Individual Project Report Name: Ciara McDonnell Date: 11/19/07 F & N 453

Transcription

1 Individual Project Report Name: Ciara McDonnell Date: 11/19/07 F & N 453 Title: The effect of artificial sweetener content on the texture, color and palatability of Meringues.

2 Abstract: The main problem at hand is that sucrose is in many foods, contributing to obesity, diabetes and dental cavities. Meringue is one of the foods with the highest sucrose content so if this could be replaced with a new sweetener or combination of alternative sweetener and sucrose mixture, the bad effects could be greatly reduced. Splenda was chosen due to it not contributing towards obesity, diabetes and dental cavities and because it doesn t breakdown when heated. However, it is important that the vital properties of the food not be compromised such as color, texture and palatability because these lead to overall consumer acceptance. It was hypothesized that replacing sugar with artificial sweetener in meringue would have no effect on the color, texture or palatability. A control of 100% sucrose meringue was made for comparison and desirability purposes along with three other variables i.e. meringues made with 100% Splenda, meringues made with 50% sucrose and 50% Splenda and meringues made with 80% sucrose and 20% sucrose. The four samples were measured objectively using a Texture Analyzer and Hunter Colorimeter. A subjective sensory test was also preformed. It was found that splenda had a great effect on the texture, not such a large effect on the color and a very large effect on consumer likability therefore, the null hypothesis was rejected. The closest sample to the control was the meringue made using 80% sucrose and 20% splenda. This also had a high rate of consumer likability. It is advised that different alternative sweeteners be tested because there are so many on the market and one may lead to greater similarities as sucrose in meringue making. 1. Introduction 2. Methods 3. Discussion 4. Results 5. References 1. Introduction Sugar is one of the main foods, that when eaten in excess, has adverse side effects on health. Although the majority of consumers are aware of this, we continue to consume approximately 14kg of sugar confectionary per head per year. This is due to sugar having a likable taste on all mammals taste buds except cats, which, do not have the receptor and also, because sugar can stimulate the appetite meaning we consume more than we may have initially intended to. The health issues related to sucrose are becoming an increasing problem.

3 Obesity is the largest chronic heart problem amongst adults globally. It leads to many, very serious illness such as coronary heart disease and severe depression. It is estimated that three hundred million people are obese worldwide with many more considered overweight. According to the Center for Disease Control and Prevention one in five American adults is now considered obese compared to one in eight in 1991 (Jacobson, 2000). This statement shows how obesity is continuously on the increase. This is the main reason for the increase in the use of artificial sweeteners. Many artificial sweeteners are non caloric while sugar contributes 4kcal per gram (Baker et al, 2004). Diabetes Mellitus is a condition where the body is unable to automatically regulate blood glucose levels, resulting in too much glucose in the blood. Insulin is the hormone made in the pancreas which regulates the glucose levels in the blood. Diabetes develops when the body stops producing insulin or stops responding to insulin, therefore blood glucose levels can become too high or too low (Itamar et al, 2003). This can have very damaging effects on the health of the diabetes sufferer. Diabetes can have implications as severe as increasing the risk of heart attack and stroke. Sugar raises the blood glucose levels significantly. For this reason, diabetes sufferers must monitor their daily intake very closely. The use of artificial sweetener in foods means that diabetes sufferers can still enjoy the sweet taste whilst not inducing hyperglycaemia. Tooth decay is another bad side effect of sucrose consumption. Sucrose causes glycoproteins to adhere to the surface of the teeth (Baker et al, 2004). These glycoproteins are metabolised by acid producing bacteria that lower the ph and erode the enamel. This too, is a growing problem in the world and has led to a desire for artificially sweetened products, especially amongst parents for their children. This growing demand for artificially sweetened products means there is such a large market. Meringue is one sweet food of extremely high sugar content. In most recipes it is one of two ingredients i.e. sugar and egg whites. If one wished to test the effects of artificial sweetener use in sweet foods, meringue is a food to show these properties and that s why it was chosen. The overall purpose of this experiment is to produce a new meringue with less bad health effects and with characteristics similar to that of meringue made with 100% sucrose. Sugar lends to the texture and color of baked foods. These two dependent variables were of concern and that s why they were chosen to be tested. Sugar causes caramelization and non enzymatic browning when heated. The Maillard reaction responsible for this can be seen on figure 1b. Splenda would not contribute the same reaction so it was expected that the colors of the meringue variations

