Temperature affects impact injury on apricot fruit

Apricot fruit (cv. San Castrese) picked at commercial harvest (14degrees Brix) were dropped from different heights (5, 10, 20, and 30 cm) onto a flat hard and smooth surface and impact injury was evaluated visually on the skin for 3-4 days at room temperature. The flesh under the impact area turned brown after 3 days in the fruit dropped from 30 cm, but no symptoms were observed on the peel. Ethylene started to rise after 12 h; even sound area on the opposite side produced more ethylene 6 h later. The effect of temperature at the impact time and after the impact was studied. Fruit were impacted at 18 degreesC and then placed at 4 degreesC or kept at 18 degreesC, or dropped at 4 degreesC and then kept at 4 degreesC or moved to 18 degreesC. Ethylene production was greatly affected by low temperature. Ethylene increased more in fruit which were impacted at 4 degreesC and moved to 18 degreesC, than in fruit which were kept continuously at 18 degreesC. Respiration was affected by temperature but not as greatly as ethylene production. L (lightness) and b (yellowness) values decreased significantly in the injured flesh compared to the sound flesh especially in fruit impacted at 4 degreesC and then moved to 18 degreesC. Good management of temperature can reduce the physiological response of the tissue to bruising and control the appearance of bruising symptoms. (C) 2002 Elsevier Science B.V. All rights reserved.