ABSTRACT
Heat transfer is one of the most important unit operations in the food industry. Nearly every process requires either heat input or heat removal to alter the physical, chemical, and storage characteristics of the product. For example, in the storage of fresh fruits, vegetables, meats, and dairy products heat is removed to decrease temperature and thereby increase storage life. On the other hand, heat is temporarily added to achieve preservation by thermal means. Examples of heat input to change the characteristics of products include cooking to alter the texture of foods and heating to develop color and flavor in candy. Removal of heat is used to produce desirable physical changes (crystallization) in frozen desserts and some candies.
