Larger-scale irradiation and marketing studies on onions. Part of a coordinated programme on pre-commercial scale radiation treatment of food

Seed grown onions of ''Alsogodi'' variety were harvested manually, partially defoliated, irradiated with a dose of 50 Gy at a throughput of 6 tons per hour in a pilot-irradiator specially designed for onions, and then stored at ambient conditions of temperature and humidity, together with non-irradiated onions. Texture, density, growth of inner bud, colour, storage losses and quality were determined. Results clearly demonstrated that irradiation for sprout inhibition has a favourable effect on maintaining good texture of onions during storage. By inhibiting the sprouting, no internal discolouration of the bud occurred during storage. This is important for the quality of fresh onions as well as for that of the final dried product, processed from fresh onions after various periods of storage. Due to sub-optimal initial quality of the onions and unsatisfactory control of storage conditions, total storage losses were too high, compared to the results of previous experiments. Yet, the beneficial effect of irradiation was demonstrated at the end of the considered storage period, since 55% of the irradiated and only 10% of the non-irradiated commodities were of acceptable marketing quality. Cost calculation based on 80% utilization of the pilot irradiator used in this study resulted in a treatment cost of 0.25 forint per kg, which is approximately 8% of the average purchasing price of onions in Hungary