The Physical Characteristics and Sensory Effects of Substituting Vegetable Extract into Chocolate Cupcakes Jessica Brown November 19, 2007 F&N 453 Individual Project Section 3 3:30 Lab
Abstract When analyzing the effects of a vegetable extract substitution on chocolate cupcakes, the results were not promising. The purpose behind the experiment was substituting an ingredient with similar raw ingredient properties (such as powders for this experiment), while changing the flavor profile. The theory was thought that the physical properties of the cupcakes would not vary, but the flavor might. This was done to test the importance of mouth feel in cupcakes and other more fattening foods. The physical tests done were a texture analysis, viscosity on the batter and water activity measurements on the final product. There was also a sensory panel to see if possible consumers would not the difference in the taste of the variables. It was found that while the physical properties were attempted to stay the same, using the same procedure, they did vary; however, the main finding was in the sensory study. It was found that the audience still preferred the control, chocolate cupcake over all the variables. While the vegetable extract substitution might provide for a healthier snack, it is not preferred. Introduction With movies such as Fast Food Nation, Americans have been starting to notice their diet trends, and might even admit that they are not as healthy as what they want or should be. With all the delicious fattening food out on the market, it would be great if something could taste just as great as dessert, but also be healthy and beneficial. The theory behind the experiment is adding vegetable extracts to cupcakes will produce no change in the product texture, water activity or taste preference. While measuring the effects on texture, flavor and batter thickness, zucchini, carrot, pumpkin, jalapeno will all be substituted for cocoa in chocolate cupcakes. The purpose of adding vegetable extracts to
cupcakes not only takes a dessert food and makes it healthy, but it adds more vegetables into the diet of Americans. Unhealthy diets are a trend that is growing rapidly among children, as well as adults. It is recommended that we should be consuming at least two servings of fruits and three servings of vegetables daily (Nebeling 2007) for a healthy diet; however, there is a report that over time, the majority of U.S. adults continue to consume fewer than five servings of fruits and vegetables daily (Nebeling 2007). This is upsetting because there is an increasing trend in obesity and weight gain. Just in 2001, a study was shown that by 2001, almost 21 percent of adults were obese, representing a nearly 75 percent increase (Salinsky 2003). This project is to help provide healthy alternatives to unhealthy foods, starting with the cupcake. Vegetables are an important food group that often gets overlooked. Sometimes it is due to the fact that they might be the least appetizing. Or maybe it is because vegetables are usually served by themselves and not mixed in with some of our favorite foods. Vegetables are important because Vegetables provide a selection of important vitamins and minerals along with other compounds, called phytochemicals that help to keep us healthy (Hirving 2007). Another reason why vegetables are healthy and an important necessity of a diet is it was found that subsets of the population who consume larger amounts of cruciferous vegetables are afforded some degree of disease protection (Lunn 2006). The amounts that Americans should be consuming are in the current guide lines suggested adults should eat at least 5 portions (400g) of a variety of fruit and vegetables each day (Hirving 2007). But sometimes it is hard to achieve the recommended 5
portions of fruits and vegetables a day. That is why adding vegetable extract to cupcakes will increase vegetable portions and also deliver a mouth watering treat. Seeing how vegetables are an important, but sometimes overlooked, food, there is much discussion on how to help vegetables play a more dominant role in diets. In an article by J. Lunn, little has been done up until now to encourage the consumption of fruits and vegetables, which have long been known to be essential for good health (Lunn 2006). The article goes into more detail about the use of a superfood and gives possible definitions of it. In the talk about a superfood, one definition is the most well-known definition of a superfood elates to the fruit and vegetable section of most supermarkets (Lunn 2006). The theory is that perhaps people, children especially, are addicted and drawn to unhealthier foods because of their physical properties. Flavor and appearance just need to be satisfactory as long as people assume they are eating something that feels good when they eat it. Mouth feel is the technical term food scientists use to describe how food feels in your mouth (Szczesniak 2005). The texture analyzer is used because it can measure the force in compression with any kind of food (Daniels 2003). It is important to measure the texture because this can help dictate the mouth feel of a food. Using water activity measurements were useful in numerous ways. Water activity is defined as measure of the energy status of the water in a system (Carter 2007). The role that water activity plays in food is that water activity decreases, or as water becomes more bound, the water in a system is less available for microbiological and chemical reactions, which can impart stability to a food system (Carter 2007). This means that in order for the food to be shelf stable and not be affected by molds, yeast or bacteria, a low
