Different Levels of Loaded Sweet Potato in Ice Creams I. Abstract You scream, I scream, we all scream for ice cream! an American proverb once stated. Nearly everyone loves ice cream as a frozen dessert. Children, women and men all enjoy eating ice cream and many have flavor preferences unique to every individual. Loaded sweet potato ice cream has never been a flavor of ice cream. Sweet potatoes also have essential nutrients that are needed daily to prevent deficiencies, which include: vitamins A, C (antioxidants), vitamin B6, iron, manganese, dietary fiber, copper, and potassium. The methods used include three trials of four batches of ice cream. The Texture Analyzer, Hunter Colorimeter, and sensory evaluation were used to evaluate the sweet potato ice cream. The control is plain vanilla ice cream, which was the most liked by the panelists. Loaded sweet potato ice cream gives everyone a reason to scream for ice cream. II. Introduction The purpose of the experiment is to develop a new flavor of ice cream and find out the preference of the taste panel. Research to improve flavor that has been completed in the past discusses replacing fats, stabilizers, and sweeteners (Boor). There is no research that has been completed that could make the nutritional value of ice cream greater by using sweet potato as a flavor that would add vitamins and minerals. Vanilla is the most liked and bought ice cream product in North America, for that reason vanilla ice cream is the control because everyone can identify the flavor and relate the other flavor as acceptable or unacceptable (Ice Cream Flavors). Color is important when it comes to a particular ice flavor. Most consumers associate color and flavor together. The dependent variables are justified by the control. All ingredients and the recipe are unchanged. The independent variable is the amount of flavor which is directly related to the dependent variable. Ice cream has been chosen because it is a popular food consumed by most people. The sweet potato is naturally sweet and tastes like a dessert by its self (WHFoods.org). Sweet potato is an anti-diabetic food, meaning that it helps regulate blood sugar levels and stabilize insulin levels. Antioxidants, vitamins A and c, can also reduce free radicals and help improve the quality of life. What better way to improve the quality of life than eating ice cream and receiving nutrients from vegetables at the same time. The methods used included Hunter Colorimeter, Texture Analyzer, and sensory evaluation. Different levels of sweet potato were added to compare each with control. Three trials were completed to compare results and replicate the product. All trials were completed in the same fashion including consistent reading of: temperature, time and ingredients. Lactose is relatively insoluble and is a problem in many dairy products including ice cream and sweetened condensed milk (Dairy science and technology). This is the reason for the coarse texture in ice cream. The structure of lactose as follows on the next page. 1
Lactose is a disaccharide which is made up of galactose and glucose. Lactase is an enzyme that hydrolyzes lactose by splitting the galactose and glucose creating a monosaccharide. The result is increased sweetness and freezing point depression. Also a common characteristic is crystal formation in the alpha form. This is a very distinct texture that is coarse and sandy. Sandy texture is the most easily detected flaw in ice cream. III. Methods The vanilla ice cream mix was prepared for all four ice cream flavors at the same time. The mix was poured into the cylinder of the ice cream machine. Salt (228 grams) and ice were added around the cylinder to freeze it to the proper temperature. The average temperature during this process was -7 to -10 degrees Celsius for about 30 minutes. Every trial was completed in the same manner. Trials 1 and 2 were completed in the same day. There were four batches of ice cream for each trial. Batch one was the control (vanilla ice cream only). Batch two was 114 grams of sweet potato. Batch three was 228 grams of sweet potato. Batch four was 457 grams of sweet potato. The sweet potato was cooked in the oven at 350 degrees F for one hour for each trial. Measurement of the results were completed using sensory evaluation with a total of 14 panelists of all ages and gender. The texture analyzer measured the texture of each ice cream and the Hunter Colorimeter measured the color using L, a, and b ranges. A of the sensory evaluation scorecard is included. The ice cream was arranged in a random order for each taste panel. Sensory evaluation, texture analyzer, and hunter colorimeter tests were all preformed after the ice reached a frozen solid condition. Sensory evaluation scorecard: How would you describe the taste of 334: (1 being strongly like and 5 being How would you describe the taste of 103: (1 being strongly like and 5 being How would you describe the taste of 786: (1 being strongly like and 5 being How would you describe the taste of 902: (1 being strongly like and 5 being 2
