Involvements of membrane lipid and phenolic metabolism in reducing browning and chilling injury of cold-stored Chinese olive by γ-aminobutyric acid treatment

Abstract

The influences of 1.0 mM γ-aminobutyric acid (GABA) treatment on browning, chilling injury (CI), membrane lipid metabolism, and phenolics metabolism in 2 °C-stored Chinese olive were explored. In comparison with the control Chinese olive, GABA-treated Chinese olive manifested lower CI index, browning index, browning degree, and cell membrane permeability. Additionally, GABA-treated Chinese olive exhibited lower values of saturated fatty acids (SFAs) and phosphatidic acid, lower activities of lipoxygenase, lipase, and phospholipase D, but higher levels of unsaturated fatty acids (USFAs), phosphatidylinositol, and phosphatidylcholine. Moreover, GABA-treated Chinese olive displayed lower PPO and POD activities, but higher activity of PAL, higher values of flavonoids and total phenolics. These data indicate that GABA treatment contributed to alleviating browning and CI occurrences in Chinese olive during the chilling process. This effect was achieved by postponing the degradations of membrane lipid and USFAs, preventing the oxidation of phenolic substances, as well as maintaining the integrity of cellular membranes.