Effect of Texture, Consistency, and Palatability of All Purpose Flour vs. Gluten Free Flour. NUTR 45300 Research Project Katie Regan, Emily Hoff, Taylor Chamberlain 12/1/2014
Hypothesis and Objectives: Abstract There is a wide population of gluten sensitive people in the United States, and that population grows more and more each year. Gluten is a protein that is found in foods such as bread and pasta. Celiac disease presents a plethora of issues in the human body such as gastrointestinal disorders, acne and fatigue. This sets the foundation for this experiment in which gluten free flours were tested to potentially replace all purpose flour in many recipes for the future and to obtain a pumpkin bread for gluten sensitive consumers. Two variations of the pumpkin bread were made: Variation 1 contained potato starch and Variation 2 contained rice flour. These variations were compared to a control group (composed of all purpose flour) in terms of palatability, texture, and consistency using a hedonic scale. Objective evaluation of the cupcakes was conducted using the Texture Analyzer and Brookfield Viscometer. The subjective data results showed that a good number of panelists found the potato starch pumpkin bread was highly acceptable based on palatability, texture, and consistency. It was concluded that potato starch has an effect on palatability, texture, and appearance of cupcakes. This experiment might serve as a starting point to find the right proportion of replacement of all purpose flour to make bread for gluten sensitive individuals without sacrificing taste. Introduction The main reason why this experiment was obtained was to give the glutenfree population more variety of foods they can consume. Many people think that a gluten free diet is only to be consumed by a person with celiac disease because it might not benefit anyone without the disease. According to a study done on celiac disease patients versus non celiac disease patients, results show that obtaining a gluten free diet will be beneficial for people with and without celiac disease because of the genetic modifications in wheat that are creating autoimmune diseases, intestinal infections and hormonal influences within the human body (Brown). In order for people to be aware of the effects of gluten on the body, they need to eat intuitively and understand what their body feels when they consume gluten versus non gluten products. According to a research study done by BMC Medicine, they tested participants that they suspected had non celiac gluten sensitivity (NCGS). They had the participants try a diet containing gluten versus a diet without gluten. The participants then were asked to compare the way they felt on both diets. Over 97% of the participants said they felt much better on the gluten free diet. They said they experienced less digestive discomfort and felt less bloated (Ludin). In order to determine shelf stability of the gluten free pumpkin bread, the water activity needs to be determined using a texture analyzer. The lower the water
activity the more stable the bread is going to be. We also are going to determine the viscosity using a Brookfield viscometer. The viscosity will measure the firmness, which will help determine how much energy will have to be expended by our machines. The higher the viscosity, the more energy will have to be put in. Therefore bills from our bakery would slightly higher. In terms of making this product appealing, we need a taste panel of non bias judges to give feedback on whether or not the gluten free is likable compared to the processed wheat pumpkin bread. We will test taste, texture, and consistency using a Hedonic scale. Null hypothesis: The use of gluten free flour used for the pumpkin bread will not have an effect on taste, texture, and consistency of the processed flour. The objectives of this experiment are to create a gluten free pumpkin bread that tastes, looks, and smells better than the processed flour pumpkin bread. Obtaining a gluten free product will give the specific gluten free population an option of having pumpkin bread that they normally would not consume because it was to gluten free. Methods Starbucks has one of the best recipes for pumpkin bread. The recipe was then modified to make for gluten free bread in which all purpose flour was replaced with either rice flour or potato starch. Overall design Ingredients: 1 cup butter 2 cups sugar 4 eggs 2 cups pumpkin puree 1 tbs vanilla 3 cups flour 1/2 tsp salt 2 tsp baking soda 2 tbsp pumpkin pie spice Flour replacers: 2 cups of Rice Flour 2/3 cups of Potato Starch Procedure:
The oven was preheated to 350 of while everything else was getting prepared. Three larges bowls were prepared. First, the butter was melted in the microwave. Then the butter, sugar, eggs, pumpkin puree, salt, baking soda and pumpkin pie spice were combined and mixed into three different bowls. The various amounts of flour or flour replacers were added into the different bowls. Loaf pans were lightly greased before pouring in the different variables. Before cooking, the viscosity of the bread dough was measured using the Brookfield viscometer. The texture analyzer was used as well to measure the texture of the dough. All variables were baked and monitored for 30 minutes. The all purpose flour rose faster than the others, so was taken out two minutes prior to the others. Each were then cooled for ten minutes. A panelist of college students was gathered to determine appeal. Students of NUTR 453 were used as well as students from Delta Delta Delta Sorority. All students were between 19 24 years of age. A hedonic scale was used through subjective testing to determine texture, taste, and consistency. On a scale of 1 9, subjects were to rank the breads. 9 was most appealing and 1 was least. To eliminate confounding variables, all variables were mixed to the same consistency before adding the flour or flour replacer. They were also cooked in the same oven and at the same temperature. Replication and Sampling: Three trials were carried out to ensure that data was consistent and allow for statistics to determine the similarities between the variables. Each variable were assigned random three digit numbers so our subjects would not have any preconceived notion when observing the product before consuming. We also tried to have them precooked because panelist could tell that the one with flour would be taller than those without.
