Jessica Dooley and Jennifer Gotsch FN 453 Team Project Written Report Effects of Acai Berry on Oatmeal Cookies Abstract: Oxidative stress can cause many diseases such as cancer, heart disease, and stoke. (Hassimotto, 2005) The use of antioxidants has been found to reduce the levels of oxidative stress on the body and thus reducing the risk of these diseases. Studies have shown that Acai berry pulp has a high antioxidant capacity. (Pozo Insfran, 2004) Through the supplementation of Acai berry juice, it will allow individuals to obtain more antioxidants in their diet which helps to decrease the amount of oxidative stress. In this experiment Acai berry juice is used to substitute orange juice in order to add greater antioxidant capacities to the oatmeal cookie. Three different variations of the oatmeal cookies are used in this experiment. The first variation consists of all orange juice, the second variation is half orange juice and half Acai berry juice, and the third variation is all Acai berry juice. The Stable Micro Systems Texture Analyzer, Hunter Colorimeter, and a sensory panel test were all used to evaluate the different variations of the oatmeal cookies. The main finding from this experiment is that as there was an increase in Acai berry juice, the acceptability of the appearance decreased. This experiment also found that the mixture of orange juice and Acai berry juice resulted in the hardest texture whereas just Acai berry juice resulted in the second hardest texture. There was not a significant difference in mouth feel in the different variations of oatmeal cookies. The cookie that had the most pleasurable flavor was the control cookie, but the all Acai berry had the second best rating of flavor. Introduction: Acai berry juice has been shown to have a high antioxidant capacity. The consumption of antioxidants has been shown to reduce the level of oxidative stress. Oxidative stress can reduce the function of lipids, proteins, carbohydrates, and nucleic acids. The result of oxidative stress can cause many diseases such as cancer, heart disease, and stroke. (Hassimotto, 2005) Acai berry pulp has been found to have a high antioxidant capacity compared to many other berries such as blueberries, strawberries, raspberries, blackberries, cranberries, and grape juice. (Pozo Insfran, 2004) The purpose of this experiment is to test whether substituting different amounts of Acai Berry juice for orange juice in an oatmeal cookie recipe will increase the antioxidant capacity of the product while maintaining desirability for the product. The independent variable is the amount of Acai Berry juice added to the oatmeal cookies making a cookie that is not necessarily healthy to have an added health benefit. It has been shown that a product that is created with a health claim, consumers are more likely to try and like the food. (Sabbe, 2009) The dependent variables that were measured were mouth feel, flavor, appearance, color and texture. The hypothesis for this experiment was that the amount of Acai Berry juice will not have an effect on the mouth feel, flavor, appearance, color and texture.
The experiment was designed to nutritionally improve a product that is not necessarily healthy but is readily consumed. Two objective methods were used to test whether the addition of a different product in a recipe will change the texture and overall color. The Texture Analyzer was used to assess the texture of the cookies and the Hunter s Colorimeter was used to assess the color changes that occurred. The consumer acceptability of the product was also tested by having consumers rate the 3 products on a 9 point hedonic scale. They assessed mouth feel, flavor, and appearance. By adding Acai berry juice to the product, the original recipe had an increased amount of antioxidants. As mentioned before, antioxidants are shown to help reduce the risks of many diseases later in life. Methods: Three variations of the oatmeal cookies were made in this experiment. The first variation was the control oatmeal cookies. The control oatmeal cookies were made following the original recipe using 73.95mL of orange juice. The second variation substituted 36.975mL of the orange juice for Acai berry juice. The third variable substituted 73.95mL orange juice for 73.95mL of Acai berry juice. The other ingredients in the recipe remained the same among the different variations. Each trial began after the previous trial was finished being made. The recipe for the different variations are as followed. Orange Oatmeal Cookies (Variation 1) 102.5g shortening 100g sugar 1 egg 84 grams quick cooking oats 115g sifted flour 6g soda 4.5g salt 2g cinnamon 73.95mL orange juice Orange/Acai Berry Oatmeal Cookies (Variation 2) 102.5g shortening 100g sugar 1 egg 84 grams quick cooking oats
