All recipes for chewing gum manufactured today share the same main ingredients: a gum base, sweeteners, primarily sugar and corn syrup, and flavorings. Some also contain softeners, such as glycerin and vegetable oil. The amount of each added to the mix varies as to which type of gum is being manufactured. For example, bubble gum contains more of the gum base, so that your bubbles don't burst…especially during class! Though gum manufacturers carefully guard their recipes, they all share the same basic process to reach the finished product. Preparation of the gum base at the factory, by far the lengthiest step, requires that the raw gum materials be melted down in sterilized in a steam cooker, and then pumped to a high-powered centrifuge to rid the gum base of undesirable dirt and bark. Once the factory workers clean the melted gum base, they combine approximately 20% of the base with 63% sugar, 16% corn syrup, and 1% flavoring oils, such as spearmint, peppermint, and cinnamon. While still warm, they run the mixture between pairs of rollers, which are coated on both sides with powdered sugar, to prevent the resulting ribbon of gum from sticking. The final pair of rollers comes fully equipped with knives, which snip the ribbon into sticks, which yet another machine individually wraps. The gum base used in these recipes is, for the most part, manufactured, due to economic constraints. In the good old days, the entire gum base came directly from the milky white sap, or chicle, of the sapodilla tree found in Mexico and in Guatemala. There, natives collect the chicle by the bucketful, boil it down, mold it into 25-pound blocks, and ship it directly to chewing gum factories. Those with little or no self-restraint, chew their chicle directly from the tree, as did New England settlers, after watching Indians do the same. The concept of chewing gum stuck, and continues to play a vital role in our economy, largely due to the many benefits associated with its use. Sales of chewing gum first began in the early 1800s. Later, in the 1860s, chicle was imported as a substitute for rubber, and finally, in approximately the 1890s, for use in chewing gum. The pure pleasure derived from enraging a schoolteacher by blowing bubbles in class, or from annoying a co-worker by snapping it, is only one of the attractions of chewing gum. Chewing gum actually helps to clean the teeth, and to moisturize the mouth, by stimulating saliva production, which helps to neutralize tooth-decay-forming acids left behind after eating fermented food. The muscular action of chewing gum also helps to curb a person's appetite for a snack or for a cigarette, to concentrate, to stay alert, to ease tension, and to relax one's nerves and muscles. For these very reasons, the armed forces supplied soldiers with chewing gum in World War I, World War II, in Korea, and in Vietnam. Today, chewing gum is still included in field and combat rations. In fact, the Wrigley Company, following the Department of Defense specifications supplied to government contractors, supplied chewing gum for the distribution to troops stationed in Saudi Arabia during the Persian Gulf War. It is safe to say that chewing gum has served our country well.

note: sweetener: 甜料 corn syrup: 玉米糖漿 flavoring: 調味品, 調味料 softener: 軟化劑; 柔軟劑 glycerin: 甘油，丙三醇 vegetable oil: 植物油   bubble gum: 泡泡糖   steam cooker: 蒸汽蒸煮器（殺菌器） centrifuge: 離心分離機   spearmint: 荷蘭薄荷 peppermint: 胡椒薄荷 cinnamon: 肉桂, 桂皮     sap: .樹液 chicle: （中美產的）一種樹膠 sapodilla: 人心果樹（赤鐵科常青樹） Guatemala: 危地馬拉             moisturize: 使增加水分 saliva: 口水, 唾液 ferment: 發(fā)酵