Research fcr the Curing of Sweet Potatoes and Elephant-foot

This research deals with the treatment of curing of Sweet potatoes and elephant-foot which can prevent its decomposition, maintain its quality and economize the energy consumed during its storage in large quantities by accumulation.<br>The result of the experiment is given as follows.<br>1. In order to cure the first stage black rot sweet potatoes (by Ceratostmella fimbriata E. et H) it is necessary to cure at rather high tamperature, 35°C-36°C of temperature sweet potatoes themselves, R. H. 90% 3.5-4.0 days.<br>2-1 It is observed that the treatment by hot water (7-10min. at 55°C, 5-7min. at 57.5°C) of the seed elephant-foot dried in a ventilated place, sterilize the epidermis of devil's tongue infected with Bacillus Carotovorus HOLLAND or suppress its activity. It is also observed that this treatment nevertheless does no damage by heat to the surface of elephant-foot.<br>2-2 When elephant-foot is put in a ventilated place at a low temperature and a low humidity (3-5°C, R. H. 60-70%, 1m/sec), Bacillus Carotovorus HOLLAND with which it is infected becomes inert in four weeks. Even if it is put under the treatment for curing immediately after this ventilation, the development of callus is not affected at all.<br>3. We build a storeroom for curing large enough to be put in practical use (40m²), where we made an experiment in the regulation of temperature for the treatment by hot water and for curing. The materials are treated by heat uniformly at a fixed temperature. Besides the overall heat transfer coefficient of the storeroom is low (0.54Kcal/°C·m²·h), and the amount of electricity consumed throughout the storage periode is 40 k. w. h. par ton of elephant-foot, which is only 1/10-1/5 of that in the conventional electric heater method.<br>Since the rate of decrease by decomposition in the storeroom above-mentioned is 0-3% and that of the decrease of moisture is 10%, it can be said that the loss during the storage is small.