Erica Nelson FN 453 Individual Project 11/19/07 I. Title: The effect of different types of peanut butter on the taste and palatability of peanut butter cookies. II. Abstract: People are looking for ways to take what they consider bad out of their foods. Many people have become very aware of the food they are consuming as of recently. This is seen by all of the nutrition information we are seeing in the news. Organic foods have been a main discussion as of lately because of all the concern on chemicals that are being used on foods. People are also very aware of the amount of fat in the products they are consuming. To address these issues the food industry has to start incorporating products that can help the consumer deal with these issues. This study compared the effects of organic peanut butter and low fat peanut butter on the taste and palatability of peanut butter cookies against a control of cookies made with regular peanut butter. All cookies were made using the same recipe with the same brand of peanut butter. The study found that there were large differences in the texture of the cookies when tested mechanically, however, when the consumer put them to the test there was less of a difference seen in preference. The take home message from this experiment is that consumers are looking for ways to be more healthy in their food choices and products made with organic products may be able to give them a product basically identical to that of a regular product, while there may be more difference seen in 1/3 less fat product but it is still liked by the consumer depending on their preference.
III. Introduction: As of recently Americans have become very conscious of what they are eating as is apparent by watching and reading the news and looking through magazines. It has also likely become a large issue due to the increases in obesity and type II diabetes in the United States. A study by Schulz and others (2006) reported that environmental factors play an important role in the determination of obesity and the onset of type II diabetes in individuals who are predisposed genetically to these diseases (Schulz and others 2006). Two groups of people who were at an increased risk of the diseases due to their genetic make up were studied. One group was living in Mexico eating the typical diet while another group was in the United States eating the typical diet there. The study found that the group in the United States saw more prevalent amounts of obesity and the development of diabetes then the group living in Mexico. This type of study is representative of why it is important that people are becoming more health conscious and an example of stories that are becoming more and more prevalent in the news causing concern for consumers. To satisfy the increasing concerns of their consumers, the food industry is making products that claim to increase the health of the food on the market. With the rising increase in obesity people are paying a lot more attention to their fat intake and in response to this many products are being made with reduced fat. However, the problem that may be found with reduced fat is the possibility of a harder product due to findings that fat in baked products provides moisture and softness by helping to incorporate air into the mix (Zimmerman and others 1996). Another
health trend that has been very popular as of lately is the organic craze. As Williams states in his review article Nutritional quality of organic food: shades of gray or shades of green, many consumers believe that organic foods are more nutritionally healthy because of the modified farming methods. Although hard scientific evidence to sustain or disprove that argument could not be found, Thompson states in an article that reviewed the consumer trends in buying organic foods are increasing (Thompson 1998). Thompson found that in the 1990s sales of organic food increased by 24% and has risen since that time. This is an indication of consumers interest in organic foods. This type of knowledge is very voluble to the food industry in preparing and selling the types of products the consumers want. They will not only satisfy the consumer but be able to be more profitable in the long run. The purpose of this study was to look at the differences in taste and texture of products when incorporating low fat and organic peanut butter into peanut butter cookies when compared to cookies made with regular peanut butter. The dependent variables are the type of peanut butter used. These variables are organic and reduced fat peanut butter. The dependent variables that are going to be measured are texture and water activity. The texture will be measured using the Texture Analyzer to determine how hard the cookies have become and the Water Activity Machine will be used to compare the varying degrees of moisture
in the cookies. A taste panel will be used to measure the preference in color, texture, and taste of the cookies. In the experiment the dependent variables will be organic peanut butter and reduced fat peanut butter. To reduce the differences due to brand choices we will be using only Skippy Peanut Butter products. The regular peanut butter and organic peanut butter cookies should be very similar in their texture and palatability because they are almost identical in their ingredients and amounts of ingredients (Skippy). The difference may fall in the texture of the peanut butter due to the differences in processing. The organic peanut butter may cause the cookies to be oilier then the regular. The reduced fat peanut butter cookie may be less palatable to most then the regular cookie. This is due to the differences in the amount of fat. Fat in baked products provides moisture and softness by helping to incorporate air into the mix (Zimmerman et al). The independent variable will be the cookies made with regular peanut butter. This will be what we measure against for moisture and texture, because the final product should be as tasteful and palatable as the original. III. Methods: The approach for this experiment was to make three separate types of peanut butter cookies using varying types of peanut butter, and measure the effect on the taste and palatability of the cookies. To measure the softness and moisture of the cookies the texture analyzer and water activity machine will be used, and a sensory panel will evaluate the impact the types of peanut butter have on the taste
