The Effects of A 25% Calorie Reduction in Lemon Bars on Sensory and Instrumental
Evaluations
By:
Jacqueline Lorimer, Erin Smith, and Amy Wright
Abstract:
The purpose of this experiment was to reduce the calories in lemon bars by 25%.
This was accomplished by replacing granulated sugar with no-calorie Splenda. Sensory evaluations measured included texture, taste, appearance, and firmness. Instrumental evaluations used include penetrometer and percent sag. The control was slightly preferred over the variation, but there was not a significant difference. The percent sag did show a difference, the control had much greater percent sag compared to the variation. It could be concluded that the low calorie option is comparable to the original in sensory qualities.
Introduction:
Lemon bars are a dessert bar with a shortbread-like crust and a lemon filling. The crust consists of flour, butter, and powdered sugar. The filling consists of sugar, lemon peel, baking powder, salt, and eggs, which is then dusted with additional powdered sugar.
One serving of the original lemon bars recipe contains 90 calories, 13 grams total carbohydrate, and 9 grams sugar. The granulated sugar contributes significantly to the high sugar and calorie content.
The purpose of this experiment is to determine the effect on appearance, flavor, texture, and firmness when sugar is replaced with Splenda to reduce calories in lemon bars

by twenty-five percent. In order to see if the reduced calorie product is comparable in these areas, a sensory evaluation must be performed.
Splenda, a non-calorie sweetener, has become a popular substitute for sugar. This is due to the drastic reduction in sugar and calories, without a loss of sweetness. Splenda is sucralose, which is made from sugar. The conversion process starts with a sugar molecule.
Three hydrogen-oxygen groups are replaced with three chlorine atoms, which yield the sucralose. This makes sucralose extremely stable, which allows it to be used as a sugar substitute in a variety of foods, including baked goods because it can withstand heat
(McNeil 2010). The Splenda website recommends using one cup of Splenda to replace one cup sugar (McNeil 2010). Sucralose is not broken down for energy in the body, so it is not recognized as a carbohydrate, and is the reason that it does not have calories (McNeil
2010). The replacement of Splenda in the lemon bars recipe reduces calories, carbohydrate, and sugar content. The recipe substituted with splenda has 60 calories, 6 grams total carbohydrate, and 1 gram of sugar per serving.
To evaluate the physical difference between the two recipes, instrumental evaluations would also be performed in addition to the sensory evaluations. Two tests were used including a penetrometer test and a percent sag test. The penetrometer was used to evaluate the texture difference in the two recipes. The percent sag test was used to evaluate the firmness difference between the two recipes. The independent variable was the Splenda, so any difference in these characteristics would be due to the Splenda substitution.

It was thought that replacing the sugar with Splenda would create a lower calorie alternative, which would be comparable in appearance, flavor, texture, and appearance.
This would mean a lower calorie option for consumers.
Methods and materials:
The objective was to create a reduced calorie lemon bar by twenty-five percent. To do this, 1 cup of granulated sugar was replaced with 1 cup of splenda. The control recipe consisted of 90 calories per serving, but after splenda was substituted, the modification recipe consisted of 60 calories per serving.
Control Recipe:
1 cup all-purpose flour
½ cup salted butter
¼ cup powdered sugar
1 cup granulated sugar
2 teaspoons grated lemon peel
½ tsp baking powder
¼ tsp salt
2 large eggs
Additional powdered sugar
Variation Recipe:
1 cup all-purpose flour
½ cup salted butter
¼ cup powdered sugar
*1 cup splenda
2 tsp grated lemon peel
½ tsp baking powder
¼ tsp salt
2 large eggs
Additional powdered sugar
The same oven was used for both variations, which was pre-heated to 350 F. Flour, butter, and powdered sugar was mixed together in a medium bowl and pressed in an ungreased 8inch square pan. Each variation baked for twenty minutes to create the crust. While the crust was baking, the remaining ingredients were mixed together with an electric mixer on high speed until the mixture was light and fluffy. This is when the granulated sugar was replaced with splenda. After the splenda was added to the variation recipe, a significant

reduction in lemon filling was noticed. The mixture was then poured over the hot crust and put in the oven to bake for 30 minutes for the control recipe and 20 minutes for the variation. The control recipe resulted in a golden brown coloring, unlike the variation, which resulted in a lighter yellow coloring. Each pan was cooled for about an hour and then dusted lightly with the remaining powdered sugar.
Results:
Table 1: Average results from sensory evaluation of lemon bars.
Lemon Bars
Control
Variation
Impression on
Appearance
3.96
3.52
Taste
3.61
3.17
Texture
3.17
3.13
Table 2: Values to calculate percent sag of lemon bars.
Lemon Bars
Control
Variation
Molded height
2.4cm
1.6cm
Unmolded height
1.2cm
1.4cm
Percent Sag
50%
12.5%

