Chapter 8 Sugar: The Simplest of Carbohydrates 145 Invert sugar is also produced commercially. This is done through the controlled addition of acids to sucrose, followed by a neutralization process. Invert sugar helps prevent the crystallization and resulting graininess of candy caused by cane and beet sugar. This is because invert sugar is a mixture of two monosaccharides and cane and beet sugars are disac- charides. Monosaccharides are more soluble in water and therefore form smaller crystals. It takes skill to make homemade candy that has the fine texture that results from the use of commercial invert sugar. Interfering Agents Interfering agents are substances that can prevent or slow crystal growth. See 8-12. The most commonly used interfering agents are corn syrup, butter, and cream. Some recipes call for egg white, cream of tartar, or vinegar as interfering agents, too. Corn syrup is high in the monosaccharide glucose. Glucose and fructose will consistently produce finer, smaller sugar crystals than sucrose. The fat molecules of butter and cream and the protein molecules of egg white help suspend and separate sugar crystals. This results in a smooth, creamy candy. Cream of tartar and vinegar are acids. Adding acids will hydrolyze the sucrose in a sugar solution. Hydrolysis results in increased levels of glucose and fructose. Agitation Agitation refers to the beating and stirring of a candy solution. The effects of agitation are directly related to the temperature of the candy solution. When the syrup is hot, even slight or occasional stirring Candy is made when sugar crystals separate from a supersaturated sugar solution during cooling. The entire candy industry revolves around understanding the concentrations of sugar to water at given tempera- tures. Candy producers know the optimum temperature for making each type of candy. See 8-11. Sugar crystals form around particles that enter a sugar solution. These particles can be as tiny as lint or dust, but the crystals that result may be large. Sugar crystals that form on the sides of the pan during cooking will also trigger further crystallization. This is why some candy recipes have you put a lid on the pan for two to five minutes. The steam trapped by the lid will wash sugar crystals from the sides of the pan. Controlling the size of the sugar crystals is very important to the production of quality candy. In most cases, the finer the sugar crystals are, the higher the candy’s quality will be. Factors That Affect Crystal Formation The following five factors affect sugar crystal formation: • type of sugar • use of interfering agents • agitation of the sugar syrup • cooling of the sugar syrup • ripening of the finished product Type of Sugar The main sugar used by candy producers is sucrose. Sucrose crystallizes rapidly and can form large crystals. Candy producers add invert sugar when they need to slow the crystal formation. You read earlier that invert sugar occurs naturally in honey and molasses. Solubility of Sugar Fructose Water molecules 8-10 The polar OH groups in fructose are attracted to water molecules. For this reason, sugar dissolves easily in water. Boiling Point of Sugar Solutions Boiling Point °C (°F) Percentage of Sugar Percentage of Water 100.4 (213) 10 90 101.0 (214) 30 70 102.0 (216) 50 50 106.5 (224) 70 30 107.3 (225) 75 25 114.9 (239) 85 15 117.7 (244) 87 13 120.8 (249) 89 11 122.6 (253) 90 10 Adapted from: Amendola J. & Lundberg D. Understanding Baking, 2nd ed., Van Nostrand Reinhold, 1992. 8-11 As the concentration of the solute increases, so does the boiling point of the solution. Copyright Goodheart-Willcox Co., Inc.