of the cookie. The first step in the process was to make the cookies. The recipe used for the experiment is one that my mother uses. She received the recipe from the cooks at her high school. Peanut Butter Cookies 1c butter 258g 1 c p-nut butter 229.92g 3 c flour 375 1 t soda 4.6 g 1/8 t salt 0.593g 1 c white sugar 200g 1 c brown sugar 220g 1 t vanilla 4.2g 2 eggs 2 The cookies will be made during the lab time allotted. The oven will be preheated to 375 C while ingredients will be mixed together. The butter and sugar will be creamed together and then the eggs and vanilla will be beat into the mixture in a room temperature bowl. The peanut butter will then be added and mixed. The dry ingredients will then be slowly added. The batter will then be put onto an ungreased cookie sheet and baked until lightly browned around 8-10min. The dependent variables for the peanut butter will be substituted for in each trial. Once done cooking the cookies were laid out on cooling racks for about 10 min. At this time the cookies texture, moisture, and taste were ready to be analyzed. The knife probe was used on the texture analyzer for each trial and all samples. The default cookie settings were used to analyze the samples with the texture analyzer to ensure that there was only minimal variability between test samples. The samples from all trials were tested on both the texture analyzer and water activity machine and then averaged. The results from each trial and the average
for the texture analyzer are shown in table 1. The results for the water activity machine are shown in table 2. The final test used to analyze the taste differences in the cookies was a sensory analysis test. The scales used are shown below. For the scale that they marked on a measure form the left end of the scale was made to the mark that was placed on the line. The measure was made in mm. This resulted in the cookie that the panelist thought was the most tender or moist having the highest number when measured in mm. The results from the sensory analysis are shown in table 3. Sensory Scales Rank samples in order of preference 1 being most liked and 3 being least liked. 564 782 273 After tasting each cookie rank it on the scale below IV. Discussion: From the tests that were conducted we were able to conclude that the regular peanut butter and natural peanut butter produced a very similar product in moisture and texture. While the 1/3 fat peanut butter produced a much less moist harder product. This is what is expected due to the differences in fat content of
the cookie. Fat is a major tenderizer in baked products as we learned in class so reducing the amount in the cookies has a large effect on reducing the softness and moistness of the cookie. A study by Koca and Mertin on cheese made with full fat using fat replaces and reduced fat mechanisms and its effects on tenderness and water activity found that the reduced fat have favorable affects on the cheese. The study found that the cheese with the fat replacers had a softer texture measured mechanically and a higher water activity compared to the low fat cheese (Koca and Mertin 2007). This outcome is what is expected due to the fat having the ability to add those characteristics it is expected that a higher amount would make a softer more palatable product. In looking at the results from the water activity in table 1 it was found that the regular peanut butter cookie had the highest water activity meaning there was more moisture in the cookie. This would indicate that that cookie would be softer and have a better texture that the consumer would prefer over the other cookies. The natural cookie had the second highest water activity score that was 0.017 below that of the regular cookies. This indicates that the natural peanut butter did change the water activity of the cookies slightly which would indicate a slightly less of an appealing texture for the consumer. The 1/3 fat cookies had the least water activity at 0.045 below the regular cookies. This is a very large amount that would impact the hardness of the cookie a lot, and in fact we found that when the consumers rated the cookies in table 3 they ranked the 1/3 fat cookie as being the hardest at an average of 58 units which is 38 units below the regular cookie. In
table 1 we do find that the 1/3 fat cookie is a more uniform product in water activity. For both trials 1 and 2 we found water activity that was the exact same, whereas the other cookies were more scattered. This would indicate that the 1/3 fat peanut butter may be more uniform and would give more precise results in scientific measurements then regular and natural peanut butter. Graph 1 compares the water activities of each variable across all three trials. From this you see that in all cases the regular and natural peanut butter cookies were higher in water activity and therefore a softer texture then the 1/3 fat cookies. In trial 3 the 1/3 fat is shown to have more water activity then the natural cookie which is unexpected looking at the rest of our results. It may be that the cookie that was chosen from testing from the natural group was taken from the outer edge of the cookie sheet and was crisper due to this. This cookie may also have been left in the oven a little longer then the 1/3 fat cookie as well. In looking at graph 3 it is found that when taking the average of the water activity scores the regular and natural cookies they are very similar and both much more then the 1/3 fat cookie. A study done by Chen and others (1988) in which a percentage of the fat used to bake muffins was replaced by apple to incorporate fiber into the muffins. The results found a muffin that had a much reduced volume due to the decreasing in the water content of the muffin because of the decrease in the fat content (Chen and others 1988). This follows the findings of this study which indicates that a lower fat content will cause there to be less water held in the product making it much harder and crispier.
