Title: The Effect of Flaxseed Meal on the Texture and Water Activity of Brownies

Transcription

1 Bonnie Janota November 19, 2007 Title: The Effect of Flaxseed Meal on the Texture and Water Activity of Brownies Abstract: Flaxseed offers many health benefits when it is consumed. One of the benefits of flaxseed meal is that it is a rich source of soluble fiber. Brownies do not offer much fiber so this is a simple way to incorporate the fiber. Flaxseed has also shown to offer many heart health benefits. It is rich in Omega 3- fatty acids. These can help to reduce blood clots and the chance of heart attack and stroke (Conforti, Davis 2006). Another benefit is that flaxseed meal comes from a plant source so it is rich in lignans which help to increase antioxidant activity and therefore may help to reduce some cancers (Woolston 2000). Flaxseed can easily be incorporated into many foods especially baked goods. It is easily incorporated into baked goods in the form of flaxseed meal. This is how it was added to the brownies. The addition of flaxseed meal and its influence on the texture and water activity of brownies was tested in this experiment. This experiment used a control and two variables. The variables had two different ratios of flour to flaxseed meal. The results show that a taste panel preferred the addition of flaxseed meal in a small amount over brownies prepared with no flaxseed meal or a large amount. By using the texture analyzer, it can be seen that brownies without the addition of flaxseed meal and brownies with a large addition have a more similar texture than brownies with a modest addition of flaxseed meal. Water activity increases as the amount of flaxseed meal increases. This also increases rancidity due to increased water activity. Through this is experiment it can be seen that the addition of flaxseed meal to brownies increases the health benefits of brownies. The texture is not hurt by the addition if it is in a small amount. The water

2 activity is increased by the addition of flaxseed meal and this may ultimately lead to an increase in rancidity. Introduction: By adding flaxseed meal to brownies the health benefits increase. The composition of flaxseed is 30 g protein, 35 g lipid, and 35 g fiber (Shearer, Davies 2005). It is rich in omega-3 fatty acids. These are alpha linolenic and linoleic fatty acids. These are polyunsaturated fatty acids (Conforti, Davis 2006). Therefore they may reduce the risk of certain blood clots that have been shown to cause heart attack and stroke. Flaxseed meal is also a source of soluble fiber. It also has lignans which promote antioxidant activity (Woolston 2000). The health benefits of brownies are greatly increased by the addition of the flaxseed. Flaxseed is growing in popularity among consumers due to the continuing research on the health benefits of this natural product. It can easily be added to foods in different forms. Sometimes flaxseed may be used to replace eggs to create a baked good that is vegan (Shearer, Davies 2005). Flaxseed oil can be incorporated into foods as well as flaxseed meal. Flaxseed meal has been proven to offer more benefits in baked goods because it offers important soluble fiber. The consumption of soluble fiber has been shown to decrease cholesterol. Past research shows that when women consumed 50 grams of flaxseed meal everyday for four weeks, had a reduction in their LDL cholesterol of 18 percent. Their overall cholesterol dropped 9 percent (Woolston 2000). Flaxseed is also a rich source of protein. It offers high quality protein. This protein may actually influence blood glucose (Oomah 200). Heat affects the nutritional value of many proteins. It can be negative effects or positive effects. For flaxseed heat has shown a favorable effect on protein utilization (Beadles, Hamilton, Mitchell 1949).

3 Not only is flaxseed meal high in soluble fiber, but it is a natural plant product and offers phytochemicals. The phytochemical contained in the product is lignan. This can spur powerful antioxidant activity. High levels of antioxidant activity have been linked to a decreased risk of certain types of cancers (Conforti, Davis 2006). Flaxseed meal has also been studied for its possible anti-tumorigenic effects (Arjmandi 2002). Lignans not only help to increase antioxidant activity and possibly reduce the risk of some cancers, but they are phytoestrogens they have a large impact on lipid metabolism and biomarkers of bone turnover. This was examined on postmenopausal women in a study at Oklahoma State University. Women who consumed flaxseed meal had reductions in both their high-density lipoprotein and their low-density lipoprotein serum levels. Although the flaxseed had an impact on the lipid serum levels, it did not seem to affect the biomarkers of bone turnover (Arjmandi 2002). A study at Duke University showed that in men who had a diet that included 30 grams of flaxseed for thirty days, they had cancer cells that grew 30-40% slower than cells in a control group (Arnst). This experiment measured and compared the texture of the brownies from both an objective and subjective point and also the water activity of the product was measured. In order to measure the texture objectively, a texture analyzer machine was used. This measured the texture in grams. To subjectively rate the texture of the brownies, a taste panel was used to evaluate the texture by using a scorecard to describe their opinion of the texture. The water activity was measured by using a water activity machine. The purpose of this experiment was to use the addition of flaxseed to increase the health benefits of brownies. Brownies offer very little nutritional value. The addition of

