Allison Ehalt F&N 453 Title: The Effect of Sugar Replacers on Sugar Cookies Abstract: This experiment attempts to demonstrate the effects that sugar replacers have on sugar cookies. The problem with sugar, is that it provides many calories which can contribute to obesity. Sugar is also responsible for increasing blood glucose, which can lead to diabetes, as well as promote dental caries. However, these problems can be corrected by trying to replace sugar with sugar replacers such as Splenda and xylitol in order to decrease the amount of calories consumed, the effect of sugar on blood glucose, as well as decreasing the amount of dental caries. This experiment used a sensory test to determine the overall acceptability of the cookies, the Hunter Colorimeter to determine the effect of sugar replacers on the browning of cookies, as well as a water activity machine to determine the water activity of the cookies. The results showed that the Splenda cookies had the most browning, followed by the sugar cookies, and finally the xylitol cookies. However, the sugar cookies had the best overall acceptability, followed by the Splenda cookies, then the xylitol cookies. The Splenda cookies had the highest water activity level followed by the xylitol cookies, and then the sugar cookies, which means that the sugar cookies had the longest shelf-life. The major take home message of this experiment is that the sugar cookies remain the goal standard of the three cookies that were tested. Introduction: The problem with sugar is that there are 4 calories per every gram of sugar that is in foods. This can contribute many calories to a person s diet, and add to the obesity epidemic. With an increased obese population, there is also an increase in those who are suffering from coronary heart disease. Another problem for people to worry about with sugar, is it s affect of elevating blood glucose levels for longer periods of time. This elevated blood glucose can contribute to the development of diabetes. Finally, the last problem associated with sugar is that it contributes to dental caries, or cavities. By finding alternative sweeteners, we can decrease the amount of dental caries, the effect of sugar on blood glucose, as well as the amount of calories that a person consumes. Both Xylitol and Splenda contain fewer calories per gram than sugar at 2.4 kcal/g, and 0 kcal/g respectively, when compared to sugar which is 4 kcal/g. Xylitol is a sugar alcohol that will not cause tooth decay, or increase blood glucose (1). Splenda provides fewer calories because there is an enzyme resistance to the compound, which prevents it from being completely digested. Xylitol is slowly metabolized and absorbed, so fewer calories are consumed than if it were fully metabolized and absorbed (2). Some of the methods used to test the effect of sugar replacers on sugar cookies included a water activity machine to determine how much water was in the cookies, a Hunter Colorimeter to determine the degree of browning in the cookies, as well as a sensory test as performed by volunteers to determine the likeability of the cookies. These methods, and the results will be discussed later. The purpose of this experiment is to determine whether splenda, or xylitol would be effective replacements for sugar in baked products, more specifically in sugar cookies. The dependent variables consisted of the color of the cookies as tested by a Hunter colorimeter, the water activity as measured by a
water activity machine, and the likeability of the different types of cookies as measured by a subjective taste test panel. The independent variables, or the items that are controlled, are different types of sweeteners which consist of sugar (the control), xylitol, and splenda. Methods: The overall design of this experiment was to reproduce the exact same cookies, with only one variation between the three types. The three different types of cookies were those which contained sugar, xylitol, or splenda. The dough was prepared the night before each test, so that it could sit in the refrigerator for at least one hour. The dough was prepared by creaming the sugar/sugar replacer into the butter using a hand mixer. Next, the vanilla and egg were added to the butter mixture, and were beaten for 30 seconds using a hand mixer. Then, the milk, baking powder, and flour were added to the mixture and beat for 1 minute and 30 seconds using a hand mixer. To control other possible variables, all ingredients were weighed so that they would be in equal amounts between the three different variables. All of the ingredients were mixed for the same amount of time to decrease the risk of having an added variable. The bowls of dough were then covered with saran wrap, and placed in the refrigerator until using them the following day. The next day, the oven was preheated to 375 degrees. Then, the three variables (three types of cookies) were removed from the refrigerator. The cookies were then all rolled out using a rolling pin, and cut into small circles. The size of the product was determined by weighing all of the cookies, so that each cookie weighed and looked approximately the same. All three variables were then placed on the same cookie sheet, and were then labeled to ensure that the three variables of cookies would be subjected to the same temperature. After 8 minutes of cooking, the cookies were removed, and allowed to cool for 10 minutes. All three replications were performed the same way. Two of the replications were done in the same day. The sensory test was then performed by volunteers who were in the lab at the time of the testing. The different samples were all placed separately by variable onto white paper plates to establish randomization. Each sample had a 3 digit number code written on a piece of paper, and placed in front of the plate to help distinguish between the three samples. The volunteers then tried 1/4 th of a cookie from each variable, and then filled out the sensory scorecard. Next, the remaining cookies were then used to test the degree of browning and water activity of the cookies using the Hunter Colorimeter and Water Activity machine respectively. These data were then recorded. Discussion: In Tables 1-3, the effect of sugar and the sugar replacers, xylitol and splenda, were measured by using the Hunter Colorimeter to determine which sugar cookies had the highest degree of browning. These three tables show the average of the direct measure of the appearance/colors of the cookies. These can be used to see which cookies showed the best browning results. Browning is considered aesthetically valuable to having a good cookie. The L, a, and b values can be used to determine the exact color of the cookies after they have been baked. In an experiment by Ronda et al, sugar-free sponge cakes (one of which included xylitol), were used to determine the effect of polyols on browning. The results showed that the L-values were up to 25% greater than the control cake that used sugar. This means that these sponge cakes were lighter in color