Sensory Evaluation Form: Variable Texture Taste Consistency 394 567 489
Results: Table 1: Viscometer Results for All Variables Viscometer Flour Type 6 RPM 12 RPM 30 RPM 60 RPM Potato Starch 155000 29500 33550 45600 Rice Flour 95500 75300 34500 16550 White Flour 45300 21800 19000 13200 180000 160000 140000 120000 Viscometer Values of Flour Types Viscosity 100000 80000 60000 40000 20000 Potato Starch Rice Flour White Flour 0 0 10 20 30 40 50 60 70 RMP Figure 1: All values were taken after 3 minutes at the given RMP to get more reliable and proper results results.
Table 2: Texture Analysis of All Variables Texture Analyzer White Flour Potato Starch Rice Flour Test 1 55 23 41 Test 2 68 28 45 Test 3 66 31 34 Average 63 27 40 70 Texture Analysis of Flour Types 60 Texture Analyzer (g) 50 40 30 20 White Flour Potato Starch Rice Flour 10 0 Flour Types Figure 2: Texture Analyzer values measures the force exerted in grams. The graph displays the average of the different tests.
Table 3: Hedonic Scale for Texture, Taste, and Consistency for All Variables, Test 1 Trial 1 Variables Texture Taste Consistency 394 7 5 7 567 8 9 8 489 5 6 5 10 Trial1 Averages of Hedonic Test Hedonic Scale 1 11 9 8 7 6 5 4 3 2 1 0 394 567 489 Texture Taste Consistency Figure 3: Average of Texture, Taste, and Consistency for all three variables of flour for Test 1. Standard deviation of error is shown. All values were not statistically significant, p> 0.05.
Table 4: Hedonic Scale for Texture, Taste, and Consistency for All Variables, Test 2 Trial 2 Variables Texture Taste Consistency 394 8 6 7 567 9 9 9 489 7 8 8 10 Trial 2 Averages of Hedonic Test Hedonic Scale 1 11 9 8 7 6 5 4 3 2 1 394 567 489 0 Texture Taste Consistency Figure 4: Average of Texture, Taste, and Consistency for all three variables of flour for Test 2. Standard deviation of error is shown. All values were not statistically significant, p> 0.05.
Table 5: Hedonic Scale for Texture, Taste, and Consistency for All Variables, Test 3 Trial 2 Variables Texture Taste Consistency 394 8 6 7 567 9 9 9 489 7 8 8 11 Trial 3 Averages of Hedonic Test Hedonic Scale 1 11 10 9 8 7 6 5 4 3 2 1 0 394 567 489 Figure 5: Average of Texture, Taste, and Consistency for all three variables of flour for Test 2. Standard deviation of error is shown. All values were not statistically significant, p> 0.05. Discussion: Viscometer: Texture Taste Consistency The first objective measurement was obtained through the viscometer by measuring the viscosity of the different dough of the three different variable samples. This measurement is of importance because if the dough is too thick or too think then it will directly affect the final product. A 50 ml sample was scooped into a 100 ml beaker and the appropriate spindle was attached to the Brookfield Viscometer. The 50 ml sample was then placed underneath the viscometer with the spindle completely immersed in the batter. The dial of the viscometer was then
adjusted to the appropriate RPM and was left to spin for approximately three minutes. The sample was spun for three minutes in order for the reading to settle and the number to become accurate. This process was done at four different RPMs and on all the different samples. The readings were recorded in Table 1. As shown by Table 1 and Figure 1, white flower had the thinnest batter consistently throughout all the different spin speeds. There was hardly any difference in the thinnest as the spin increased in speed. As shown by Table 1 and Figure 1, rice flower started out as initially having a thicker batter and thinned out as the spin speed increased. Table 1 and Figure 1 also showed that potato starch started out by being the thickest batter and then quickly thinned out as spin speed increased and then leveled out to be the thickest batter once more by the final spin. Viscosity directly affects baking by how much the product will expand (Gaines and Donelson 1981.) If a product has thicker batter then it will tend to expand more during cooking, resulting in a larger surface area of product. It is important to take into consideration viscosity in the baking of pumpkin bread because of the container it is being baked in. Bread tins can only hold so much batter and if it expands too much then it will overflow the tin and spill. Based off Table 1 and Figure 1, potato starch would expand the most while baking. Rice Flour will moderately expand