Research Project. Gina Bressani Alicia Porras Brittany Wonnell. Purdue University

Transcription

1 Fiber Supplemented Oatmeal Bars 1 Running Head: Fiber Supplement Oatmeal Bars Research Project The effect of an added fiber supplement on the physical and sensory properties of fruited oatmeal bars Gina Bressani Alicia Porras Brittany Wonnell Purdue University Dr. James R. Daniel FN 453 Food Chemistry Section 003 Report Submitted: November 21, 2011

2 Fiber Supplemented Oatmeal Bars 2 ABSTRACT Research has shown that large portions of the population in the United States fail to incorporate the recommended amounts of fiber in their daily diets. Dietary fiber can be essential to support heart health, as well as to promote colon health. The effects of added fiber to fruited oatmeal bars on the viscosity, color, texture, and overall consumer acceptance was evaluated. Three variations of fruited oatmeal bars were prepared: Control (0% added fiber), Variation I (1.5% added fiber), and Variation II (3.0% added fiber). The viscosity of apple butter showed to follow a Non- Newtonian pseudoplastic behavior. Added fiber increased the apparent viscosity of apple butter for every measured speed, from 40,156 cp in the Control to 45,511 cp in Variation II (at 10 rpm). The added fiber did cause the apple butter to have a slightly lighter color for Variation II, but did not affect consumer acceptance. In terms of texture, the added fiber caused the maximum compressive force to decrease. Consumers perceived this same tendency, where Variation I and II were consistently rated softer than the Control. Overall consumer acceptance was not affected by added fiber. Further research may be conducted to determine the maximum amount of fiber that can be added to this product without affecting consumer acceptance. I. Introduction Dietary fiber in the United States is a vital nutrient that many individuals do not meet recommendations to on a daily basis. Americans, on average consume half of the twenty to thirty- five grams of fiber a day. 1 Foods that are high in fiber can be difficult to implement in diets or are unfavorable in taste. A solution to this problem would be the addition of the natural fiber, Benefiber. Benefiber is a soluble fiber supplement which contains the ingredient wheat dextrin. This supplement is used to increase the overall weight of fiber in a variety of food when added (Benefiber 2001). Wheat dextrin has the ability to produce short chain fatty acids while fermenting in the colon. These fatty acids are beneficial to the body in regards to improving water absorption of the body and its colonic salts. Adding a fiber supplement to food also shows apparent viscosity increase in food products without changing the overall behavior of the product. 2 For purposes of this study, key physical properties were measured to determine the viscosity, color, and texture variations in differing added Benefiber amounts in fruited oatmeal bars. Fruited oatmeal bars were prepared using a controlled method of no addition of extra fiber supplement. The first variation included the same ingredients as the control, but 14 grams of Benefiber was added (1.5% of the total recipe weight). The second variation introduced Benefiber in larger amounts, with the addition of 28 grams of Benefiber (3% of the total recipe weight). A. Effect of Viscosity The methods utilized throughout the study included the measurement of overall viscosity of the apple butter for each version of the fruited oatmeal bars. Color as well as texture differences were also analyzed in regards to the different variations. To evaluate viscosity readings as well as differing shearing rates, the Digital Brookfield Viscometer was used in regards to the amount of apple butter plus added Benefiber used in each version. These objective methods were varied in regards to the apple butter and fiber variation in the control (0% added fiber), Variation I (1.5% added fiber), and Variation II (3% added fiber).

