Title: The effects of substituting coconut oil in brownies Abstract: In baking brownies, canola oil was replaced with coconut oil in the same amount to test the effect on texture, flavor and overall satisfaction. Results showed that the coconut oil had the greatest overall satisfaction using a 9 point hedonic scale rating. Using the texture analyzer, the baked variation of half canola and half coconut oil required the least amount of force, while the all canola oil variation took the greatest amount of force. The linespread test showed that variation one (all coconut oil) had the greatest viscosity, while variation two (the mixture of half coconut and half canola oils) had the least viscosity in the unbaked batter. Introduction: Canola oil is the most commonly used oil in brownie recipes. However, other oils such as coconut oil contain beneficial properties such as polyunsaturated fatty acids (PUFAs) which promote heart health, can help lower cholesterol, and contain antibacterial properties. The methods used in this experiment included baking brownies following the directions from a standard Betty Crocker brownie mix. The independent variable was the type of oil used in the brownies. The dependent variables included sensory characteristics including flavor, texture, and satisfaction and thickness of the batter. Three different variations were used: 1) typical brownie recipe using all canola oil, 2) typical brownie recipe using half canola oil and half melted coconut oil, and 3) typical brownie recipe using all melted coconut oil. The objective of this experiment was to document the effects of substituting coconut oil for canola oil. Methods: Several analytical methods were used in this experiment to test the effects of substituting coconut oil for all, part, or none of the canola oil in brownies. Three separate trials were conducted. For each trial, the thickness of the batter was recorded using the linespread apparatus, the moistness and overall texture was measured using the texture analyzer machine, consumer preference ranking was evaluated using a Hedonic scale, and overall flavor and texture satisfaction of the consumer was measured using a sensory evaluation scorecard. Recipe Procedure Step 1: Brownie batter was prepared for each oil variation following the recipe on the Betty Crocker brownie mix box. Variation 1: Variation one followed the traditional brownie recipe and was prepared using all canola oil and no coconut oil. In a medium bowl 519g of Betty Crocker brownie mix, 166.7 ml canola oil, 62.5 ml water, and 2 large eggs where mixed with an electric whisk until well blended. Variation 2:
Variation two followed was prepared using half canola oil and half melted coconut oil. In a medium bowl 519g of Betty Crocker brownie mix, 83.3 ml canola oil, 83.3 ml melted coconut oil, 62.5 ml water, and 2 large eggs where mixed with an electric whisk until well blended. Variation 3: Variation three was prepared using all melted coconut oil in place of all of the canola oil. In a medium bowl 519g of Betty Crocker brownie mix, 166.7 ml melted coconut oil, 62.5 ml water, and 2 large eggs where mixed with an electric whisk until well blended Step 2: The batter for each variation was poured into a separate into a greased 13" X 9" pan and baked for 25 minutes in a 177 degree Celsius oven. The brownies were allowed to cool for 5 minutes. Linespread Apparatus Measurements After the batter for all three variations was made, the viscosity of each was measured using the linespread apparatus. A sample of each variation s batter was poured to the top of the metal ring on the apparatus. The ring was removed and the batter was allowed to spread for one minute. The number of circles from the middle to where the substance reached was counted for each of the four angles. The four readings were averaged to produce the final line spread number in inches. Texture Analyzer Measurements After baking the texture of the brownies were measured using the texture analyzer. Small 1 X 1 squares were cut from the middle section of each brownie variation to be tested. One piece of each brownie variation was tested in three different spots and the numbers were added up and divided by three in order to obtain the most precise measurements. This prevented skewed results from possible particularly moist spots or dry spots in each sample. The texture analyzer was placed on the cake setting. Table 1 demonstrates the texture analyzer probe settings used for each trial in this experiment. Table 1: Texture Analyzer Probe settings Pretest speed 1.0 mm/s Test speed 1.0 mm/s Post test speed 1.0 mm/s Rupture speed 1.0mm/s Distance 3.0 mm Force 200.0 g Time 5 seconds Hedonic Scale and Sensory Evaluation Scorecard Measurements To test consumer taste preferences, a Hedonic scale and sensory evaluation scorecard was used. 1 X 1 square samples extracted from the middle of the baked brownie pan of each variation were given to consumers to taste test. Each brownie variation was disguised by a number so taste testers were blind as to which variety they were sampling. Variation one (all canola oil) was labeled as 317, variation two (half
canola oil and half coconut oil) was labeled as 479, and variation three (all coconut oil) was labeled as 630. Taste testers sampled each brownie variety and filled out the scale and scorecard paper provided to them. Tables 2 and 3 provide examples of the hedonic scale and sensory evaluation scorecard used. Table 2: Sensory Evaluation Scorecard Sensory Evaluation Rank the brownie samples in order of preference from 1 to 3. (One being your favorite, three being your least favorite) 317 630 479 Table 3: Hedonic Scale Hedonic Scale For the three different brownies, please rate flavor, texture and overall satisfaction based on the 9 point hedonic scale. Sample #317 Flavor Texture Satisfaction Like Extremely Like Very Much Like Moderately Like Slightly Neither like nor Dislike Dislike Slightly Dislike Moderately Dislike Very Much
