The Effect of Soy Flour Content on the Texture and Preference of Pasta Beth Bessler
Abstract: The objective of this experiment was to replace part of the wheat flour in pasta with soy flour without sacrificing texture and preference by consumers. Soy flour is a more healthful option than wheat flour. We used a basic pasta recipe to make three variations of pasta using different proportions of wheat flour to soy flour. The pasta was then subjected to tests with the texture analyzer and Hunter colorimeter, as well as sensory tests with a taste panel. Although the pasta with wheat flour was preferred, the pasta with 30% soy flour was not disliked, and the preference was similar to that of the wheat flour. The texture and color values were not substantially different. It would be possible to create pasta with partial soy flour that would be preferable to wheat flour pasta in taste and texture. Introduction: The purpose of this project was to create pasta that would be health beneficial compared to regular pasta made with wheat flour. In order to accomplish this, wheat flour was replaced with soy flour in a pasta recipe. Soy flour has been found to have numerous health benefits after multiple research studies have been performed. Multiple research studies have been done due to the fact that Asia has a particularly great consumption of soy products. Many of these studies have linked the consumption of soy to certain health benefits and disease prevention. By replacing wheat flour with soy flour, a pasta with additional health benefits was created. After numerous research studies have been conducted, soy flour has been found to reduce the risk of coronary heart disease as well as lower LDL cholesterol, which is a factor that can cause heart disease itself. Americans today have an increasing rate of developing disease such as coronary heart disease. According to the research article proposed by Umprhess, foods with added soy products contain plant compounds called isoflavones. Soy flour contains these isoflavones. Isoflavones are known to have antioxidant properties, protecting cells from damage caused by free radicals. Isoflavones have also been claimed to have lower mortality rate, lower incidence of heart disease, type II diabetes, osteoporosis, and certain cancers (Brouns). Isoflavones have the ability to prevent heart disease because they can reduce the oxidation of LDL which is important in preventing vascular damage and disease. Soy flour has been widely used to produce high protein products. Due to this, it has been shown to lower blood cholesterol as well as affect the distribution of plasma lipid fractions (Ugarcic-Hardi, Z). Therefore, soy flour has the ability to help reduce the frequency of heart disease. Isoflvaones have also been shown to reduce certain menopausal symptoms in women. Under certain study conditions, it was shown that with an intake of soy isoflavones, there was a reduced frequency in hot flashes in menopausal women (Brouns). Another health benefit of soy has been on bone health. In a specific study that Brouns mentions in his article, 66 menopausal women, with the addition of 90mg/day of soy protein, were found to have reduced bone loss in the lower spine region compared to those that had taken the placebo. With this being found, soy could have an effect on reducing the occurrence of osteoporosis as well.
With theses previously mentioned health benefits that soy products contain, the objective tests consisted of the use of a texture analyzer and a Hunter Colorimeter. The texture analyzer tested the texture of each variable. The Hunter Colorimeter helped to determine the color of each variable and how different or similar each variable was. The subjective test consisted of a structure rating scale to rate each sample on its texture. There was also a hedonic rating scale included, based on what each panelist personally liked. The independent variable is the amount of soy flour substituted for wheat flour in the pasta recipe. The various amounts of sour flour that were used were 0%, 40%, and 50%. The dependent variables are the texture, or chewiness, color, and taste panel preference. Methods: Overall Design: The design of this experiment was to prepare pasta with varying amounts of soy flour in proportion to traditional wheat flour. Three different variations were prepared from scratch using the same recipe, varying only the amount of soy flour used. The following table outlines the variables. Variable Control Variable 1 Variable 2 Variation 100 g. wheat flour 30 g. soy flour and 70 g. wheat flour 40 g. soy flour and 60 g. wheat flour Recipe: Following is the recipe used for the pasta preparation. The recipe was obtained from the Marcato Atlas Pasta Machine Product manual, which is the machine we used to roll and cut the dough. Ingredients: 500 g. soft wheat flour and 5 eggs. Procedure: Pour the flour into a bowl and the eggs into the middle of the flour. Mix the eggs with a fork until they are completely blended with the flour. Knead the mixture with your hands until it is completely homogenous and consistent. If the mixture is too dry add some water, if it is too soft add some flour. A good mixture should never stick to your fingers. Remove the mixture from the bowl and place it onto a lightly floured table. If necessary, continue to knead the mixture and cut it into small pieces.
