Effect of γ-Aminobutyric Acid on Postharvest Quality of Lentinus edodes

In order to explore the effect of γ-aminobutyric acid (GABA) on the quality of postharvest Lentinus edodes, the effects of different concentrations of GABA on the weight loss rate, hardness, color difference, cell membrane permeability, respiratory intensity, ascorbic acid, total phenol and protein contents of L. edodes were studied. The results showed that GABA treatment could reduce the weight loss rate, electrical conductivity and malondialdehyde contents of L. edodes, inhibit the respiratory intensity of L. edodes, maintain the L^* value and hardness of L. edodes, and promote the accumulation of ascorbic acid, total phenol and protein. In terms of respiratory intensity, GABA treatments only inhibited the respiration of L. edodes in the early stage (9 d), among which 5.0 g·L⁻¹ GABA treatment had the best effect. Similarly, 5.0 g·L⁻¹ GABA treatment had the best effect from the indicators of the weight loss rate, L^* value, hardness and the contents of ascorbic acid, total phenol, protein. According to relative conductivity and malondialdehyde content, 2.5 g·L⁻¹ GABA treatment had the best effect, but there was no significant difference between 2.5 g·L⁻¹ GABA treatment and 5.0 g·L⁻¹ GABA treatment. Considering the effects of GABA treatment on various indexes of L. edodes, the optimal concentration of GABA treatment was 5.0 g·L⁻¹. The results showed that GABA could not only keep the hardness and color of L. edodes better by inhibiting respiration, slowing down the increasing of cell membrane permeability, reducing the water loss of L. edodes, but also maintain the nutritional quality of L. edodes by promoting the accumulation of ascorbic acid, total phenol and protein.