How would you describe the color of 334: (1 being strongly like and 5 being How would you describe the color of 103: (1 being strongly like and 5 being How would you describe the color of 786: (1 being strongly like and 5 being How would you describe the color of 902: (1 being strongly like and 5 being Which of the following describes the texture the best for 334: 1.Creamy 2.Smooth 3.Soft 4.Coarse 5.Oily 6.Hard Which of the following describes the texture the best for 103: 1.Creamy 2.Smooth 3.Soft 4.Coarse 5.Oily 6.Hard Which of the following describes the texture the best for 786: 1.Creamy 2.Smooth 3.Soft 4.Coarse 5.Oily 6.Hard Which of the following describes the texture the best for 902: 1.Creamy 2.Smooth 3.Soft 4.Coarse 5.Oily 6.Hard Overall, which did you enjoy the most? And why? What is your age range: 0-18 19-25 26-35 36-50 51 and up Are you a student: Yes No Recipe: Vanilla ice cream mix with three different levels of flavoring of loaded sweet potato ice cream. (http://homecooking.about.com/library/archive/bldairy19.htm) 1360 grams (3 potatoes) of sweet potatoes (Carver or TU-1892s are recommended) 237 ml (1 cup) Brown sugar (Splenda) 10 ml (2 teaspoons) nutmeg 414 ml(1 (14-ounce) can) sweetened condensed milk 710 ml(2 (12-ounce) cans) evaporated milk 710 ml(3 cups) sugar (Splenda) 6 medium eggs 3
30 ml(2 tablespoons) vanilla extract 237 ml(1 cup) Marshmallow cream Amy Porter Procedure: Bake sweet potatoes. Mash and add one cup sugar and 10 ml (2 teaspoons) nutmeg. Cool. in a large saucepan, combine sweetened condensed milk and evaporated milk. Add sugar and eggs and mix well. Heat, stirring constantly, until steam begins to rise from the custard. Do not allow mixture to boil. Remove from heat and add vanilla. Cool. Process custard in an ice cream freezer according to manufacturers' directions. Just before the custard freezes completely, add 237 ml (2 cups) of the sweet potato mixture and marshmallow cream. Continue processing until frozen. IV. Results Table 1. Description of code numbers Sample 334 (Control) Vanilla Ice cream mix only Sample 786 Vanilla ice cream mix and 114 grams of sweet potato Sample 103 Vanilla ice cream mix and 228 grams of sweet potato Sample 902 Vanilla ice cream mix and 457 grams of sweet potato Table 2. Trial 1 data for color, taste, texture, and overall rating Averages 334 786 103 902 Color 1 3 3 3 Texture 2 3 5 5 Taste 3 4 5 5 Average rating 2 3.3 4.3 4.3 Taste, color, texture, and overall rating for trial 1 6 Rating 5 4 3 2 1 0 334 786 103 902 Color Texture Taste Overall rating Sample code Figure 1. Graph of date for trial 1 including taste, color, texture, and average rating 4
Table 3. Trial 2 data table for all s including color, taste, texture and average rating Averages 334 786 103 902 Color 2 2 2 2 Texture 2 4 5 5 Taste 4 4 5 5 Average rating 2.6 3.3 4 4 Trial 2 data for all s 6 rating 5 4 3 2 1 Color Texture Taste Average rating 0 334 786 103 902 Sample code Figure 2. Graph of data for trial 2 including taste, color, texture and average rating Table 4. Trial 3 data table for all s and averages of texture, color, taste, and average rating Averages 334 786 103 902 Color 3 3 4 5 Texture 2 4 5 5 Taste 3 3 5 5 Average rating 2.6 3.3 4.6 5 5
Trial 3 data 6 Rating 5 4 3 2 1 Color Texture Taste Average rating 0 334 786 103 902 Sample code Figure 3. Trial 3 date for all s including texture, taste, color, and average rating Table 5. Information about panelists age and gender. age range 0-18 19-25 36-50 51+ Female 0 8 0 2 male 0 2 0 2 Table 6. Texture analyzer results for trials 1,2, and 3 Trial 1 Trial 2 Trial 3 Texture Samples analyzer Force (g) 334 16.9 786 8.2 103 13 902 18.9 Samples 334 14.5 786 11.9 103 10.3 902 17.8 Samples 334 18.2 786 12 103 8.4 902 16.7 6
