Food Chemistry Special Project Written Report. II. Abstract: Dietary fiber is widely under consumed in the United States. Fiber fortification of

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1 Michelle Klink and Chelsea Kingston FN 453 Written Report November 24, 2008 Food Chemistry Special Project Written Report I. Title: Effect of fiber fortification on soft pretzels II. Abstract: Dietary fiber is widely under consumed in the United States. Fiber fortification of bread products is a growing industry trend. The purpose of the experiment is to observe the effect of fiber fortification on soft pretzels. Thirty six grams of fiber, Benefiber and Nutrifiber, was added to two of the three trial recipes. Benefiber and Nurtifiber trials were compared to the Normal soft pretzel recipe. The texture was optimal in all three soft pretzels; however the color and taste were not optimal. All trials were not significant when compared to a p-value<0.05. Future research is warranted to expand upon the work conducted in this experiment to produce an overall appealing and delicious fiber fortified soft pretzel. III. Introduction: Obesity is now an epidemic in the United States. In addition, many Americans fall short of the recommended fiber consumption guidelines. Therefore, it is desirable to create a snack product that is convenient, tasty, and rich in fiber. According to the National Cancer Institute, Americans should consume grams of fiber per 2,000 calories per day. However, the average American consumes only grams of fiber per day, roughly half of what is recommended for consumption (Baylock and others 1996). Due to this fact of limited fiber consumption, we propose the fortification of a soft pretzel product with a dietary fiber supplement.

2 Dietary fiber refers to the portion of carbohydrate which cannot be digested in the large intestine. Diets rich in dietary fiber have been associated with a host of health benefits such as increased satiety, decreased risk of chronic constipation, cardiovascular disease and colon cancer. For the purpose of this project, we have chosen to market this product as a functional food, providing protection from colon cancer (Bente and others 2008). According to Slavin and colleagues, several mechanisms occur within the body to decrease carcinogenic growth when adequate amounts of dietary fiber are ingested. For instance, one such mechanism is the increased production of the short chain fatty acid (SCFA) butyrate (Salvin and others 1999). The production of butyrate is specifically caused by the fermentation of dietary fiber within the large intestine. Slavin and colleagues hypothesize when butyrate increases, the effects are cytotoxic (Salvin and others 1999). Tabernero and colleagues also concur with the production of butyrate when adequate dietary fiber is ingested in the diet (Tabernero and others 2007). Dietary fiber was found by Tabernero et al. to increase dietary antioxidants which led to bacterial metabolism within the colon, producing fermentation, which led to protection against tumor growth (Tabernero and others 2007). Tabernero et al concludes when butyrate is increased, it produces positive effects on abnormal cellular activity leading to antioxidant and proliferation of mutated cells (Tabernero and others 2007). In addition to the increased production of butyrate, dietary fiber also leads to decreased fecal transit time within the colon. Kojima and colleagues found that dietary fiber produces many mechanisms within the large intestine such as leading to increased fecal bulk which dilutes carcinogenic compounds within the stool (Kojima and others 2004). Thus, when carcinogenic

3 compounds have decreased transit time within the large intestine, carcinogenic growth is less likely to occur. Therefore, due to the need to increase American s fiber consumption and the hypothesized association of dietary fiber and decreased risk of colon cancer, a fiber fortified soft pretzel snack would be optimal for individuals to quickly and easily increase fiber consumption while consuming a familiar food. Wang and colleagues tested the effect of fiber on bread products in Results concluded the fiber fortified breads were acceptable, with increased product softness. In addition, Wang et al concluded that the bread products increased in crumb production, leading to a more tender product (Wang and others 2002). Thus, Wang et al concludes that fiber can be used in bread making to fortify the diet. When implementing the fortification of fiber into the soft pretzel product, it was chosen to produce a pretzel that is traditionally shaped, as opposed to a stick or circular shape. In order to maintain a chewy outside and soft inside, the folded shape was intended to produce maximum surface area for Maillard browning. When baking the soft pretzel product fortified with fiber, color and flavor are key. The intended desire for the color of the pretzel product was to be slightly golden brown, however not producing a product which is burnt, crunchy or crispy. Therefore, it is vital that excessive Maillard browning will be limited. Maillard browning would occur due to the presence of a sugar and an amino acid leading to a browning of color on the exterior of the product. It is important to note that the concern of Maillard browning is not a pressing issue within this experiment. For example, all bread products have some Maillard browning. Therefore, almost all bread products are affected by the browning, shown through flavor and color. This