How to prepare the dough and the pasta with Atlas machine: Set the machine regulator to position 1, pulling it outwards and turning it so that the two smooth rollers are completely open. Pass a piece of mixture through the machine turning the handle. Repeat this operation 5-6 times, folding the dough over and adding some flour to the middle if necessary. When the dough has taken a regular shape, pass it through the rollers once only with the regulators set on number 2, then once again on number 3 continuing until you obtain the desired thickness. With a knife, cut the dough crossways in pieces approximately 25 cm long. Insert the handle in the hole for the cutting rollers, turn it slowly and pass the dough through so as to obtain the type of pasta you prefer. Cooking the pasta: Bring a pan of salted water to boil to which you will add the pasta. Fresh pasta cooks in just a few minutes, averaging 2-5 minutes, depending on the thickness. Stir gently and then drain the pasta once it has finished cooking. Variations to procedure: For each variable, we used 100 grams of flour and 1 egg. Originally for trial 1, Variable 2 was to be made with 50% soy flour, but the dough was too dry and tough to be put through the pasta machine. So for the last two trials, we used 40% soy flour for Variable 2. For rolling the dough, we used setting 7 to roll the dough out. We also added olive oil to the cooking water to prevent sticking. After cooking the pasta was mixed with a store-brand spaghetti sauce before given to tasters. After the preparation of the pasta, it tested objectively with the texture analyzer and Hunter Colorimeter, and subjectively with a sensory panel, using a triangle test and ranking. Texture analyzer procedure: The Stable Micro Systems Texture Analyzer was used. The procedure was obtained from The Food Chemistry Laboratory Manual, CM Weaver and JR Daniel, 2003, pages 127-129. We used the knife probe when performing tests. Hunter Colorimeter procedure: The procedure for this equipment was also obtained from The Food Chemistry Laboratory Manual. Sensory Evaluation: Each pasta was assigned a random 3-digit number and placed randomly. A random sampling of semi-trained people tasted the pasta and filled out a sensory scorecard, giving their opinions. Following is the sensory scorecard given to the panelists who taste-tested the pasta.
Please check the boxes that describe your preference of each sample. Sample 452 Neither dislike nor like Sample 230 Neither dislike nor like Sample 305 Neither dislike nor like Rating Scale: Rate samples (452, 230, 305) for texture against the descriptive terms below. Extremely soft Very soft Moderately soft Slightly soft Neither soft not hard Slightly hard Moderately hard Very hard Extremely hard
Discussion: Because of its health benefits, as well as economic significance, incorporation of soy flour into pasta is of great interest. The pasta must have acceptable texture, color and taste preference. Sensory evaluation results are summarized in Tables 1 and 2, as well as Figures 1 and 2. As shown in Table 1, the pasta prepared with 40% soy flour was preferred over the other variations. Table 2 and Figure 2 shows that the texture of the pasta with 100% wheat flour was preferred over the texture of the pastas made with soy flour. The results from the texture analyzer are shown in Table 3 and Figure 3. The pasta with 100% wheat flour had the highest breaking strength. Because of the small standard deviation, the line of error in Figure 3 is small. According to a study of pasta made with sweet potato and soy protein, the soy decreased the firmness of the pasta (Limroongreungrat 2005). Color is an important characteristic of perceived pasta quality. Consumers prefer bright yellow translucent pasta products (Ugarcic-Hardi 2003). The pasta in this test showed no significant variance in color, as seen in Table 4 and Figure 4. The take-home message of this experiment is that soy flour can be used to partially replace wheat flour in pasta without significantly impacting texture, color, and flavor. Further work could be done to improve the texture of pasta made with soy flour so that it is more comparable to pasta made with wheat flour. Results: Table 1: Average Subjective Analysis Scores of Flavor Preference of Each Sample Containing Varying Amounts of Soy Flour. The Scale Was a 9 Point Scale, 1 Being d Extremely and 9 Being d Extremely. All 3 trials. Averages of all 3 trials STD Deviation 30 g soy flour 4.7 1.093 40g soy flour 7.3 1.118 100g wheat flour 6.0 1.581
Flavor Preference (1 9 Scale) 9 8 7 6 5 4 3 2 1 0 Average Preference Rankings 30g 40g 100g Variables Figure 1: Average Preference Ranking According to the Subjective Tests Compared Among Varying Soy Flour Substitutes in Pasta: Trials 1, 2, & 3 Table 2: Average Subjective Analysis Scores of Texture Preference of Each Sample Containing Varying Amounts of Soy Flour. The Scale was a 9 point Scale, 1 Being Extremely Soft and 9 Being Extremely Hard Averages of all 3 trials STD Deviation 30g 5.2 0.8333 40g 3 1.118 100g 5.8 1.054
Texture Preference Rating (1 9 Softness Scale) 8 7 6 5 4 3 2 1 0 Average Texture Preference Rating 30g 40g 100g Variables Figure 2: Average Texture Preference Rating According to the Subjective Tests Compared Among Varying Soy Flour Substitutes in Pasta. Trials 1, 2, & 3 Table 3: Average Texture Analyzer Values for All Three Trials Average Values (g) STD Deviation 30g 231.6g 1.150 40g 250.6 0.9074 100g 282.2 0.4509
300 Average Texture Analyzer Force (g) 250 200 Force (g) 150 100 50 0 30g 40g 100g Variables Figure 3: Texture Analyzer Force among Varying Soy Flour Substitutes in Pasta. Averages of Trial 1, 2, & 3. Table 4: Average Colorimeter Values for Trials 1, 2, & 3 L a B 30g 46.84 5.2 18.43 40g 39.59 4.94 17.15 100g 47.63 4.2 17.79 STD Deviation 4.431 0.518 0.640
60 Average Colorimeter Values Colorimeter Values 50 40 30 20 10 L a b 0 30g 40g 100g Variables Figure 4: Average Colorimeter Values Among Varying Soy Flour Substitutes in Pasta: Trials 1, 2, & 3
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