The Effect of Almond Flour on Texture and Palatability of Chocolate Chip Cookies Joclyn Wallace FN 453 Dr. Daniel 11-22-06
The Effect of Almond Flour on Texture and Palatability of Chocolate Chip Cookies Abstract: In a quest to find healthy alternatives to snacks, some use whole wheat flour in chocolate chip cookie recipes. This recipe change is beneficial for most individuals, but it does not work well for those who need a gluten free diet. In an effort to find a reasonable substitute for such individuals, almond flour was tested because it does not form gluten as whole wheat flour does. In a Food Chemistry study, designed to find if exchanging almond flour for whole wheat flour had any effect on taste or texture of chocolate chip cookies, no significant difference was found in taste; however, there was a significant change in texture. Therefore, if individuals do not mind the texture diierence, using almond flour in chocolate chip cookies would be a great alternative for whole wheat flour.
Introduction: There is a growing number of individuals with Celiac disease which causes them to be unable to tolerate products containing gluten. For this reason, they are unable to have baked goods containing wheat. Chocolate chip cookies, made with whole wheat flour, can be a very tasty treat that people prefer to eat over cookies made with all white flour. Individuals who are unable to consume gluten products are unable to eat whole wheat flour cookies. Gluten proteins are classically divided into two groups, the gliadins and glutenins, based on their extractability (gliadins) or unextractability (glutenin). The unique viscous and elastic properties of wheat dough are primarily due to these prolamins. The balance of these two properties being important addition in determining the suitability of flours for different baking uses (Shewry P.R.; Tatham A.S. 2006). Almond flour is gluten free, which makes it unable to trap air and rise as well as conventional flour. Although research has been done on almond flour to test for possible allergens, none have been performed to test sensory or functional evaluation when used in recipes as a wheat flour substitute. The main reason for performing this experiment is to create a cookie that is healthy, but gluten free. Chocolate chip cookies are made with whole wheat flour to make them healthier for individuals, but people who are allergic to wheat (due to gluten content) are unable to eat them. Those who are allergic to gluten should be able to have an alternative to white flour that they are not allergic to. Almond flour is gluten free, so it will be used to replace wheat flour. For this experiment, almond flour is going to be substituted for whole wheat flour to see if it might be an acceptable replacement. There is concern about how well it will perform, texture wise, due to it being unable to rise as well as conventional flour. The independent variable is the amount of almond flour used in the recipe. The dependent variables that will be measured are texture, volume, area of cookie and the taste preference. These variables will be gathered using the Texture Analyzer; Seed- Volume apparatus, a ruler and calculations and a taste panel.
Methods: The plan of the experiment was to make test samples, measure them and then repeat the process to see if the measurements and sensory evaluations could be duplicated. The original recipe that will be used was acquired from a home recipe alteration of the Toll House recipe. Control Recipe: 1 ¼ C all-purpose flour (155g) 1 ¼ C whole wheat flour (155g) 1 tsp. baking soda (5g) 1 tsp. salt (6.7g) 1.5 sticks butter (185g) ¾ C granulated sugar (185g) ¾ C packed, light brown sugar (185g) 2 large eggs (112.4g) 2 tsp. pure vanilla extract 2 C Nestle Toll House Semi-Sweet Chocolate Morsels (340g) Variable Recipe: 1 ¼ C all-purpose flour (155g) 1 ¼ C almond flour (155g) 1 tsp. baking soda (5g) 1 tsp. salt (6.7g) 1.5 sticks butter (185g) ¾ C granulated sugar (185g) ¾ C packed, light brown sugar (185g) 2 large eggs (112.4g) 2 tsp. pure vanilla extract 2 C Nestle Toll House Semi-Sweet Chocolate Morsels (340g) Preheat oven to 375 F, 190 C. Combine flour, baking soda and salt in small bowl. Beat brown sugar, butter and granulated sugar in large mixer bowl until creamy. Beat in eggs, milk and vanilla extract. Gradually beat in flour mixture. Stir in oats, morsels and nuts; mix well. Drop by rounded tablespoon onto un-greased baking sheets. Bake for 9 to 11 minutes or until golden brown. Cool on baking sheets for 2 minutes; remove to wire racks to cool completely.
The temperature will be controlled by keeping the oven set at the same temperature throughout the experiment. The size of the product will be consistent because it is being measured before being placed on the cookie sheet. The cookies were allowed to cool for 20 minutes before being tested. A sample cookie from the whole wheat recipe and the almond recipe were wrapped in a thin layer of plastic wrap then measured for diameter. The two sample cookies were then measured in the Seed-Volume apparatus and the Texture Analyzer. The operational procedures were followed for each individual machine according to the instructions (Weaver & Daniels 2003). The metal plate in the center tube was pulled out to allow the seeds to fall to the bottom container of the apparatus. The center tube was tapped 4 times to allow seeds to finish falling before a measurement was taken and recorded from the numbers marked on the center tube. The seed volume apparatus was then turned upside down to allow the seeds to empty from the bottom. The plate was then pushed in to stop the seeds from reentering the bottom as the apparatus was turned right side up again. The bottom container was unlatched and the first sample cookie was placed inside. The container was re-latched and the plate was pulled back to allow the seeds to fall back into the bottom container. The center tube was again tapped 4 times to allow seeds to finish falling into the bottom container before a second measurement was taken and recorded. The apparatus was again turned upside down to allow the seeds to travel back to the top and the plate was pushed in to the center tube again. The apparatus was turned right side up and the sample cookie was removed from the bottom container. This procedure was repeated for the second sample cookie. The difference of the first and second recording from the apparatus was the volume of each cookie. Due to the age of the apparatus, seeds are lost during sampling. It was necessary to add seeds to the apparatus. Each time a test was run, the volume in the apparatus was taken before and after the sample cookies were placed in the bottom container. This ensured a more accurate starting volume in the apparatus. The samples were then tested on the Texture Analyzer. The directions for the texture analyzer were followed with the cookie setting being used and the cone probe. Each sample cookie was tested in three different places on the cookie to get an average force. The cookies not used for measurements were tested by multiple randomly selected individuals. Three males tested samples from each trial, but the rest were different each time. This allowed for a less bias sampling result. Each sample was labeled with a random three digit number and had its own score card so each subject filled out two separate sheets. See Sensory Score Card in the attached Appendix. The experiment was repeated three times to see if results would be the same. Each time the experiment was performed, all procedures were executed the same.
