Omega Fatty Acids in Veggie Burgers. Sasha Harrison, Laura Schmidt, and Margaret McCann

Transcription

1 Omega Fatty Acids in Veggie Burgers Sasha Harrison, Laura Schmidt, and Margaret McCann

2 2 Omega Fatty Acids in Veggie Burgers Abstract: Vegetarian diets tend to be low in omega fatty acids due to the lack of seafood, meats, and eggs. The aim of this experiment was to look at the effects of added hemp and flax seed, which contain omega fatty acids, on a homemade vegetarian burger. These entrees were compared to the control, which was the same recipe, but with no added seeds. It was found that these variables, in comparison with the control, had no significant difference on the texture or water activity of the final products. There was also no significant difference found in the palatability, which was determined with the categories of taste, appearance, and texture using a triangle test. It was concluded that the addition of omega fatty acids will improve the nutritional content of the vegetarian burger without significantly altering the texture and palatability.

3 Omega Fatty Acids in Veggie Burgers 3 Introduction: The goal of this project was to create a product that would increase the fatty acid content of vegan and vegetarian diets. This deficiency is present among this population of people due to lacking intake of EPA and DHA. Essential fatty acid alpha-linoleic, or ALA, is an omega-3 fatty acid that can be converted to EPA and DHA. Omega-3s are required for cell signaling molecules, metabolic functions, and possess anti-inflammatory characteristics as found in a scholarly article published in Critical Reviews in Food Science and Nutrition by K.K Singh (2011). Since EPA and DHA are primarily found in food sources eliminated by vegetarians, such as seafood, lean red meats, and eggs, it is crucial for these amino acids to be provided by other means. ALA can be converted to EPA and DHA, therefore serving as a desirable component of a vegan or vegetarian diet. Found in nuts, seeds, and seed oils, ALA can be effectively incorporated into other food products such as breads, rolls, muffins, and dressings (Harper, 2006). Not only is it crucial to incorporate these omega-3 fatty acids into the diet, but to do so in a way that meets the recommended ratio range of 4:1 to 10:1 omega-6:omega-3 fatty acids. This ratio has been determined based on the competition of enzymes between these two fatty acids, and consequently interferes with their metabolism (Schwab, 2006). Vegetarian style burgers were selected as a product to enrich with omega-3 fatty acids due to their commonly approved and enjoyed taste, texture and appearance. In addition, this product renders itself practical to enrich due to the various sensory and chemical characteristics of the product. Flax seed provides about 3 times the adequate intake of ALA and hemp seed contains the ideal ratio of omega-6:omega-3 fatty acids. As a result, these two sources are ideal to use as a source of enrichment for vegetarian burgers. When preparing this product, certain factors must be monitored in order to preserve the palatable taste, texture, and appearance. For example, water activity is a crucial factor to measure as it relates to spoilage and microbial activity (Daniel, 2003). Flaxseed in particular has a high-water absorption and moisture binding capacity, so controlling water activity will be necessary in order to preserve taste, texture, as well as the overall structure and safety of the product (Singh, 2011). Another crucial factor to monitor is the Maillard Browning reaction occurring during the cooking of a veggie burger. This reaction occurs when both sugar and amino acids are present and they are treated with heat. Vegetarian burgers contain both of these molecules, and when cooked it results in a darkening throughout the patty. This non-enzymatic browning combined with the dark crust surrounding the patty give the texture and look that had become standard for this vegetarian entrée.

