Abstract
A considerable browning was observed especially in cortex tissue and along xylem of potato tubers harvested at Sakai in Osaka Prefecture, after irradiation with 10, 20 and 50 krad doses of cobalt-60 gamma rays. This phenomenon was accompanied by the marked increase in polyphenol content and peroxidase activity, and the transient increase in o-diphenol oxidase activity. Total reducing compounds in the tissue were also increased by gamma irradiation.
The browning phenomenon depended on the storage period from the harvest to gamma irradiation treatment. The browning and the transient increase in o-diphenol oxidase activity were completely suppressed in the case of tubers irradiated 3 months after harvest.
There was no significant change in α-amylase activity in all tubers tested.