In table 2 the texture analyzer force in grams is compared for each of the variations of cookies. The findings showed that on average the natural cookie took a lot less force to break then both the regular and 1/3 fat cookie. It took 279.8g less then the regular cookie and 1209.3g less then the 1/3 fat cookie. From the water activity readings it would be expected that the 1/3 fat cookie would take more force to break because having less water in it would tend to make it harder. However, it would also then be expected that the regular cookie would take less force to break then the natural cookie because it has an average higher water activity then the natural cookie. In table 2 we find that the natural cookie takes less breaking force then the regular cookie. This may be due to the regular cookie that was chosen for the test being picked from the outside of the tray that may make it crispier. However, both variables are very similar in their breaking forces showing that they do produce a similar cookie product. Graph 2 depicts the breaking force for each variable over each trial. In looking at graph 2 it was found that the 1/3 fat cookie was the most uniform or precise in the measurement. From the mechanical measurements it was found that the natural and regular peanut butter cookies produced the most moist and best texture of cookie. It was assumed at the beginning of the experiment that the consumer would be looking for these characteristics in the end product as the cookie that was most desired. However, when the ranking order of the cookies in terms of the most and least liked products it was found that many of the consumers actually preferred the 1/3 fat cookie. Overall of the trials the regular cookie was preferred the most
followed by the 1/3 fat cookie with the natural cookie being preferred the least. In trial one the 1/3 fat cookie was the most preferred and in trial 2 and 3 the regular cookie was the most preferred. The differences between the cookies preference was only one or two surveys for each variation. This shows that there is not much difference between the taste preferences between all of the cookies. This is surprising because it was thought that the natural and regular cookies would be preferred much more the then 1/3 fat cookies due to the differences seen in texture and water activity as measured by the machines and relative tenderness as measured by the sensory panel. This difference may be due to the preferences of the audience liking a crispier cookie. If the population had been larger there may have been a different outcome with a more clear answer as to the preferred cookie. In this experiment, while the natural and regular cookies mechanically gave a more appealing product the consumers enjoyed all three variations closely the same and even preferred the 1/3 fat cookie to a greater extent then the natural peanut butter cookie. A study by Harker in 2004 looked at the preference in taste of products that were made using organic products and those same products using non-organic products. The study found that the taste preference by the consumers were the same for both products for the most part. They did see a small difference in more consumers rating the organic product as preferred over the regular product but not a significant rate (Harker 2004). In this study it was found that the product of the natural and regular products were very close and the preference between them
was not significantly different, however, this study found a greater preference in the regular cookie by consumers. A study by Banks in 2004 looked at the taste preference of low fat products by consumers. Banks found that consumers usually ranked the lower fat products significantly lower in taste preference in comparison to a regular fat item due to its hardness (Banks 2004). These studies found what this study expected to find, but results show that the preference for the different variations of cookies were not significantly different in this study. The take home message from this study is that variations of peanut butter do have an effect on the texture and palatability of food. However, in this study there was not enough of an effect to hinder the consumer from enjoying the product. The regular and natural peanut butter produced a similar product and the 1/3 fat, however, most different from the control or regular cookie provided the most discrepancy was not significantly different from the other cookies. In the future studies should be done on different types of organic products. The one used in this study was a natural one that had been specially modified to be closer to the texture of regular peanut butter. There should also be studies done on different amounts of fat taken out instead of just one variable that had a different amount of fat. This study would have been better if it had been done on just organic peanut butter or just on variations of fat peanut butter rather then incorporating both. In the future the experiment should be broken down into two different ones.
