Effect of High Temperature Treatment on the Quality of Strawberries during Storage

Abstract

The effect of heat treatment (30°C-4, 8, 24hr, 35°C-4, 8, 24hr, 40°C-4 hr and 45°C-4 hr) on the quality of strawberry fruits (Fragaria x ananassa Duch. cv. Nyoho) stored at 1°C for 28 days was investigated. 1. No visible change of the fruits was found immediately after heat treatment. The heat treatment at 35°C for 24hr and at 40°C and 45°C for 4 hr was effective to reduce the decay of the fruits during storage. 2. Fungal growth of microorganisms isolated from strawberries including Rhyzopus and Botrytis on the White medium was also inhibited by the heat treatment (35°C-45°C). 3. The fruits treated with 30°C-24hr and control fruits softened gradually during storage at 1°C, while softening of the fruits treated with 35°C-24hr and 45°C- 4 hr was inhibited markedly. 4. The content of total pectin (TP) decreased in all of fruits treated with different temperatures during storage and TP content in the fruits treated with 30°C-24hr and control fruits decreased rapidly in the latter half of the storage period. 5. Anthocyanin content of the fruits increased slightly in the early period of storage, then decreased gradually except for the fruits treated with 35°C-24hr and 45°C-4 hr. Judging from these results, it was suggested that the heat treatment can be useful for long-term storage of strawberry fruits.