The Effect of PromOat on Palatability, Texture, and Water Activity of Peanut Butter Cookies.

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1 Danielle Drake Grace Jang Beth Spangler The Effect of PromOat on Palatability, Texture, and Water Activity of Peanut Butter Cookies. Abstract: Dietary fiber has long been shown to have a plethora of health benefits, from aiding in digestion, to reducing cholesterol, and helping increase feelings of satiety. Americans generally are deficient in dietary fiber, the result of which can have negative repercussions on health. A recently developed product called PromOat contains beta-glucan, extracted from oats. Betaglucan is a soluble fiber, providing many beneficial properties for health. In this project, PromOat was incorporated into a conventional recipe for peanut butter cookies, in an attempt to increase the fiber content without negatively impacting the texture, moisture or palatability of the product. In order to determine the percentage of PromOat that could be substituted for All- Purpose flour without negatively impacting the sensory properties of the product, several subjective and objective tests were employed. Objective tests that were employed were the Stable Micro Systems Texture Analyzer and the Water Activity System. Six panelists were utilized for the subjective test; the unstructured ranking test. Three independent trials of the experiment were conducted. Although statistical analysis showed that the preferred product was the unmodified one, the product with a 10% adjustment in flour content came in a close second, indicating that a moderate adjustment to fiber content could produce a palatable and enjoyable product with no adverse side effects. Introduction: Having high blood cholesterol is a risk factor for developing metabolic syndrome and heart disease. This is of much concern for the United States since 1 in 6 American adults have high blood cholesterol (Schober 2007). With showing no signs or symptoms, people rarely know if they have high blood cholesterol or not. Diets high in saturated and trans fats are a huge contributing factor to the problem since they are the main component of popular American foods such as red meats, butter, cheese, ice cream, and fried foods (Turcotte 2009). With an increase in cholesterol levels in individuals in the United States, a product to reduce these levels is a great way to try bettering the health of Americans. PromOat is such a product. PromOat contains the soluble dietary fiber beta glucan; consuming 3 grams of beta glucan a day has shown to reduce blood cholesterol levels (PromOat). A study published in Nutrition Journal confirmed that beta glucan can reduce blood cholesterol levels by showing that 3-4 grams of beta glucan can lower LDL-cholesterol levels significantly by between 4.8 and 6.5% (Wolever 2011). Just two grams of PromOat contains 0.75 grams of beta glucan (PromOat), so with a small change in the flour content of foods the recommended amount of beta glucan can be met. In a text by Frances Sizer and Ellie Whitney, in reference to soluble fibers, it is stated that these form gels (are viscous) and are easily digested by bacteria in the human colon (are easily fermented). Commonly found in oats, barley, legumes and citrus fruits, soluble fibers often lower blood cholesterol levels and can help to control blood glucose, thus protecting against heart disease and diabetes (Sizer, 2011).

2 Amylose 1 Amylopectin 1 The chemical structure of starch is described as natural starches contain 10-20% amylose and 80-90% amylopectin (Antonio Zamora). The control with 0% of PromOat only consisted of these molecules without the beta-glucan in the formula. Since it has no β 3 linkage for every three or four 1β 4 linkages (Zamora 2012), this molecule cannot function as fiber due to the ability to digest and absorb of the molecules.

3 Beta Glucan 1 This is the chemical structure of beta-glucan which consists of glucose monomers just like other carbohydrates. However, these are connected at the 1, 4 and 1, 3 positions. (Bread and Flour Regulations 1998) The structure is bulkier, so it is harder to stack in layers; therefore, it aids to be the soluble fiber. When this molecule is combined with water, the -O from H 2 O will bind to the -OH group making the compound water soluble. The proposed change in the flour content of foods is represented in this research project. A traditional peanut butter cookie recipe was used and modified to test the texture, water activity, and palatability of peanut butter cookies with 0%, 10%, and 20% PromOat for flour in them. A cone probe texture analyzer was used to test the texture, a water activity system was used to test water activity, and sensory tests were used to test palatability of the cookies. The main goal of this project was to increase the nutritional value of a traditional peanut butter cookie by adding PromOat to the recipe. The null hypothesis is that the fiber content of peanut butter cookies will not have any effect on texture, water activity, and palatability of the cookies. The independent variables are the amount of PromOat used in the recipe: 0%, 10%, and 20%. The dependent variables are water activity and texture analysis. Methods: The objective of this project was to incorporate additional dietary fiber into a conventional peanut butter cookie recipe, in order to increase the nutritional content and potential health benefits upon consumption. Ideally, the texture, water activity and palatability of the product would be unaffected. In an attempt to achieve this objective, varying amounts of PromOat were substituted for All-purpose flour in the conventional peanut butter cookie recipe, and then tested via subjective and objective methods. The unmodified recipe used for this

