SUBSTITUTING OMEGA-3 OIL FOR VEGETABLE OIL IN BROWNIES

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1 Joshua R. Swift /8/06 SUBSTITUTING OMEGA-3 OIL FOR VEGETABLE OIL IN BROWNIES People are going to eat sweet goods no matter how bad they can be for their bodies. More and more people are being diagnosed with heart disease than ever were before. One reason that can account for this increase could be due to an increase in saturated fatty acids. So, knowing that people are not going to stop eating brownies and other sweet goods, one way would be substituting polyunsaturated omega-3 oil in place of other oils or fats. Omega-3 oils are filled with essential fatty acids that the body needs but cannot make. They have also been shown to decrease the chance of developing heart disease. However, the main source of the omega-3 oil is primarily found in fish. This makes it a challenge to try and substitute this perceived fishy taste into sweet goods. By substituting omega-3 in small amounts, the taste of sweet goods will not have a perceived difference and the sweet goods will be better for health than they would if no substitution were made. The purpose of this experiment was to try and substitute omega-3 oil for another fat and have no difference in the perceived texture, appearance, and overall taste of the brownies. The independent variables for this experiment were the box of brownie mix, two eggs, and three tablespoons of water, the cooking temperature, the cooking time, and the cooling time. The dependent variable was the amount and type of oil that was used. The control was always a half cup of vegetable oil. The other variables were cod liver oil and flaxseed oil, two omega-3 oils. Three objective measures were done and they were the water activity machine, the Hunter Colorimeter, and the Texture Analyzer. The Texture Analyzer utilized the puncture probe. Methods done for this test were set up for simplicity. Betty Crocker Supreme Brownie mix, which had peanut butter chips added, was used to make the brownies. The oven was set at 350 F for the cooking of the brownies. For the procedure to make the brownies: The brownie box was opened and the dry mix was placed in a mixing bowl. To the dry mix, two eggs, three tablespoons of water and a half a cup of vegetable oil were placed in the bowl. This was the control. In the other three trials, all of the other ingredients were the same, except the oil. In the first trial, a half cup of cod liver oil was used, in the second trial, a half cup of flaxseed oil was used, in the third trial a fourth cup of flaxseed was mixed with a fourth cup of vegetable oil. For the fourth trial, a half cup of vegetable oil was used, which is the same as the control. This was done to test the unprofessional taste panel to see if the results were reliable. So, once all of the wet ingredients were placed in the dry ingredients, they were mixed together with a wooden spoon for exactly 75 times, or 75 full rotations of the spoon in the mix. This batter was then poured into a non stick 9X3 baking dish and placed in the preheated 350 F oven and baked for exactly 28 minutes. When the timer went off, the brownies were checked for doneness by sticking a toothpick in the center of the pan. All of the pans were done cooking after the 28 minutes and the pans were taken out of the oven and allowed to cool for 20 minutes. The objective tests then followed. Half of the brownie pan was used to do the objective tests. The reason was that the outside edges of the brownie were a lot more

2 cooked than the center of the brownie. There were three objective tests performed and they were the Water Activity machine, the Hunter Colorimeter, and the Texture Analyzer. These tests were done to check the moistness, appearance, and texture. For the Texture Analyzer, the puncture probe was used. For all of the tests, which were done in triplicate, three different pieces of the brownie were utilized. The outer crust, the very inside, and a piece containing a peanut butter chip, which were about nickel sized, were used for all of the objective measures. Variations in the finalized data may be for the reason of using different textures in the measurements and this will be discussed in the discussion section. The sampling was done with the three ways just described, meaning three water activities were taken, one of a piece of the outer crust, another from the inside of the brownie, and the last from the middle of the brownie with a peanut butter chip in it. The same three types were checked in the Hunter Colorimeter and also by the puncture probe on the Texture Analyzer. Here is a sample of the sensory scorecard used for this experiment. Paired Comparison Test 652 and 34 Taste both of these samples? Which do you prefer? Are these samples the same or different? What about sample 652 did you like? What about sample 652 did you dislike? What about sample 34 did you like? What about sample 34 did you dislike? Rate on a scale from to 9, being dislike extremely and 9 being like extremely Discussion of the results will start with the first trial which the variable was a substitution of cod liver oil. From the objective tests, the water activity for both the control and the cod liver oil were very similar. Also, the L,a,b values for the Hunter Colorimeter showed no specific variation. The Texture Analyzer showed a difference of ten grams, but since the Texture Analyzer was done in three different spots on the brownie, their will be variations. As for the most important test, the sensory test (Graph ), the cod liver oil was not correlated to the control in any way. Threrefore, the cod liver oil was not a good substitute for vegetable oil in brownies. As for the next variable, the