4 4 Omega Fatty Acids in Veggie Burgers Figure 1. Maillard Reaction Review of methods: Subjective tests for food products are varied, and each method has its associated pros and cons. For this experiment the most suitable subjective test was a ranking test on three important qualities of the product: appearance, taste and texture. These qualities are what will most likely determine customer satisfaction, so it is essential that they be up to standard in a product. The independent variable in this product is the addition of Omega Fatty Acid containing ingredients. In this experiment 20 grams of hemp seed and 20 grams of Flaxseed were used as the variables. The control did not contain any seeds. The dependent variable is the palatability of the product tested through subjective measures including taste, appearance and texture. Objective testing was also done using the texture analyzer and water activity machine. Purpose of project The purpose of this project is to test the incorporation of Omega Fatty Acid containing ingredients into a vegetarian entrée. This would be beneficial to vegetarian consumers because the many essential fatty acids, such as Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) specifically, are found in seafood, lean red meats, organ meats, and eggs. Vegetarians and vegans, who exclude these sources, will display "very low or negligible intakes of EPA and DHA". (Rosell, 2005). Between 5 and 10 percent of dietary alpha-linoleic acid can be converted to EPA and DHA. By increasing dietary status of alpha-linoleic acid in vegetarians through inclusion of hemp or flax seeds we can improve the EPA and DHA status as well. Approach: Ingredients for one batch 114 g cooked black beans, drained and rinsed 27 g minced onion

5 Omega Fatty Acids in Veggie Burgers 5 18 g grated carrot 33 g cooked brown rice 14 g oatmeal 10 g whole-wheat flour 10 ml soy sauce 10 ml water 10 ml vinegar 0.17 g thyme 1.67 g rosemary 0.87 g chili powder 0.33 g cumin 20 ml vegetable oil -Variable: 20 g seeds- Hemp or Flax seeds, chopped. -38 g bread crumbs for dredging Procedure/Instructions: 1. Preheat oven to 177 Degrees C 2. Process beans in a food processor until homogenous consistency. 3. Mix in all other ingredients, except dredging materials (bread crumbs). 4. Take 70 grams of mixture at a time and shape into patties. Coat both sides of the patties in the crumbs or wheat germ. Let them set for 20 minutes. 5. Bake the burgers at 177 Degrees C for 30 minutes. Methods: The burgers were prepared according to the above directions. Three variations of the recipe were prepared. Batches a-c of 118 contained no addition of a variable. Batches a-c of 489 contained 20 grams of hemp seeds as a variable. Batches a-c of 779 contained 20 grams of flax seed as a variable. For each variation three batches were made. A food processor was used to ensure consistency of the burger blend. The entire mass of the blend was divided into equal gram amounts. Burgers were cooked in an oven to remove the variability of the oil temperature, and so all the batches were cooked at the same time and under the same conditions. Subjective Tests: Subjective sensory evaluation was done with 1/6 of a burger per taster. Tasters were NUTR 453 students and they were asked to rank burgers based on taste, appearance and texture. (see Figure 1 below). The type of test used was a ranking test. Please rank from 1 (most preferred) to 3 (least preferred) for each variable and quality Variable Taste Appearance Texture Figure 2. Subjective Scorecard

6 6 Omega Fatty Acids in Veggie Burgers Randomization: The organization of the samples was done to avoid bias. The triangle method for organization was used, as can be seen in Figure 2, below. Figure 3. Sample Table Design 489 A 489 B 799 A 118 B 118 C 489 C 799 B 799 C 118 A Sampling: Each sample portion was 1/6 of a patty, approximately 12 g. Samples were served on white paper plates with white napkins and white plastic utensils. Objective Tests: Objective tests that were done include a texture analyzer and water activity. The texture analyzer was operating using the Meat setting and the cone probe. See The Food Chemistry Laboratory Manual pp. 125, 127 and for instructions. Discussion: The null hypothesis for this experiment stated that increasing omega fatty acids would not affect the taste, appearance, texture, or water activity (aw) of the vegetarian burger. All of the data collected from the texture analyzer and water activity machine were analyzed using a statistical program called InStat. It was found that there was no statistical significance for the Texture Analyzer data, Water Activity Data, and Water Activity Temperature data. The statistical reasoning for there being no significance, is because the p value for all three data sets were greater than A p value > to 0.05 means the results were not significant, p < 0.05 being significant, and p < 0.01 being highly significant (McCluskey 2007). The p values were 0.53, 0.96, and 0.99 for the Texture Analyzer, Water Activity, and Water Activity temperature, respectively, proving the results were not statistically significant for this experiment. The results from the objective tests support the null hypothesis that the overall texture and water activity of the vegetarian burgers did not change when omega fatty acids were added. It is recommended that vegetarians, who are not consuming adequate amounts of omega fatty acids, try adding flaxseed into their diet as a way to increase these fats (ADA 2003). Having no significant results from these tests shows that adding products such as flaxseed or hemp to foods to increase the amount of fatty acids will not make a significant difference in the overall product. For this experiment, these results are what the experimenters were looking for. If the vegetarian burger with added hemp or flaxseed did not have a significant difference on texture in comparison with the control, than it seems omega fatty acids can be added to products such as