water activity is preferred. Low water activity also inhibits chemical activity as well. Water activity is dependent on the temperature (Carter 2007); therefore, it is important to record the temperature along with the water activity value. It is important to monitor the water activity in order to control the retardation of the staling process (or perceived freshness of the baked good) (Tessier 2001). The water activity aids in the main physical property, texture, by observing how high the water activity is. The higher the water activity, the product will have a softer crumb (Tessier 2001). The role that water activity plays in cupcakes is that if vegetable extract substitution is successful, it still must maintain microbial and chemical properties as well to be considered safe for consumers. Adding in vegetables in cupcakes will give a healthier product to the market, but will consumers want to buy it and will it play a definitive role in their health? In a study conducted by Lassen and colleagues in Denmark showed an increase in fruit and vegetable consumption at lunchtime in five worksite canteens when these foods were made more easily available and appealing (Buttriss 2004). This study proves that people will eat healthier if there is more availability of healthy foods. While the article goes on to recommend price changes of food and even counseling, it can also be concluded and recommended that vegetables need to be made more attractive and available to consumers. The project of The Effect of Vegetable Extract Substitutions to Cupcakes will be focused on reproducing a well known product, cupcakes, with healthier additions, vegetable extracts. While the trials will be tested compared to the standard, there will also be a sensory test to evaluate how well the other trials compared based on a nine point
hedonic scale. The null hypothesis is that there will be no difference between the standard cupcake and the vegetable cupcakes. Methods: The design of the experiment was to take a known recipe for chocolate cupcakes and substitute the flavor. The recipe used was chosen because the chocolate was in a powder form. Since the vegetable extract was also in flavor form, it was assumed that little to no change in the texture or physical properties would take place. The color of the powders and flavor were the main targets of the experiment, assuming that the physical properties had little variation. This would then help show how people prefer the mouth feel and texture of a food while the flavor varies. For the experiment of substituting vegetable extract into chocolate cupcakes, the following recipe was used. 689.76 grams all-purpose flour 459.84 grams granulated sugar 114.96 grams variable (HERSHEY'S Cocoa, vegetable extract) 9.49 grams baking soda 4.745 grams salt 470 ml water 180 ml vegetable oil 30 ml white vinegar 10 ml vanilla extract
The variables used were zucchini powder, carrot powder, pumpkin powder, jalapeno powder and the control was chocolate cocoa. The control was a Hershey product while the vegetable extracts came from The Food Source Inc. The oven was heated to 350 F. There were twenty-four muffin cups (2 1/2-inches in diameter) with paper or foil bake cups lined inside two twelve cupcake trays. The dry ingredients, flour, sugar, cocoa/vegetable extract, baking soda, and salt were combined. In fact, most of the dry ingredients were pre-weighed and to shorten the baking preparation. The wet ingredients water, oil, vinegar and vanilla were then mixed in large bowl with the dry ingredients, and the mixture was thoroughly blended. The muffin cups were then filled ¾ full with the cupcake batter. The cupcakes were baked 25 minutes. The cupcakes were then cooled. The experiment was performed in the food chemistry baking laboratory in Stone Hall. The room temperature was approximately 25ºC for all three trials. To test the different variables, the viscosity was measured at room temperature (25ºC) using the Brookfield viscometer with spindle number 7 at 60 RPM. Once the cupcakes were baked then cooled, the crust was taken first, then the body of the cupcake was taken for a water activity reading using the water activity system. While the water activity system was stabilizing and finding a reading, the texture of the cupcake was found using the Stable Micro Systems Texture Analyzer with the cone probe. Since the cupcake had different texture levels, there were at least three replicate samples taken for each trial. The viscosity and texture were also measured in a room at room temperature (25ºC). Once the tests were finished, the cupcakes were then dispersed to a sensory panel. The panel was chosen at random, and there were seven panelists for each trial. The panelists
rated the cupcakes on appearance and overall (flavor and mouth feel) using the nine-point Hedonic scale, then the panel rated the cupcakes in order of preference one to five; one being their favorite, and five being their least favorite. Altogether, only three trials were done on separate days for the experiment. The original recipe can be found at Cooks Recipes http://www.cooksrecipes.com/cake/easy_bake_shoppe_cupcakes_recipe.html The replications were done on separate days in case human and preparing error played a crucial role. The reason replications were done on separate days was to try to minimize any error and allow the preparer to take time making and baking the cupcakes. The people chosen for the sensory panel were chosen based on physical proximity. Those who were in the laboratory while the physical properties were being tested usually sampled the cupcakes. No person sampled the cupcakes twice. People who were also asked to sample were those collegiate students in the Purdue Society of Women Engineers since they typically had an event on an evening that a replication was carried out. Also, those who did participate in the sensory panel did not know the variables of the cupcakes until afterwards. This was to avoid any preconceived opinions. The typical panelist was a college student of age 18-22. This is not the targeted demographic; however, it is still important to get the general audience s opinion. Below is a sample of the sensory scorecard. The key for the 3-digit coded numbers and their corresponding variables are: 827 is the Control, Cocoa Powder 946 is Zucchini Powder 159 is Carrot Powder