3 Fiber Supplemented Oatmeal Bars 3 B. Effect of Color Color deviations of the apple butter were measured using the Hunter Colorimeter for each variation. The coloring of the food is usually a key factor affecting the general acceptance of the product in regards to consumer demands. This measurement was taken to see if the addition of the Benefiber supplement would lighten or darken the overall appearance of the fruited oatmeal bars. C. Effect of Texture Texture was assessed to determine the compressive strength of the fruited oatmeal bars. The Stable Micro Systems Texture Analyze with the cone probe was used to determine these potential changing factors. 3 Oatmeal and other snack bars have the essential need of consumer acceptance in regards to texture. The data measured would show how hard the fruited oatmeal bar is in regards to the amount of fiber that was added to each version. 3 The factors manipulated in this experiment, or independent variables, include the amount of Benefiber that is added to the fruited oatmeal bars. This includes the no fiber added, 14 grams of Benefiber, and 28 grams of fiber variations. To measure the effects of the changes of the independent and to test the overall purpose of this study, dependent variables including measuring viscosity, texture, and the overall taste. To directly observe the effects on the dependent variables, some variables were kept constant, such as, temperature, cooking time, and the overall main recipe (not including the addition of increasing Benefiber ). II. Methodology The experiment began with a fruited oatmeal bar recipe obtained from the Benefiber website. Preparation included mixing all dried ingredients, preparing three variations (the control, 0% added fiber; Variation I, 1.5% added fiber; Variation II, 3% added fiber) of the apple butter/ Benefiber mixture, and then combining all ingredients until a homogenous mix was achieved. After, the mix was evenly spread onto a 20X33 cm nonstick pan. To avoid any discrepancies in the results, the only change in the recipes between the three variations was the amount of fiber added in each. The three types of variations were then properly labeled using random three digit numbers. Random three digit numbers were used to ensure randomization and avoid any bias that could have come from specific numbering of the variations. The numbers used included 489, 732, 954. The recipes used for the control variable, variable I, and variable II are as follows: Recipe: Control Quaker Dry Oats Ground Cinnamon Dried Mixed Berries Almonds Apple Butter 240 g 2.3 g 240 g 47.5 g g Recipe: Variation I Quaker Dry Oats Ground Cinnamon Dried Mixed Berries Almonds Apple Butter Benefiber 240 g 2.3 g 240 g 47.5 g g 14 g Recipe: Variation II Quaker Dry Oats Ground Cinnamon Dried Mixed Berries Almonds Apple Butter Benefiber 240 g 2.3 g 240 g 47.5 g g 28 g After all recipes of the three variations were prepared, the variations were placed in an oven preheated to 177 C. Each variation was placed in the same oven for twenty minutes. To ensure all variations received the same amount of heat, each variation was individually baked on the same

4 Fiber Supplemented Oatmeal Bars 4 shelving unit, in the same oven. After the recipes baked for 20 minutes, they were immediately cut into 24 5x5 cm square pieces. After the pieces were cut, they were cooled off in room temperature. Once cooled, the bars were removed from the pan and placed in a closed container for 24 hours. Pictures of the baked fruited oatmeal bars are shown in the Appendix. To compare the three recipes, subjective and objective methods were used. Viscosity, color, and texture were selected as the key physical properties to measure (pictures shown in Appendix). These properties were selected based on current research and the principle properties that can alter consumer acceptability. In regards to viscosity, it is essential to understand the effects added fiber has on the viscosity of the apple butter, not the oatmeal bar. The viscosity of the apple butter was measured using a Brookfield Viscometer. To accurately obtain correct readings from the Brookfield Viscometer, each variation of the apple butter was individually placed in a 600- ml beaker. The temperature of each sample was then taken to assure that all samples were within a temperature range of 20 to 25 C (avoiding any viscosity variations due to temperature). For this specific experiment, spindle 6 was used. The viscosity readings were recorded at 10 rpm, 20 rpm, 30 rpm, 50 rpm, and 60 rpm. In order to obtain the most accurate data, three replications were done for each of the speeds with each variable. Data for each replication was recorded when the viscometer displayed a constant or near- constant value. The next objective measurement taken was the color of the apple butter. This measurement was taken to determine if there were any color deviations within the three oatmeal bars. These measurements were obtained using a Hunter Colorimeter. Readings were recorded for the L, a, and b values from the Master Color Data window. The texture of oatmeal bars was the final objective measurement taken. To compare the texture of fruited oatmeal bars with added fiber in comparison to the control sample, a Stable Micro Systems Texture Analyzer with the cone probe was used. The granola sample setting was used (pre- test speed: 2.0 mm/s, test speed: 3.0 mm/s, post test speed: 10.0 mm/s, rupture test distance: 1.0 mm, distance: 8.0 mm, force: g, time: 5.00 seconds, count: 5). The maximum force in compression was determined for each sample. Three random samples of the finished fruited oatmeal bars were taken from the three types of variations. Samples were uniform in size and shape (10 cm x 10 cm). All the data that was obtained from the texture analyzer was recorded, but only the maximum force in compression was used for analytical purposes. A subjective taste panel was utilized in order to obtain feedback on various sensory characteristics. The variables measured by the panel were taste, texture, and overall appeal. Samples of the three variables were placed on trays and once again coded using the same random 3 digit codes used during preparation. The subjective taste panel consisted of Food Chemistry students. The panel was not given information on the ingredients used or the objectives measured. The subjective testing took place in Stone Hall room 229. The panel was asked to rank the samples based on the hardness of the texture. Next, they were asked to rank the samples from most palatable to least palatable. Finally, they were asked to individually score each sample using a hedonic ranking scale. A sample of the sensory score card is represented in the following page.

