Changes in Sugar, Organic Acid, Amino Acid, Ascorbic Acid and Carotenoid Contents of Citrus 'Shiranuhi' Fruit during Cold Storage

Abstract

In this study ， we investigated the changes in the sugar ， organic acid ， amino acid ， ascorbic acid and carotenoid contents of citrus ‘ Shiranuhi' fruit stored at 5 0 C and packaged in polyethylene film for 5 months. Fruit weight slightly decreased during the storage. A significant reduction in organic acid content was observed with no significant change in sugar conten t. Consequently ， sugar-acid ratio increased significantly during the storage. Sucrose content showed no change during the storage ， whereas glucose and fructose contents decreased. The organic acids detected were citric acid and malic acid. Both citric acid and malic acid contents decreased during the storage. Asparagine ， arginine and aspartic acid were the major amino acids detected. No significant change in total amino acid content was observed throughout the storage; however ， the changes in the amounts of all amino acids tested differed. A small change in L-ascorbic acid content was observed during storage with a decrease in dehydroascorbic acid conten t. s-Carotene and β-cryptoxanthin were the main carotenoids detected. No significant change inβ-cryptoxanthin content was observed.β-Carotene content increased markedly and ， after five months of storage ， reached a value approximately threefold higher than that at the initial storage time.