4 flaxseed meal will increase the health benefits of the product. In this experiment, the independent variable is the ratio of flaxseed meal to all-purpose flour that is added to the brownies. The control will contain 37.5 g all-purpose flour, one variable will contain 12.5 g flaxseed meal and 25 g all-purpose flour, and the other variable will contain 25 g flaxseed meal and 12.5 g all-purpose flour. The dependent variables will be the texture, water activity, and the panel s preference based on texture. Methods: The overall design of the experiment is to bake three different batches of brownies three times. The three different types differ in the amount of flaxseed meal that is present in them. There is a control which contains no flaxseed meal and then two different variables. The brownies will be baked, allowed to cool, cut and then they will be analyzed by the texture analyzer and the water activity machine. A sensory panel will also taste the brownies and rank them based on the overall texture of the product. Each variable will be replicated 3 times to ensure accuracy and to obtain good data. They include: The first step in the process is to gather all of the ingredients that are needed g flaxseed meal g all-purpose flour 42.5 g unsweetened baking chocolate g unsalted butter 0.45 g double-acting baking powder Pinch of salt 3 eggs 375 g sugar 6.3 g vanilla Materials also needed include, 3-small loaf pans, a small sauce pan, measuring utensils, a gram scale, spatula, knife, electric mixer, 2-medium size mixing bowls. The oven needs

5 to be preheated to 350 degrees Fahrenheit. Spray the insides of the pans with non-stick cooking spray and lightly flour. The three variables will be made separately. The first to be made is the control. Then the other two variables will be made. The recipe for the brownies should be followed. In a small saucepan met the chocolate and the butter over low heat, stirring until the mixture is smooth. Let the mixture cool completely. Sift the flour, baking soda, and salt in a bowl. In another bowl, with an electric mixer, beat the egg. While beating add the sugar, a little at a time and beat the mixture at high speed for three minutes or until it is pale and thick. Add the chocolate mixture and the vanilla. Then add the flour mixture. Using a low speed, mix until the mixture is blended. Pour the batter into the baking pans. Place brownies in the middle of the oven for 28 minutes. A cake tester inserted into the center of the brownies should come out with crumbles attaching to it. Let the brownies cool completely before cutting them. Cut into small squares about 12 squares. Next, the brownies will be evaluated by using a taste panel, water activity machine, and texture analyzer. Take a brownie from the side of the pan but not a corner brownie. When using the texture analyzer, the cone probe attachment was used to measure the texture in grams. One variable will contain 12.5 g flaxseed meal and 25 g flour. The other will contain 25 g flour and 12.5 g flaxseed meal. The brownies will all be made three times. Replication is done to ensure that the results are accurate. Many aspects could vary the end result of the brownies. If they are each made three times a better understanding of how the flaxseed meal affects the brownies can be observed. When the taste panel tasted the brownies, they tasted them

6 randomly. They did not know which brownie was which because the brownies were given three numbers to identify them. The brownies were not tasted in a particular order. The panel filled out the following sensory evaluation scorecard: Sensory evaluation: Please place an X in the charts below to rank the brownies. 607 Very poor texture Poor texture Moderate Texture Good Texture Very Good Texture 406 Very poor texture Poor texture Moderate Texture Good Texture Very Good Texture 503 Very poor texture Poor texture Moderate Texture Good Texture Very Good Texture

7 Discussion: The results from performing this experiment agree with what the literature said would happen if the addition of flaxseed meal to baked goods was made. It has been said that the polyunsaturated fatty acids of flaxseed can increase rancidity of a food product (Conforti, Davis 2006). Increased rancidity is due to increased water activity within a food. This is because of hydrolytic rancidity. Hydrolytic rancidity is caused by the hydrolysis of triglycerides. They must be in the presence of moisture in order for this to occur (Rossell 1983). Free fatty acids then cause rancidity in products. This means that the higher the water activity of a product the more likely it is to become rancid. The brownies showed what could be predicted based on the understanding that flaxseed meal has an increased amount of fatty acids in it. It could be assumed that the brownies with the higher ratio of flaxseed meal to flour would have a higher water activity level. This proved to be true in this experiment. The brownies that contained 25 g of flaxseed meal had an average water activity level of 0.67 as compared to the brownies that contained no flaxseed meal and had an average water activity level of The water activity increased as the amount of flaxseed meal increased. This would eventually cause an increase in the rate of rancidity in the brownies that contained flaxseed meal. The next aspect of the brownies that was being tested was the affect of the flaxseed meal on the texture of the brownies. Flaxseed meal is rich in fatty acids such as alpha-linolenic acid (Oomah 2001). This could be predicted to increase the softness of