4 would be different. This effect was seen in the use of artificial sweetener in hamburger bun making where the L, a and b values were significantly different from the desired color (Esteller, M.S et al). Heat is one factor that causes an increase in the amount of browning so it was important that this variable be controlled. This was tested objectively using the Hunter Colorimeter and subjectively using a panel. It was expected that the texture would also be affected due to the initial difference in texture of the raw ingredients. Sugar had large particles that had a crystal like shape whilst Splenda had small light white particles. The tests used to analyse this property was a Texture Analyser and a taste panel. The final property that needed to be tested was the palatability and overall consumer acceptance. An untrained taste panel was thought best for this. A structured rating scale was used for analysis of texture and color whilst a hedonic scale was used for the preference section of the sensory test. Due to this test being done with an untrained taste panel it was importamt to get as many subjects to take the test as possible. A total of 24 people done the test and average scores were used to conclude. Due to these dependent variables (i.e. texture, color and palatability) being analysed, it was very impotant not to tamper with the results due to inadequate control of independent variables i.e. ingredients, temperature, technique etc. 2.Methods It was important to make a dersirable meringue containing 100% sucrose, as the sweetener. This would be used as a control and means of comparison towards the other meringues. It was decided to make a meringue with 100% Slpenda as the sweetener just to see if it would be acceptable because if so, it would have a large decrease in adverse health effects. Due to the difference in the characteristics of Splenda and sucrose it was thought good to try a mixture of Splenda and sucrose. This was hoped to lead to a meringue similar to the control with less bad effects on health. Two recipes of this kind were used. One contained 80% sucrose and 20% Splenda and the other contained 50% sucrose and 50% Splenda. The dependent variables were tested using a cone probe Texture Analyzer, a Hunter Colorimeter and a sensory panel using structures rating and hedonic scales. Three trails were done. One was done on one day but the other two were preformed on the same day. The second and third trial showed much better results than the first trial. This is thought to be because of a slight difference in the method. In trial one the sugars and sweeteners were mixed into the whipped

5 egg whites using a hand held whisk while on trial two and three, the sweeteners were folded into the whipped egg whites using a spoon. This was much better because mixing the sweetener in with a high speed whisk led to the fluffiness of the egg white to be lost. Once the products were made they underwent the appropriate analysis. Recipes of Meringues: Variation 1 100% Sucrose: 5 egg whites and 265g of sugar Variation 2 100% Splenda: 5 egg whites and 8.4g of Splenda Variation 3 80:20 mixture: 5 egg whites, 212g sugar and 1.7g of Splenda Variation 4 50:50 mixture: 5 egg whites, 132.5g sucrose and 4.5 g of Splenda Procedure: On all trials the procedure was followed in the same manner. Firstly, utensils and equipment was prepared. It was important to use ceramic or glass mixing bowls because plastic bowls retain fat easier and fat in the mixure would taint the results. Ingredients were gathered and weighed out using a scale. This was done by placing a bowl on the scale and the scale was teared to zero. Then the appropriate sweetener was weighed out. Four large bowls were set up containing 5 egg whites each. The eggs where beaten until fluffy and peaking. On the first trial, the sweeteners were mixed in using a whisk but on the other two trails they were folded in using a spoon. After mixing, four baking trays were set up with grease paper on them. The mixture was spooned on using a tablespoon. This ensured that all end products were consistant in shape, therefore, inducing no biased opinions amongst panelists. The oven was preheated to 350 F. Each tray was entereed into the oven at the same time and kept there for 15minutes. This meant that the independent variables of time and temperature were controlled. The resulting meringues were removed and allowed to cool for a few minutes. For the Texture Analyzer testing, it was necessary to calibrate the equipment to the appropraite settings. The probe type used was a cone. This was most suited to meringue due to the softness. In the Texture Analyzer settings, it was set as cake because meringue was not an option and cake is the category it would fall into. This meant that the pretest speed was at 2.0mm/s, the test speed was at 5.0mm/s and the protest speed was at 5.0mm/s. The meringues that were used were the ones of most uniform shape and size. The results were presented as grams of force.

