Abstract
Effects of the low pressure storage on the keeping quality of fruit were studied with tomato, peach, satsuma mandarine and apple fruits. These fruits were stored using closed and aerated types of storage. Tomato and peach fruits were stored at 90 and 30Torr in the closed type and at 380, 190 and 76Torr in the aerated type. Satsuma mandarine and apple fruits were stored at 380, 190 and 76Torr in both closed and aerated types. Normal pressure storage was used as control. Storage temperature was 11_??_12°C with tomato and peach fruits, and 6_??_7°C with satsuma mandarine and apple fruit. Effects of low pressure on respiration and ethylene production of apple fruits were also studied.
1. Weight loss
In all kinds of fruits, weight loss was less in the storage of closed type and greater in that of aerated type than in the normal pressure storage, and wilting of the skin was found at 190 and 76Torr in the storage of aerated type.
2. Fruit firmness and coloring of the skin
In the storage of closed and aerated types, softening was retarded in tomato, peach and apple fruits and coloring of the skin and yellowing of the skin ground color were also retarded in tomato and peach fruits. While, in satsuma mandarine fruit, rind puffing, pitting and yellowing of the albedo were found at 76Torr in the storage of aerated type.
3. Sugar content and acidity
With tomato fruit, increase in the sugar content and decrease in the acidity were retarded in the low pressure storage of both closed and aerated types. With peach and apple fruits, decrease in the sugar content was retarded in the storage of aerated type, and with apple fruit, flesh browning and consequently, decrease in the acidity were found in that of closed type.
4. Ethanol content
With peach and apple fruits, ethanol content increased in the storage of closed type but was retarded in that of aerated type. With satsuma mandarine fruit, high ethanol content was found at lower pressures in the storage of aerated type.
5. Respiration and ethylene production
With apple fruit, accumulations of CO2 and C2H4 were much less in the low pressure storage than normal pressure storage. Evolutions of them after transferred to the normal pressure storage were lower in the fruit which had been stored at lower pressures.
Thus, with tomato, peach and apple fruits, the storage at 190_??_76Torr proved to be effective in retardation of over ripening, although with satsuma mandarine fruit, it showed no clear effect.
