The Effect of Different Suppliers of Flaxseed on Sensory Properties and Texture of Oatmeal Cookies Danielle Cherry Sophie Maier Kaitlyn Wolak NUTR 453 November 19, 2012
Abstract Flaxseed has been growing in popularity due to its health benefits because of the Omega- 3 fatty acid content. One of the health it has been linked to is decrease in risk of heart disease, which is the number one killer of Americans today. Additionally, flaxseed has an effect on texture, color, and sensory properties. We measured the properties of oatmeal cookies by the addition of 3 tablespoons of flaxseed from three different suppliers of flaxseed. We concluded that none of the suppliers had a significant effect on the taste, texture, and color of the cookies. There was only a slightly higher subjective rating of Bob s Red Mill flaxseed versus the other suppliers and control. Introduction Many health benefits have been linked to flaxseed because of the Omega-3 fatty acid content. In several studies that were conducted, flaxseed also had an impact on texture and other sensory qualities. There are several studies that look at the effect of flaxseed on the texture and taste of a product, but not many studies seem to look at the different manufacturers of the flaxseed and their affect on the product. (Alani 2012) The health benefits that are studied include cardiovascular. Because flaxseed has a high content of Omega-3 fatty acids, it allows the membrane of the cells to be more permeable allowing specific proteins to function better in the membrane. Omega-3 fatty acids are also known to have anti-inflammatory affects, which greatly affects the cardiovascular system in vasodilation and formation of plaque in the arteries. (Corcoran 2007) These are only a few of the benefits of the Omega-3 fatty acids in flaxseed. Instead of measuring quantities of flaxseed, we will determine the different sensory measurements and measure texture from different suppliers. Texture will be measured using the texture analyzer and a hunter colorimeter will be used to evaluate the color of the final products. The standard recipe we are using is one that has already been tried and tested that incorporates flaxseed. Flaxseed contains multiple nutrition benefits and can increase the nutritional benefits of a variety of baked goods. The main nutritional components of flaxseed include soluble fiber, phenolic compounds, lignans, and high amounts of α-linolenic acid (ALA) (Alpers et. al 1996). These benefits lead to decreases in cancer and Coronary Heart disease. Research has shown the ingestion of flaxseed moderately decreases plasma low density lipoprotein cholesterol levels, increases n-3 polyunsaturates levels in plasma and adipose tissue and urinary lignin excretion with minimal side effects. When higher levels of ALA are ingested, eicosapentaenoic acid levels increase which aids in preventing hypertension and coronary heart disease (Alpers et. al 1996). Flaxseed can also replace unhealthy sources of fat such as trans fatty acids (TFA) in the diet due to its ALA content. ALA inhibits atherogenic functions of TFA and cholesterol. It also protects the build up of atherosclerotic plaques and cholesterol in the body (Bassett et. al 2010). It has been show that fifty grams of flaxseed are safe for consumption per day (Alpers et. al 1996). The physical characteristics of baked goods, in particular the cookies created in this experiment, are important to human consumption. In one study the control cookie containing no flaxseed was
paler than the cookie that contained 33% flaxseed. The flaxseed cookies were rated near optimum for tenderness and flavor on the hedonic scale (Alpers et. al 1996) Flaxseed not only has an impact on human health, but also on the physical properties of food. A study published in The Journal of the Science of Food and Agriculture shows that as the amount of flaxseed incorporated into a food increases, water activity decreases and firmness increases. Cookies were prepared using 0%, 6%, 12%, and 18% percent flaxseed and then tested to measure various physical properties. Higher percentages of flaxseed in cookies resulted in diameter to height ratios beyond the desirable range. Diameter increased and height decreased with increasing flaxseed content. Color and appearance were also a function of flaxseed present in the cookie. Consumers rated cookies containing 0% and 6% flaxseed in the overall composition as more favorable than cookies containing higher percentages of flaxseed (Aramouni and Khouryieh 2012). The challenge to overcome involves utilizing flaxseed for its benefits without negatively impacting the quality of foods. Materials and Methods Objective: The objective of this experiment is to determine whether the source of a flaxseed impacts texture and sensory qualities in oatmeal cookies. Variables: The independent variable is 3 tbsp. (42.705 g) of flaxseed from three different suppliers. The dependent variables are the analysis of texture, color, water activity, and sensory testing. The control will be a cookie containing no flaxseed. Null hypothesis: There is no difference in texture, taste, and color from flaxseed from each supplier. Procedures: The recipe we are using is from sparkrecipes.com. The ingredients for the recipe in American units are as follows: 1 cup Smart Balance Buttery Spread 1 cup Brown sugar, packed 1 Egg (large) 1 tsp Vanilla 1.5 cups All-purpose Flour 1 tsp Baking Soda 0.25 tsp Salt 2 cups Quick-cooking rolled oats (not instant) 3 tbsp Flax Seeds The ingredients for the recipe in metric units are as follows: 229.92 g of buttery spread 229.92 g of brown sugar packed
1 egg 4.745 g of vanilla 344.88 g of all purpose flour 4.745 g of baking soda 1.186 g of salt 459.84 g of quick rolled oats 42.705 g of flaxseed To begin, we preheated the oven to 176.67 degree Celsius. To make the cookies, we first creamed the butter and brown sugar into a room temperature bowl. After, we added egg and vanilla and beat well. Next, we added flour, baking soda, and salt; and mixed until no dry flour remains. Next we added oats and flaxseed; and mixed well. We dropped one tablespoon each, about two inches apart onto a cookie sheet. Lastly, we baked at 176.67 degrees Celsius for 8-10 minutes. We began the baking at 9:30 on the assigned workday and left plenty of time to make all of our trials of cookies. A panel of students in the lab tasted the cookies. We did four variations of the recipe using a control, Bob s Red Mill, Carrington Farms, and Hodgson Mill. A sample of the subjective evaluation is included below. We also tested the cookies objectively for the water activity, change in color using Hunter colorimeter, and the texture using the texture analyzer. The sensory evaluation scorecard can be seen below as figure 1.
