1963 Volume 32 Issue 4 Pages 247-255
In Tokyo, it is generally difficult to get Bartlett pears of high quality, if ripened at room temperature. This investigation was carried out to find a solution of this difficulty, by temporary cold storage or by keeping fruits at various temperatures for after-ripening.
Bartlett pears picked from late August to middle of September on three dates in 1962, and on two dates in 1963 in Yamagata prefecture, were transported to the laboratory. In addition to these fruits, one lot of fruits was brought from Nagano prefecture in 1963. On arrival, some of the fruits were after-ripened at a room temperature (higher than 25°C excepting later several days), 20° and 15°C, while the remaining fruits were kept in a cold room at 4°C for one and two weeks, before removing them to the rooms of above mentioned temperatures.
Fruits after-ripened at room temperature generally ripened later than those kept at 20°C, and were not uniform in ripeness. Percentage of loss due to rot was also high in these fruits. The ripe fruits were poor in their appearance, flavor and texture, while those ripened at 20°C were good. The result revealed that room temperature was too high for the proper ripening of Bartlett pears, and in turn deteriorated the quality of ripe fruits.
Fruits stored at 4°C for one or two weeks before after-ripening ripened quickly and uniformly, and the resulting fruits were good in their appearance and flavor. Even those after-ripened at room temperature after the cold storage had much better appearance and flavor than those ripened at room temperature without cold storage. Fruit rot was also almost controlled by the temporary cold storage.
Refractive index of fruit juice was hardly affected by either temporary cold storage or after-ripening temperature. Acid content was decreased by cold storage, and longer the storage period, more the reduction in acidity.
Signs of internal breakdown were found in the fruits picked late and stored for two weeks in cold room.
It was suggested that Bartlett pears should be kept at 20°C or lower for after-ripening, or stored in cold room for one to two weeks before ripening, to get fruits of high quality in Tokyo or localities having similar climatic conditions to Tokyo.