8 the brownies. Sometimes flaxseed is used as a fat replacer in foods. It was not being used as a fat replacer in this experiment. Normally, the more fat that is incorporated into a brownie, the softer it is. This means that the brownies with the higher ratio of flaxseed meal should have a softer texture compared to the brownies with less or no flaxseed meal in them. The results for this part of the experiment come from the texture analyzer. They show that the brownies with the most flaxseed meal in them actually have the greatest number of grams of force from the texture analyzer. This is not what one would predict. However, the brownies with no flaxseed meal in them have a higher number than those with a modest amount of flaxseed meal added to them. The brownies with no flaxseed meal have an average measurement of g and the brownies with a modest amount of an average measurement of 30.4 g. The brownies with the most flaxseed meal have an average measurement of 44.2 g. Texture was also evaluated by the taste panel. Seventeen people tried the brownies and the results ranked the brownies as follows according to texture: the brownies with the modest amount of flaxseed had the best texture, then the brownies with no flaxseed meal, and then the brownies with a large amount of flaxseed meal. This is interesting because the taste panel actually liked the brownies with the addition of flaxseed more than the brownies that were prepared normally. This experiment showed some interesting results based on the addition of flaxseed meal and how it affects both the texture and water activity of brownies. As expected, the addition of flaxseed meal increased the water activity in the brownies. This can be seen in Table 2 and Figure 2. Figure 2 shows how the water activity was greatest in variable 406 which had the most flaxseed meal. The brownie with the most flaxseed meal had the

9 highest level of water activity. The results of texture were not the same as predicted. The texture analyzer showed that the brownies with the most flaxseed had the highest measurement. This can be seen in Table 1 and Figure 1 shows this well. The taste panel ranked brownies with some flaxseed meal as the best compared to no flaxseed meal or a larger amount of flaxseed meal. Overall, flaxseed meal may help to increase the health benefits of brownies and they are preferred when it comes to texture. The addition of flaxseed meal should be small so that water activity and texture are not greatly affected. Future work in this area is endless. Flaxseed meal is an easy addition to many products. It may affect products very differently based on how they are prepared and cooked. The heat may affect the product and therefore change the water activity. The water activity could be measured in products that have flaxseed added to them but are not cooked at a high temperature. Also, other properties could be measured when flaxseed meal is added to baked goods. Other experiments measured the affect that flaxseed meal had on the color of a product (Shearer, Davies 2005). Results: Table 1: Texture Analyzer (g) Variable Trial 1 Trial 2 Trial Table 2: Water Activity Variable Trial 1 Trial 2 Trial

10 Texture Texture (g) Variable Figure 1 Water Activity Water Activity Variable Figure 2

11 References: Alternative Health: Flaxseed. Consumer Health Interactive. Woolston, C November < Arjmandi, B., Daggy, B., Hammond, L., Juma, S., Khalil, D., Lucas, E., Stoecker, B., Wild, R Flaxseed Improves Lipid Profile without Altering Biomarkers of Bone Metabolism in Postmenopausal Women. The Journal of Clinical Endocrinology and Metabolism. Vol. 87, No. 4. Arnst, C Of Flaxseed Doses and Therapeutic Vaccines. Business Week. Issue 4039, pg. 71. Beadles, J.R., Hamilton, T.S., Mitchell, H.H The Nutritional Effects of Heat on Food Proteins, with Particular Reference to Commercial Processing and Home Cooking. Journal of Nutrition, Vol. 39, No. 3: pg Conforti, F.D., Davis, S.F The Effect of Soya Flour and Flaxseed as a Partial Replacement for Bread Flour in Yeast Bread. International Journal of Food Science & Technology,Vol. 41. pg Davies, C., Shearer, A Physicochemical Properties of Freshly Baked and Stored Whole-Wheat Muffins with and Without Flaxseed Meal. Journal of Food Quality. Vol. 28, pg Measurment of Rancidity. Applied Science Publication. Rossell, JB.1983.pg November < cid=693040&q=&uid= &setcookie=yes>. Oomah, B Flaxseed as a Functional Food Source. Journal of the Food of Science and Agriculture. Volume 81, Issue 9, pg

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