4 experiment only objectively tested taste and not color. Therefore, Maillard browning was not an initial concern within the final outcome of the product. In conjunction with Wang and colleague s findings which support supplementation of fiber in carbohydrate sources and the growing trend of fiber consumption within the United States, the production of a fiber fortified soft pretzel is marketable and practical. As previously stated, creation of a fiber-fortified soft pretzel snack should have involved the chemical process of Maillard browning. Maillard browning is a chemical process which requires sugar, amino compound and heat. Maillard browning is dependent on many variables such as temperature, ph, and water content of the food. Specifically, increasing temperature impacts Maillard browning by increasing the brown pigments of the product. As ph decreases, Maillard browning decreases as well. Maximum Maillard browning occurs when food water levels are within the middle range (about 50%) (Daniel 2008). Maillard browning is vital to the aesthetic properties of food products. Foods which endure high Maillard browning may not have a pleasing taste or appearance. In addition, Maillard browning is important when considering nutritional losses. Maillard browning results in the loss of the essential amino acid, lysine, which is found within grain (cereal) products. Our panel included 30 individuals on Purdue s campus. Each person tasted the regular soft-pretzel as well as the two fiber-fortified pretzels and completed a scorecard. Results were used to determine which pretzel was most liked by our panel. The variables which were controlled in the experiment include: temperature, mixing procedures, size of the product, size of the samples given to the panelists, presentation products, division of the sample and amount of fiber. Three grams of fiber were added to each pretzel. The recipe produced 12 pretzels;

5 therefore the total addition of fiber was 36 grams. Eighteen grams of flour was removed from the Benefiber and Nutrifiber recipes. The purpose of this experiment was to observe and test subjective (taste panel) and objective (Seed Volume Apparatus and Texture Analyzer) properties of soft pretzels which have been fortified with dietary fibers, Benefiber and Nutrifiber. The dependent variables were texture and taste. The independent variables of the experiment were the temperature and time of baking. IV. Methods: The procedure that was followed is as follows: Start by preheating the oven to 325 degrees Fahrenheit (165 degrees Celsius). The ingredients that were used in making these pretzels include: Yeast, warm water, honey, flour, salt, and two different fiber substances, Benefiber and Nutrifiber. The yeast was placed in a small bowl with the warm water and honey. It was stirred together, and sat for 5 minutes. The flour and salt were mixed in a medium-size bowl. After 5 minutes, it was examined and the yeast mixture was larger than it was at the beginning and a little bubbly. The yeast mixture was then added to the flour and salt combination. With a mixing spoon, it was stirred together, and hands were used to mix. The dough was ready to use once it was crumbly as well as flaky. The dough was put on a cutting board and kneaded into a big ball. A piece of dough was then pulled off and rolled into a snake like shape. The dough was twisted into the size of the stencil and placed on a cookie sheet. This processed was continued until all dough was gone, making 12 pretzels. The pretzels were baked for 10 minutes at 325 degrees Fahrenheit and were then cooled. The products that were used include: grams of yeast (1 tbsp), milliliters of water (1/2 cup), 4.73 grams of honey (1 tsp), grams of flour (1-1/3 cup), and 4.73 grams of salt (1 tsp). For the sensory

