Effect of Irradiation on Sprouting of Water Yam (Dioscorea Alata) Using Different Doses of Gamma Radiation

Water yam (Dioscorea Alata) tuber samples from Abuja, Nigeria were irradiated with gamma radiation of doses 60, 80, 100, 120 and 140 gray respectively at an average dose rate of 3 gray/min and some un-irradiated used as control. All were monitored during storage for 7 months. Results indicated that all the un-irradiated water yams sprouted by the end of the 3rd month of storage. 90% of the irradiated water yams at 60 gray, 30% of the irradiated water yams at 80 gray and only 10% of the irradiated water yam at 100 gray sprouted within the storage period. None of the irradiated water yams at 120 and 140 gray sprouted. The results suggest that gamma radiation dose range of 100 - 140 gray could effectively inhibit sprouting in water yams for 7 months. 80% of the un-irradiated water yams rotted while none of the irradiated water yams rotted within the storage period. The percentage weight loss (64.79±13.45%) in the un-irradiated was significantly (p ≤ 0.05) higher than the irradiated tubers. There were no significant differences (p ≤ 0.05) in the average values of the lipid, protein and carbo- hydrate content of the irradiated and un-irradiated water yam tubers. The results suggest that radiation processing preserved the quality of water yam tubers through sprout inhibition, reduction of weight loss, preservation of macronutrients such as protein, lipid, and carbohydrate content.