5 Fiber Supplemented Oatmeal Bars 5 1. Rate samples 732, 489, 954 on the hardness of texture None Slight Moderate Strong Extreme 2. Rank samples 732, 489, and 954 in descending order based on the pleasant of taste Most Palatable Least Palatable 3. Hedonic Test: Rate Sample 732 by checking box: [ ] Dislike extremely [ ] Dislike very much [ ] Dislike moderately [ ] Dislike slightly [ ] Neither like or dislike [ ] Like slightly [ ] Like moderately [ ] Like very much [ ] Like extremely Rate Sample 489 by checking box: [ ] Dislike extremely [ ] Dislike very much [ ] Dislike moderately [ ] Dislike slightly [ ] Neither like or dislike [ ] Like slightly [ ] Like moderately [ ] Like very much [ ] Like extremely Rate Sample 954 by checking box: [ ] Dislike extremely [ ] Dislike very much [ ] Dislike moderately [ ] Dislike slightly [ ] Neither like or dislike [ ] Like slightly [ ] Like moderately [ ] Like very much [ ] Like extremely

6 Fiber Supplemented Oatmeal Bars 6 III. Results Table 1.1 below shows the viscosity mean and standard deviation values obtained from the Brookfield Viscometer for five different spindle speeds: 10, 20, 30, 50, and 60 rpm. From the table it is apparent that for every given speed, both Variation I and Variation II were statistically different from the Control viscosity readings. At higher speeds (30, 50, 60 rpm) the table shows that the viscosity readings for Variation I and II were statistically significantly different from each other. Table 1.1 Recorded Viscosity Readings at Varying Spindle Speeds 10 rpm Viscosity cp 20 rpm 30 rpm 50 rpm 60 rpm Control - 0% added fiber b ± b ± c ± c ± c ± 524 Variation I - 1.5% fiber a ± a ± b ± b ± b ± 604 Variation II - 3.0% fiber a ± a ± a ± a ± a ± 576 Mean viscosity ± standard deviation. a- c Data baring different superscripts in the same column are statistically significant (p < 0.05). The corresponding Figure 1.1, shows the pseudoplastic (shear thinning) behavior of apple butter, where increasing shear rates resulted in decreasing apparent viscosity. The figure also shows that the Control had consistently the lowest viscosity, with a maximum viscosity of 40,156 cp and minimum viscosity of 9,062 cp. Variation I was consistently in between the values of the Control and Variation II, with a maximum viscosity of 43,844 cp and a minimum of 10,631 cp. Variation II, therefore, consistently resulted in the highest viscosity for all measured speeds, with a maximum viscosity of 45,511 cp and a minimum of 11,511 cp. Added fiber, therefore, increases the overall apparent viscosity of apple butter Control - 0% added fiber Variation I - 1.5% fiber Variation II - 3.0% fiber Viscosity (cp) Spindle Speed (rpm) Figure 1.1 Viscosity readings of apple butter at varying spindle speeds.

