EFFECTS OF STERILIZATION BY GAMMA RADIATION OF EDIBLE STORED VIGNA MUNGO L. AND TRITICUM AESTIVUM L. SEED INFESTED WITH SURFACE MICROFLORA IN INDIA

An effective 60Co gamma irradiation method for the removal of contaminating surface microorganisms (fungi) of mung (Vigna mungo L.) and wheat (Triticum aestivum L.) stored seeds, without the loss of germination capacity and minimum loss of nutritional values, are described. Significant depletion of surface fungal population on wheat (96%) and mung (94%) was noticed within 2 kGy, while complete inhibition of surface fungal population was observed at 4.2 kGy. Although the irradiation did not significantly alter the germination potential of the treated grains, it reflected delay in germination as a function of absorbed dose. The seed membrane permeability and nutritional values like carbohydrate and protein content of the radiation-exposed seed were significantly altered. The radiosensitivity of wheat was found more than that of the mung. It was also observed that the germinating potential of the treated seeds did not alter significantly. However, membrane permeability of seeds was altered as a result of gamma irradiation. Precisely, the investigation reflected that the dose range from 1 to 2 kGy was most effective for seed sterilization, keeping their viability and minimum loss of nutritional value like protein and carbohydrate intact. PRACTICAL APPLICATIONS There are many reports on radiation sterilization of stored seeds without any consideration of the nutritional quality of the seeds, which is very important for quality control. We should look upon change of quality of seed during seed sterilization. We need to protect/or estimate minimal loss of the nutritional value of stored seed by loss and benefit assessment. The significance and originality of this manuscript is that we try to look for an effective 60Co gamma irradiation method for the removal of contaminating surface microorganisms (fungi) of mung (Vigna mungo L.) and wheat (Triticum aestivum L.) stored seeds, without the loss of germination capacity and minimum loss of nutritional values. The study was concentrated on germination pattern, protein, carbohydrate and intensity of seed membrane damage during radiation processing. Also, our present work emphasized on radiosensitivity of different seed-borne fungi that frequently infected seed grain during storage. This study may help to sterilize the stored seed with consideration of nutritional value.