Chapter 8 Sugar: The Simplest of Carbohydrates 143 bonds to taste buds for a short time. The nervous system registers this bond as a sweet flavor. The more of these bonding sites a molecule has, the sweeter the substance will seem to be. The perceived sweetness of the substance will also increase as the length of the bonding period increases. In cooking, sweeteners help to balance or mask sour, bitter, and spicy components in food. Sugar is used in tomato-based sauces, pickling mixtures, salad dressings, and meat rubs to balance the acidic elements in the food. Preservatives Sugar helps prevent food spoilage. Water will be drawn to sugar molecules before it is drawn to bacteria. Therefore, most single-celled contaminants will dehy- drate and die in concentrated sugar solutions. This is why sugar is the only preservative needed in most candies, jams, jellies, and syrups. Sugar plays another preservative role in baked goods. It helps products such as cakes stay moist. Invert sugar has been found to maintain freshness of baked goods considerably longer than sucrose. Sugar also helps maintain the color in cut fruits like peaches, apples, and pears. Adding sugar strengthens fiber and helps maintain the shape of fruits during cooking. Tenderizers When sugar is added to a dough, it will tenderize the product. You can observe the effects of this function by taste testing an Italian hard roll that has no sugar added. Compare this with white bread that contains a small amount of sugar. Also, test a sweet roll that has almost twice the sugar of white bread. Most of the difference in tenderness of the three products is due Functions of Sugars in Food Preparation Sugars from all sources have chemical structures that are similar but not identical. The similarities allow food manufacturers to use one sugar in place of another for some purposes. The unique aspects of each sugar structure, however, determines which type of sugar is best suited for each function in foods. Sugars have up to six functions they can perform in food products. They act as sweeteners, preservatives, and tenderizers. They also have a key role in the processes of crystallization, caramelization, and fermentation. Sweeteners Sugar’s ability to sweeten is its major function in most food products. The ability to sweeten is connected to sugar’s molecular structure. Sugars contain up to 10 basic units of monosaccharides. Sensory evaluations have shown that most people rate the sweetness of sugars similarly. That is, most agree fructose is sweeter than sucrose and lactose is the least sweet of the three. Scientists have compared the structure of sugar molecules to the sweetness of the sugars. The scientists have found that the sweeter the sugar is, the simpler the structure of the molecule is. In general, the longer the sugar chain is, the less sweet the sugar will seem to be. See 8-8. Recent research has revealed more information about sugar’s ability to sweeten. Researchers have identified a triangular form on sugar molecules that Leon Rafael/Shutterstock.com 8-7 This beautiful pear dessert is possible because isomalt can be pulled, spun, cast into molds, and blown into bubbles. Relative Sweetness of Sugars Sugar Relative Sweetness Fructose 1.8 Sucrose 1.0 Glucose 0.8 Mannitol 0.7 Glycerol 0.6 Sorbitol 0.5 Galactose 0.3 Maltose 0.3 Lactose 0.2 8-8 The sweetness of sucrose, or table sugar, is the standard to which the sweetness levels of other sugars are compared. Copyright Goodheart-Willcox Co., Inc.