Discussion: Overall, the experiment went well. The texture of the almond flour cookies was different than that of the whole wheat flour cookies in that they did not rise much at all. The almond flour cookies spread out instead of rising up and were a bit chewier. Averages of the raw data were taken and used for the graphs found below. Average data was calculated by adding results together and dividing by the number of results recorded. There were numerous possibilities for sources of error in the subjective and objective measurements. In objective measurements the sources of error can be due to systematic or operator related. Systematic error is hard to avoid and some will be present no matter how closely the operator follows proper procedures. Operator error can be corrected by strictly following guidelines (Michael O. Mahoney 1986). Sensory error can be due to varying reason such as what a subject has already eaten before testing the product or personal bias against the particular ingredient being used in the experiment. The Seed- Volume Apparatus readings were very likely to be imprecise due to the loss of seeds from the crack in the center tube. Zeroing the apparatus before each measurement was the only way to help decrease the potential error from the seed leakage. The project was deemed successful in that the texture difference of the almond flour cookies was not important to the sensory panel. Subjects still enjoyed the almond cookies as they did the whole wheat flour cookies. Some panelists stated they preferred the texture of the almond flour cookies over that of the whole wheat flour cookies. It is assumable that individuals looking for a whole wheat flour alternative would be very likely to use almond flour. At the end of the experiment, a bag of wheat flour was found that had substitution instructions. The bag stated to substitute ¼ C of almond flour for each cup of wheat flour called for in a recipe. This information was unknown prior to the experiment. Prior to finding this bad no information had been discovered on the correct substitution of almond flour for wheat flour. In future substitution tests of almond flour; it might be an excellent idea to try the ratio suggested on the bag. This might eliminate some of the texture problems found in the experiment.
Results:. Table 1: Sample area of cookies Product Trial Area (cm^2) Wheat Trial 1 22.88 Wheat Trial 2 25.64 Wheat Trial 3 22.87 Almond Trial 1 31.66 Almond Trial 2 41.86 Almond Trial 3 38.3
Seed Volumes; Wheat vs. Almond Flour 66 64 62 Seed Volume (cubic cm) 60 58 56 54 52 50 Trial 1 Trial 2 Trial 3 Almond 60 65 65 Wheat 55 65 60 Figure 1. Results of Seed-Volume Apparatus (cubic cm). Figure 1 shows the results from the seed-volume apparatus test. It can be seen that the values are very similar and only vary by no more than five cubic centimeters. Also in trial two the values for seed-volume are identical between the two products; wheat flour and almond flour.
Texture Analyzer; Almond vs. Wheat Flour 2000 1800 1600 1400 1200 Force (g) 1000 800 600 400 200 0 Trial 1 Trial 2 Trial 3 Almond 1027.8 1670.6 1256.6 Wheat 1920.2 1224.5 522.8 Figure 2. Results of Texture Analyzer (g) of force. Figure 2 shows the results from the texture analyzer test. Some error can be seen to have been produced when analyzing this value. The third trial wheat analysis shows only 522.8 grams which is believed to be in error. The values across the other two trials seem to not follow a consistent pattern.
Ratings; Almond vs. Wheat Flour Trial 1 9 8 7 6 Rating (1-9) 5 4 3 2 1 0 opinion appearance flavor texture Almond Flour 7.75 5.375 8.25 6.625 Wheat Flour 7.25 7.875 6.5 7 Figure 3. Results from Sensory Score Card of Trial 1 using a 9 point scale. Figure 3 is the results of Trial 1 s sensory evaluation. For trial 1 the overall opinion was in favor of the almond flour cookie. Although the almond flour scored the lowest for appearance and texture. This would show that taste outweighed texture and appearance on the first trial.
Ratings; Almond vs. Wheat Flour Trial 2 8 7 6 5 Rating (1-9) 4 3 2 1 0 opinion appearance flavor texture Almond Flour 7.25 5.625 7.75 6.75 Wheat Flour 7.5 7.125 7 7.25 Figure 4. Results from Sensory Score Card of Trial 2 using a 9 point scale. For trial 2 the wheat flour cookie took overall opinion. This was likely due to its better appearance and texture. This being said the flavor is still in favor of the almond flour cookie.
Ratings; Almond vs. Wheat Flour Trial 3 8 7 6 5 Ratings (1-9) 4 3 2 1 0 opinion appearance flavor texture Almond Flour 7 5.25 7.375 6.875 Wheat Flour 6.625 7 6.875 6.25 Figure 5. Results from Sensory Score Card of Trial 3 using a 9 point scale. For trial 3 the almond flour cookie took the lead in overall opinion. This again was likely due to the better flavor.
References: 1. Shewry, P R., and A S. Tatham. "Disulphide Bonds in Wheat Gluten Proteins." Journal of Cereal Science25 (1997): 207-227. Science Direct. EBSCO. 22 Nov. 2006. 2. Weaver & Daniels. The Food Chemistry Laboratory, Second Edition CRC Press. pp. 107-132. 3. Michael O. Mahoney. Sensory Evaluation of Food. Marcel Dekker Inc. pp. 399.
Appendix: