Studies on the browning of potato tubers by gamma radiation, 1

The relations between the browning of potato tubers caused by gamma radiation and the time of irradiation after harvest or maturity of the tubers at harvest were referred. The effects of polyethylene package and low temperature on the browning were also discussed. Potato tubers were irradiated with the doses of 5-40 Krad and stored at room temperature.The browning induced by radiation was partially observed around the vascular bundle of the tubers and the death of the cells was occurred. It was enhanced from 3 to 7 days after irradiation. The partial browning occurred in the tubers irradiated with the doses of 10-40 Krad one month after harvest. However, when the tubers were irradiated 2 months after harvest, little browning was observed with the doses of 10 and 20 Krad, but at 40 Krad still became brown. The browning may be enhanced more in immature tubers (small tubers) than in mature ones (large ones). The polyethylene packing during irradiation and the following several days may reduce the browning. The treatment of low temperature (5-7°C) after irradiation may also supress the deve-lopment of the browning.