Some Effects of Gamma Radiation on Stored Onions

Abstract

Gamma radiation doses of 3200, 4700, 6500, 7900 and 9500 rad completely inhibited sprouting of Brigham Yellow Globe onions in a 300-day test period during which 75 per cent of the non-irradiated controls sprouted. In a second test of equal duration, using controlled temperature storage and shed storage, less than 3 per cent of Autumn Spice onions exposed to either 4000 or 8000 rad sprouted, whereas more than 79 per cent of the non-irradiated bulbs sprouted. Irradiation reduced sprouting of Yellow Sweet Spanish onions in both tests.Some evidence indicated that the smaller bulbs in both the irradiated and non-irradiated lots were less susceptible to storage rot. In Brigham Yellow Globe, the incidence of internal discoloration of the growing point was greatest with the highest radiation dose. Irradiated onions were milder in flavour.

Comparative Effects of Gamma Irradiation and Maleic Hydrazide on Storage of Garlic1,2

“…The above-mentioned results were in accordance with those of Nuttall et al (16), Lewis and Mathur (12), and Kepkowa (9) working with irradiated onion bulbs. Tewfic^ reported that spraying of garlic with MH before harvest caused a reduction of disease during storage and improved the quality of the bulbs.…”

“…Moreover, the brown leaves increased in length throughout the storage period. Browning was also observed by Nuttal et al (16) and by Hori et al (7) in the inner buds of onions.…”

“…Also, gamma irradiation has been shown to be effective for sprout inhibition in root, bulb, and tuber crops. Dallyn et al (6), Dallyn and Sawyer (5), Truelsen (21), Nuttall et al (16), Korableva and Metlitskii (11), Lewis and Mathur (12), and Solanas and Darder (19) reported that gamma irradiation effectively inhibited the sprouting of onions. The effective dose ranged from 2 to 12 Krad, depending on cultivar, time of exposure, storage conditions, and the physiological state of the onion bulbs.…”

Gamma Radiation

“…Several investigations involving botanicals follow. Nuttall et al (1961) found that yellow sweet Spanish onions exposed to 4000 or 8000 rad prevented sprouting in 97% of their experimental group suggesting that irradiation might be a viable method of prolonging storage life for onions. This study, while intriguing, has not been generally accepted by a public concerned with the problems of radiation.…”

Entreposage commercial des fruits et des légumes

“…Cependant, les oignons traités au champ ou avant entreposage avec des inhibiteurs de germination, tels que l'hydrazide maléique ou l'irradiation aux rayons gamma, peuvent demeurer indéfiniment à l'état latent (78,124). C'est ainsi que leur durée d'entreposage est prolongée de 8 à 10 mois selon l'efficacité du traitement, le cultivar des oignons, la présence de maladies et le procédé de séchage des bulbes.…”