Chapter 11: Food Irradiation Chemistry

Irradiation is an alternative food preservation technique that allows processing foodstuff without heating or cooking, preserving its natural and unaltered aspects, which is increasingly a requirement of consumers. Nevertheless, the ionizing radiation is not only absorbed by the intended microorganism DNA molecules, but it also affects all of the absorber constituents. Among them, carbohydrate, protein, and lipid modifications are of special importance since, to be considered a feasible preservation alternative, irradiation should not affect the nutritional purpose of foods. The effects of radiation in carbohydrates, lipids, and proteins have been extensively investigated, but the way it can affect specific foodstuff is of great interest because irradiation probably does not induce the same effects in isolated molecules as in complex food matrices. Furthermore, the conditions under which this technique is applied have a crucial impact in the subsequent chemical reactions, namely the applied dose and dose rate, the temperature and pH, and the presence of water and/or oxygen, among others. The effect of electron beam, gamma, and X-ray irradiation in the major components of food is discussed and the results of recent studies performed in several food matrices under a variety of conditions are presented.