7 Fiber Supplemented Oatmeal Bars 7 Table 2.1 and Figure 2.1, below, show the mean Hunter Colorimeter readings for the three tested variations. The Control and Variation I were not statistically different from each other, but Variation II was statistically different from both the Control and Variation I. Variation II showed to have a lighter color, since it had an L value of 15.82, which was higher than the Control and Variation II (14.08 and 14.28, respectively). It also resulted in a higher a value, and therefore, a redder color. The higher b value of 7.94 for Variation II shows that it had a more yellow color than the Control and Variation I (6.81 and 6.98, respectively). Table 2.1 Hunter Colorimeter Readings Hunter Colorimeter L a b Control - 0% added fiber b ± b ± b ± 0.06 Variation I - 1.5% fiber b ± b ± b ± 0.17 Variation II - 3.0% fiber a ± a ± a ± 0.30 Mean colorimeter reading ± standard deviation. a- b Data baring different superscripts in the same column are statistically significant (p < 0.05). Control - 0% added fiber Variation I - 1.5% fiber Variation II - 3.0% fiber Hunter Colorimeter Reading L a b Figure 2.1 Hunter colorimeter L, a, b readings.

8 Fiber Supplemented Oatmeal Bars 8 Table 3.1 and Figure 3.1, below, show the mean and standard deviation values for the maximum compression force obtained from the Texture Analyzer. The table shows Variation I, as compared to either the Control or Variation II, was not statistically different from either variation. The Control and Variation II, on the other hand, showed to have a statistically significant difference in terms of measured maximum force. The Control had the largest compression force, with a force of N, followed by Variation I (3.067 N), and Variation II had the lowest average compression force of N. This shows that higher percentages of added fiber contributed to lower compressive forces. Table 3.1 Maximum Compression Force Maximum Force N Control - 0% added fiber a ± Variation I - 1.5% fiber ab ± Variation II - 3.0% fiber b ± Mean force ± standard deviation. a- b Data baring different superscripts in the same column are statistically significant (p < 0.05) Maximum Force (N) Control - 0% added fiber Variation I - 1.5% fiber Variation II - 3.0% fiber Figure 3.1 Observed mean values for maximum compression force of different variations of fruited bars.

9 Fiber Supplemented Oatmeal Bars 9 The response distribution for Question 1 in the subjective taste panel, where the panelists were asked to rank the samples in terms of hardness of texture, is shown in Table 4.1 and Figure 4.1. For all variations, twenty percent of the panelists categorized the hardness of texture as none, and zero percent rated the samples as extreme. Differences in panelist distribution were shown for the categories of slight, moderate, and strong. Variation II, was in general, categorized as the least strong, where 50% categorized the variation as slight, and 30% as moderate. The Control, on the other hand, was categorized as the strongest in terms of texture, since it had the highest percent (15%, versus 5% for Variation I, and 0% for Variation II) of panelist ranking the samples as strong. Variation I, in general, was categorized in the middle of both the Control and Variation II. These results correlate with the objective data obtained from the texture analyzer, where higher percentages of added fiber contributed to lower compressive forces. Table 4.1 Panelist Distribution According to "Hardness of Texture" Panelist Distribution (% ) None Slight Moderate Strong Extreme Control - 0% added fiber 20% 35% 30% 15% 0% Variation I - 1.5% fiber 20% 30% 45% 5% 0% Variation II - 3.0% fiber 20% 50% 30% 0% 0% Panelist Distribution 100% 90% 80% 70% 60% 50% 40% 30% None Slight Moderate Strong Extreme 5% 15% 30% 30% 45% 50% 35% 30% 20% 10% 0% 20% 20% 20% Control - 0% added fiber Variation I - 1.5% fiber Variation II - 3.0% fiber Figure 4.1 Panelist distribution on the rating of texture (hardness) category.

10 Fiber Supplemented Oatmeal Bars 10 Table 4.2 and Figure 4.2 show the panelist distribution for the response of the second question in the subjective taste panel, where panelist were asked to rank samples in descending order based on the pleasant of taste, from most to least palatable. The results show that for 43% of the panelists, Variation I was the most palatable. The Control, on the other hand, was ranked as least palatable by 46% of the panelists. When considering the overall rankings, Variation II was generally liked the most. Only 18% of the panelist categorized Variation II as the least palatable, whereas for Variation I, 36% of the panelists ranked it as least palatable. Table 4.2 Rank Distribution in Terms of "Pleasant Taste" Panalist Distribution (% ) Most Medium Least Control - 0% added fiber 25% 29% 46% Variation I - 1.5% fiber 43% 21% 36% Variation II - 3.0% fiber 32% 50% 18% Most Medium Least 100% 90% 18% Panelist Distribution 80% 70% 60% 50% 40% 30% 46% 29% 36% 21% 50% 20% 10% 25% 43% 32% 0% Control - 0% added fiber Variation I - 1.5% fiber Variation II - 3.0% fiber Figure 4.2 Panelist distribution on the rating of samples in terms of "pleasant taste".

