The effect of omega-3 fatty acid supplements on the texture and quality of blueberry muffins

Becca Wharton & Leigha Hale FN 453 11/22/2010

Abstract: Cardiovascular disease is a growing problem in the United States today. One preventative step towards lowering the risk of developing cardiovascular disease is the consumption of omega-3 fatty acids. Omega-3 fatty acids added to baked products can potentially have a positive effect on the over all nutritional value of the product while having a minimal effect on the flavor and texture of the product. There has only been a small amount of research done on the benefits of fish oil in baked products. Therefore, the purpose of this experiment was to study the effects that fish oil has on blueberry muffins. Variable one contained all vegetable oil, but no fish oil. This variable is the control group. Variable two contained 50% fish oil and 50% vegetable oil. Variable three contained all fish oil and no vegetable oil. The three different variables were tested and compared subjectively and objectively over a course of three different trials. By subjective measurement on a 9-point hedonic scale, it was revealed that muffins made with fish oil were more liked, tasted better, smelt better, and was favored over the other variables. Subjective results also displayed that the 50% fish oil variable was more tender. Objectively, results showed that the addition of fish oil made the batter less viscous and made the product more sour or acidic. This acidity is due to the presence of lemon in the added fish oil. However, the subjective data showed that the addition of fish oil had a minor impact on flavor and was preferred over the control in some trials. Therefore, the addition of fish oil results in a functional product that is desirable to consumers and has the heart healthy benefits of the omega-3 fatty acids. Introduction: Edible oils are a great way of obtaining essential fatty acids in the body. These oils play a role as an energy source, and provide the diet with many beneficial micronutrients. One of the

main edible oils claiming to have beneficial health results is fish oil which contains omega-3 fatty acids (Bester, 2010). Omega-3 fatty acids have shown a decreasing effect for the risk of cardiovascular disease. Cardiovascular Disease is the leading cause of death in America and, unfortunately, does not have a direct method of treatment. This disease is exponentially victimizing the population as the years go on, and the outcome of diagnosis is often times fatal. According to the American Heart Association, in 2006, 81,100,000 people had a form of cardiovascular disease, 831,272 of which died (Cardiovascular). Cardiovascular Disease is affecting the lives of many people daily, and in the worst case scenario, killing. To say that this disease is harming America is an understatement. Prevention for cardiovascular disease is critical. To target a means of prevention for Cardiovascular Disease (CVD), there needs to be a change in the American diet. Omega-3 fatty acids have been correlated with reduced incidence of Cardiovascular Disease. In both Penny M. Kris-Etherton’s journal article, Fish Consumption, Fish Oil, Omega-3 Fatty Acids, and Cardiovascular Disease, there were studies done with Omega-3 fatty acids supporting this claim (Kris-Etherton, 2002).

Not only does the Omega-3

Fatty acids reduce the Cardiovascular Disease diagnosis, but it also reduces the deaths. B. McEwen found that these fatty acids “decreased total cardiovascular mortality” (McEwen, 2010). In order to incorporate Omega-3 fatty acids into the diet, they must be consumed in a particular amount. To have a healthy impact on the heart, omega-3 fatty acids need to be consumed in some way, whether it be supplemental or in a food. This fatty acid should be consumed daily by eating 0.8-1 grams in order to have an effect on the body (Anonymous). Therefore, this study will add a fish oil containing omega-3 fatty acids in the appropriate amount to which one can benefit.

Fish oil contains two beneficial omega-3 fatty acids, docosahexaenoic acid (DHA) and

eicosapentaenoic acid (EPA). Because it is high in omega-3 fatty acids, fish oil should be incorporated into the foods that people like. In this project, fish oil will be added to blueberry muffins, a food loved by many people whether it is eaten for breakfast, or for a snack. One muffin will have the amount of omega-3 fatty acids that is sufficient enough to have an effect on decreasing the probability of being diagnosed with Cardiovascular Disease. People typically eat what they eat because they like the taste. In order to make the product desirable, any odd flavor that the fish oil might cause will be disguised by cinnamon and honey. The blueberry muffins will be a way for omega-3 fatty acids to be consumed more regularly by being hidden in a commonly-eaten food. Methods: This project is intended to produce a blueberry muffin with all the health benefits of omega-3 fatty acids without altering the desirable taste and texture. Testing will be done both objectively by the viscometer and texture analyzer and subjectively by the structured ranking system. By comparing the original muffin recipe to two altered recipes with added omega-3 fatty acids. One group will be the control group with 59.71 ml of vegetable oil. One group will have 59.71ml of each oil, or 29.84 ml of vegetable oil and 29.84 ml of fish oil. The third group will be made up of 59.71 ml of fish oil. This will be done by following the originals recipe procedure: http://allrecipes.com/Recipe/Zucchini-Muffins/Detail.aspx

