Food chemists are concerned with the composition and properties of food products and the chemical and physical changes they undergo during postharvest handling, processing, storage, and preparation. In addition to those specifically educated in food chemistry, analytical chemists, organic chemists, natural product chemists, physical chemists, biopolymer chemists, biochemists, and chemical engineers are employed in the food and related industries. Polymer physicists and materials scientists are increasingly in demand. Any discussion of the role of chemical scientists in maintaining or improving the quality of food requires an understanding that most food consumed in developed countries has been processed in some way. Chemists determine the most effective type of processing treatment for each food product.
Foods are complex, heterogeneous biological materials.
Food chemists also deal with milk, a biological fluid, and single-cell sources of food such as eggs, yeast, and other microorganisms. Food products are often highly hydrated, but their moisture content may vary from more than 95 percent to less than 4 percent. Appearance, color, flavor, and texture are important aspects of the organoleptic quality of foods. Texture is the response to forces involved in chewing, swallowing, cutting, or spreading. Instability of foods, which limits their shelf life, can be caused by chemical reactions, biochemical reactions, or physical changes.