ABSTRACT
Food processing encompasses a wide range of steps that enable our foods to be transformed from raw agricultural commodities into ready-to-eat foods on our plates. These processing steps take place at the farm level, in distribution centers or in food manufacturing facilities. Food processing includes washing, sorting, and transporting fruits and vegetables, which have minimal impact to the nutrient content of foods. It also includes processing steps such as freezing, canning, dehydration, and fermentation, which greatly affect the final presentation, flavor, texture, and nutrient content of foods. These steps are carried out with the main objective of extending shelf life, increasing product availability, increasing value for the manufacturer, adding nutrients, and delivering products that comply with food safety standards. Food transformation also happens at home or in commercial kitchens. The use of various cooking methods, including boiling, steaming, baking/roasting, frying, grilling, braising, and others, produces an extensive range of flavors and textures. At the same time, these preparation methods and the processing steps involved in making these foods available to us impact the nutritional content of foods in several ways.
Fruit and vegetable processing includes several steps such as grading, washing, and sorting as well as secondary steps including peeling, dicing, blanching, freezing, or canning. The effects of cooking and industrial processing on retention levels of various nutrients depend on the food product and the specific nutrient in question. The same principle holds true when comparing nutrient retention levels across several industrial processing steps. In general, the levels of several nutrients including most vitamins and minerals tend to decrease with the use of heat, whether in the kitchen or in a food manufacturing plant, due to thermal degradation or leaching out into the cooking medium. These losses are usually more pronounced during storage of frozen or canned goods. Conversely, dietary fiber and polyphenol levels experience small reductions irrespective of the food processing or cooking method selected.
Cereals include commodities such as wheat, corn, rice, oats, rye, barley, and many more used throughout the world. Cereals and grains undergo several processing steps after harvest including storage and handling, milling, and separation of the components of the kernel. Whole grains include all the components of the kernel (endosperm, germ and bran) after the removal of inedible parts such as the hull and the husk. Whole grains are rich in dietary fiber, vitamins, and polyphenols, which are components that are present primarily in the bran and/or germ and are thus present at lower levels in refined grains. Cereals can be processed into breads, flat breads, and tortillas, ready-to-eat cereals, pasta, starch, and oils. The proportion of nutrients retained after each of these industrial or cooking processes depends largely on the type of nutrient and the process used.
Fermentation is a biochemical process in which glucose or other carbohydrates are broken down in the absence of oxygen. Fermentation brings about changes in flavor and texture and can be applied to a wide range of food substrates such as fruits, vegetables, legumes, grains, dairy products, and meat products to enhance flavor, texture, and extend their shelf life. Fermentation enriches the nutritional value of many including levels of B vitamins and phenolic compounds.