Here is a copy of the recipe used: Variable 1 (Independent): Control, Original recipe • 459.84 grams of Hodgson Mill Whole Wheat Graham Flour • 14.24 grams tablespoon baking powder • 2.37 grams teaspoon salt • 14.24 grams teaspoon ground cinnamon • 179.13 ml of non fat milk

• • • •

1.00 oz of egg whites 59.71 ml of vegetable oil 59.71 ml of honey 229.92 grams of blueberries

1.

Preheat oven to 190 degrees C. Grease muffin tins lightly with oil or spray with a nonstick cooking spray. 2. Combine whole wheat flour, baking powder, salt and ground cinnamon, mix thoroughly. 3. Mix the milk, slightly beaten egg whites, oil*, honey and blueberries together. Pour into the dry ingredients and stir until just barely moistened. Batter should be lumpy. Fill muffin tins 2/3 full with batter. 4. Bake at 190 degrees C for 20 minutes or until lightly browned. These directions are for the independent variable, for the dependent variables, an added 2.019 oz of fish oil will take place of 2.019 oz of vegetable oil*. The experiment performed had three separate trials. All three trials used the same recipe and experimental procedures. The viscometer was used to objectively measure the viscosity of each variable’s batter. The viscometer instrument is used to measure the force needed to rotate the spindle in centipoises. This was done using spindle number of 1 and the speed setting of 6 rpm. The muffins were also measured with the texture analyzer to determine the grams of force used to compress the muffin. The cone probe was used to determine texture and penetration of the blueberry muffins. The pH meter was used to measure the sourness of the batter in order to see if it carried over into the baked product. It is important to measure the acidity because if it is not monitored, the palatability may be negatively affected. To measure the variable subjectively, six subjects volunteered to test the blueberry muffins on the most desirable variable for appearance, taste, smell, overall liking, and texture of each variable. The numbers used for each variable were randomized. The control was numbered 839, variable 2 was made of half fish oil and half vegetable oil and was assigned the number 221, and variable 3 was made of only fish oil and was assigned the number 719. For all three trials, the muffins were cut into 6 pieces (one for each subject) and placed on a plate that had the assigned number written on them. The subjects were asked to sample each variable and record

their preference on the ranking system cards provided. Below are examples of the ranking system scorecards used. Example of the structured ranking system 1 Dislike Extremely

2 Dislike very much

3 Dislike moderatel y

4 Dislike Slightly

5 Neither like or dislike

6 Like slightly

7 Like moderatel y

8 Like very much

9 Like extremely

Appear ance Taste Aroma Overall Liking

5

Most Tender

4 3 2 1

Most Tough

A 9-point hedonic scale, with 9 being the most desirable and 1 being the least desirable, was used to evaluate each subject’s preference on appearance, taste, aroma, and overall liking for each trail sample. This ranking system allowed an average desirability to be determined for each variable. To determine the tenderness of the product a 5-point ranking system was used. The most tender produced received a 5 and the least tender product received a 1. The results from this ranking system were added together and averaged to determine the overall tenderness of each variable for each trial.