6 evaluation, the Hedonic Scale was used to see if the panelists liked the fiber-fortified soft pretzels as much or even more than the Normal pretzel. The taste panel included 30 individuals on Purdue s campus. Each person tried the regular soft-pretzel as well as the two fiber-fortified pretzels and then filled out a scorecard. The results were then recorded and it was determined which pretzel was most liked by the panel. The variables that were controlled in the experiment included the following: temperature, mixing procedures, size of the product, size of the samples given to the panelists, presentation products, division of the sample and amount of fiber. Temperature was controlled by preheating and manually checking the oven via thermometer before placing pretzels in the oven. Mixing of the pretzel dough was performed in the same way throughout all three trials. The addition of ingredients and mixing of the dough was done according to the directions of the recipe, following the procedure exactly. In order to keep the size of each of the pretzels the same, a stencil was used in which each pretzel was folded in a uniform way. The pretzels were cut into 1 inch pieces thus keeping the sample size given to the panelists the same. During each trial, the presentation of the products was kept the same. In this case, napkins were used to pass the pretzels out, which contained a 1 inch piece of the Normal pretzel, Benefiber pretzel, and Nutrifiber pretzel. A metal knife was used to cut each of the pretzels which controlled the division of the sample. The amount of fiber was also controlled in our experiment. Three grams of fiber was added to each pretzel. The recipe produced 12 pretzels, therefore 36 grams of fiber was added to each of our batches. Eighteen grams of flour was removed from the recipe for the Benefiber and Nutrifiber pretzels to adjust for the addition of the fiber.

7 Sensory Scorecard: Hedonic Scale Ranking Pretzel: 124 Like extremely Like slightly Dislike moderately Like very much Neither like nor dislike Dislike very much Like moderately Dislike slightly Dislike extremely Pretzel: 667 Like extremely Like slightly Dislike moderately Like very much Neither like nor dislike Dislike very much Like moderately Dislike slightly Dislike extremely Pretzel: 835 Like extremely Like slightly Dislike moderately Like very much Neither like nor dislike Dislike very much Like moderately Dislike slightly Dislike extremely

8 Recipe: (Note: Recipe can also be found in paragraph form in the Methods section) Prep time: about 30 minutes Ingredients: 1 tbsp. yeast 1/2 c. warm water 1 tsp. honey 1 1/3 c. flour 1 tsp. salt Utensils: oven (You'll need help from your adult assistant.) small bowl mixing spoon medium-size bowl cutting board, sprinkled with flour baking sheet, sprayed with nonstick spray measuring cups and spoons Replication: To replicate the Normal pretzels, place 1 tbsp. yeast in a small, 8 ounce bowl with ½ cup warm water and 1 tsp. honey. Stir together for 15 strokes, and let the mixture sit for 5 minutes. To ensure that time requirement it properly met, set a timer to notify when yeast activation is complete. After 5 minutes, examine the yeast mixture to make sure it is larger than it was at the beginning and bubbly. Mix the 1 1/3 cup flour and 1 tsp. salt together in a separate, 12 inch bowl. Pour the yeast mixture into the flour and salt combination. With a mixing spoon, stir mixture for 20 strokes, or until all wet ingredients are incorporated into the dry ingredients. The dough is ready to use once it is a little crumbly as well as flaky. Within the 12 inch bowl, form dough into a ball. Remove dough ball with hands. Put the dough on the cutting board and knead for 5 minutes. Divide dough into thirds. Take thirds and divide each third into four equal portions. At this point there should be twelve equally sized dough pieces. Pick up each individual piece of dough and roll it into a snake like shape. Twist the piece of dough into the