3 flaxseed oil, the water activity was very similar. There was no significant difference with the Hunter Colorimeter and the Texture Analyzer. As for the sensory test (Graph 2), the oil just falls out of the range for the vegetable oil and therefore there is a difference between them and oil would not be a good substitute. For the third trial, the and the vegetable oil, there were no significant differences in the water activity or the Hunter Colorimeter values. However, there was a significant difference in the Texture Analyzer value, but because of the random puncturing of the brownie this could be allowed. Some of the peanut butter chips could have been in more than one of the punctures allowing for a higher gram value. The sensory test (Graph 3) showed a high correlation between the control and the mixture. However, the range for the deviation was too high and therefore there were differences in this variable and this would not make a good substitution. The last trial was done to see if the panelists were reliable. This trial was identical to the control. This is interesting because there are variations with all of the objective tests and while the sensory tests (Graph 4) showed the highest correlation, they still were not greater than a 95% correlation. So, this shows that even when a variable was done in the same manner as the control, there could still be variability in the machine and variability with the human taste buds. A similar test was done where omega-3 oil was infused into foods. Issues were described in this article by Hernandez and as quoted, deterioration of omega- 3 oils during processing; microencapsulation; aroma and taste issues were explored (Hernandez, pg.9). Another article states the health benefits of the omega-3 oils stating; Fish with the 30%-fat diet reduced cholesterol, LDL cholesterol, and triglycerides and increased HDL2 cholesterol. Results suggested that plasma lipids are affected similarly by fish or fish oil in men consuming a 40%-fat diet. Adverse effects of omega3 fats on total and LDL cholesterol are reversed by a 30%-fat diet (Mori, pg. 46). Overall, the mix was a decent substitution, and in this small amount of substitution of omega-3 oil, these brownies would be healthier for the consumer. For future trials, the utilization of encapsulated omega-3 oil could be used and this encapsulation would be used to reduce the perceived fishy taste of the oil. Another good idea for a substitution would be to utilize omega-3 eggs in place of the two eggs used in the recipe. To be completely honest, the best way would be to just not eat sweet goods that are high in saturated fats. The results for the experiments are as follows: Table. Averages for s for the Control and Four Trials Control- Cod Liver Control 2-8.3±.3.63± ± ± ± ± 5.88± ±.75

4 For the second control, this control was matched up against the last three variables and three different sensory tests were done on the same control. This was also a way to test that the panelists were reliable for the sensory tests. Table 2. Averages for Objective Tests for the Control and the Four Trials Objective Tests Control- Cod Liver Control 2- Water Activity Texture Analzer (g) Hunter Colorimeter (L) value (a) value (b) value Variables Graph : Control vs. Cod Liver Graph 2: Control vs. Variables

5 Variables Graph 3: Control vs. with Graph 4: Control vs. Control Same Variable References Hernandez E., Infusing foods with fish oils. Functional Foods and Nutraceuticals. Vol. May, pg. 36, 38, 40; 9 ref. Mori, T.A., Vandongen R, Beilin LJ, Burke V., Morris J, Ritchie J, 994, Effects of varying dietary fat, fish, and fish oils on blood lipids in a randomized controlled trial in men at risk of heart disease. American Journal of Clinical Nutrition Vol.59(5) pgs ; 46ref. Appendix See attached pages.