Figure 1: Comparison of sensory score card evaluations.
4
3,5
3
2,5
2
1,5 Control
1
0,5
Variation
0
Appearance Taste Texture
* For impression on appearance and taste ranked 1-5 with 1 being really disliked to 5 being really liked. For texture 1-really fluffy, 2-slightly fluffy, 3-just about right, 4-slightly grainy, 5-much too grainy.

Figure 2: Average comparison of texture between control and variation lemon bars.
gooey
9% soft
41% firm
50%
soft
32% gooey
59% firm
9%

Discussion:
The variation recipe aimed at making a lemon bar with 25% reduced calories per serving while maintaining the look and taste appeal. The way that this was achieved was by replacing the one cup of sugar with one cup of Splenda. Splenda is an intense sweetener made by selective substitution of hydroxyl groups of sucrose with chlorine. This molecule is 600 times sweeter that sucrose and is stable at high temperatures and acid which is why it is a good substitute for sugar. (Binns2003) Splenda is a good substitute because it adds the sweet taste without the additional calories. The American Dietetic
Association supports the use of Splenda when consumed in a well balanced diet that follows current nutrition recommendations. (Peil2005) On the other hand some have reported that sugar substitute proved to be disappointing in cooking situations, particularly in baked goods. The sugar does more than sweeten, it also helps batter rise, providing volume and texture. (McGlaughlin2010)
There were several sensory evaluations that were done. The impression on appearance and how well you liked the taste was ranked 1 through 5 with 1 being really disliked to 5 being really liked. The average for the variation on appearance was 3.53 and the average fore the control recipe was 3.96. The average for taste on the variation was 3.17 and the control was 3.61. For texture, it was ranked 1 through 5; 1 is really fluffy, 2 is slightly fluffy,
3 is just about right, 4 is slightly grainy, and 5 is much too grainy. The variations average on texture is 3.13 and the control is 3.17. Looking at these averages one will notice that the averages are really similar to one another. The control is slightly higher on all evaluations, but this shows that the variation is definitely comparable to the control recipe.

The percent sag was calculated using the formula:
% sag= molded ht. – unmolded ht. *100
molded ht.
When this was calculated the percent sag of the control is 50% where the variations percent sag is 12.5%. The stronger the gel the lower the percent sag should be. The percent sag isn’t measure of flavor or texture, but can have an effect on appearance. Even though the percent sag between the variation and the control had a 37.5% difference they still had close to the same average with the sensory evaluations. The other instrumental evaluation that was used was a penetrometer. Due to difficulties with the instrument we had to just estimate the difference. With the control the penetrometer went down the full length of the cone and with the variation it only went halfway down the cone.
Conclusion:
This recipe was successful at reducing the calories per serving by 25% while maintaining a good impression on appearance, taste, and texture. This was achieved by substituting 1 cup of Splenda for 1 cup of sugar. All of the sensory evaluation results showed that the control was not greatly preferred over the variation. The end result was greatly accepted and showed to be very comparable with its original counterpart.

Work Cited
Binns, Nino, M. Sucralose-all sweetness and light. Nutrition Bulletin. Volume 28, Issue 1, pages 53–58, March 2003
Peil, Kelly, Helling, Kathryn. The Skinny on Splenda. Dietetic Interns, Saint Louis University. http://slu.edu/doisycollege/nd/nutrition%20spotlight.Fall%202005.pdf
. 2005.
McLaughlin, Lisa. “Sweet Stand-Ins.” Time 164.25 (2004):161. Acedemic Search Complete.
Ebsco. http://web.ebscohost.com/ehost/detail?vid=8&hid=13&sid=c27515e2-
79be-4b82-
8ac7b9d59c2554de%40sessionmgr4&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d
#db=a9h&AN=15343698
.
24 Oct.2010.
McNeil Nutritionals, LLC. 2010. http://www.splenda.com/faq/no-calorie-sweetener .
(Accessed October 24, 2010)