204 is Pumpkin Powder 571 is Jalapeno Powder Sample #827 Dislike Extremely Dislike Very Much Dislike Moderately Dislike Slightly Neither Like nor Dislike Like Slightly Like Moderately Like Very Much Like Extremely Sample #204 Dislike Extremely Dislike Very Much Dislike Moderately Dislike Slightly Neither Like nor Dislike Like Slightly Like Moderately Like Very Much Like Extremely
Sample #946 Dislike Extremely Dislike Very Much Dislike Moderately Dislike Slightly Neither Like nor Dislike Like Slightly Like Moderately Like Very Much Like Extremely Sample #571 Dislike Extremely Dislike Very Much Dislike Moderately Dislike Slightly Neither Like nor Dislike Like Slightly Like Moderately Like Very Much Like Extremely Sample #159
Dislike Extremely Dislike Very Much Dislike Moderately Dislike Slightly Neither Like nor Dislike Like Slightly Like Moderately Like Very Much Like Extremely Rank the sample in order of 1-5 (1 being favorite and 5 being least favorite) 827 946 159 204 571 Discussion The focus of the experiment was to attempt to have the variables match or come close to the physical properties of the control. This was measured by a texture analyzer,
viscosity of batter and also water activity. There was a control used in the experiment, because the chocolate cupcake s physical characteristics were trying to be replicated. The tests performed were aimed to deviate very little from the results of the control. The texture analyzer was done to give a better idea of the mouth feel of the cupcakes. Water activity was used to control the microbial/safety aspects and also the quality. The viscosity of the batter was used to see when the chemical changes started to take place, pre-baking or during baking. If the viscosity of the batter was consistent with the control, but the texture analysis was different, this leads to the conclusion that the baking conditions played a role in the experiment. Table 1.1 and Figure 1.1 compares the thickness of all the batters. Figure 1.1 shows that zucchini powder is the most similar to the control, but the other variables are not too close to the control. This could be due to the composition of the vegetable powders compared to the cocoa powder. Right away it is seen that the results will not be favorable since the substitution impacted the physical properties. Table 1.2 and Figure 1.2 show the results from the Texture Analysis. The control has the highest texture which means it is the strongest since more force is required to compress the product. Since the other variables have a lower Texture force, this could mean that they need more baking time, and a more appropriate bake time and temperature should be reviewed and recommended. It could also mean that regardless of flavor, consumers could still favor the control because it has the consistency that is on the market. There is also a wide range of values for texture. This could be do to the equipment since there were some technical difficulties while running the trials with this machinery. It could also be due to the time when the texture analysis was performed. If
the cupcakes were not cooled, they would yield a lower texture analysis because they are still hot and soft. An observation made during the procedure was that those cupcakes that had a higher difference in water activity from the crust and body of the cupcake could be due to cooking time. Some cupcakes had very similar water activity, which also led to the visual observation that those cupcakes had a weak crust. The pumpkin cupcake did appear to be softer and more moist than the other variables. Having similar water activities throughout the cupcake could lead to the conclusion that it was not cooked as long as necessary; however, the data for the control results refute that theory. The control, which had the highest force for texture, did not have the largest difference in water activities between the crust and the body of the cupcake. If there is a link between cook time and water activity difference, more testing would be needed. Another point of interest is comparing the variables values to the control while using Figure 1.3. It seems that the zucchini and jalapeno are the closest variables to the control. This could also show that by having differences in the water activity, the texture of the crust compared to the body could be observed. Table 1.4 shows the data from the water activity results. These results could not be averaged due to the temperature dependency of the results. All the results have a different temperature that they were taken at, which does not allow the data to be standardized. Since the purposes of the water activity results were to observe the safety of the food, it can be seen that the food products have a higher water activity than some foods. This could lead the cupcakes susceptible for yeasts and mold.