Results: Table 1: Averages and standard deviations of the means of viscosities (centipoises) measured with the viscometer for variables 1, 2, and 3 in each trial Control

50% Fish 100% oil Fish oil 310.00 253.67 210.33 14.80 4.04 9.07

Average SD

350

a

300

b

Viscosity (cps)

250

c 200

Average

150 100 50 0 Control

50% fish Variable

100% fish

Figure 1: Average Viscosities (cps) vs. Three Variables—Control (0% Fish oil), 50% Fish oil, and 100% Fish oil Table 2: Averages and standard deviations of the means of grams of force measured with the texture analyzer for variables 1, 2, and 3 in each trial Control Average SD

50% Fish 100% oil Fish oil 27.73 51.73 53.53 1.10 1.42 0.57

60

a

a

50

Grams of Force

40

30

Average

b

20

10

0 Control

50% fish Variable

100% fish

Figure 2: Average Grams of Force (g) vs. Three Variables—Control (0% Fish oil), 50% Fish oil, and 100% Fish oil Table 3: Averages and standard deviations of the means of pH measurements measured with the pH meter for control, 50% Fish oil, and 100% Fish oil in each trial Control Average SD

7.22 0.03

50% Fish oil 6.96 0.12

100% Fish oil 6.17 0.03

7.4

a

7.2

b

7 6.8

pH

6.6 6.4 6.2

c

Average

6 5.8 5.6 5.4 Control

50% fish

100% fish

Variable

Figure 3: Average pH Measurements vs. Three Variables—Control (0% Fish oil), 50% Fish oil, and 100% Fish oil Table 4: Averages and standard deviations of the means for appearance measured subjectively for variables Control, 50% Fish oil, and 100% Fish oil in each trial on a 9-point hedonic scale with 9 being the most appealing and 1 being the least appealing Control Averages SD

6.43 0.21

50% Fish oil 7.20 0.26

100% Fish oil 5.33 0.15

Table 5: Averages and standard deviations of the means for taste measured subjectively on a 9point hedonic scale for control, 50% Fish oil, 100% Fish oil in each trial with 1 being dislike extremely and 9 being like extremely Control Averages SD

5.37 0.64

50% Fish oil 8.40 0.35

100% Fish oil 6.77 0.31

Table 6: Averages and standard deviations of the means for aroma measured subjectively for variables control, 50% Fish oil, and 100% Fish oil in each trial on a 9-point hedonic scale with 1 being the worst aroma and 9 being the best aroma Control Averages SD

5.1 0.32

50% Fish oil 7.4 0.40

100% Fish oil 8.1 0.12

Table 7: Averages and standard deviations of the means for overall liking measured subjectively for control, 50% Fish oil, and 100% Fish oil in each trial on a 9-point hedonic scale with 1 being the least favored and 9 being the most favored Control Averages SD

5.73 0.25

50% Fish oil 7.40 0.17

100% Fish oil 7.13 0.15

Table 8: Average subjective ratings on a 9-point hedonic scale of different muffin characteristics

Control 50% Fish oil 100% Fish oil

Appearance Taste Aroma Overall Liking 6.43 5.37 5.1 5.73 7.2 8.4 7.4 7.4 5.33 6.77 8.1 7.13

Average Score on a 9-point Hedonic Scale

9 8 7 6 5 Control

4

50% Fish oil

3

100% Fish oil

2 1 0 Appearance

Taste

Aroma

Overall Liking

Muffin Characteristics

Figure 4: Average Scores on a 9-Point Hedonic Scale vs. Muffin Characteristics Table 9: Significant differences of means for tenderness preferences measured subjectively for control, 50% fish oil, and 100% fish oil in each trial on a 5-point structured ranking system with 1 being the most tough and 5 being the most tender Control Averages SD

2.50 0.50

50% Fish oil 4.17 0.29

100% Fish oil 1.73 0.46

Average Score on a 5-point structured Ranking System

4.5 4 3.5 3 2.5 2

Average

1.5 1 0.5 0 Control

50% fish

100% fish

Variable

Figure 5: Average Score on a 5-Point Structured Ranking System vs. Three Variables—Control (0% Fish oil), 50% Fish oil, and 100% Fish oil Discussion: The results of this experiment were analyzed by using objective and subjective measurement tools. Viscosity, texture, and pH are all important factors when developing a successful product. Viscosity determines how the product should be handled, stored, and discarded. Texture or mouth-feel can affect the quality of foods. Texture is especially important because it is graded directly by the consumer without a good texture. Texture can also be used as a criterion to determine what materials should be used in food products. PH is important because it can effect microbial growth in food products. Also, if the pH is not exactly right, especially in dairy products, the food product will not develop correctly, making the product unmarketable. The product has a high possibility of not being liked by consumers if these three qualities are not at their best. This can cause consumers to refuse to purchase this disguised omega-3 fatty acid muffin and render it unsuccessful and, thus, unbeneficial and ineffective to the human heart.