Table 7. Hunter Colorimeter results for trials 1, 2, and 3 Amy Porter Trial 1 Trial 2 Trial 3 Hunter colorimeter Samples averages L A B 334 22.40 7.05 5.89 786 20.09 6.95 4.02 103 20.01 7.20 5.81 902 20.23 7.01 5.73 Samples 334 23.45 4.87 6.41 786 23.09 4.30 5.88 103 22.40 4.32 5.82 902 23.40 4.33 5.80 Samples 334 17.06 5.70 6.37 786 17.09 5.65 6.34 103 18.03 7.16 6.00 902 17.45 5.80 6.10 V. Discussion The results were all similar for s 902, 103, and 786. The control, 334, was rated the highest on the scale of 1 strongly like and 5 strongly dislike. This could be due to the fact that vanilla ice cream is the most popular ice cream flavor and many recognized the taste and color of the ice cream. Table 1 describes the numbers based on the amount of sweet potato added. The control stayed consistent for the average rating for all trials. Sample 902 had the highest amount of sweet potato added and 902 also had the highest rating of 5, strongly dislike. This could be due to the coarse texture. The coarse almost sandy texture was very noticeable and undesired. Lactose crystals are to blame for the coarse texture. They can be formed by slow freezing, temperature fluctuation, or high room temperature (Dairy Science and technology). This was the result for all trials of 902. Sample 103 was very similar but had a slightly higher rating. The degree of crystallization was less due to the less amount of sweet potato. Still both s rating were nearly the same, figure 1 and 2 show very similar results. Sample 786 was moderately liked. It was most similar with the control in trial 3. Trial 1 and 2 the control was the most liked by a small margin. The texture for 786 was not gritty and most similar to the control. The amount of sweet potato added was less than 902 and 103. More flavoring was not the best idea for this experiment. The assumption that more is better does not work for ice cream. The entire panel could detect and distinguish flavor and texture problems. The color of the control was most liked. Also this was the most recognized ice cream which could be the reason for the higher rating. The color was off white for the control, slightly orange for 786, little orange for 103, and slightly deep dark orange for 902. Most panelists did not like the color of 902 due to the fact it was a 7
darker color toward the bottom of the container and slightly littler color toward the top; therefore giving inconsistent results for all trials. Also the color was not a recognizable due to the fact that the panelist have never tasted sweet potato ice cream before. Uneven color of the ice cream can affect a human s ability to taste it. One will associate the color of a food with the taste (Daniel). The panelist could have miss rated the ice cream due to the off color or inconsistent color in 902. Color is very important for a panelist unless it is a blindfolded study. Dye could have been added to all s to make them consistent. Everyone has a different perception of color, flavor and texture due to personal preferences. It is nearly impossible to create one ice cream to suite everyone, which is the reason for creating a new flavor. Another way to complete the experiment would be to use canned sweet potatoes or yams instead of fresh cooked baked sweet potato or to compare canned sweet potato ice cream to fresh baked sweet potato ice cream. Also sweet potato and Splenda could have been removed to help with the texture and taste. If there were more panelists available to do the sensory evaluation results would be more reliable. The freezing temperature needed to be faster to improve the texture. In the future this experiment could have been improved by adding a dye to all the s for consistent results for color evaluations. The vanilla ice cream needed to be the same color as the other s. The sensory evaluation scorecard could be improved by adding the question: do you enjoy eating ice cream and frozen desserts? 8
VI. References Daniels, James R. Food Chemistry F and N Lecture Notes. Pages 3-55. Daniels, James R.,Weaver Connie M. The Food Chemistry Laboratory. A manual for experimental foods, dietetics, and food scientists. Second edition. Published by CRC Press LLC. 2003. Boor, Kathryn J, Roland, Ann, Phillips, Lance. Effects of Fat Replacers on the Sensory Properties, Color, Melting, and Hardness of Ice Cream. National Dairy Food Research Center. Department of Food Science. Cornell University, Ithaca, NY 14853. Worlds Healthiest foods. George Mateljan Foundation. 25, September 2006. <http://www.whfoods.com/genpage.php?tname=foodspice&dbid=64#healthbenef its> Dairy Science and Technology. Universtiy of Geulph. Mix Calculations for Ice Cream and Frozen Dairy Desserts. http://www.foodsci.uoguelph.ca/dairyedu/iccalc.html Becky Mercuri. George Washington Carver Sweet Potato Arts and Craft Association of Macon County, Alabama. Sweet Potato Pecan Ice Cream. http://homecooking.about.com/library/archive/bldairy19.htm El-Rahman Adb A.M., Shalabi S.I., Hollender R, Kilara A. The effect of milk fat fraction on the sensory evaluation of frozen dessert. Journal of Dairy Science. Volume 80, No. 9. 1997. Pages 1936-1940. 9