Chewing chewing, the food (now called a bolus) is swallowed. It enters the esophagus and via peristalsis continues on to the stomach, where the next step of digestion occurs. Premastication is sometimes performed by human parents for infants who are unable to do so for themselves. The food is masticated in the mouth of the parent into a bolus and then transferred to the infant for consumption. (Some other animals also premasticate.) Cattle and some other animals, called ruminants, chew food more than once to extract more nutrients. After the first round of chewing, this food is called cud. Chewing is
Chewing gum who were supplied chewing gum as a ration and traded it with locals. Synthetic gums were first introduced to the U.S. after chicle no longer satisfied the needs of making good chewing gum. By the 1960s, US manufacturers had switched to butadiene-based synthetic rubber, as it was cheaper to manufacture. Gum base composition is considered proprietary information known by select individuals within each gum-manufacturing company. Information about the other components of chewing gum are more accessible to the public and they are listed in Table 2. Table 2: Common Ingredients in the Formulation of Modern Chewing Gum Gum base is