Figure 1: Sensory evaluation scorecard Work Plan: 9:30am- Set up work area for preparing the recipe by gathering ingredients and utensils and preheat oven to 176.67 degrees Celsius 9:35am- Measure all ingredients for each cookie recipe 9:40am- Check to make sure everyone has measured out the right ingredient amounts for each recipe 9:45am- Mix all the ingredients together according to the instructions and add the correct flaxseed amount from each supplier to three of the cookie dough batches 9:50am- Measure the cookie dough out and place them on baking sheets 9:55am- Bake at 176.67 degrees Celsius for 8-10 minutes 10:15am- Check to make sure cookies are completely done and allow to cool off 10:20am- Product is ready, use Hunter colorimeter to measure color. Utilize the sensory analysis scale and pass out samples for peers to evaluate. 10:30am- Conduct texture analyzer 10:50am-Conduct water activity
This work plan was repeated for all four trials. Discussion Objective measurements were completed using a Hunter Colorimeter, water activity meter, and texture analyzer. The texture analyzer was used to identify texture discrepancies between the control and cookies containing flaxseed obtained from three different suppliers. Breaking force required was reported in grams, and results for these measurements can be found in table 1 and figure 2. Carrington Farm s flaxseed required a breaking force lower than the other cookie variations, with an average of 70.57 g. Using the statistical software Insatat, the p value was calculated to be.1542 suggesting that although the use of different suppliers of flaxseed has some effect on the texture of oatmeal cookies, it is statistically insignificant. The Instat summary of this calculation can be found in figure 9 of the Appendix section of this report. Large variations between trials are present in the recorded data for breaking strength. This could be due to differences in cooling time or storage conditions as well as human error while operating the texture analyzer. Water activity was measured using a water activity meter as a tool to investigate texture properties and as a potential indicator of shelf life. Data for water activity can be found in table 2 and figure 3. Carrington Farm s flaxseed cookies reported a water activity of.754, higher than the control and cookies containing Bob s Red Mill flaxseed and Hodgson Mill flaxseed. This supports the data obtained from the texture analyzer suggesting an insignificant correlation between brands of flaxseed and physical properties of oatmeal cookies. Using Instat for statistical analysis, a P value of.9681 (figure 10 of the Appendix) was calculated further supporting this argument. Sources of error in these measurements could be due to improper sample size and lack of highly environmentally controlled storage conditions. The Hunter Colorimeter was used to measure the color of the oatmeal cookie variations. The L value indicates darkness of a sample, with white and black representing values of 100 and 0 respectively. The a values rate color on a scale of green to red, with +a being mostly red and a being mostly green. Hunter b values identify color as blue or yellow; with negative representing blue and positive values representing yellow. Values obtained from the Hunter Colorimeter are located in table 3 and figure 4. Statistical analysis of the L, a and b values can be found in the appendix as figures 11, 12 and 13 respectively. P was calculated to be equal to.8033 for the L value, which is considered to be statistically insignificant. The a and b values both had a P value equivalent to.0575, which was determined to be not quite significant. Error in these measurements could be due to improper calibration of equipment or improper placement of samples, allowing ambient light to enter the Hunter Colorimeter.
In the experiment we used a 9-point hedonic scale with a panel that consisted of twenty semitrained individuals. The nine point scale measured the flavor of the control cookies versus the cookies with flaxseed added with nine being like extremely and one being dislike extremely. The cookies were given numerical values for each variable including #436 for the control, #563 for Bob s flaxseed brand, #759 for Carrington s flaxseed, and #895 for Hodgson s flaxseed. The average ranking for Bob s brand ranked the highest followed by Hodgson, Carrington, and Control ranking last with the results listed in table 4 of the appendix. The cookies with added flaxseed can be seen in the Appendix figures 5,6, and 7 with the control shown as figure 8. It is apparent that the cookies with added flaxseed had more surface cracking, which is often appealing to consumers. The control cookie was slightly more uniform in texture due to the absence of flaxseed, with less surface cracking. In this experiment we tested variables such as water activity, texture, color, and utilized a hedonic scale. For future experiments the cookies should be analyzed for nutritional content such as: α-linolenic acid, dietary fiber, and lignan percentages contained in the flaxseed. Instead of using different brands of flaxseed the amount of flaxseed in each batch of cookies could be increased to test for palpability and texture. The highest amount of flaxseed possible in the cookies that does not change the overall flavor and texture significantly should be used as a substitution in recipes for the highest nutritional value. Conclusions The null hypothesis was proven correct after analyzing the results of the experiment. The texture, taste, and color did not significantly change. The objective quality of texture did not change significantly with added flaxseed as evidenced by the measurements taken from the texture analyzer. We discovered that cookies with added flaxseed, in particular Bob s brand ranked the highest for flavor. Subjects seemed to like cookies with flaxseed added and the different texture versus the control with no flaxseed.
Results Table 1: Texture Analyzer readings for the required breaking force of variations of oatmeal cookies Control Bob's Red Mill Carrington Farms Hodgson Mill Trial break force(g) break force(g) break force(g) break force(g) Trial 1 79.00 122.00 53.00 127.70 Trial 2 170.60 155.20 82.50 202.40 Trial 3 130.10 106.60 76.20 118.40 Average 126.57 127.93 70.57 149.50 Standard Deviation 45.90 24.84 15.54 46.05 Average Breaking Force (g) 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 Control Bob's Red Mill Carrington Farms Hogdson Mill Figure 2: Texture Analyzer readings reported as average required breaking force of variations of oatmeal cookies
Table 2: Water activities for four variations of oatmeal cookies Control Bob's Red Mill Carrington Farms Hodgson Mill Trial a w a w a w a w Trial 1 0.714 0.681 0.842 0.677 Trial 2 0.627 0.677 0.695 0.698 Trial 3 0.649 0.842 0.726 0.699 Average 0.663 0.733 0.754 0.691 Standard Deviation 0.045 0.094 0.077 0.012 Average a w 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 Control Bob's Red Mill Carrington Farms Hogdson Mill Figure 3: Reported average water activities for four variations of oatmeal cookies
Table 3: Hunter Colorimeter values for four variations of oatmeal cookies Control Bob's Red Mill Carrington Farms Hodgson Mill Trial L a b L a b L a b L a b Trial 1 30.42 5.45 8.49 30.03 6.12 8.28 27.17 3.58 6.06 30.71 4.75 8.57 Trial 2 30.60 6.02 8.68 31.05 5.76 8.82 31.61 4.53 8.62 31.84 4.44 8.78 Trial 3 31.63 5.05 9.09 31.17 4.92 8.59 31.38 4.97 8.26 30.72 4.87 8.45 Average 30.88 5.51 8.75 30.75 5.60 8.56 30.05 4.36 7.65 31.09 4.69 8.60 Standard Deviation 0.65 0.49 0.31 0.63 0.61 0.27 2.50 0.71 1.38 0.65 0.22 0.17 35 Average Hunter Colorimeter Values 30 25 20 15 10 5 L a b 0 Control Bob's Red Mill Carrington Farms Hodgson Mill Figure 4: Hunter Colorimeter values, reported as averages, for variations of oatmeal cookies Table 4: Hedonic scale results Control Bob's Red Mill Carrington Farms Hodgson Mill Average Ranking on Hedonic Scale 6.00 6.56 6.25 6.50 Standard Deviation 1.97 1.46 1.82 1.37
Appendix Figure 5: Hodgson Mill flaxseed variation Figure 6: Bob s Red Mill variation
Figure 7: Carrington Farms variation Figure 8: Control cookie containing no flaxseed
Figure 9: ANOVA testing of Texture Analyzer results Figure 10: ANOVA testing of water activity results
Figure 11: ANOVA testing for Hunter Colorimeter L values Figure 12: ANOVA testing for Hunter Colorimeter a values
Figure 13: ANOVA testing for Hunter Colorimeter b values
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