Effect of postharvest treatment with gamma-aminobutyric acid and salicylic acid on some biochemical characteristics of ‘Shablon’ plum

Plums are highly perishable and deteriorate quickly during storage and shelf life. On the other hand the use of chemicals in postharvest technology of horticultural products is highly limited and it is necessary to introduce natural and safe methods to maintain the safety of food products. In this experiment, the effect of postharvest treatment with gamma aminobutyric acid (GABA) (at 0, 10 and 20 mM) and salicylic acid (at 0, 1 and 2 mM) during 16 and 34 days of storage at 1 ± 0.5 °C with 85 to 95% RH on some biochemical indices of plum fruit was studied. The study was carried out as a factorial completely randomized design with four replications. Biochemical indices including catalase enzyme activity, phenylalanine ammonia-lyase (PAL) enzymes activity, total phenolics and total flavonoid content were measured after 16 and 34 days of cold storage plus 24 H at 25 0C. Combination of GABA and salicylic acid significantly maintained fruit total phenolic and total flavonoid contents and enhanced PAL enzyme activity, and treatment with salicylic acid at 2 mM increased catalase enzyme activity in comparison to the control and other treatments. Overall, results revealed that the use of GABA and salicylic acid treatments can maintain the quality of "Shablon" plum fruit during cold storage.