Effect of DE of Corn Syrup - staging.files.cms.plus.com

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industry, then the dry solids percentages must be calculated before the percentage of reducing sugars can be found. Total reducing sugars in a hard candy affects color, equilibrium relative humidity (ERH), sweetness and shelf life. Reducing sugar content depends on the type of corn syrup used and the level of corn syrup in the formulation. However, inversion of sucrose into glucose and fructose during cooking (temperature, time and pH dependent) can cause a significant increase in reducing sugar content in a hard candy. That is, inversion occurs more rapidly at higher temperatures and low pH, so the longer an acidified candy is held at high temperature, the less sucrose (and more glucose and fructose) will be present in the final candy. Definitions Corn starch polymeric molecules of glucose found in corn Corn syrup a sweetener made by hydrolysis of corn starch (sometimes called glucose syrup) Baume' scale for hydrometer readings (measures specific gravity or density) DE Dextrose Equivalent: measure of reducing power ERH Equilibrium Relative Humidity: the RH of air at which a product neither picks up or loses moisture Hygroscopicity Capacity of a material to pick up moisture from surrounding air APPARATUS Copper cooking kettles or electric skillets Gas burner Stirring spoon 8 oz. glass jars Aluminum pans for weighing Balance PROCEDURES The 27 formulations shown on the attached Table 2 have been pre-weighed for you in the copper kettles (or electric skillets). In addition to the sweeteners, approximately one part of water per two parts of dry sugar is added in order to dissolve the sugar. All batches have the same total weight so that cooking times should be constant, but record the time from when your batch starts to boil to when it reaches the desired temperature. Stir the formula slowly as it heats. When the sugar is completely dissolved, it is no longer necessary to stir. Keep the flame (or electric setting) rather low when temperature is between 230 and 250°F because there will be moderate foaming. After foaming has subsided, the gas fire (or electric setting) can be increased slightly. However, we want to keep the cooking rate as constant as possible for all cooks so that the cooking times are constant and are not a factor in color comparisons. Shut the flame off at the required final temperature and quickly fill the two metal weigh boats about half full by using the wooden spoon. Be careful to control the amount of syrup in each weigh boat. Then carry the kettle to the cooling table and pour it out. With a knife, score several one-inch squares that will be used for moisture uptake tests. When the candy is cool, break off enough squares to fill an 8 oz. jar identified with your code number. Note that the syrup is still losing water while it is held at high temperature even though the flame is not on and the syrup is not boiling. So be as quick as possible (while still being safe) once your syrup has reached the desired temperature. Cautionary note. Sugar syrup at 300°F is extremely hot and therefore, extremely dangerous. If you get any of it on you, it will burn you severely before you get a chance to wash it off. Always use gloves 2
when handling hot surfaces, never touch a hot sugar syrup with your hands and be careful not to allow the syrup to spill when you carry the kettle to the table. Be very, very careful! Record the weight of one of the aluminum weigh boats (use an empty weigh boat to tare the scale). Place these samples in the oven at elevated temperature and humidity. Tomorrow morning weigh your sample again (remember to tare the scale again with an empty pan). Calculate the percent moisture pickup (see below) and report the results in the appropriate column in Table 2. Please let me know if you can not weigh your sample during this time period and we’ll make other arrangements for you. Percent moisture pickup can be calculated as follows: % moisture pickup = {(Wf - Wi)/ Wi}x 100 where Wf is the final weight and Wi is initial weight of sample. The second weigh boat will be used to measure color with the Hunter colorimeter. Each sample will be placed on the stand and the L,a, b values recorded at three points on the disk. The average of the three readings should be recorded in Table 2. These samples will also be used to measure water content (Karl Fisher titration) and Tg (differential scanning calorimeter). You need to calculate the percentage of reducing sugars in each formulation. The remainder of Table 2 will be filled out in the follow-up class period based on data obtained from each of the other students. DATA ANALYSIS AND DISCUSSION OF RESULTS Once all the data has been compiled, you need to analyze the results. This data set provides numerous comparisons and correlations that demonstrate the principles discussed in class. Some example of analyses/correlations for you to consider include: 1. What factors affect Tg? 2. What factors affect water content? 3. What factors affect color development? 4. What factors affect water sorption? 5. What other connections can you make? ADDITIONAL QUESTIONS 1. What would be effect of using more or less water in the sugar mixture before boiling? 2. If you were to use high fructose corn syrup (basically a 97 DE corn syrup in which some of the glucose is enzymatically converted to fructose) to make a hard candy, what would you predict would happen to color and moisture uptake and why. 3
Page 1: Hard Candy Variations Effects of Co
Page 5 and 6: Code Composition Sucrose/Corn Syrup
Page 7 and 8: that are cooked for a long time at
Page 9 and 10: Corn Syrup & Sugars in Hard Candy H
Page 11 and 12: Experimental Design Ingredients Per
Page 13 and 14: 25 min (225°F) Effect of Protein o
Page 15 and 16: N H 2 O H O H H O H H O H H O H OH
Page 17 and 18: Relative Sweetness of Nutritive Swe

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