Effect of Gamma Irradiation on the Physicochemical Properties of Rye

Abstract

The effect of irradiation (60Co) on the nutritional value of rye was determined using a chick growth assay. In vitro irradiation increased significantly the solubility of rye solids in water. Total protein (N × 6.25) was not changed appreciably by irradiation but its solubility in water was increased. Compared with non-irradiated rye, the pH of irradiated rye suspension in water was reduced. In vitro digestibility of irradiated rye protein determined by a mixture of trypsin, chymotrypsin, and peptidase was increased. Solubility of carbohydrate from rye in water was increased and viscosity of a water extract was decreased by irradiation. In vitro α-amylolysis of water extracts of the grain indicated no beneficial effect of gamma irradiation for α-amylase activity. In vitro enzymatic digestibility of a diet containing 62.55% irradiated rye was enhanced by a combined pepsin-pancreatin treatment over a non-irradiated rye containing dye. Dry feces, expressed as percentage of dry matter consumed, were less for chicks fed irradiated rye diets than for those fed nonirradiated rye diets. The nutritional value of rye, based on a chick growth assay, was significantly increased by gamma irradiation (60Co). Irradiation of rye decreased nitrogen and mineral excretion by chicks in relation to intake of these nutrients.