Postharvest Calcium Salt Treatment of Fresh Jujube Fruit and its Effects on Biochemical Characteristics and Quality after Cold Storage

Abstract Jujube fruit quickly undergoes spoilage and normally has a short shelf life. Therefore, the effect of immersion treatment in different calcium salts on qualitative and biochemical characteristics of fresh jujube fruit was evaluated. Treatments included control (distilled water) and solutions of calcium chloride, calcium nitrate, and calcium sulfate at a concentration of 0.5 and 1%. Fruits were immersed in water or calcium salt solution for 5 min, air-dried and then cold stored at 4 °C for 50 days. The results showed that such treatment did not affect significantly the pulp color and the anthocyanin concentration in the fruit. However, the soluble solids in the treated fruits significantly decreased compared with the control. Interestingly, all levels of calcium salts, except 0.5% calcium nitrate, preserved the total antioxidant capacity in comparison with the control. Concentrations of 1% calcium nitrate, chloride, and sulfate significantly increased crispness compared with the control. The taste of fruit treated with calcium sulfate significantly deteriorated compared with the control and other treatments. In general, 1% calcium nitrate and 1% calcium chloride applied before storage preserved or strengthened the jujube fruit qualities after storage compared with control. It can be concluded that such treatment is recommended for practical application.