Studies on the nutritional value of foods treated with γ‐radiation. II.—effects on the protein in some animal feeds, egg and wheat

Abstract

The effect of y-radiation on the protein nutritive value of certain animal feeds (protein concentrates), frozen whole egg, whole wheat and wheat gluten was measured by use of a microbiological method. There was little change in nutritive value of the animal feeds with doses of 0.5 and 1.0 Mrad and no change with frozen egg aL0.5 and 5.0 Mrad. Whole wheat showed no loss a t 0.2 Mrad; a 6% loss at 1 . 0 Mrad was not increased further a t 5.0 Mrad. Gluten prepared from wheat and then irradiated was unchanged a t 0.02.Mrad but losses of 5. 7 and 26% were shown with doses of 0.2, 1.0 and 5.0 Mrad respectively. Following amino-acid supplementation studies and microbiological assays for methionine, loss of availability of this amino-acid was demonstrated to be principally responsible for the lowering of the nutritive value of the 5-o-Mrad-irradiated wheat gluten.

Irradiation of cereal grains and cereal grain products

“…consistent difference in amino acid composition with irradiation doses of 5 Mrad. However, the amino acid composition of gluten irradiated with a dose of 5 Mrad indicated small losses (10%) of leucine, isoleucine, and methionine (Kennedy, 1965b). A considerable reduction in the cysteine content of wheat gluten irradiated with a dose of 10 Mrad has been reported by Doguchi (1969).…”

Nutritional Aspects of Food Irradiation: An Overview

“…'Deceased. Kennedy (1965) observed little change in nutritive value of animal feeds (protein concentrates) when 0.5 and 1.0 Mrad doses were appliedand no nutritional changes with frozen eggs irradiated at 0.5 and 5.0 Mrad. Ley (1972Ley ( , 1975 noted excellent results with radappertized feed for germ-free rat and mouse colonies which were maintained for 5 years.…”

Sterilization of laboratory animal diets using gamma radiation

“…It is important, therefore, that initial contamination should be kept to the minimum. A more detailed discussion of the kinetics of inactivation of micro-organisms by radiation or heat, and of the choice of dose for radiation sterilization, has been published elsewhere (Ley & Tallentire, 1964, 1965.…”

“…This procedure has been shown to give (for a wide variety of proteins) results that correlate well with those of biological tests with rats. Kennedy (1965) used the same microbiological test to study the effects of irradiation on the quality of some protein constituents of animal feeds, but in many of his tests the doses of irradiation were lower than those commonly used for the treatment of laboratory animal diets. At 1.0 Mrad he found no serious diminution of the RNV of air-dried fish meal, meat meal or meat-and-bone meal; the effects were even smaller in samples with a higher moisture content of about 14 per cent.…”