A source of error could be done by the preparer of the experiment. Until the experiment had been carried, little to no knowledge and practice of the equipment had be demonstrated. A recommendation would be for the experiment to be carried on with trained professionals who are better trained to work the equipment. The large standard of deviation values could be due to the human error in working the equipment. The subjective methods were done by two methods. The first method that the cupcakes were evaluated at was the nine-point Hedonic scale. Figure 1.4 show the results from the overall characteristics of the cupcakes. This includes the flavor, mouth feel and even aroma of the product. The results show that the most favored variable was the control. Figure 1.5 shows the results from the appearance only evaluation. Once again, the control is favored among the other variables. The reason that appearance was done separately from the overall evaluation was that while preparing the cupcakes, it was observed that the powder had some color to it. While the zucchini and jalapeno could have been pleasing flavor-wise to a consumer, a green cupcake was not aesthetically pleasing. To eliminate another variable such as appearance, it was rated separately so as to provide data based on appearance alone. The second method to evaluate the sensory portion of the experiment was to rank the variables in order of preference. Once again, overall characteristics were ranked, then appearance. The rank was one to five with one being the most desired cupcake and five being least favorite. Both Figures 1.6 and 1.7 show that the control was ranked as the most preferred cupcake, both on overall and appearance properties. This shows that the vegetable substitution proved that it did have an effect on texture; therefore, also having an effect on flavor and consumer likeableness. This coincides with a study that was done
on children with eating disorders. It was found that altering food type and texture may alter the aversive or reinforcing properties of eating in other ways (Patel 2002). The subjective portion of the experiment could be due to human and instrumental error. Since the target age demographic is children, children should be used on the sensory panel. Another approach to the sensory panel would be to use trained food tasters can be surprisingly accurate and consistent when it comes to rating such properties on scales of, say, 1 to 10 (Szczesniak 2005). Another way to analyze the texture of food to flavor is to correlate these subjective sensory ratings with objective measurements of the way food samples flow and deform when a force is applied, a branch of physics known as rheology (Szczesniak 2005). Results Table 1.1 The Averages of the Viscosity Results for All Three Trials of Vegetable Extract Substitution on Chocolate Cupcake Trial 1 4080 cp 3120 cp 12400 cp 11800 cp 10085 cp Trial 2 5600 cp 8200 cp 8800 cp 6470 cp 7400 cp Trial 3 4080 cp 3120 cp 12400 cp 11800 cp 10085 cp Average 4586.667cp 4813.33 cp 11200 cp 10023.33 cp 9190 cp Standard Deviation 877.5724092 2932.939367 2078.460969 3077.276935 1550.185473
Effect of Vegetable Extract on the Batter of the Cupcake's Viscosity Viscosity (cp) 12000 10000 8000 6000 4000 2000 0 Variable Series1 Figure 1.1The Effect of Vegetable Extract Substitution on the Viscosity of Chocolate Cupcake Batter Table 1.2 The Averages of the Texture Analysis for All Three Trials of Vegetable Extract Substitution on Chocolate Cupcake Trial 1 206 g 98.4333g 38.16667g 49.26667g 128.7g Trial 2 44.64 g 59.6g 55.98g 36.96g 44.64g Trial 3 37.28 g 48.28g 50.3g 40.02g 37.28g Average 95.97333g 68.77111g 48.14889g 42.0822g 70.20667g Standard Deviation 95.35692 26.30439 9.099405 6.407268 50.79021 Effect of Vegetable Extract on Texture in the Cupcake Texture (g forced used) 120 100 80 60 40 20 0 Series1 Variable