Table 1 is a summary of the values given by the Brookfield viscometer and the measurements for each variable. It displays the averages found for all the variables in each trial. According to the data found, the more fish oil added, the less viscous the product became. The lower viscosity could be due to the fact that the fish oil was a thinner consistency than the vegetable oil. Figure 1 is a visual showing that the viscosities of the control, 50% fish oil, and 100% fish oil were all significantly different. The data collected from the texture analyzer is shown in Table 2. It indicates the averages grams of force obtained from the control, 50% fish oil, and 100% fish oil for all three trials. In variable 1, the control had the least grams of force which means it was the toughest. In 50% fish oil and 100% fish oil, very similar numbers were obtained. This could be because the fish oil had a thinning effect on the viscosity and, therefore, may have affected the final product texture similarly between the two variables that contained fish oil. Table 2 displays the averages for all three variables with the control measuring 27.73 grams, 50% fish oil measuring 51.73 grams, and 100% fish oil measuring 53.53 grams. Figure 2 provides a visual for the 50% fish oil and the 100% fish oil not being significantly different in texture. The control, however, is significantly different in texture from the two fish oil variables. These results may have been obtained due to the presence of the fish oil in the fish oil muffins causing different textural effects than if there was no fish oil at all. Table 3 clearly displays the data obtained for the effect of pH on the muffins. Referring to Figure 3, the more fish oil added, the lower the pH became. The control muffin’s pH was 7.2 which ended up being the highest of the three variables. This variable was the most alkaline of the three. The 50% fish oil had a pH of 7. The 100% fish oil had a pH of 6.17 which was the lowest pH of the three variables. It was the most acidic variable. Since the fish oil was lemon

flavored, the acid from the lemon could be why the pH became more acidic in the fish oil variables as opposed to the control which had no lemon flavoring. Figure 3 visually displays the quantitative data, reiterating that the control, 50% fish oil, and 100% fish oil variables were all significantly different in their pH value averages. This could be due to the fish oil having a more acidic nature that is significant enough in acidity to increase the pH when added in increasing amounts. Table 4 shows average subjective preferences of each variable’s appearance based on a 9-point hedonic scale with 9 being the most appealing and 1 being the least appealing. On average the subjects rated the 50% fish oil as the most appealing with an average around 7.2. These results may be from the textural effects that fish oil has on the muffin. It also shows the significant differences of means for appearance measured subjectively for all trials and all variables. The highest significant differences were 50% fish oil with a .26 and the lowest was 100% fish oil with .15. Table 5 shows the average subjective preferences of each variable’s taste based on a 9point hedonic scale with 9 being the most palatable and 1 being the least palatable. The subjects rated the 50% fish oil as the most palatable in all three trials with an average around an 8.4 on the ranking scale. This could be because too little fish oil left the muffin plain and dull tasting, but too much fish oil mail have caused the muffin to be overpowering with lemon flavor. Table 5 also shows significant differences of means for taste measured subjectively for all trials and all variables. 100% fish oil had the lowest significant difference with .31 and the control had the highest with a .64. Table 6 shows the average subjective preferences of each variable’s aroma based on a 9point hedonic scale with 9 being the best aroma and 1 being the worst aroma. The subjects

