Relationship between the Occurrence of Rind-oil Spot in Hassaku Fruit and the Content of Ascorbic Acid and Chlorogenic Acid in the Peel

Abstract

Rind-oil spot of Hassaku (Citrus hassaku Hort. ex Tanaka) fruits occurred in high percentages when the fruits were stored at 20°C for 10 or 30 days (experimental storage) after removal from cold-storage room (5°C). Changes in ascorbic acid (AsA) and chlorogenic acid (Chl) content of the peel (flavedo and albedo) were determined during the experimental storage.
AsA content of flavedo was higher than that of albedo and markedly decreased during storage. Rind-oil spot was observed only when AsA content of the flavedo was less than 200mg per 100g fresh weight. A weak AsA oxidase activity was detected in the flavedo and the activity changed slightly during storage. Chl was locally present in the flavedo and increased a little during storage. Polyphenol oxidase activity was very weak in the peel of the fruit.
AsA and Chl content of the healthy section of flavedo was higher than in the injured section due to rind-oil spot. Brix, acidity and AsA content of the fruit juice varied slightly during storage.