V. Results: Table 1: Values for water activity for each variable of peanut butter for all three trials. Water Activity Peanut Butter Trial 1 Trial 2 Trial 3 Average Standard Deviation Regular 0.565 0.531 0.622 0.573 0.046 1/3 Fat 0.520 0.520 0.545 0.528 0.014 Natural 0.562 0.579 0.528 0.556 0.026 Table 2: Values for texture analyzer for each variable of peanut butter for all three trials. Readings are taken for force measure as grams. Texture Analyzer (g) Peanut Butter Trial 1 Trial 2 Trial 3 Average Standard Deviation Regular 2187.1 3182.3 1191.8 2187.1 995.3 1/3 Fat 2217.5 4629.7 2502.6 3116.6 1318.1 Natural 2790.9 1042.4 1888.5 1907.3 874.4 Table 3: Values for sensory test for tenderness on a scale from extra hard to extremely hard. Readings measured in mm from the extremely hard end of scale. Sensory preception of tenderness Peanut Butter Trial 1 Trial 2 Trial 3 Average Standard Deviation Regular 111 86 90 96 13 1/3 Fat 43 62 68 58 13 Natural 73 93 86 84 10 When ranking their preference of cookie, the regular cookie was ranked the most liked for both trials 2 and 3 by one more vote. For trial 1 the 1/3 fat cookie was ranked the most liked by 1 extra vote. Overall there was only 1 vote separating the cookies in terms of most liked taste and palatability. Table 4: Most preferred cookie during the trial Peanut Butter Trail 1 Trial 2 Trial 3 Variation 1/3 fat Regular Regular
Graph 1: Water Activity values for each variable of each trial. The variables include regular peanut butter, 1/3 fat peanut butter, and natural peanut butter. Graph 2: Texture Analyzer values for each variable of each trial as force measured in grams. The variables include regular peanut butter, 1/3 fat peanut butter, and natural peanut butter.
Graph 3: Average Water Activity for each variable including all trials Graph 4: Average Texture Analyzer results for each variable including all trials. Measure in grams of force. References: Banks JM. 2004. The technology of low-fat cheese manufacture. International Journal of Dairy Technology 57(4):199-207. Chen H, Rubenthaler GL, Leung HK, Baranowski JD. 1988. Chemical, physical, and baking properties of apple fiber compared with wheat and oat bran. Cereal Chem 65(3):244-247. Harker FR. 2004. Organic food claims cannot be substantiated through testing of samples intercepted in the marketplace: a horticulturalist s opinion. Food Quality and Preference 15(2):91-95. Koca M, Mertin N. 2007. Textural, melting and sensory properties of low-fat kashar cheeses produced using fat replacers. International Dairy Journal 14(4):365-373. Schulz LO, Bennett PH, Ravussin E, et al. 2006. Effects of traditional and western environments on prevalence of type 2 diabetes in Pima Indians in Mexico and the U.S. Diabetes Care 29:1866-1871 Williams CM. 2002. Nutritional quality of organic food: shades of grey or shades of green? Proceedings of the Nutrition Society 61(6):19-24. Thompson GD. 1998. Consumer demand for organic foods: what we know and what we need to know. American Journal of Agricultural Economics 80(5):1113-118. Zimmerman EL, Carey JM, Slade L, Levine H. 1996. Tenderized baked good production with reduced fat, low fat, or no added fat. Accessed on the web at http://www.google.com/patents.