Effect of the ripening period of fruit harvested at different degrees of maturity on the quality of fruit and processed Ume liqueur made from 'Nanko' Japanese apricot (Prunus mume)

Effect of the duration of ripening on quality of harvested fruit and processed Japanese apricot liqueur (ume liqueur) were investigated in 'Nanko' Japanese apricot (Prunus mume Sieb. et Zucc.). Rapid softening of harvested fruit was observed, followed by yellowing with the increase of ethylene production. Beta-carotene concentration in the flesh (with skin) sharply increased from 3-5 days after harvest. Antioxidant activity of the flesh changed becoming equal or below the level at harvest, except for that in immature fruit. When fruit picked before the commercial harvest time was processed to ume liqueur, sorbitol content and extracted volume from fruit in the ume liqueur decreased as the processed fruit was stored for longer periods. However, ume liqueur possessed the highest concentration of citric acid, total organic acid, phenolics and the highest browning strength in the stored period when fruit ripened for 4-6 days were processed. When fruit were picked after the commercial harvest and ripened for 4 days then processed into ume liqueur, it showed the highest browning strength. However, concentrations of malic acid, total organic acid, sorbitol and extracted volume from fruit in the ume liqueur were highest when the fruit was processed immediately after harvest. Therefore, it is suggested that mature fruit should be processed to ume liqueur immediately while immature fruit should be held for about 4 days before processing.