6 The Hunter Colorimeter also required some calibrating. It was standadized by first placing a black tile on the machine and clicking scan. After which, the same was done using a white tile. When the screen said Sensor Successfully Standardized it was ready to analyze the the samples. They were placed in a petri dish and the on top of the sensor. Results were given as L,a and b values. This was recorded for each sample on each trial. The final test to be carried out was the sensory test. Samples were laid out on paper plates. Each plate had a label of three random numbers. This was so as not to introduce bias into any of the panelists or give them any awareness of the variables in the meringues. Panelists were chosen at random and asked to complete a form with structured ranking and hedonic scales. This can be seen as follows: Sensory Evaluation Appearance: 1. Please rate the color of the following samples by placing an X on the scale. 299 White Brown 908 White Brown 645 White Brown 367 White Brown

7 Now please taste each sample in front of you. 2. Please mark on the scale the point that best describes the sample: 367 Soft Hard Extremely soft Very Soft Neither soft or hard Very Hard Extremely Hard 299 Soft Hard Extremely soft Very Soft Neither soft or hard Very Hard Extremely Hard 908 Soft Hard Extremely soft Very Soft Neither soft or hard Very Hard Extremely Hard 645 Soft Hard Extremely soft Very Soft Neither soft or hard Very Hard Extremely Hard 3. Please Rate the foods aftertaste on the following scale. 367 Bad Good Extremely Bad Very bad No Aftertaste Very Good Extremely Good

8 299 Bad Good Extremely Bad Very Bad No aftertaste Very Good Extremely Good 908 Bad Good Extremely Bad Very Bad No Aftertaste Very Good Extremely Good 645 Bad Good Extremely Bad Very Bad No Aftertaste Very Good Extremely Good 4. Please rate the following in order of preference. 1 being your most favorite and 4 being your least favorite Comments:

9 The numbers corresponded to the samples in the following way: 229= 100% Sucrose 908= 100% Splenda 645= 50% Sucrose and 50% Splenda 367= 80% Sucrose and 20% Splenda It was important to keep the test conditions good. That is, the test was carried out in a room with no distraction and colors and smells were neutral. The noise level was low. It was important that panelists test the samples in a random order. It is also good to have all samples look as similar to each other as possible so panelists don t automatically assume a large difference; however, this was difficult because the samples did vary significantly in color and size. The average of the marks was found by making evenly spaced numbers across the scale. The average number was found and this was marked on the scale for analysis purpose. Discussion: Overall, this experiment shows that meringue made with 100% sucrose is the most desirable amongst consumers and none of the other variations were acceptable for use, therefore, the null hypothesis must be rejected. Figure 1 shows that the 80% sucrose and 20% Splenda had very similar overall texture. This was the same for sensory analysis. On the sensory test, the average consumer rated the meringue made with 50 %sucrose and 50% Splenda as extremely soft and least favorite. This was because the sensory tests were done up to 20 minutes after the objective analysis. After a short time, this variation had deteriorated and became an extremely moist, sticky, almost liquefied substance. The reasons for this are numerous. If egg whites are overheated they weep out moisture. It seems that this is what happened but all meringues were heated the same way and this did not happen to them. If the sugar is not appropriately dissolved a problem with the moisture may occur. The smallest amount of egg yolk in the mixture may cause bad meringues due to the fat content. The fat makes it difficult for the egg whites to whip and trap air. This may also have led to the collapsing. For future purposes, it is important to make sure these factors don t occur and it may also be good to use a stabilizer in the recipe. The use of an ingredient such as cream of tartar would stabilize the emulsion. Meringue made with 100%

10 Splenda was big and fluffy whilst the 100% sucrose was much more compact in texture. The results of figure 7 show this. A suggestion to improve on the texture is that a different sweetener be used. It was expected that Splenda would give a much better texture than it did. This was due to Splenda being a chlorinated form of sucrose. The chemical structure is very similar as seen in figure 1a. This was also considered a good choice for the baking because it doesn t breakdown during heating (Chapello, 1998). Difficulties presented with this sweetener are that it is 600 times more sweet than sucrose meaning it s difficult to decide how much to use in a recipe(hunter et al,1990). Splenda is also only one tenth as dense as sucrose (Johnson, 2006) so this would have an adverse affect on the texture of the meringue. With so many artificial sweeteners being available on the market and many more undergoing testing, it would be good to try other sweeteners with a more similar density to that of natural sugar. The color of the meringues was also affected substantially by the sucrose or Splenda content. As seen in figure 6, the 80% sucrose and 20% Splenda had the nearest L, a and b values to the control. This is expected due to there being a high sucrose content. Sugar causes two reactions in this kind of cooking. One is caramelization, which is the oxidation of the sugar producing a golden color. The other reaction is Maillard browning. This is a reaction of sugar with amino acids (Ashor et al,1984). Egg is high in protein so this reaction was likely. It can be seen in figure 1b. Both reactions are non enzymatic browning reactions. Splenda doesn t undergo these reactions so that would explain the high difference in the color of 100% Splenda and 100% sucrose variations and also the similarity in color of the 100% Sucrose and the 80%Sucrose; 20% Splenda meringues. There are not many suggestions on how to make the color of an artificially sweetened meringue the same as desired meringue color. One method, may be to use artificial coloring to cover up the difference and make the product more appealing. Heat affects the degree of browning so this variable could be monitored and changed to find the best temperature to cook at. In terms of palatability the 80% sucrose, 20% Splenda variable was ranked closest to the control and it was also ranked second to the control in the preference section. The control was ranked favorite. Other variables were not liked amongst consumers very much. To conclude, humans love sugar and its sweet taste. Splenda was not a very good replacer of sucrose in meringue making. To improve on this experiment, one should try using stabilizer in the ingredients to improve on the texture or use another sweetener such as brown sugar. One should use variations in

