Microwave heating of foods ‐ changes in nutrient and chemical composition

Industrial microwave applications have increased considerably over the years and so has the number of microwave ovens in American homes. Remarkable characteristics have been attributed at times to microwaves without sound scientific information to back up these claims. Heating foods in a conventional and a microwave oven to comparable internal temperatures will generally result in greater moisture losses in the microwave heated products. The effects of microwaves on proteins and lipids are minor and due to heat, rather than the radiation in a microwave oven. Data of the effects on carbohydrates are virtually nonexistent. The degree of destruction of vitamins and pigments during microwave processing is not greater than that observed in conventionally heated foods. There are differences in flavor and taste in certain food products prepared in a conventional and a microwave oven. Data from different laboratories are not always in complete agreement, which is understandable considering the great variability in food products. It is concluded that nutritional and chemical changes in microwave heated foods are of approximately the same magnitude as those in foods prepared or processed by conventional methods. Microwave radiation is not powerful enough to break chemical bonds to cause the formation of radicals which might be hazardous to human health.