Sodium lactate treatment maintains the quality and promotes energy metabolism of ‘Kyoho’ table grape during storage

Abstract ‘Kyoho’ grape ( Vitis viniera L. × Vitis labrusca L.) is the most widely cultivated table grape variety. However, it is prone to fruit abscission after harvest, which affects the development of the market. The aim of this study was to evaluate the effects of applying different concentrations of sodium lactate (0.1%, 0.5% and 1% NaL) on postharvest table grape preservation. After harvesting, ‘Kyoho’ grapes were immersed in sodium lactate solution at various concentrations (0 [as control], 0.1%, 0.5% and 1% NaL) for 2min and stored at 20±1℃ for 10 days. Physiological indicators including weight loss rate, browning level of rachis, contents of vitamin C, sugar, malondialdehyde (MDA), membrane permeability, and activities of polygalacturonase (PG), peroxidase (POD), cellulase (Cx) and lipoxygenase (LOX) were investigated. Additionally, it was also determined for ATP content, energy charge and activity of energy metabolism-related enzymes. These results showed that NaL treatment inhibited berry abscission and maintained berry quality due to the decrease of cell wall degrading enzyme activity, the increase of energy metabolism-related enzyme activities and high level of ATP content and energy charge. This study provides a new and effective method for the postharvest storage of table grapes that can help minimize economic losses.