9 size of the stencil and place on the cookie sheet. Continue until all dough is gone, making 12 pretzels. Bake the pretzels for 10 minutes. To ensure equal cooking time, set timer to 10 minutes. Remove from oven when cooking time is finished. Remove from baking sheet with a spatula. Place pretzels on cooling rack for 15 minutes. Remove pretzels from cooling rack and cut one-inch pieces with a metal knife to prepare for Texture Analyzer, Seed Volume apparatus, and hedonic taste rating. When replicating the Nutrifiber and Benefiber soft pretzels, place 1 tbsp. yeast in a small, 8 ounce bowl with ½ cup warm water and 1 tsp. honey. Stir together for 15 strokes, and let the mixture sit for 5 minutes. To ensure that time requirement it properly met, set a timer to notify when yeast activation is complete. After 5 minutes, examine the yeast mixture to make sure it is larger than it was at the beginning and bubbly. Pre-measure 1 1/3 cup flour amount and remove 18 grams of flour from pre-measured amount. Place 6 inch plastic bowl on metric scale and zero scale. Add 30 grams of Nutrifiber and Benefiber, respectively, to each of the two bowls. Remove bowl from scale. Pour respective fiber supplement into respective bowl to be combined with flour and salt. Mix the flour/ fiber and 1 tsp. salt together in a separate, 12 inch bowl. Pour the yeast mixture into the flour and salt combination. With a mixing spoon, stir mixture for 20 strokes, or until all wet ingredients are incorporated into the dry ingredients. The dough is ready to use once it is a little crumbly as well as flaky. Within 12 inch bowl, form dough into a ball. Remove dough ball with hands. Put the dough on the cutting board and knead it for 5 minutes. Divide dough in thirds. Take thirds and divide each third into four equal portions. At this point there should be twelve equally sized dough pieces. Pick up each individual piece of dough and roll it into a snake like shape. Twist the piece of dough into the size of the stencil and place on the cookie sheet. Continue until all dough is gone, making 12 pretzels. Bake the pretzels for 10

10 minutes. To ensure equal cooking time, set timer to 10 minutes. Remove from oven when cooking time is finished. Remove from baking sheet with a spatula. Place pretzels on cooling rack for 15 minutes. Remove pretzels from cooling rack and cut one-inch pieces with a metal knife to prepare for Texture Analyzer, Seed Volume apparatus, and hedonic taste rating. V. Results: Table 1.1: Texture Analyzer Values Normal Benefiber NutriFiber Trial Trial Trial Average Table 1.2: Seed Volume Apparatus Values Normal Benefiber NutriFiber Trial Trial Trial Average

11 Pretzel 124 (Nutrifiber) # of people answered Like Extremely Like Very Much Like Moderately Like Slightly Neither Like Nor Dislike Dislike Slightly Dislike Very Much Dislike Moderately Hedonic Scale Ranking Dislike Extremely Series1 Figure 1.1 Taste Panel Hedonic Scale Ranking (Nutrifiber) Pretzel 667 (Benefiber) # of people answered Like Extremely Like Very Much Like Moderately Like Slightly Neither Like Nor Dislike Dislike Slightly Dislike Very Much Dislike Moderately Hedonic Scale Ranking Dislike Extremely Series1 Figure 1.2 Taste Panel Hedonic Scale Ranking (Benefiber)

12 # of people answered Like Extremely Like Very Much Like Moderately Like Slightly Neither Like Nor Dislike Pretzel 835 (Normal) Dislike Slightly Dislike Very Much Dislike Moderately Hedonic Scale Ranking Dislike Extremely Series1 Figure 1.3 Taste Panel Hedonic Scale Ranking (Normal) Trial Average (Seed Volume) Average Volume Pretzel Types (Normal, Benefiber, Nutrifiber) Series1 Figure 2.1 Average Volume For Normal, Benefiber, Nutrifiber Pretzels

13 Trial Average (Texture Analyzer) Average Texture Analysis (g) Pretzel Types (Normal, Benefiber, Nutrifiber) Series1 Figure 2.2 Average Texture Analysis For Normal, Benefiber, Nutrifiber Pretzels Standard Deviation (Seed Volume) 50 Standard Deviation Pretzel Types (Normal, Benefiber, Nutrifiber) Series1 Figure 2.3 Standard Deviation from Seed Volume Apparatus for Normal, Benefiber, Nutrifiber Pretzels