4 experiment is a standard recipe called Classic Peanut Butter Cookies, and can be found online at allrecipes.com. The original recipe itself has been tested by many, and is a highly recommended, quality recipe. The recipe amount in grams used for one trial of all three variables is as below. The quantities listed were divided to produce three different doughs, with the PromOat being adjusted appropriately at 10% and 20% and substituted for all-purpose flour. Materials: 225 g unsalted butter 260 g crunchy peanut butter 200 g white sugar 220 g packed brown sugar 2 eggs 315 g all-purpose flour 5 g baking powder 3 g salt 7 g baking soda With a hand mixer, the first four ingredients listed were creamed together in a separate bowl, then the eggs were beaten in. The remaining, dry ingredients were mixed together in a separate bowl, including the PromOat flour when applicable. The two mixtures were then incorporated together. The dough was formed into approximately 1-inch spheres and distributed evenly onto three separate baking sheets lined with parchment paper and baked for approximately 10 minutes in an oven heated to 375 degrees F. Then all baked cookies were allowed to cool to room temperature. The product was then tested via subjective and objective analysis, with the goal being to determine which variable may be an acceptable alternative to conventional peanut butter cookies with no added nutritional benefit. All objective procedures were done twice, with the average value being considered. All subjective testing was done by panelists of eight. In the objective testing, the Stable Micro Systems Texture Analyzer was used to assess hardness, penetrability and spreadability, utilizing the Cone Probe at a setting of 2 mm. The sample that was used for testing was a whole cookie. The Water Activity System was used to analyze the water availability of the product. The way that the sample was prepared for administering this test was a partial cookie crumbled to uniform consistency into the bottom of the sampling dish. One subjective sensory method was used to assess the product; an effective test. The effective test that was used was the unstructured ranking scale. An example of the sensory scorecard is below.

5 Unstructured Sensory Test Please make a vertical Line Dislike Extremely Like Extremely This graph rating scale requires two word anchors at the each ends and requires a mark or a position on the line to measure the intensities of rated attributes. This is more accurate then rating because it eliminates the tendency of panelists to use only the central part of the scale avoiding very low or very high scores. To calculate the percent on overall liking this equation has been used. ( ) 100 In the subjective testing, all three variables were assigned random, three-digit numbers in order to avoid any bias in the sensory panel. All samples were placed in a random order to avoid the middle bias. This entire process, from the creation of the product to all analysis was repeated to obtain a total of three independent replicates. Results: Objective Testing TABLE 1 Cone-Probe Texture Analyzer Values for the Three Variations of Peanut Butter Cookie in Trials 1-3 Control 10% PromOat 20% PromOat Trial Trial Trial Average 75 a b 174 b Standard Deviation Averages not bearing the same superscript are statistically different, p < 0.05.

6 TA values (g) Average Texture Analyzer Values vs PromOat Added a Control 10% PromOat 20% PromOat b Cookie Variables b Figure 1 Average texture analyzer values of trials 1-3 of the three different peanut butter cookie variations. TABLE 2 Water Activity Values for the Three Variations of Peanut Butter Cookie in Trials 1-3 Control 10% PromOat 20% PromOat Trial Trial Trial Average a a a Standard Deviation Averages bearing the same superscript are not statistically significantly different, p > 0.05.

7 Aw Values Average Water Activity Values vs PromOat Added a Control 10% PromOat 20% PromOat a Cookie Variations a Figure 2 Average water activity values of trials 1-3 of the three different peanut butter cookie variations. Subjective Testing TABLE 3 Percentages of How Well Each Liked Each Cookie for Each Trial Sensory Evaluation Average Trial 1 Control 73% 91% 60% 99% 86% 67% 79% 10% PromOat 59% 54% 30% 73% 61% 72% 58% 20% PromOat 92% 68% 74% 40% 24% 19% 53% Trial 2 Control 90% 91% 62% 98% 92% 89% 87% 10% PromOat 77% 90% 51% 51% 87% 76% 72% 20% PromOat 20% 43% 25% 24% 43% 13% 28% Trial 3 Control 88% 92% 74% 65% 79% 82% 80% 10% PromOat 64% 56% 45% 63% 77% 65% 62% 20% PromOat 14% 34% 28% 44% 2% 21% 24%

