152 C H A P T E R 8 Review and Assess Summary Carbohydrates are the main source of energy for people. This energy comes from the sun and is stored in plants as carbohydrates through photosynthesis. The simplest carbohydrates are called sugars. The most common sugars are the monosaccharides glucose, fructose, and galactose. Disaccharides are two joined monosaccharides. Disaccharides can be broken into two monosaccharides through hydrolysis. For hydrolysis to occur, there must be water and the addition of an enzyme, heat, or an acid. Alcohols are organic compounds that have chemical structures similar to sugars. Most sweeteners used by the food industry have natural sources, such as sugarcane, sugar beets, sugar maple trees, corn, and grass crops. Honey is produced by bees. Other names for sugar that may appear on food labels include invert sugar and dextrose. The main function of sugar in food preparation is as a sweetener. Sugar also performs several other functions in foods. Understanding factors that affect sugar crystal formation is necessary in the production of cooked candies. Controlling the growth of sugar crystals in candy involves the type of sugar and the use of interfering agents. The timing of stirring, the cooling speed, and the ripening process also affect the growth of sugar crystals. Sugars fit into a healthful diet. They provide energy and aid in the digestion of proteins. Sugars only become a problem when they exceed the recommendations for added sugars and are the source of too many total calories in the diet. Check Your Understanding 1. Explain what happens during photosynthesis. 2. What are the three categories of carbohydrates in food ingredients? 3. What elements make up all carbohydrates? 4. Name three monosaccharides and give a source of each. 5. Name the monosaccharides that make up each of the disaccharides and give a common food source of each disaccharide. 6. How are the molecular structures of sugars and alcohols similar? How do they differ? 7. What is the difference between brown sugar and granulated sugar? 8. Identify the six functions of sugars in food preparation and name a food in which sugar performs each function. 9. Name four interfering agents used to prevent crystal formation in candies and explain how one of them works. 10. How and where does the body store glucose that is not needed as an immediate source of energy? 11. Describe how the body regulates blood glucose levels. Copyright Goodheart-Willcox Co., Inc.