14 Standard Deviation (Texture Analyzer) Standard Deviation Pretzel Types (Normal, Benefiber, Nutrifiber) Series1 Figure 2.4 Standard Deviation from Texture Analyzer for Normal, Benefiber, Nutrifiber Pretzels VI. Discussion: The addition of various fiber supplements to the soft pretzel recipe produced changes in dough texture, color, and taste. The most drastic color change occurred within the Nutrifiber pretzel. However, a small color change was noted in the Benefiber pretzel in comparison to the normal pretzel. The most drastic change in dough texture occurred in both the Nutrifiber and the Benefiber pretzels compared to the normal pretzel dough. The Nutrifiber dough was extremely dry and crumbly and was difficult to form into the stencil of the pretzel shape. Conversely, the Benefiber pretzel dough was extremely wet and sticky which made it difficult to form into the stencil of the pretzel shape. To determine the penetration and hardness of the three individual soft pretzels, the cone probe of the Texture Analyzer was used. The most noticeable change in the pretzel s final texture occurred in the Nutrifiber product. The Nutrifiber pretzel had a more

15 dense texture and had a grainy consistency. Referring to Table 1.1, it can be observed that the Nutrifiber pretzel had the highest value of grams, followed by the normal pretzel with a value of 86.5 grams and the Benefiber pretzel with the lowest value of 35.1 grams. Based on the results indicated in Table 1.1, it has been concluded that each pretzel varied in hardness and overall texture. Referring to Figure 2.4, the standard deviation for the Texture Analyzer of all three of the pretzels yielded a value of 19 grams, in which case the variance was small between each of the three trials. According to the InStat ANOVA statistics, the p-value was concluded , which is not significant when compared to the significance level of p<0.05. Therefore, when comparing Trial 1 to Trial 2, Trial 1 to Trial 3, and Trial 2 to Trial 3, no values were significant indicating that the data obtained was skewed and endured human or mechanical error. Another apparatus, Seed Volume Apparatus, was used to assess the volume of the pretzel trials. Referring to Table 1.2, it can be concluded that the Benefiber pretzel had the highest volume with a value of 113 grams, followed by the normal pretzel with a value of 80.7 grams and the Nutrifiber pretzel with the lowest value of 76.7 grams. Referring to Figure 2.3, the standard deviation for the Benefiber pretzel was the lowest at a value of 5.2 grams followed by the Normal pretzel with a value of 22.1 grams and the Nutrifiber pretzel had the highest standard deviation of 34.0 grams. Based on the numbers, results show that there was less variance in the Benefiber pretzel than the Normal and Nutrifiber pretzel. Based on these results of the Seed Volume Apparatus and the Texture Analyzer, it can be concluded that the results from these two machines cannot be correlated due to contradictory results. After preparation and baking of the fiber fortified soft pretzels, no Maillard browning was observed in any of the 3 different pretzel varieties. Due to the absence of Maillard browning, two of the three pretzels had a white, unbaked appearance. The pretzel that contained Nutrifiber

16 appeared brown and speckled due to the type of fiber that was incorporated into the dough mixture. Park and colleagues concluded a defect in color when fortifying bread with fiber (Park and Others 1997). They observed an off-color with black specks which was also found in the Nutrifiber soft pretzel. Referring to the Hedonic Scale Figures 1.1, 1.2 and 1.3, the following results were concluded by a taste panel of 30 Purdue students. As indicated in Figure 1.1, taste preference for the Nutrifiber pretzel was varied. Seven individuals liked the pretzel moderately and six individuals disliked the pretzel moderately. Therefore, based on these preferences, it is hard to come to a conclusion how the taste panel really perceived the Nutrifiber pretzel. Referring to Figure 1.2, it be concluded that the taste panel had a low preference for the Benefiber pretzel. Seven individuals stated they disliked the product moderately, with the other 23 results being widely dispersed throughout the options. Referring to Figure 1.3, the Normal pretzel had a bellshaped curve indicating that taste preference was about average and students neither liked nor disliked the product. After reviewing Figures 1.1, 1.2 and 1.3, all pretzels were inconclusive with results varying across each preference option. Based on the results concluded for each of the three soft pretzel trials, Normal, Benefiber, and Nutrifiber, additional research concerning the topic of fiber fortification on bread (soft pretzel products) is needed. Wang et al. concluded that fiber fortified bread products are acceptable, however additional research is warranted based on results which were concluded in lab. Maillard browning is desirable in baked goods, especially breads. Due to the absence of Maillard browning in all three pretzel products, research in this area would prove beneficial. For instance, investigation of addition of different egg (protein) washes to the pretzel prior to baking

