Exogenous treatment of spermine to maintain quality and extend postharvest life of table grapes (Vitis vinifera L.) cv. Flame Seedless under low temperature storage

Potential of spermine as a postharvest dip treatment for maintaining quality and extending storage life of table grapes (Vitis vinifera L.) cv. Flame Seedless was investigated. Grape clusters were dipped in different concentrations (0.0 - control, 0.5, 1.0 and 1.5 mmol/l) of spermine for 5 min, thereafter stored in the cold room (3-4 °C, 90-95% RH). Evaluation of physico-chemical parameters and other fruit quality attributes were made at 0 day (before treatment) and at 30, 45, 60-75 days after treatment. Spermine at the dose of 1.0 mmol/l effectively maintained berry firmness, peel colour (L*, a*, b*), stabilized anthocyanins, suppressed the activity of pectin methyl esterase, while reducing the rate of membrane electrolyte leakage. In addition, it effectively retarded the degradation of TSS and TA on the contrary to other two doses and the control. In conclusion, postharvest dip treatment of 1.0 mmol/l spermine extended the postharvest life of grape cv. Flame Seedless up to 60 days in contrast to control, which was commercially acceptable only up to 45 days.