Changes in Physical and Chemical Compositions of Plums During Maturation

Food Chemical Studies on Plum Fruits (Part III)

Abstract

Changes of physical property and chemical composition of plums during maturation were investigated using "Ooishi Wase" and "Sordum" variety which were harvested in Yamanashi Prefecture at the period of 15-20 days before full ripeness. The following results were obtained: (1) The increase of weight and the decrease of hardness were observed during maturation. (2) Developement of Red pigments over the peel of "Ooishi Wase" and in the pulp of "Sordum" were observed at the end of the harvest period. (3) The contents of titratable acid in "Ooishi Wase" decreased during maturation, and that of total and reducing sugars in "Sordum" plum increased. (4) Hydrochloric acid-soluble pectin was the main part to total pectin at the beginning of the harvest period, and decreased during maturation. Water-soluble pectin in "Ooishi Wase" increased at the end of the harvest period, on the other hand, that in "Sordum" plum did not change. (5) Glucose, fructose, sucrose and the trace amounts of xylose were detected in the juices, and their contents changed during maturation. The amount of sucrose in "Sordum" increased, especially.