| 摘要 |
<p>PURPOSE:A specified multi-stage cooling process is applied to shorten the time for vacuum cooling and prevent completely the deterioration of vegetables caused by local supercooling. CONSTITUTION:Vegetable packed in corrugated cardboard boxes, as they are, are rapidly evacuated with high-performance steam ejector booster of 3-2 torr end vacuum and when the vacuum reaches the predetermined value of about 5 torr, the pressure of the steam fed into the steam ejector-booster is reduced to change the end vacuum to the prescribed level. Thus, the deterioration of vegetables by local supercooling is prevented and the level of vacuum is kept for a predetermined period to effect uniform cooling.</p> |