7 Omega Fatty Acids in Veggie Burgers 7 this to increase the health benefits without having to sacrifice the consistency or texture of the product. When looking at the data from the water activity tests, even though the data was not statistically significant, the values can still produce information about the product. Water activity is a test that represents the ratio of water vapor pressure of the food to the water vapor pressure of pure water, under the same conditions (UC Davis 2001). For water activity there is a scale from 0 (bone dry) to 1.0 (pure water). The closer the value is to 1.0 the more moist the product is. In this experiment, the control (with no added omega fatty acids) had an average of The added hemp had a water activity of 0.91 and the flaxseed One problem that water activity could have on this product would be food spoilage. It has been found that foods with a water activity value between are the most susceptible for microorganisms to grow (Beuchat 1981). The water activity of the hemp had a value close to the control but the flaxseed had a value almost 0.1 higher than the control. This could have been due to experimental error because a value of 0.99 means it would be almost the same as pure water. Even though the same water activity machine was used for all 9 trials, it could have been incorrectly calibrated. Another source of error could be which part of the veggie burger was used. If the sample had been taken from the center where it was the most moist, the value would have been higher than if the sample was taken from the outside edge of the burger, which would have been more crispy and less moist. After performing subjective tests on our food samples, it can be concluded that no significant difference exists between the two variables and the control. While the control sample received the highest least preferred rating, the data was not overwhelmingly conclusive in favor our hypothesis. In evaluating taste, the control sample averaged a score of 3.33 most preferred ratings and an average score of least preferred ratings, which can be referenced in Table 6. The hemp and flax seed samples both received average ratings of 9.33 for most preferred while the hemp samples received an average of 4.67 ratings of least preferred the flax samples received 4 least preferred ratings, as indicated in Tables 7 and 8. The InStat analysis revealed that no statistically significant difference is present among the samples. The mean difference for all samples was between and 1.890, so therefore not a large enough difference to be considered significant. The p value of , was not significant since p was not found to <0.05. Although these results are not statistically significant, it can be observed that a slight preference for flax and hemp seed occurs over the control. The sensory characteristics of food samples is crucial in determining the acceptability of the product as supported by the American Journal for Clinical Nutrition, sensory factors play a major role in food cravings and in food selection. Furthermore, the mechanism that is involved is most likely sensitive to the sense of taste (Drewnowski, 2013). Both received a greater average of most preferred and preferred ratings than the control and received a very low average of least preferred ratings. The hemp and flax received slightly higher approval ratings due to the potential to provide for a meaty mouthfeel as well as a nutty flavor. In addition, the flax and hemp seed have high-water absorption and moisture-binding capacity (Singh, 2011). This correlates to higher texture ratings for both the flax seed and hemp seed samples, most likely due to increased moistness of the sample. Since the flax and hemp seed samples contain a higher fat content this can be identified to positively correlate with higher preference rankings. As stated in an article published in the American Journal of Clinical Nutrition, Fat is responsible for the characteristic texture, flavor, and aroma of many foods, and largely determines the palatability of the diet (Drewnowski, 2013). This serves as proof that while the

