Physicochemical quality of hardy kiwifruit (Actinidia arguta L. cv. Cheongsan) during ripening is influenced by harvest maturity

Hardy kiwifruit is popular among consumers, but it has a short shelf-life. In this study, the influence of harvest maturity on the physicochemical properties of 'Cheongsan' hardy kiwifruit was investigated during storage at 22 degrees C. Harvested fruit were divided based on the soluble solids content (SSC) into 'harvest 1' and 'harvest 2' with 6% and 8% SSC, respectively. As the fruit continued growing on the vine, the fresh and dry weights at harvest were 1.3 and 1.7 times higher in 'harvest 2' than in 'harvest 1', respectively. There was no significant difference in titratable acidity between the two groups. Harvest maturity significantly affected the content of total phenolic compounds; 'harvest 2' fruit had 2.1 times higher concentration than that of 'harvest 1' fruit. The respiration rate rapidly increased after harvest, and the SSC also increased throughout the ripening, regardless of fruit maturity. 'Harvest 2' fruit exhibited significant reduction of weight loss and retained firmness during ripening compared with those of 'harvest 1' fruit. The 'harvest 1' fruit were not of adequate quality and spoiled before ripening. These data suggest that 'Cheongsan' hardy kiwifruit should be harvested when the SSC is greater than 8% to retain premium quality fruit.