Postharvest Changes in Sugar, Organic Acid, Glutamic Acid and Antioxidant Contents in Tomato Fruit Grown under Salinity Stress

Abstract

The postharvest changes in taste-related compositions (sugar, organic acid and glutamicacid) and antioxidants (ascorbic acid, lycopene and β-carotene) in tomato fruit grown under salinity stress were examined. Salinity stress was applied by adding nutrients (N, P, K, Ca and Mg) of the same ratios as those in the control solution (EC =1.6 dS m-1), until the EC reached by 4.0 dS m-1. Fruits were harvested at a breaker stage (when blossom-end turned red), and then they were stored under the conditions of 20°C, 50-60% of relative humidity in a darkroom. The sugar, organic acid, glutamic acid and ascorbic acid contents on a fresh weight basis of salinity-stressed fruit were higher than those of control fruit throughout the storage. In addition, the results of dry weight basis suggested that the changes in chemical composition during storage in salinity-stressed fruit cannot be induced only by the concentration effect with fruit water loss, but also by the net accumulations. Furthermore, proline content as an indicator of salinity damage was increased in salinity-stressed fruit during storage. These results suggest that postharvest changes in rhemiral composition are influenced by the salinity-effects before harvest.