Characteristics of Sugar Composition of Various Fruits in Relation to Maturity and Storage

Abstract

Fruits of 17 varieties belonging to 14 species cultivated in Japan were harvested at different maturities and those at commercial ripeness was stored at 20±3°C. The sugar content of these fruits and their composition were analyzed by HPLC and they were classified into several groups accordiing to the main sugar composition. The changes in sugar composition of the fruits were considered from various viewpoints. (1) Main sugars in fruits were composed of sucrose, glucose, fructose and sorbitol. (2) Sugar composition of the fruits at commercial ripeness was classified to following four categories: (a) Sucrose group, (b) Reducing sugar group, (c) Balance group and (d) Sorbitol group. (3) Total sugar content in fruits increased with the progress of harvest time, remarkably in sucrose content, but at full ripeness the total sugar and sucrose contents of most of fruits decreased, whereas those of melon and plum increased rapidly. (4) The total sugar contents of Japanese apricot, plum and melon decreased during storage and those of the other fruits slightly changed. It was considered that sucrose in most of the fruits examined was hydrolyzed during storage. Rapid hydrolysis of sucrose in persimmon was observed at the end of the storage period. Glucose content increased in 'Chojuro' pear and sucrose content increased remarkably in Satsuma mandarin. Reducing sugar in Japanese apricot and all composed sugars in plum and melon decreased. (5) Sorbitol content in fruits increased with the progress of harvest time and decreased during storage.