17 would provide the information to discern whether Maillard browning was more likely to occur under different conditions. In addition, effect of oven temperature could also be investigated, as temperature often impacts the presence of Maillard browning. For instance, increasing the temperature of the oven to 400 degrees Fahrenheit, rather than 325 degrees Fahrenheit may produce an increased presence of Maillard browning. Therefore, additional research concerning the aspect of Maillard browning is warranted with the fortification of soft pretzels. There are a variety of sources of error that could have occurred during the experimentation of the soft pretzels. One source of human error could have been the Seed Volume Apparatus which could have been incorrectly used due to the lack of knowledge on how to use the machine. Another source of human and mechanical error could have been the Texture Analyzer not working properly or the correct settings may not have been used. A third source of error could have been not following the directions exactly, which could have led to a variety of inaccurate results. For example, too much or too little of the ingredients could have been added to the pretzel dough which could have resulted in an inconsistent pretzel batch. A final source of error could have been conversion factors of each of the ingredients. These calculations could have been done incorrectly which could have led to inaccurate amounts being added to the dough. In conclusion, future research is needed due to sources of error. In summary, the effect of fiber fortification on soft pretzels resulted in an undesirable product. Maillard browning was not present in any of the three pretzel trials leading to a nonaesthetically pleasing product. The taste of the three pretzel products was also not desirable as rated by the taste panel using the Hedonic Scale. Despite product downfalls, the texture of each of the three pretzel products was desirable and yielded a texture that resembled soft pretzel

18 products available at the grocery. Overall, the pretzels were not optimal in taste, however future research and experimentation could yield a pleasing fiber fortified product. Appendix 1: Sample calculation for the Seed Volume apparatus can be found on the blue carbon copies of the data collection. VII. References 1. Baylock J, Smallwood D, Variyam JN Dietary Fiber: Is Information the Key? Moving Towards Healthier Diets. Food Review Bente L, Hiza H, Fungwe T "Dietary Fiber in the United States Food Supply." United States Department of Agriculture Center for Nutrition Policy and Promotion. Washington, DC Daniel JR Food Chemistry Lecture Notes Kid s Health Pretzels. Retrieved September 20, 2008, from Kids Health for Kids Web site: 5. Kojima M, Wakai K, Tamakoshi K, Tokudome S, Toyoshima H, Watanabe Y, et al Dietary fiber and risk of colorectal cancer in the Japan Collaborative Cohort Study. Cancer Epidemiol Biomarkers Prevention. 50(1): Park H, Seib PA, Chung OK Fortifying bread with a mixture of wheat fiber and psyllium husk fiber plus three antioxidants. Cereal Chem. 74(3): Slavin JL, Martini MC, Jacobs DR, Marquart L Plausible mechanisms for the protectiveness of whole grains. Amer J Clin Nutr. 70 (3):459S-463S. 8. Tabernero MM, Serrano JJ, Saura-Calixto F, Fulgencio JA Dietary Fiber Intake in Two European Diets with High (Copenhagen, Denmark) and Low (Murcia, Spain) Colorectal Cancer Incidence. Food Chem. 55(23): Wang J, Rosell CM, Barber CB Effect of the addition of different fibres on wheat dough performance and bread quality. Food Chemistry.79 (2):