Storability of 'Thompson Seedless' grapes: Using biopolymer coating chitosan and polyvinyl alcohol blending with salicylic acid and antioxidant enzymes activities during cold storage

摘要

Storage ability of 'Thompson seedless' bunches stored at 4 degrees C for 70 days, in related the effect of coating treatment (CS/PVA) blending with salicylic acid (SA) at different concentration (0, 1, and 2 mM). The storage experiment was conducted in two seasons (2017-2018). The obtained results proved that the presence SA with biopolymers CS/PVA at 2 mM increased antioxidant enzymes ascorbate peroxidase (ADC), catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) activities. Therefore, it delayed the malondialdehyde (MDA), protein carbonyl group (PCG) accumulation and cell membrane leakage. Accompanying, it protected phenolic substances such as total phenol (TP) and flavonoid (FL) due to inhibited polyphenol oxidase (PPO), so less browning symptoms in rachis through cold storage. Also, the CS/PVA-SA (2mM) decreased the accumulation of O-2(center dot)- and H2O2. These results suggested that the CS/PVP-SA (2 mM) coating treatments can be applied as a beneficial technique for increasing the storage ability of 'Thompson seedless' grapes by enhancing antioxidant system activity leading to higher membrane integrity showed by lower electrolyte leakage, MDA, and PCG content coincide with less browning symptoms in rachis.