115g sifted flour 6g soda 4.5g salt 2g cinnamon 36.975mL spoons orange juice 36.975mL Acai berry juice Acai Berry Oatmeal Cookies (Variation 3) 102.5g shortening 100g sugar 1 egg 84 grams quick cooking oats 115g sifted flour 6g soda 4.5g salt 2g cinnamon 73.95mL Acai berry juice Preheat the oven to 177 o C. Cream together shortening and sugar until light and fluffy. Add egg and beat well. Stir in the oats. Sift together flour, soda, salt, and cinnamon. Add creamed ingredients, alternately with Acai berry juice, beating well after each addition. Drop from teaspoon onto greased baking sheet that is at room temperature. Bake in a moderate over at 177 o C for 10 to 12 minutes. Once the first variation of the cookies were finished cooking, the next variation of cookies were started. The same baking sheet was used to cook each variation of cookies. The baking sheet was at room temperature before the cookie batter could be placed on it. After the cookies were done baking, they were taken out of the oven and set on cooling rack to cool to room temperature. Once the cookies were at room temperature, two cookies were taken from each trial to be used to test for texture and color. The Stable Micro Systems Texture Analyzer was used to assess the cookie s texture. The cookie setting and the knife probe were used to complete this analysis. The second cookie was used to test for color using Hunter Colorimeter. This cookie was broken up into small pieces and then firmly packed into the bottom of a 300mL clear beaker. Once the cookie was
completely covering the bottom of the beaker, the beaker was placed onto of the Hunter Colorimeter. Each variation was tested and the results were recorded for each of these two tests. The remaining cookies from each variation and trial were cut in half and used for the sensory panel that tested for mouth feel, flavor, and appearance. The cookies for each variation were placed on separate plates that were labeled appropriately. Score sheets were placed on the table next to the plates. A 9 point hedonic scale was used to complete the sensory evaluation. Three trials were completed for each of the three variations. Repetition was used to make sure that the results were consistent. The order that the variations were made in each trial were different. The variations for each trial were put on the table in different orders to help prevent bias from previous trials. Sampling was completed by semi trained individuals. Different individuals were used to sample each of the three trials but the individuals sampled all three variations in a trial. The use of different individuals also helped to prevent bias. Please circle the appropriate response for each variable. Mouth Feel Variable 349 Variable 857 Variable 631 Like extremely Like extremely Like extremely Like very much Like very much Like very much Like moderately Like moderately Like moderately Like slightly Like slightly Like slightly Neither like nor dislike Neither like nor dislike Neither like nor dislike Dislike slightly Dislike slightly Dislike slightly Dislike moderately Dislike moderately Dislike moderately Dislike very much Dislike very much Dislike very much Dislike extremely Dislike extremely Dislike extremely Flavor Variable 349 Variable 857 Variable 631 Like extremely Like extremely Like extremely Like very much Like very much Like very much Like moderately Like moderately Like moderately Like slightly Like slightly Like slightly Neither like nor dislike Neither like nor dislike Neither like nor dislike Dislike slightly Dislike slightly Dislike slightly Dislike moderately Dislike moderately Dislike moderately Dislike very much Dislike very much Dislike very much Dislike extremely Dislike extremely Dislike extremely
Appearance Variable 349 Variable 857 Variable 631 Like extremely Like extremely Like extremely Like very much Like very much Like very much Like moderately Like moderately Like moderately Like slightly Like slightly Like slightly Neither like nor dislike Neither like nor dislike Neither like nor dislike Dislike slightly Dislike slightly Dislike slightly Dislike moderately Dislike moderately Dislike moderately Dislike very much Dislike very much Dislike very much Dislike extremely Dislike extremely Dislike extremely Results: Table 1 The Average of the Effect of the Addition Acai Juice on the Mouth Feel, Flavor, and Appearance of the Oatmeal Cookie as Measured by Subjective Tests* from All Three Trials: Variable 349 (Control) Variable 857 Juice and Orange Variable 631 Mouth feel 6.6 6 5.9 Flavor 6.8 5.14 5.8 Appearance 7.1 5.1 3.1 (* 9= Like Extremely, 8=Like Very Much, 7=Like Moderately, 6=Like Slightly, 5=Neither Like Nor Dislike, 4=Dislike Slightly, 3=Dislike Moderately, 2=Dislike Very Much, 1=Dislike Extremely)
Table 2 The Effect of the Addition of Acai Juice on the Texture (g) of the Oatmeal Cookie as Measured by the Texture Analyzer: Variable 349 (Control) Variable 857 Juice and Orange Variable 631 Trial 1 82.7 429.3 269.5 Trial 2 185.4 430.5 305.6 Trial 3 116.2 404.0 166.3 Average 128.1 421.3 247.1 Std. Dev. 52.4 14.9 72.3 Table 3 The Effect of the Addition of Acai Juice on the Texture (g) of the Oatmeal Cookie as Measured by the Hunter Colorimeter: Variable 349 (Control) Variable 857 Juice and Orange Variable 631 L A B L A B L A B Trial 1 33.78 8.38 13.33 31.48 5.23 11.14 26.37 6.55 9.91 Trial 2 38.11 8.72 15.95 26.80 7.02 10.51 33.25 2.35 10.03 Trial 3 41.41 8.31 16.41 35.92 4.31 12.69 33.73 2.03 10.24 Average 37.8 8.47 15.23 31.4 5.52 11.44 31.11 3.64 10.06 Std. Dev. 3.8 0.2 1.66 4.6 1.38 1.12 4.11 2.52 0.17
9 point Hedonic Scale 8 7 6 5 4 3 2 1 0 Mouth Feel Flavor Appearance Tested Variables Variable 349 (Control) Variable 857 (Addition of Acai Juice and Orange Variable 631 (Addition of Acai Figure 1 Average of the effect of the addition of Acai berry juice on the mouth feel, flavor, and appearance of the oatmeal cookies as measured by subjective test from all three trials. Grams 500 450 400 350 300 250 200 150 100 50 0 Trial 1 Trial 2 Trial 3 Average Trials Variable 349 (Control) Variable 857 (Addition of Acai Juice and Orange Variable 631 (Addition of Acai Figure 2 The effect of the addition of Acai berry juice on the texture in the oatmeal cookie as measured by the texture analyzer.
