Pre-harvest application of GABA and CaO delays senescence and maintains of physicochemical characteristics of fresh ‘‘Ahmad Aghaei’’ pistachio during cold storage

The present study was conducted to determine the effects of preharvest application of calcium oxide 1% (CaO), gamma-aminobutyric acid 20 mM (GABA), and the combined treatment of CaO and GABA on shelf life and quality of fresh pistachio in cold storage (at 4 ± 1 °C with 85 ± 5% RH) for 75 d. Post-harvest quality and biochemical characteristics of fruits were measured during 0, 25, 50, and 75 d of storage. The investigation results showed that with the increase in storage time, the hull and kernel firmness (63% and 75%, respectively) and kernel lipid (55%) decreased in treated fruits. Still, the phenolic compounds (45%) and antioxidant activity (10%) of the kernel, hull malondialdehyde (66%), and kernel and hull anthocyanin (71%) increased. Fruits treated with CaO 1% (contained the most kernel lipids and flavonoids and the lowest hull), kernel anthocyanin, and kernel carotenoids. As a result, CaO + GABA pre-harvest treatment was recognized as the best treatment by maintaining antioxidant properties, better overall acceptance, and a higher percentage of healthy fruits during storage. However, applying the treatment before harvesting in the orchard takes a lot of time, but water does not accumulate in the pistachio hull, and the treatment is better absorbed.