8 8 Omega Fatty Acids in Veggie Burgers nutritional value may be in question, fat content plays a significant role in determining preferable taste and texture characteristics. The appearance of the control sample was also lower than both the flax and hemp seed samples. The addition of the seeds most likely contributed to a more typical, or expected burger-like appearance, which the control may have appeared to be lacking when paired with the other samples. The texture data displayed the most consistency in terms of ranking, with the control once again resulting in the least preferred. The quality and acceptability of the texture was affected by the addition of the seeds, which served to provide a meaty mouthfeel in our product. This contributed to a greater palatability, which was found to be lacking in the control. Based on these findings, it can be concluded that the initial hypothesis of this project is incorrect and the addition of flax and hemp seeds did not increase the overall palatability of the vegetarian burgers. This can be attributed to a variety of factors, each posing a means for future evaluation. Although our samples contained fatty-acids, an increase in fat content may be needed to provide for a more widely preferred taste and texture as fat content plays a large role in determining product flavor and richness (Daniel, 2003). Increasing fat content by incorporating larger quantities of hemp seeds, flax seeds or other ingredients such as vegetable oil or beans can also serve to improve desirability. Other possible areas of error may stem from the temperature of the food at time of tasting, time of day when tasting, the other samples tasted during that time period, and the individual preferences of the test subject. Variations in cooking times may have affected the appearance of the samples, causing some to appear more browned than others, so more uniform time and temperature scrutiny will prevent this error in the future. In regards to measuring results, a more specific scale would be helpful in determining particular reasons a sample was liked or disliked. While a simple scale is easy to gather results from, it is difficult to interpret why a test subject preferred one sample to another. The preference scale could be expanded to 1-5 or 1-10 to provide for a more detailed evaluation of a consumer s level of satisfaction with a particular sample. The take home message of this report is that the addition of Omega Fatty Acid containing ingredients improved the nutritional content of the product without significantly altering the texture and palatability. Further studies could be done to improve the fatty acid ratio in vegetarian burgers. This could be done through the incorporation of other fatty acid containing oils or supplement powders. Studies could also be done testing the effect of varying amounts of the ingredients used in this experiment. The amount made in further studies could also be tested, as the batches made in this experiment was very small.

9 Omega Fatty Acids in Veggie Burgers 9 Results: Figure 4: Post Preparation Sample Pictures Sample 118- Control Sample Sample 489- Hemp Seed Sample Sample 799- Flax Seed Sample Table 1: Texture Analyzer Data Control (118) Hemp (489) Flax (799) Trial A Trial B Trial C Average Standard Deviation

10 10 Omega Fatty Acids in Veggie Burgers Table 2: Water Activity Data Control (118) Hemp (489) Flax (799) Trial A Trial B Trial C Average Standard Deviation Table 3: Water Activity Temperature Control (118) Hemp (489) Flax (799) Trial A Trial B Trial C Average Standard Deviation Figure 5: Texture Analyzer Data Force (g) Texture Analyzer Data Control Hemp Flax TA Figure 5: The data collected from the texture analyzer for all three trials, for each variable, was averaged and graphed in the above figure. Results were not statistically significant, with a p value greater than 0.05, computed using InStat.

11 Omega Fatty Acids in Veggie Burgers 11 Figure 6: Water Activity Data 1.05 Water Activity Data Water Activity WA 0.8 Control Hemp Flax Figure 6: The water activity data was collected for all three trials, for each variable, and the values were averaged and graphed in the above figure.results were not statistically significant, with a p value greater than 0.05, computed using InStat. Figure 7: Water Activity Temperature Temperature ( o C) Water Activity Temperature Control Hemp Flax Temp Figure 7: The temperature from the water activity data was collected for all three trials, for each variable, and the values were averaged and graphed in the above figure. Results were not statistically significant, with a p value greater than 0.05, computed using InStat. Table 4: Preference Ranking Averages for each Variable and Subjective Test: Average Number of Test Subjects Preference Ranking Control Average Hemp Seed Average Flax Seed Average Standard Deviation Most Preferred (1) Prefer (2) Least Preferred (3)

