The Effect of Postharvest Treatment of Gamma-Aminobutyric Acid (GABA) on the Physico-Chemical Characteristics of Physalis peruviana Fruit during the Storage

Physalis (Physalis peruviana L.) is a popular fruit, which has received great attention due to its nutritional and medicinal properties. This valuable fruit has a short shelf life and so far, very little research has been done on postharvest physiology of shelf life. For this purpose, a factorial experiment was conducted based on a completely randomized design with three replications. The first factor was the different levels of γ- aminobutyric acid (GABA) concentrations (0, 5, 10 and 15 mM), the second factor was the storage time in three levels (7, 14 and 21 days) and the third factor was the harvesting stage (based on the appearance color of the fruit into two levels: yellowish green and orange). The obtained results showed that the weight loss in fruit treated with GABA at the end of the storage period was lower than untreated fruit, and the most weight loss (12.62%) was found in fruit harvested in the orange stage without any treatment. At the end of the storage period, the fruit firmness in fruit treated with GABA showed a lower decrease compared to the untreated fruit, so that the maximum decrease was observed in the orange stage after 21 days of storage in the untreated fruits. The application of GABA significantly reduced the fruit decay. The highest fruit decay (43.83%) was observed in the fruit harvested at the orange stage without GABA at the end of storage. The results showed that the application of GABA increased the activity of antioxidant enzymes during the storage period compared to untreated fruit. The highest activity of superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) enzymes was observed in fruit treated with 15 mM GABA compared to untreated fruit. Overall, application of GABA after harvesting at a concentration of 15 mM is recommended to maintain the quality of physalis fruit.