1967 年 29 巻 3 号 p. 149-154
Lavoratory scale model of vacuum cooling, by using desiccator, was devised, and the precise characteristics of vacuum cooling concerning the effect of packaging, pre-moistening and crop difference of Japanese perishables were investigated. (Fig 2)
1. The change of air pressure, product temperature and water loss of crop in desiccator, following the evacuation of air were observed every moment. (Fig 3)
2. In completely closed packaging, the fall of temperature of crop was prevented owing to the evaporated moisture.
Pre-moistening on the surface of crop in case of vacuum cooling, is very effective both for reducing the weight loss and maintaining the freshness. (Fig 4)
3. Vacuum-cooled temperature differed due to the kind of crop, packed into the unperfolated polyethylene bag, and influenced much due to the sealing. (Fig 5)
Cooling mechanism of the vacuum cooling were stated compared with other cooling.
4. The temperatures of the parts of crop in vacuum-cooling were measured. (Fig 6)
(1) The difference of temprature by 2.5°C occ-ured between the parts of lettuce.
(2) On the progress of vacuum-cooling of Brussels sprout, the temperature of the outer layer was lower than the center by 1°C, while the tend-ency was inversed with the stop of vacuum-pump.
(3) The temperature distribution in the crop by vacuum cooling, was not affected much due to the packaging, pre-moistening of the crop.