8 100% 90% 80% Average of Overall Liking Scale vs PromOat Variables 70% Overall Liking (%) 60% 50% 40% 30% 20% Trial 1 Trial 2 Trial 3 10% 0% 0% PromOat 10% PromOat 20% PromOat Trial 1 79% 58% 53% Trial 2 87% 72% 28% Trial 3 80% 62% 24% Figure 3 Average palatability levels of trials 1-3 of the three different peanut butter cookie variations. Discussion: Comparing the values from using a texture analyzer, in additions 10% PromOat and 20% PromOat, have significant differences in texture from the peanut butter cookies. Figure 1 demonstrates the definite changes in strength of cookies when comparing between 0% PromOat and any additional amount of PromOat. However, when comparing differences between 10% PromOat and 20% PromOat, the texture analyzer values have subtle with very little change. On the other hand, a trend can be detected from observing Figure 1 which proves that when the more PromOat is added to the cookies, the higher the texture analyzer value is. This implies that when PromOat is added to the cookies, the texture is altered in increase of hardness, firmness, adhesiveness. Moreover, the cookies with 0% PromOat have a trend of decrease in breaking point and fracturability. Therefore, addition of beta-glucan will increase resistance of cookies due to increase in texture value of cookies. The water activity of a food is the ratio between the vapor pressure of the food itself, when in a completely undisturbed balance with the surrounding air media, and the vapor pressure of distilled water under identical conditions (Food and drug inspection 2011). Water activity (A w) can determine or predict the safety of food or the shelf life of food by observing the growth of microorganism. The microorganisms need nutrients such as water or moisture in order to survive and to support the growth. Having this idea, three different A w were measured. From

9 Figure 2, the averages of each variable were 0.536, 0.557, and which can imply that they are similar among the three variables: 0% PromOat, 10% PromOat, and 20% PromOat. Since the A w values are similar and adjacent to each other, the safety of this product, shelf life, would remain the same. Figure 3, illustrates the overall liking on 6 different panelists using an unstructured sensory test. 0% PromOat had the highest overall liking, averaging 86% overall liking. On the other hand, 10% of PromOat and 20% of PromOat each averaged at 72% and 28% respectively. This data demonstrates that the most preferable product was the control with 0% PromOat. The more PromOat added to the formula, the lower the overall liking(%) is. Table 3 and Figure 3 evidence that there is a definite change in palatability, texture, and flavor of peanut butter cookies when PromOat is added. More work would need to be done to assess whether a method as described in this paper should be used in various food products. More testing would need to be done on a variety of food products, of various textures and consistencies. Conclusion: This study found that there is not a significant change in the texture of peanut butter cookies when PromOat is added to the recipe, but there is a significant change in water activity and palatability. With these results, the null hypothesis, the fiber content of peanut butter cookies will not have any effect on texture and palatability, is rejected. References: Andersson, M., Ellegård, L., & Andersson, H Oat bran stimulates bile acid synthesis within 8 h as measured by 7alpha-hydroxy-4-cholesten-3-one. American Journal of Clinical Nutrition 76:5 Bloomquist, M. Benefits of Fiber: Fiber Basics. Everyday Health website Retrieved Sept 22, 2012 from Brinkley, R. D., Lutjohann, D., Bergmann, K., & Chandalia, M Beneficial Effects of High Dietary Fiber Intake in Patients with Type 2 Diabetes Mellitus. The New England Journal of Medicine, 342(1392), Food and drug inspection Retrieved from m Fuchs, C., Giovannuchi, E., Colditz, G., & Hunter, D Dietary Fiber and the Risk of Colorectal Cancer and Adenoma. The New England Journal of Medicine, 340 Hanne, B., Hensen, B., & Mollar, B Grain characteristics, chemical composition, and functional. In B. Hanne (Ed.), Journal of Agriculture and Food Chemistry 52: Lattimer, JM, Haub MD Effects of Dietary Fiber and Its Components on Metabolic Health. Nutrients 2:

10 Lawther, M Beta-glucans and cereal soluble fibres: Their role in functional foods. Retrieved September 22, 2012 from PromOat: The goodness of oat. A natural healthy ingredient Schober SE, Carroll MD, Lacher DA, Hirsch R. High serum total cholesterol an indicator for monitoring cholesterol lowering efforts; U.S. adults, NCHS data brief no 2, Hyattsville, MD: National Center for Health Statistics Sizer F.S., Whitney E Nutrition: concepts and controversies. 12th ed. Belmont California: Cengage Learning. p 120. The bread and flour regulations Retrieved from Turcotte M. What foods contribute to high cholesterol? Livestrong Wolever TM, Gibbs AL, Brand-Miller J, et al Bioactive oat beta-glucan reduces LDL cholesterol in Caucasians and non-caucasians. Nutr J 10:130. Zamora, A. (2012). Retrieved from