation for each variable calculated using all 9 tests in trials. L a b L a b L a b Trial 1 52.98 3.87 17.31 44.04 5.49 14.83 42.5 6.19 15.56 Trial 2 39.82 8.81 16.11 43.88 3.23 13.71 37.87 5.92 14.28 Trial 3 43.37 7.37 17.46 40.55 4.55 13.8 41.47 5.62 15.5 Average 45.39 6.686 16.958 42.82 4.425 14.11 40.61 5.907 15.11 SD 6.43 2.32 1.012 2.08 1.099 0.751 2.76 0.6754 0.8175 Table 6: Hunter Colorimeter mean with Statistical significance. L 45.39 a 42.82 a 40.61 a a 6.686 b 4.425 c 5.907 bc b 16.958 d 14.11 e 15.11 e Means within a row not bearing the same letter are statistically significantly different p < 0.05 B p<0.001
Hunter Colorimeter 60 50 40 Values 30 20 765 433 518 10 0 L a b Parameters Figure 3: Average L, a & b values for each variable measured using the Hunter Colorimeter. Table 7: Subjective testing average rating scores on Flavor, Palatability and Texture for trials 1-3, with the overall average and standard deviation for each variable calculated using all 9 tests in trials. Flavor Palatability Texture Flavor Palatability Texture Flavor Palatability Texture Trial 1 7 6.67 7.33 7 6.33 6 6.67 5.67 6.33 Trial 2 8 8 4.75 7 7.5 6 6 6 6.5 Trial 3 7.2 7.2 5.8 6.6 6.4 5.8 5.2 5.2 5.8 Average 7.42 7.33 5.833 6.833 6.75 5.916 5.833 5.583 6.166 SD 1.379 1.371 1.467 1.267 1.658 1.311 1.267 1.24 1.642 Table 8: Subjective testing mean with statistical significance. Flavor 7.42 a 6.833 ab 5.833 b Palatability 7.33 c 6.75 cd 5.583 d Texture 5.833 e 5.916 e 6.166 e Means within a row not bearing the same letter are statistically significantly different p < 0.05.
Sensory Evaluation Average Hedonic Rating 10.00 9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 765 433 518 0.00 Flavor Palatability Texture Parameters Figure 4: Average subjective testing scores for each variable measured using 9-point hedonic scale.
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Appendix 1 Variable 765 Variable 433 Variable 518