11 Fiber Supplemented Oatmeal Bars 11 The results for mean overall taste ratings are shown Table 4.3 and Figure 4.3, below. The Control had a mean ranking of 5.67, which is between 5 neither like or dislike and 6 like slightly. Variation I was ranked 6.10, which is between 6 like slightly and 7 like moderately. Variation II was given a 6.23 rating in the hedonic scale, which was also between 6 and 7. The data shows that although Variation II had the largest overall hedonic scale rating of 6.23, the differences in the ratings were not statistically significant to the Control and Variation I. The results show that added fiber does not affect the overall taste of fruited oatmeal bars. Table 4.3 Results for Overall Taste Rating of Samples Overall Taste Liking Hedonic Scale Control - 0% added fiber 5.67 a ± 1.07 Variation I - 1.5% fiber 6.10 a ± 0.26 Variation II - 3.0% fiber 6.23 a ± 0.90 Mean value ± standard deviation. a Data differences are not statistically significant (p < 0.05) Hedonic Rating Control - 0% added fiber Variation I - 1.5% fiber Variation II - 3.0% fiber Figure 4.3 Hedonic scale results for overall taste of samples.

12 Fiber Supplemented Oatmeal Bars 12 IV. Discussion This randomized blinded study showed the effects of added Benefiber in terms of viscosity, color, and texture in association to consumer preferences of texture and overall general taste. A. Effects of Viscosity When viewing the effect of viscosity of the apple butter on added fiber, results showed that the ingredient had a non- Newtonian pseudoplatic behavior. As the shear rate was increased the apparent viscosity of the apple butter in the control and added fiber variations decreased in consistent forms. This result is consistent with previous scientific research, which has shown that apple butter followed a Non- Newtonian fluid behavior. 4 Figure 1.1 shows that fiber has an added viscosity effect of the apple butter. The results also show that fiber does provide a statistically significant difference in the viscosity of the variations of fiber added compared to the control (p < 0.05). Studies have found that adding a soluble fiber to foods can increase the apparent viscosity of the overall product, but not change on the overall behavior of the product. 5 The obtained results correlate to process design parameters, such as pumping and mixing force required. If processes were designed behind the conclusions made in this study, varying machinery parameters would need to be considered. In regards to manufacturing the overall addition of Benefiber in increasing amounts, pumping force would need to be analyzed to determine what type of machinery could be used. Since the controlled variable (no added fiber) was statistically significantly different to the variations with added fiber, researchers would need to design a plan to use a different type or size of machinery to be able to manufacture at higher viscosities. B. Effects of Color Results showed that the overall color of the control and variation I (14 grams of Benefiber ) was not statistically different in color appearance. As well, differences between variation I (14 grams of Benefiber ) and variation II (28 grams of Benefiber ) were also not statistically significant. As shown in Table 2.1, the color of the control and the highest added variation, variation II, were statistically different. This shows that the more fiber that was added to the product the lighter the product became. Though variation II had the most fiber and therefore the lightest exterior, appearance was not unfavorable to consumer preferences and did not show causation to lighter the color, least the consumer preference. C. Effects of Texture The effect of added fiber on the overall texture measured in this study showed contrary results to what was hypothesized. There was no statistical significance difference in the control and variable I texture, as well as in texture of the variation I and variation II. There was, though, statistical significance between the textures of the control and variation II. When the greatest amount of fiber was added in variation II, the texture of the fruited oatmeal bar was significantly less hard than the texture of the control (no added fiber). Studies have shown that when fiber is added, the overall firmness of texture is reduced. For this significant decrease in hardness of texture, the added fiber amount must be at high levels compared to the control. This conclusion of the addition of fiber will decrease the hardness of foods could be due to

