Maintenance of fresh fruit quality in summer-bearing strawberry utilizing subzero nonfreezing storage and 1-MCP postharvest treatment
Takashi Suzuki (Hokkaido Univ.), Ryosuke Shimaoka (Hokkaido Univ.), Hanako Shimura (Hokkaido Univ.), Hirotaka Sakakibara (Rohm & Haas Japan Inc.), Mitsuko Ukai (Hokkaido Univ. of Education)
Cultivation of ever-bearing strawberry in summer-fall season utilizing plastic film greenhouse is increasing in northern region of Japan. However, greenhouse production can result in an unstable fruit supply to the market. To prolong shelf life of the fruits, usually less than a week at 5 degree C, effects of subzero nonfreezing storage and 1-MCP postharvest treatment on keeping quality of the fruits were investigated. Fruits of ‘Pechika Santa’ and ‘Pechika Pure’ harvested in summer, 2012 and 2013 were used for experiments. Subzero nonfreezing storage: fruits in lidded 1L-glass bottles were kept at -0.5 degree C in a programmable freezing chamber. In the preliminary tests the freezing temperature of the fruits was found to be about -2.0 degree C. 1-MCP postharvest treatment: fruits were kept in atmosphere containing 10 ppm 1-MCP for the first 24 h during storage at 5 degree C. Changes in quality of the fruits during storage were evaluated and compared with that of the fruits conventionally stored at 5 degree C. Indices of fruit quality were as follows: surface color (chroma meter); hardness (rheometer); degree of rot; sugar content (HPLC); % water; % frozen fruits. As a result varietal differences were confirmed in both methods. Hardness and color of ‘Pechika Pure’ fruits stored at -0.5 degree C was maintained without freezing for 28 days after harvest. The shelf life was also prolonged by 1-MCP treatment, but the effect was weaker than that of subzero nonfreezing storage.