Irradiation of potatoes - after cooking darkening - Fusarium susceptibility during storage. Part of a coordinated programme on the shelf-life extension of irradiated fruits and vegetables

The after-cooking discolouration of Bintje potatoes, cultivated from five different origins in the Netherlands, irradiated by gamma rays or electron was assessed. For comparison, samples of unirradiated potatoes treated by IPC/CIPC sprout inhibitor were also studied. Sprout inhibition and rotting of potatoes treated by different methods were also investigated. It appears that there exist differences in the degree of after-cooking discolouration of potatoes harvested from different origins. Slight discolouration was observed in electron-irradiated potatoes, those exposed to 0.5MeV showed less greying than those treated by 1MeV. Potatoes treated with IPC/CIPC showed the least, and those treated by gamma rays showed the strongest after-cooking darkening. No sprouting occurred in gamma irradiated samples. Sprouting of IPC/CIPC treated samples was minimal during storage but was enhanced after reconditioning. Those treated by electrons showed severe sprouting. Two to 4 weeks reconditioning at 150C of irradiated potatoes, previously held at 7 - 100C for several months, did not reduce the degree of after-cooking discolouration