121lab01 - Laboratory 1 – Food Processing: Food Qualities...

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Unformatted text preview: Laboratory 1 – Food Processing: Food Qualities and Additives Learning Objectives Students will be able to: • Compare the chemical and physical properties of three different food thickening/emulsifying agents. • Test for Vitamin C content and how storage conditions affect this value. • Understand how enzymes are used in food production. • Analyze a food label for additives and their function in processed foods. After reading these guidelines, students should be able to answer the following questions: • What are the thickening agents to be used? • How will you test for vitamin C? What food will be used? • What is used to make cheese? Where does it come from? • Why are food additives used in foods? Introduction Much of the food eaten today, whether in restaurants or at home, has been processed in some way by the food industry. Commercial processing of foods, such as freezing, canning, and drying, is done to extend the useful shelf life. Compounds (food additives ) are added to food to impart favorable color, texture, and flavor. These include stabilizers and emulsifiers, which keep ingredients in foods such as mayonnaise and peanut butter from separating, thickeners that improve the texture of foods such as soups, desserts, and jams, and natural and artificial colors and flavors that improve appearance and taste. Other additives enhance the nutritional value of foods. Examples are the addition of vitamins A and D to milk, B vitamins and iron to cereals, and calcium to orange juice. Benzoates, sorbates, and proprionates protect foods from microbial contamination, and antioxidants such as ascorbate (vitamin C), BHA, and BHT prevent oxidation of the fatty acids in foods (rancidity). Food processing and the use of preservatives are not a recent phenomenon. For thousands of years people have preserved food by smoking, drying, and adding salt, sugar, and spices. More than 700 food additives have been used for a long enough period of time to be considered safe for human consumption without having to go through the lengthy testing required of new food additives. These additives are included on the GRAS (generally recognized as safe) list. Additives on the GRAS list are subject to further scrutiny if evidence is presented that indicates they may be harmful. Saccharine is an example. 1 In Part A of this lab assignment, the chemical and physical properties of three commonly used thickening agents will be examined. Modified food starch, cornstarch, and guar gum, are used in a number of ways, including thickening milkshakes, preventing creamy salad dressing from separating, and stabilizing frozen desserts. The effect of modified food starch is to stabilize and thicken foods. This is accomplished by the cross-linking of glucose chains in the starch. Natural food starches, such as cornstarch, are also used to thicken foods. However, modified starches tend to have higher solubility and greater stability, so are preferred by food processors for certain uses. food processors for certain uses....
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This note was uploaded on 01/16/2012 for the course NUTR 121 taught by Professor Heathergraham during the Fall '11 term at Truckee Meadows Community College.

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121lab01 - Laboratory 1 – Food Processing: Food Qualities...

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