Figure 1.2 The Effect of Vegetable Extract Substitution on the Texture of Chocolate Cupcake Batter Table 1.3 The Averages of the Difference of Water Activities of the Crust from the Body of the Cupcake for All Three Trials of Vegetable Extract Substitution on Chocolate Cupcakes Trial 1 0.109 0.118 0.067 0.018 0.103 Trial 2 0.074 0.124 0.038 0.018 0.103 Trial 3 0.06 0.113 0.039 0.015 0.099 Average 0.081 0.118333 0.048 0.017 0.101667 Standard Deviation 0.025239 0.005508 0.016462 0.001732 0.002309 Difference in Water Activity Between the Crust and Body of the Cupcakes Water Activity Difference 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Variable Trial 1 Trial 2 Trial 3 Average Standard Deviation Figure 1.3 The Effect of Vegetable Extract Substitution on the Differences of Water Activity between the Crust and Body of the Cupcake as Compared to Chocolate Cupcakes Table 1.4 The Raw Data of Water Activity in the Crust and Body of the Cupcake and their Differences Trial 1 Crust.739 @ 23.5 0.715 @ 24.721 @23.3.803 @23.6.76 @24 Body.848 @ 23. 3.833 @ 23.4.788 @ 23.5.852 @ 24.865 @23.5 Difference 0.109 0.118 0.067 0.049 0.105 Trial 2 Crust.780 @ 25.3.722 @ 25.1.753 @25.4.848 @25.2.752 @25.4 Body.854 @ 25.3.846 @ 25.4.791 @ 25.4.866 @ 25.2.855 @ 25.2 0.074 0.124 0.038 0.018 0.103
Trial 3.788 @.738 @.748 Crust 25.1 25.3.763 @25.4.856 @25.5 @25.3 Body.848 @ 25.3.851 @ 25.1.802 @ 25.1.871 @ 25.3.847 @ 25.2 0.06 0.113 0.039 0.015 0.099 Subjective Evaluation of the Overall Properties of the Cupcakes Using the Nine Point Hedonic Scale Number of Panelists 14 12 10 8 6 4 2 0 1 2 3 4 5 6 7 8 9 827 946 159 204 571 9 Point Hedonic Scale Figure 1.4 The Subjective Evaluation of the Cupcakes on the Nine Point Hedonic Scale on the Overall Characteristics of the Cupcake Subjective Evaluation of the Overall Appearance of the Cupcakes Using the Nine Point Hedonic Scale Number of Panelists 10 8 6 4 2 0 1 2 3 4 5 6 7 8 9 827 946 159 204 571 9 Point Hedonic Scale Figure 1.5 The Subjective Evaluation of the Cupcakes on the Nine Point Hedonic Scale on the Appearance of the Cupcake
Ranked Order of Overall Preference of the Cupcakes by Sensory Panel Number of Panelists 20 15 10 5 0 827 946 159 204 571 Variable Number 1 2 3 4 5 Figure 1.6 The Subjective Evaluation of the Cupcakes on a Ranked System on the Overall Characteristics of the Cupcake Ranked Order of Appearance Preference of the Cupcakes by Sensory Panel Number of Panelists 20 15 10 5 0 827 946 159 204 571 Variable Number 1 2 3 4 5 Figure 1.7 The Subjective Evaluation of the Cupcakes on a Ranked System on the Appearance of the Cupcake
References: Buttriss, J. Successful ways to modify food choice: lessons from the literature. British Nutrition Foundation. volume 29, 333-343, 2004. Carter, Brady R&D Seminars: Challenged R&D -- October 2007. Prepared Foods: Development Trends & Technologies for Formulators & Marketers. October 9, 2007. Daniel, James R. and Weaver, Connie M. The Food Chemistry Laboratory New York, 2003. Hirving, Tony. Increase your vegetable intake The Basics. Get Fit Nutrition. 2007. http://www.theleanteam.co.uk/tips/vegetables/ Lunn, J. Superfoods. British Nutrition Foundation: Nutrition Bulletin. volume 31, 171-172 2006. Nebeling, Linda. Still Not Enough: Can We Achieve Our Goals for Americans to Eat More Fruits and Vegetables in the Future? American Journal of Preventive Medicine. 356-357 2007. Patel, Meeta R. et. al. An Evaluation of Food Type and Texture in the Treatment of a Feeding Problem. Journal of Applied Behavior Analysis. 183-186 2002. Salinsky, Eileen. Obesity in America: A Growing Threat NHPF Background Paper. 1-31 July, 2003. Szczesniak, Alina Mouth Feel New Scientist Vol. 187 Issue 2509. 47-47, 1/2p 2005. Tessier, Jenny Increasing Shelf-Life without Preservatives Bakers Journal. July 2001.
