Abstract
The germination controls of potato and onion were the most important and successful problems in the field of the preservation of foods by gamma-ray irradiation. In the case of sweet potato the same effects would be expected. Therefore authors wished to determine the optimum conditions. After irradiation at the dose from 0.25×104r to 150.0×104r samples were storaged in a temperature and moisture controled room for 4-9 months. Outward appearances, germination, tastes, weights, contents of water, vitamin B1, B2 and C were estimated.
Results obtained were as follows:
1) Necessary dose for germination control
just after harvest…………………1.2×10r
just before planting…………0.8×104r
2) Outward appearances
less than 5.0×104r………unchanged
more than 20.0×104r………brown spots were appeared
0.5×104r-1.2×104r……unchanged and better than control (after 4 months)
3) Generally, the weight changes in the storage period were not influenced by low dose of irradiation and rather small at the dose of 1.2×104r, but over this dose the weights decreased rapidly with increase of irradiation dose.
4) Immediately after irradiation, samples which were irradiated at the dose of less than 5.0×104r were good to eat, but after 4 months storage this value decreased to 1.2×104r.
5) Immediately after irradiation, water contents were not influenced by irradiation, but during storage these values were rapidly decreased with increase of irradiation dose.
6) Vitamin B1 contents were decreased in small quantities by irradiation at the dose of below 20.0×104r. Under the dose of 20.0×104r vitamin B2 contents were not influenced and vitamin C contents were unchanged in any case.
7) Irradiation under 1.2×104r did not cause any appreciable change in outward appearances, tastes, vitamin contents against the controls.