because they did not have a bulking agent in them. The sponge cakes with bulking agents in them had an L-value up to 18% less than the control. This means that the sponge cakes with the bulking agents in them were darker in color (3). By looking at our own L-values in tables 1-3, we can tell that Splenda cookies had the darkest color, followed by the sugar cookies, and finally the xylitol cookies. Table 4 is used to show the water activity of the different sugar cookies using variables consisting of sugar, xylitol, and splenda. Water activity is referred to as the ratio between free and total water in food. Water activity is important because it determines the shelf-life of a food. Most chemical reactions stop at a water activity of < 0.8. This table shows that all of the cookies have a water activity level below the 0.8 limit. According to Table 4, this means that cookies made with splenda will have the lowest shelf-life, followed by cookies made with xylitol, and finally the cookies made with sugar. Table 5 is used to show the results of the sensory evaluation which used a Hedonic scale to determine the overall acceptance of the cookie. These results showed that the cookies made with sugar were the ones that were liked the most, followed by those made with Splenda, then the cookies made with the xylitol. The cookies made with sugar had an average rating of 2.86, which falls between like very much, and like moderately. The cookies made with Splenda had an average rating of 4.49, which falls between like slightly, and neither like nor dislike. Finally, the cookies made with Xylitol had an average rating of 6.13, which falls between dislike slightly, and dislike moderately. This table showed that by taste and look, the sugar cookies were still the goal standard. Overall, the sugar cookies were the better cookies of the three which disproves the hypothesis that there was no difference between cookies made with sugar, xylitol, or Splenda. The sugar cookies were the best of the three because they had the lowest water activity which means that they had a longer shelf-life. They also had the best score for the sensory test. As for the browning of the cookies, that all depends on how brown a person likes their cookies. The Splenda cookies tasted better, but they had a higher water activity than the xylitol cookies so their shelf life was not as long. The major message of this experiment is that the sugar cookies remain the goal standard between the three cookies. There was a big difference between the ideal tastes of the Splenda cookies, and the xylitol cookies. This means that people would prefer to eat the Splenda cookies over the xylitol cookies. Future work should include testing more sugar replacers in cookies because there are so many different types of sugar replacers. The Splenda cookies could be retested in the future using the Splenda blend for baking instead of just the plain sugar. These may provide better aesthetically acceptable results than those that we found. Results: Table 1. The Effect of Sugar on Browning of Cookies Avg. L Avg. a Avg. b Trial 1 51.85 13 22.91 Trial 2 66.61 3.07 22 Trial 3 52.06 12.96 21.34
Average 56.84 9.67 22.08 Table 2. The Effect of Splenda on Browning of Cookies Avg. L Avg. a Avg. b Trial 1 59.46 6.72 19.76 Trial 2 44.02 13.06 20.62 Trial 3 56.32 7.13 20.05 Average 53.26 8.97 20.14 Table 3. The Effect of Xylitol on Browning of Cookies Avg. L Avg. a Avg. b Trial 1 64.32 5.92 22.54 Trial 2 55.56 10.73 23.56 Trial 3 60.66 6.82 22.74 Average 60.18 7.82 22.94 Table 4. The Effect of Sugar Replacers on Water Activity of Cookies Sugar Xylitol Splenda Trial 1 0.537 0.597 0.756 Trial 2 0.537 0.73 0.707 Trial 3 0.556 0.695 0.737 Average 0.543 0.674 0.733
Table 5. The Effect of Sugar Replacers on the Overall Acceptance of Sugar Cookies Number x Number of People Sample 534= Splenda 1- Like Extremely = I = 1 1 2- Like Very Much = I = 1 2 3- Like Moderately = IIIIIII = 7 21 4- Like Slightly = III = 3 12 5- Neither Like nor Dislike = II = 2 10 6- Dislike Slightly = III = 3 18 7- Dislike Moderately = III = 3 21 8- Dislike Very Much = II = 2 16 9- Dislike Extremely = 0 Overall value = 101/ 22= 4.59 (Between Like Slightly and Neither Like nor Dislike) Sample 768 = Sugar 1- Like Extremely = II = 2 2 2- Like Very Much = IIIIII = 6 12 3- Like Moderately = IIIIIIIIII = 10 30 4- Like Slightly = I = 1 4 5- Neither Like nor Dislike = III =3 15 6- Dislike Slightly = 0 7- Dislike Moderately = 0 8- Dislike Very Much = 0 9- Dislike Extremely = 0 Overall value = 63/22= 2.86 (Between Like Very Much and Like Moderately) Sample 961 = Xylitol 1- Like Extremely = 0 2- Like Very Much = I = 1 2 3- Like Moderately = I = 1 3 4- Like Slightly = III = 3 12 5- Neither Like nor Dislike = III = 3 15 6- Dislike Slightly = II = 2 12 7- Dislike Moderately = IIIIIII = 7 49 8- Dislike Very Much = III = 3 24 9- Dislike Extremely = II = 2 18 Overall value = 135/22= 6.13 (Between Dislike Slightly and Dislike Moderately) Best Taste= those with the lowest value References:
1. Gallo-Torres, J.M., 2002. How sweet it is- Sweeteners- new products over the past year. Prepared Foods. Retrieved from http://www.findarticles.com/p/articles/mi_m3289/is_4_171/ai_84652260/print. 2. Pierini, C., 2001. Xylitol: A Sweet Alternative. Retrieved from http://www.worldwidehealthcenter.net/articles-250.html. 3. Ronda, F., Gomez, M., Blanco, C.A., Caballero, P.A., 2005. Effects of polyols and nondigestible oligosaccharides on the quality of sugar-free sponge cakes. Food Chemistry, 90(4):549-555.