thought that 100% fish oil had the best aroma with an average ranking of 8.1. 50% fish oil averaged out to have the second best aroma with a ranking of 7.4 while the control had an average ranking of 5.1. These results could be due to the panel enjoying the lemon scent that the fish oil gave off, thus resulting in the 100% fish oil variable being ranked as the best smelling. The 100% fish oil had the lowest significant difference with a .12 and 50% fish oil had the highest with .40. Table 7 shows the average subjective preferences of each variable’s overall liking based on a 9-point hedonic scale with 9 being the most favored and 1 being the least favored. The 50% fish oil averaged out to 7.4 and 100% fish oil averaged out to a 7.13, while the control had an average overall liking score of a 5.73. Therefore, the muffins with the fish oil added were favored over the muffin without the fish oil. This table shows significant differences of means for overall liking measured subjectively for all trials and all variables. 100% fish oil had the lowest significant difference with a .15 and the control had the highest with a .25. Table 8 shows the average subjective data on a 9 point hedonic of different muffin characteristics. This table displays the appearance, taste, aroma, and overall liking for the variables control, 50% Fish oil, and 100% Fish oil. The 50% fish oil took the highest in all four categories with 7.2 for appearance, 8.4 for taste, 7.4 for aroma, and 7.4 for overall liking. 100% Fish oil had the lowest appearance rating with a 5.33, but exceeded the control variable in the other three categories of taste, aroma, and overall liking. Figure 4 provides a visual of the four different characteristics measured subjectively compared between the 3 variables in each trial. This figure shows that the muffins with some amount of fish oil were the more desired muffins compared to the control without any fish oil.

Table 9 displays the significant differences of means for tenderness preferences measured subjectively for the control, 50% fish oil, and 100% fish oil for each trial on a 5-point structured raking system. The average for the control variable was 2.50, the average for the 50% fish oil was 4.17, and average for the 100% fish oil was 1.73. The significant differences for the control were .50, .29 for 50% fish oil, and .46 for 100% fish oil. Between Table 9 and the visual Figure 5 provides, it can be observed that the 50% fish oil variable had a much higher tenderness rating average than the other two muffin variables. This may be from the less viscous quality of the fish oil combined with the viscous vegetable oil. Any source of error may have been from a simple human error. Human error for these experiments could have been wrong measurements of ingredients, baking times could be unequal, misreading data from the instruments, and not reading the subjective data correctly. Overall, through all of the results, it has been determined that there is consumer liking in the muffins with the fish oil over the muffins without fish oil. This may be from the lemon flavoring in the muffin which adds to a better palatability. The control, with no fish oil, was not ever averaged out to be the most appealing, best tasting, best smelling, or most favored muffin. Instead, the lemon-flavored, omega-3 filled muffins, whether 50% fish oil or 100% fish oil, resulted in higher ratings on the scales and ended up being the more favored muffin over the non-fish oil product. In order to have such a delicious, heart-healthy food be marketable, further research must be done. First and foremost, future researchers need to do more than three trials. Three trials are beneficial because there is room for error and correction of error. However, more trials need to be performed in further studies to assure that all of the data are similar when repeated and are accurate. Another aspect that needs to be considered to better this research is the product’s shelf

life. For a product to be sold in stores as packaged muffins or restaurants as fresh muffins, the shelf-life needs to be measured. Therefore, further studies should have the same panel taste test and evaluate each muffin again after 5 days, making note of difference in taste and staleness. Objectively, the water activity of each of the muffins should be tested each day with the water activity machine. In further experiments, researchers should provide store-bought blueberry muffins, blueberry muffins from muffin mix, and homemade regular blueberry muffins (with white flour, sugar) as three additional variables for the tasters to try. These three must be labeled with 3 randomized 3-digit numbers, as the omega-3 muffins are. By comparing the experimental muffins with the other various muffins, panelists can sample each one and evaluate each based on overall appearance, taste, aroma, overall liking, and tenderness. By doing this, many muffin possibilities will be up for evaluation and the tasters will reveal which products are most liked. Researchers will then know if this new, omega-3 fatty acid rendition could be as or more desirable to consumers than the other muffin options already marketed.

References: Anonymous. University of Massachusetts Worcester Campus, Healthy Heart. 27 September 2010 . Bester D., AJ Esterhuyse., EJ Truter., J Van Rooyen. 2010. Cardiovasular effects of edible oils: a comparison between four popular edible oils. Nutr Res Rev. Sept 2010; 20:1-15. Cardiovascular disease statistics. (n.d.). American Heart Association . Kris-Etherton, P. M. 2002. Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Circulation, Vol. 106 pg 2746-2757. McEwen, B. 2010. Effect of Omega-3 Fish Oil on Cardiovascular Risk in Diabetes. The Diabetes Educator, Vol., 36 No. 4 pg 565-584.