11 temperature an d cooking time to see if the amount of browning is affected. The palatability of the 80% sucrose and 20% Splenda sample was acceptable so if the other properties of this sample were improved it may be adequate for marketing. Figure 1a: Comparisons in the structure of Sucrose and Splenda Sucrose Splenda Figure 1b. A Maillard Reaction

12 Results: Texture Analysis Table 1: Results of Texture Analyzer Trial 1 Trial 2 Trial 3 Average St.Dev Variation Variation Variation Variation Figure 1: Bar Chart of Average Texture Color Analysis: Table 2: Results of Hunter Colorimeter for meringue made with 100% sucrose L a b Trial Trial Trial Average St.Dev

13 Figure 2: Bar chart for 100% sucrose meringue Table 3: Results of Hunter Colorimeter for 100% Splenda Meringue L a b Trial Trial Trial Average St.Dev Figure 3: Bar Chart for 100% Splenda meringues using Hunter Colorimeter

14 Table 4: Results of Hunter Colorimeter for 80:20 meringues L a b Trail Trial Trail Average St.Dev Figure 4: Bar Chart for 80:20 meringues using Hunter Colorimeter Table 5: Results of Hunter Colorimeter for 50:50 meringues L a b Trail Trial Trail Average St.Dev

15 Figure 5: Bar Chart for 50:50 Meringues using Hunter Colorimeter Figure 6: Average L, a and b values.

16 Figure 7: Average sensory evaluation answers where the star marks the average marking Sensory Evaluation Appearance: 1. Please rate the color of the following samples by placing an X on the scale. 299 White Brown 908 White Brown 645 White Brown 367 White Brown Now please taste each sample in front of you. 2. Please mark on the scale the point that best describes the sample: 367 Soft Hard Extremely soft Very Soft Neither soft or hard Very Hard Extremely Hard

17 299 Soft Hard Extremely soft Very Soft Neither soft or hard Very Hard Extremely Hard 908 Soft Hard Extremely soft Very Soft Neither soft or hard Very Hard Extremely Hard 645 Soft Hard Extremely soft Very Soft Neither soft or hard Very Hard Extremely Hard 3. Please Rate the foods aftertaste on the following scale. 367 Bad Good Extremely Bad Very bad No Aftertaste Very Good Extremely Good 299 Bad Good Extremely Bad Very Bad No aftertaste Very Good Extremely Good

18 908 Bad Good Extremely Bad Very Bad No Aftertaste Very Good Extremely Good 645 Bad Good Extremely Bad Very Bad No Aftertaste Very good Extremely Good 4. Please rate the following in order of preference. 1 being your most favorite and 4 being your least favorite Comments: 908 had a raw egg taste and was yellow in color 645 were off the scale soft in the texture section.

19 References: Itamar R Diabetes: From Research to Diagnosis and Treatment. Page 91 Jacobson, M.F 2000 Obesity in America: inevitable? American Health Letter, Vol. 27, issue 2. Hunter B.T 1990 Sucralose, Consumers Research Magazine vol.73 pg 8 9 Johnson F Splenda & Sucralose, Citation Ecologist, vol. 36, issue 5 pg Baker C.W. and Seagall J.K Free Sugars and Human Health vol 364 pg Ashor, S.H and Zent, J.B (July /August 1984): Maillard Browning of common amino acids and sugars. Journal of Food Science vol.49 page Esteller, M.S, Orlandi de lima A.C, Sileva Lannes S.C (2006) Color measurement in hamburger bums with fat and sugar replacers. Food Science Technology vol. 39 pages Chapello W.J (1998) The use of Sucralose in baked goods & mixes, Cereal Foods World pages Daniel, J.R (2007) Virtual Classroom Lecture Notes accessed at