Effect of melatonin and gamma-aminobutyric acid treatments on fruit quality of quince cv. eşme during storage

This study investigated the effects of pre- and postharvest MEL, GABA and MEL+GABA treatments on fruit quality of quince fruit cv. Eşme during storage. For this purpose, control, MEL (200 μmol L−1), GABA (5 mM) and MEL+GABA (100 μmol L−1 + 5 mM) were applied to the quince trees 14 days before the estimated harvest date. All groups were picked up at the optimum harvest time and transported to the laboratory. For postharvest treatments, the fruits divided into 4 different groups were dipped into distilled water (control), MEL (200 μmol L−1), GABA (5 mM) and MEL+GABA (100 μmol L−1 + 5 mM) solutions during 10 minutes. All treated fruits stored at 0±1°C and 90±5% relative humidity for 6 months in normal atmosphere conditions. For shelf life studies, the fruits were kept at 20°C and 50-60% relative humidity for 5 days. All treatments except for GABA relatively reduced weight loss, respiration rate and ethylene production during cold storage. The treatments had no meaningful effect on the soluble solids content and titratable acidity. MEL treatments were prominent for fruit flesh browning. MEL and GABA were effective in reducing chilling injury and decay rate compared to the control. MEL treatments gave the highest scores for external appearance during cold storage and shelf life. All treatments significantly suppressed PPO enzyme activity compared to the control. It was determined that quince fruits treated with postharvest MEL can be successfully stored at 0±1°C for 180 days.