Colorimeter Values 45 40 35 30 25 20 15 10 5 L a B 0 Variable 349 Variable 857 Variable 631 Variables Figure 3 The effect of the addition of Acai berry juice on the color in the oatmeal cookies as measured by the colorimeter. Discussion: After all three variations and trials were complete the data was collected and analyzed. The first piece of data that was analyzed was the subjective assessment. The data collected from each trial was averaged for each variable (see table 1 and Figure 1 for results). The results showed that as more Acai berry juice was added, the mouth feel for the oatmeal cookie decreased. The flavor was relatively similar to the control when the Acai berry juice was added. The oatmeal cookie with the mixture of Acai berry juice and orange juice had the least acceptability in flavor. The acceptability of the appearance of the cookie decreased as the addition of Acai berry juice increased. As more Acai berry juice was added, the cookie turned to be a bluer color. The results from the texture analyzer showed that the addition of the Acai berry juice increased the breaking force of the oatmeal cookie (see table 2 and figure 2). When comparing the full Acai berry juice cookie to the mixture of the orange juice and Acai berry juice, the Acai berry juice cookie had a lower breaking force. The oatmeal cookie with only orange juice had the lowest breaking force of all three variations. These results showed that there was a significant difference (P=0.01) in breaking force for full orange juice and half orange juice and Acai berry juice. There was also a significant difference (p=0.035) between the full Acai berry juice and the half orange juice and Acai berry juice. This
experiment found that there was no significant difference (p=.095) in the breaking force between the full orange juice and the full Acai berry juice. The colorimeter demonstrated the changes seen in the oatmeal cookie appearance in statistics (See table 3 and figure 3). As the Acai berry juice was added to the cookie, there was a decrease in the L, a, and B values. This shows that the color does not remain the same and would help to indicate why there was a different in the acceptability in appearance among the different variations. The results from the study showed that there was significant difference in L value for the full orange juice and the full Acai berry juice (p<0.05). There was significant difference in the a value for the full orange juice and the half orange juice and Acai berry juice (p<0.05). There was significant difference in the B value for the full orange juice and the Acai berry juice (p<0.05). There were no significant difference in the L values for the full orange juice and the half orange juice and Acai berry juice, and the half orange juice and the Acai berry juice and the full Acai berry juice. There was also no significant difference in the a values for the full orange juice and the full Acai berry juice, and the half orange juice and Acai berry juice and the full Acai berry juice. There was no significant difference in the B values for the full orange juice and the half orange juice and Acai berry juice, and the half orange juice and Acai berry juice and the full Acai berry juice. The results from this study show that the addition of Acai berry juice can be used as juice substitute to increase antioxidant capacity of foods when the appearance of food would not be affected. The dark colored foods or purple foods would be best to have Acai berry juice to be used as a substitute. The overall taste and mouth feel is not generally affected by using Acai berry juice making this juice be a good substitute. Acai berry juice should not be substituted in lighter color foods due to the unacceptable change in food color. Through the completion of this experiment, the original hypothesis tested was found to be incorrect. The addition of Acai berry juice to the oatmeal cookies resulted in reduced consumer acceptability, flavor, color, and texture. The recommendations formed from the completion of this experiment are that Acai berry juice should not be added to light food products in high quantities due to its ability to change the product s appearance. The Acai berry juice is a good substitute to add antioxidant capacities to food while maintaining acceptable flavor. A source of error that could have occurred in this experiment was weighing and measuring errors of the ingredients. If there were differences in the ingredients that were added to the different products, the results and acceptability would have been altered. The proper use of the Texture Analyzer and the Hunter Colorimeter could have also resulted in error. If these machines were used incorrectly, the results that were obtained would not have been accurate. Further research should be done on the use of Acai berry juice. Experiments could be completed to determine what effect Acai berry powder versus Acai berry juice has on the texture of an oatmeal cookie and the consumers acceptability of the product. The use of powder might be able to be added in greater quantities resulting in the cookies having a greater antioxidant capacity.
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