Physiological responses and quality attributes of ‘Kyoho’ grapes to controlled atmosphere storage

This research studied the physiological responses and quality attributes of Kyoho grapes (Vitis vinifera X V. labrusca) to controlled atmosphere storage. The grapes were stored for up to 60 days in 95% relative humidity with four different conditions, 4% O2+9% CO2, 4% O2+30% CO2, 80% O2, and air, as control. The examined physiological responses and quality attributes included polyphenol oxidase (PPO) activity, ethanol concentration, fruit detachment force (FDF), firmness, color, soluble solid content (SSC), titratable acidity (TA), ascorbic acid concentration (Vc), and sensory quality. PPO activity, FDF drop and decay incidence when stored in 4% O2+30% CO2 were more effectively controlled, but unacceptable alcoholic flavor and browning were detected after 45 days, compared with those stored in 4% O2+9% CO2 or 80% O2. The fruits kept in 4% O2+9% CO2 or 80% O2 had good quality during 60 days of storage. The results suggested that high O2 atmosphere exhibited a potential for maintaining the quality of ‘Kyoho’ grapes during long-term storage.