12 12 Omega Fatty Acids in Veggie Burgers Table 5: Control Subjective Preference Ratings 118 Taste Appearance Texture Average Standard Deviation Table 6: Flax Subjective Preference Ratings 799 Taste Appearance Texture Average Standard Deviation Table 7: Hemp Subjective Preference Ratings 489 Taste Appearance Texture Average Standard Deviation Figure 8: Control Subjective Test Data Control Number of Test Subjects Taste Appearance Texture Subjective Test "Preference Ranking 1" "Preference Ranking 2" "Preference Ranking 3" Figure 8: The data collected and graphed above represents the average preference rankings (either 1, 2 or 3) for each subjective test. Results, calculated using InStat, were not statistically significant since the p value is greater than 0.05.

13 Omega Fatty Acids in Veggie Burgers 13 Figure 9: Hemp Seed Average Subjective Data Hemp Seed Number of Test Subjects Taste Appearance Texture "Preference Ranking 1" "Preference Ranking 2" "Preference Ranking 3" Subjective Test Figure 9: The data collected and graphed above represents the average preference rankings (either 1, 2 or 3) for each subjective test. Results, calculated using InStat, were not statistically significant since the p value is greater than Figure 10: Flax Seed Average Subjective Data Flax Seed Number of Test Subjects Subjective Test Preference Ranking 1 Preference Ranking 2 Preference Ranking 3 Figure 10: The data collected and graphed above represents the average preference rankings (either 1, 2 or 3) for each subjective test. Results, calculated using InStat, were not statistically significant since the p value is greater than 0.05.

14 14 Omega Fatty Acids in Veggie Burgers References: American Dietetic Association and Dietitians of Canada Vegetarian Diets. Journal of the American Dietetic Association. Vol 103 No.6: pg Beuchat Water Activity of Some Foods and Susceptibility to Spoilage by Microorganisms. Penn State Extension. extension.psu.edu/food/.../water- activity...foods/water-activity-of-foods Drewnowski, Adam Energy intake and sensory properties of foods. The American Journal for Clinical Nutrition. Vol 62 No. 5: pg Ajcn.nutrition.org/conten/62/5/10815.full.pdf+html Harper, Charles R Flaxseed Oil Increases the Plasma Concentrations of Cardioprotective (n-3) Fatty Acids in Humans. American Society for Nutrition 136, no. 1: pg McCluskey, A Statistics IV: Interpreting the results of statistical tests. Continuing Education in Anaesthesis, Critical Care and Pain. Vol 7 No.6: pg Ceaccp.oxfordjournals.org/content/7/6/208.full Rosell, MS et al Long-Chain n-3 Polyunsaturated Fatty Acids in Plasma in British Meat- Eating, Vegetarian, and Vegan Men. American Journal of Clinical Nutrition 82, no. 2: pg Singh, K.K et al Flaxseed: A Potential Source of Food, Feed and Fiber. Critical Reviews in Food Science and Nutrition 51, no. 3: pg Schwab, US ; Callaway, JC ; Erkkila, AT ; Gynther, J ; Uusitupa, MIJ ; Jarvinen, T Effects of Hempseed and Flaxseed Oils on the Profile of Serum Lipids, Serum Total and

15 Omega Fatty Acids in Veggie Burgers 15 Lipoprotein Lipid Concentration and Haemostatic Factors. European Journal Of Nutrition 45, no. 8: pg University of California, Davis. (2001). Water Activity in Food. drinc.ucdavis.edu/dairychem4_new.htm Weaver, C. and Daniel, J Physical Properties of Food. The food chemistry laboratory: A manual for experimental foods, dietetics, and food scientists. Ed 2., pg 44,55, 125, 127, Boca Raton: CRC Press.