Owing to higher unsaturated fatty acids (unSFA) which are beneficial for human health, walnut kernels have high economic value. But higher unSFA makes walnut kernels vulnerable to oxidative rancidity development, especially during long storage or storage at high temperature, due to unSFA oxidation by reactive oxygen species (ROS) or lipoxygenase (LOX) enzyme activity. In this study, the impact of gum arabic coating (0, 5, 10, 15 and 20 %) enriched with γ-aminobutyric acid (GABA; 0, 0.01, 0.1, 1 and 10 mM) on oxidative rancidity of walnut kernels during storage at 20 °C for 18 weeks were investigated. Our results showed that the walnut kernels coated with gum arabic (5 %) enriched with GABA (0.1 mM) exhibited lowest kernels oxidative rancidity, revealed by lower peroxide value (POV) and malondialdehyde (MDA) accumulation, as kernels oxidative rancidity markers. Also, walnut kernels coated with gum arabic (5%) enriched with GABA (0.1 mM) exhibited a higher unsaturated/saturated fatty acids (unSFA/SFA) ratio, which caused by lower lipoxygenase (LOX) enzyme activity concurrent with lower H2O2 accumulation. Based on our findings, gum arabic coating (5%) enriched with GABA (0.1 mM) may have a commercial potential for maintaining nutritional quality of walnut kernels.
