Effect of Processing on Chemical and Nutritional Changes in Food Lipids

Commercial processing of fats and oil into edible products is done to remove the impurities from the oil. Unless the oil is hydrogenated, very few chemical changes occur during this process to alter the nutritional quality of the oils. Trans fatty acids that are formed during hydrogenation have limited nutritional and metabolic effects if consumed with an adequate supply of essential fatty acids. When lipids or foods containing lipids are heated in the presence of oxygen, they undergo oxidation, which causes degradation of the fatty acids. The free radicals produced in these oxidation reactions may react with proteins, vitamins, or other food constituents and reduce the nutritive quality of the food. However, destruction of flavor or color by these reactions is often noticed before major nutritional damage can occur.