Dislike Extremely Sample #630 Flavor Texture Satisfaction Like Extremely Like Very Much Like Moderately Like Slightly Neither like nor Dislike Dislike Slightly Dislike Moderately Dislike Very Much Dislike Extremely Sample #479 Flavor Texture Satisfaction Like Extremely Like Very Much Like Moderately Like Slightly Neither like nor Dislike Dislike Slightly Dislike Moderately Dislike Very Much Dislike Extremely Replication, Randomization, and Sampling
The above procedures and measurements were completed three times for each brownie variation. For example, we made and tested the batter of each variation three times, baked and measured the texture of the variations three times, and had taste testers sample our end products three times. Additionally, as mentioned above, the samples were randomly assigned numbers so testers did not know which variation of brownie they were sampling. All samples and tests were taken from the baked middle portion of the brownie pan and not the edges to ensure consistent and reliable results. Results Three separate trials were completed using a control and 2 different variations. The variations were all canola oil, all coconut oil or half canola oil and half coconut oil in the brownies. Each of the trials was tested objectively and subjectively. The objective data was obtained from a linespread test and the Texture Analyzer. The subjective data was obtained from a 9-point hedonic scale and a ranking of preference between the three variations. The control is the all canola oil, variation 1 is all coconut oil and variation 2 is the half canola and half coconut oil. Table 1. The Preference Ranking (1-3), with 1 being the favorite and 3 being the least favorite. Variations Control Variation 1 Variation 2 Trial 1 2 2.2 1.8 Trial 2 1.4 2 2.6 Trial 3 2 2.4 1.6 Average 1.8 a 2.2 a 2 b Standard Deviation 0.83 0.83 0.73 *Average bearing the same superscript are not significantly significant, p<0.05
Figure 1. Sensory preference scores for control, variation 1 and variation 2 for brownies. The lines on the bars are standard deviations. Table 2. Averages of 9-Point Hedonic Scale rating for all trials on flavor Control Variation 1 Variation 2 Trial 1 2.6 3.4 2.6 Trial 2 2.8 2.6 3.6 Trial 3 2.4 2 1.8 Average 2.6 2.667 2.667
Figure 2. This shows the results of the 9-point hedonic rating scale for flavor for all variations using the averages. Table 3. Averages of 9-Point Hedonic Scale rating for all trials on texture Control Variation 1 Variation 2 Trial 1 2.4 4 2 Trial 2 3.8 4.6 3 Trial 3 2.4 3.2 3.6 Average 2.87 3.93 2.87
Figure 3. This shows the results of the 9-point hedonic scale for flavor for all variations using the averages. Table 4. Averages of 9-Point Hedonic Scale rating for all trials on overall satisfaction Control Variation 1 Variation 2 Trial 1 2.6 3.6 2.2 Trial 2 2.8 3.2 3.6 Trial 3 2.4 4.8 2 Average 2.6 3.87 2.6
Figure 4. Results of the 9-point hedonic scale for overall satisfaction for all variations using the averages. Figure 5. Average of the Texture Analyzer measurements.
Table 5. Linespread results and the averages. Variations Control Variation 1 Variation 2 Trial 1 5.5 7.5 4.25 Trial 2 5.6 7.5 5.33 Trial 3 5.67 7.6 4.25 Average 5.59 7.53 4.61 Figure 6. The average of the linespread test for all variations from all three trials.
Discussion: There are many health benefits associated with coconut oil that have recently been discovered. Coconut oil is one of the richest sources of lauric acid, a medium chain fatty acid, containing about 50 percent of this type of fatty acid. In recent years there has been a trend of producing coconut oil that does not go through the refining, bleaching and deodorizing (RBD) process, deemed virgin coconut oil. This oil is obtained by wet processing which entails the extraction of the cream from the coconut milk and breaking the cream emulsion. This process is more desirable, as no chemical or high heat treatment is imposed on the oil (Marina, Man & Amin, 2009). This virgin coconut oil was found to have the highest total phenolic content and possessed the highest antioxidant activity (Marina, et al., 2009). According to Nevin and Rajamohan (2006), the antioxidant activity as determined by catalase and superoxide dismutase, was increased by virgin coconut oil. These two work mutually for defense against reactive oxygen species and prevent lipid peroxidation (Agyemang-Teboah, 2011). It was this research that brought us to use virgin coconut oil in place of the standard canola oil. Table 1 shows the three trials with results from the preference ranking of 1 to 3. The control, all canola oil, averaged a score of 1.8 with a standard deviation of.83. Variation 1, all coconut oil, averaged a score of 2.2 with a standard deviation of.83. Variation 2, half coconut and half canola oil, averaged a score of 2 and a standard deviation of.73. In all cases the differences between the average scores were not significantly significant. For the trial on flavor, the average on a Hedonic rating was a 2.6 for the control and 2.67 for both variations 1 and 2. The similarity in results suggests that all trials had the same approximately the same taste. Texture results for the control were 2.87, 3.93 for variation 1 and 2.87 for variation 2. From this
test we can conclude that variation 1, with the highest score, was the most desired texture from the three. Table 5 shows the linespread average results. The control showed an average of 5.59 cm of spread, variation 1 showed 7.53 cm and variation 2 showed 4.61 cm. As shown by Table 3, the most desirable texture came from variation 1, and Table 5 shows a large difference in linespread averages. Variation 1, the largest from the linespread test, shows the least amount of viscosity from the uncooked batter, while the variation two showed the most viscosity.
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