during the baking process. White flour will expand only slightly during the baking process. Looking at Figure 1, it is possible for there to have been a skew in the data. This skew was most prominent in the potato starch results. When looking at the graph, there is a large drop at the second RPM and then an increase in at the third PPM. Ideally, it should have been more of a linear slope downward was RPM increased. This skew might have happened in the spindle was not completely dispersed in the dough or if the spindle spun off the dough after a period of time. Texture Analyzer: Texture analysis was used as another objective measurement of the three variables. The texture analyzer measures amount of forces, which was requires to puncture the bread. In this experiment, a cone probe was used and the force in grams was then recorded in Table 2. A piece small piece of bread was then place in a dish and put underneath the cone. The test was then run and the computer complied the data into a graph, which was then converted into data points. As displayed in Table 2 and Figure 2 rice flour and potato starch had very similar values whereas white flour had much higher values. Products with lower texture analysis values will have a lower firmness level than those of products with high texture analysis values (Zaszab, Csima, Lambert Meretei, and Fekte.) This data shows that potato starch and rice flour will have much more soft and pliable products than white flour products. This is important because consumers will want different firmness for different products. For example, a consumer will more likely want a softer, less firm dessert type bread compare to that of a sandwich type bread. Sources of error could have been found in machine settings not being changed to the appropriate settings for bread or the machine may not have been properly cleaned after another student ran a test on it.
Sensory and Preference Evaluation: For the sensory and preference test of the products, a survey was given using a hedonic scale from 1 to 11, 1 being least favorable and 11 being most favorable. There were three separate trials of the three different flour types. In each trail, eight different people, ages 18 to 24, filled out the evaluation survey based off their preferences and opinions. The surveys were then collected and the average was taken from each trail and recorded into Table 3, 4, and 5. Figures 3 5 displayed the differences amongst the three different flours by three different criteria; texture, taste, and consistency. Each trial seemed to have a slight different outcome compared to the other trials. However, in every trial the data showed that the testers seemed to enjoy the texture, taste, and consistency of the potato starch pumpkin bread. In Trial 1, consumers liked the texture and consistency of the white flour pumpkin bread second best but preferred the other two in taste comparison. In Trial 2, consumers preferred the taste and consistency of the rice flour pumpkin bread more than regular flour but they still preferred the texture of the white flour more. In Trail 3, the consumers just barely preferred the texture, taste, and, consistency of white flour to the rice flour. Based off the data presented here if pumpkin bread makers were trying to come up with a good tasting, good texture, and good consistency product then they should look into using a potato starch flour based flour substitute. Producers should also consider the cost of switching to potato starch vs. the cost of just plain flour.
Works Cited Brown, Amy. "Gluten Sensitivity: Problems of an Emerging Condition Separate from Celiac Disease." Gale Cengage Learning Center: Health Reference Center. Expert Reviews Ltd., 2012. Web. 29 Sept. 2013. Donelson, J.R., Gaines, C. S. "Cake Batter Viscosity and Expansion upon Heating." Cereal Chemisty 59.4 (1982): 237 40. Print. Lundin, Knut E A. "Non celiac Gluten Sensitivity Why Worry?" National Center for Biotechnology Information. U.S. National Library of Medicine, 23 May 2014. Web. 29 Sept. 2014. Timea, Kaszab, Gyorgy Csima, Aniko Lambert Meretei, Andras Fekete. Food Texture Profile Analysis by Compression Test (n.d.): n. pag. Web. 29 Nov. 2014. Weaver, C. & Daniel, J. 2003. Equipment Guide. In: The Food Chemistry Laboratory: A Manual for Experimental Foods, Dietetics, and Food Scientists. 2nd Ed. Boca Raton, Florida. CRC Press. p. 107 132