Appendix Trial 1 Texture Analyzer Results 190.5 95.6 9.9 44 139.3 221.6 106.2 68 70.4 146.2 205.9 93.5 36.6 33.4 100.6 Average 206 98.43333333 38.16666667 49.26666667 128.7 Std dev 15.55024116 6.807593799 29.08166662 19.05395847 24.57864927 Trial 2 Texture Analyzer Results 31.7 92 41.7 21.1 19.8 45.4 74.7 66 38 50.5 25.3 47.4 54 40.5 19.1 48.4 45 65.6 44.5 43.4 72.4 38.9 52.6 40.7 31.4 Average 44.64 59.6 55.98 36.96 44.64 Std dev 18.21271534 22.73906331 10.1514531 9.16504228 18.21271534 Trial 3 Texture Analyzer Results 33.5 52.7 36.8 42.2 25 28.4 44.9 52.8 41.8 42.6 44.7 42.5 55.5 37.2 36.4 30.8 37.9 56.1 38.9 32.9 49 63.4 50.3 40 44.1 Average 37.28 48.28 50.3 40.02 37.28 Std dev 9.049143606 10.00909586 7.892718163 2.069299398 9.049143606 Trial 1 Water Activity Results Crust 0.739 @ 23.5 C 0.715 @ 24 C 0.721 @23.3 C 0.803 @23.6 C 0.76 @24 C Body 0.848 @ 23. 3 C 0.833 @ 23.4 C 0.788 @ 23.5 C 0.852 @ 24 C 0.865 @23.5 C Difference 0.109 0.118 0.067 0.049 0.105 Trial 2 Water Activity Results Crust 0.780 @ 25.3 C 0.722 @ 25.1 C 0.753 @25.4 C 0.848 @25.2 C 0.752 @25.4 C Body 0.854 @ 25.3 C 0.846 @ 25.4 C 0.791 @ 25.4 C 0.866 @ 25.2 C 0.855 @ 25.2 C 0.074 0.124 0.038 0.018 0.103 Trial 3 Water Activity Results Crust 0.788 @ 25.1 C 0.738 @ 25.3 C 0.763 @25.4 C 0.856 @25.5 C 0.748 @25.3 C
Body 0.848 @ 0.851 @ 0.802 @ 0.871 @ 0.847 @ 25.3 C 25.1 C 25.1 C 25.3 C 25.2 C 0.06 0.113 0.039 0.015 0.099 Overall 827 946 159 204 571 1 3 1 12 2 3 1 3 7 3 8 6 2 2 4 1 2 2 7 5 1 1 6 6 7 6 7 1 7 10 8 3 1 1 1 9 Appearance 827 946 159 204 571 1 1 2 1 8 2 7 6 2 7 3 6 1 2 3 4 3 2 3 5 1 1 5 3 1 6 3 2 1 6 1 7 9 2 3 1 8 7 1 2 1 9 1