13 Fiber Supplemented Oatmeal Bars 13 the added fiber supplement disrupting the protein- starch matrix in the food that the fiber is being added to. Therefore, this study suggests that the protein- matrix in the oatmeal bar would have been disrupted by the Benefiber that was added in variation II (28 grams). 6 D. Consumer Taste Test Survey When assessing consumer opinion on the texture of the different variations of the fruited oatmeal bars, taste testers chose variation II (most fiber added) as the softest of the three variations. This subjective testing matched the objective test that was performed to test effects on compressive force of the oatmeal bars. Consumers believed that variation I and variation II were softer than the control, where no fiber was added. In terms of ranking the most favorable, or pleasant, more consumers chose variation I as having the most favorable taste. Variation II was shown to be disliked the least though, so Variation I and Variation II would be the most favorable in terms of taste of the oatmeal bars. According to the Hedonic Test that was performed, results showed the ranking to be very similar, but there was no statistical significant data of one variation of the bars compared to the other variations. Added fiber did not have a negative effect on the overall taste and feel of the fruited oatmeal bars. V. Conclusion After analyzing the data received from conducting the experiment, many key messages evolved. In regards to viscosity, viscosity decreases with increasing shear rate. However, viscosity also increases with increasing amounts of added fiber. In regards to the color, added fiber slightly changed the color of Variation II (3% added fiber). Although Variation II was slightly darker in color than the control and Variable I, the color of Variation II was still favorable to consumers. Thus, the slight change in color due to the added fiber did not affect the consumer acceptability of the product. In reference to the effect added fiber had on the texture of the product, it made the product less hard. Consumers perceived the sample with the most fiber to be the softest. Overall, the consumers preferred the product with the most added fiber. Thus, for this specific product, one can add fiber (up to 3% more), without decreasing consumer acceptability. Further research should be conducted on how added fiber can affect consumer acceptability of a product. Past research has primarily focused on how added fiber decreases consumer acceptability. The outcome of this experiment shows increasing the amount of fiber in a product, made the product more favorable to the consumer. With more and more products incorporating added fiber into its ingredients, more research should be conducted on how added fiber can increase consumer acceptability. If more reputable evidence shows that consumers favor products with added fiber, many food companies may consider incorporating fiber into their products.

14 Fiber Supplemented Oatmeal Bars 14 VI. References 1 Benefiber FAQs. January 1, Benefiber Fiber Supplement Website. Novartis Consumer Health Inc. 2 Timm, DA, Stewart, ML, Hospanttankar, A Wheat dextrin, psyllium, and inulin produce distinct fermentation patterns, gas volumes, and short- chain fatty acid profiles in vitro. Journal of Medicinal Food 13(4): Weaver, CM, Daniel, JR Equipment Guide. In: Weaver, CM, Daniel, JR. The Food Chemistry Laboratory: A manual for experimental foods, dietetics, and food scientists. 2ND ed. Boca Raton: CRC press. p Chhabra, RP, Richardson, JF Chapter 1 Non- Newtonian fluid behavior. In: Chhabra, RP, Richardson JF. Non- Newtonian flow and applied rheology. 2ND ed. Oxford: Butterworth- Heineman. p Ramirez, J, and others Enrichment of stirred yogurt with soluble dietary fiber from Pachyrhizus erosus L. Urban: effect on syneresis, microstructure and rheological properties. Journal of Food Engineering 101(2010): Tudorica, C, and others Nutritional and Physicochemical Characteristics of Dietary Fiber Enriched Pasta. Journal of Agricultural Food Chemistry 50(2): 349.

15 Fiber Supplemented Oatmeal Bars 15 VII. Appendix 1. A sample of Variation II 2. A close up view of a sample

16 Fiber Supplemented Oatmeal Bars A snap shot of the Texture Analyzer Settings 4. Obtaining data from the Texture Analyzer

17 Fiber Supplemented Oatmeal Bars Recording the viscosity of a sample 6. The samples along with the scorecard