Effect of preharvest application of calcium chloride, putrescine, and salicylic acid on antioxidant system and biochemical changes of two Indian jujube genotypes.

The effects of the preharvest application of calcium chloride (1 and 2%), salicylic acid (1 and 2 mM), and putrescine (1 and 2 mM) on the quality attributes and biochemical changes of two ber (Ziziphus mauritiana Lamk.) genotypes ("Sibi" and "Khormaee") were investigated at harvest and after 30 days of storage (5 ± 1°C and 85 ± 5% RH). The results showed that softening and weight loss in the treated fruit were significantly lower in comparison with the control. The antioxidant capacity of the fruit was higher in treated fruit than the control. Moreover, all the treatments significantly reduced the polyphenol oxidase (PPO) activity, increased the catalase (CAT) and peroxidase (POD) activities, and prevented the quick color change of ber fruit. The best overall visual quality (OVQ) was observed in the fruit treated with calcium chloride (1.5%) and putrescine (2 mM). Compared to the two genotypes, "Khormaee" showed a better appearance, relative to the "Sibi" genotypes. PRACTICAL APPLICATIONS: Ber (Ziziphus mauritiana Lamk.) fruit is a popular fruit which is cultivated widely in the tropical and subtropical countries of the world, due to its high nutritional value. It is rich in bioactive compounds and minerals. However, Indian jujube as a climacteric fruit is highly perishable and have a limited shelf life due to softening, browning, and shrinking. So that, the researchers still need more challenge to keep the quality of this fruit for consumers. In this study, the results showed that the preharvest application of calcium chloride (1.5%), putrescine (2 mM), and salicylic acid (2 mM) effectively kept the total quality of the Indian jujube fruit during storage by improving the firmness of the fruit, retarding the color change and browning, increasing the antioxidant enzymes such as; CAT and POD, and preserving the higher ascorbic acid. Therefore, these treatments can be useful to maintain the quality of Indian jujube during storage.