Effect of calcium lactate in combination with hot water treatment on the nutritional quality of persimmon fruit during cold storage

Quality reduction and quick softening, occurring after harvest, limit shelf-life of persimmon fruit. In the present research, the effects of hot water and calcium lactate treatments on maintaining the firmness and preserving the quality of persimmon fruit during cold storage were investigated. 'Karay persimmon was harvested at commercial maturity stage and treated with hot water at three levels of 25 degrees C for 25 min, 45 degrees C for 30 min and 50 degrees C for 20 min, and calcium lactate at three levels of 0, 0.5 and 1%, and their combinations. The treated fruits were then stored at 1 degrees C with a relative humidity of a >= 80%. At 20 and 40 days of the storage, fruits were removed from the refrigerator and some traits were evaluated three days after storage under shelf-life conditions. The evaluated traits were calcium content, firmness, weight loss, soluble tannin content, carotenoid, ascorbic acid, antioxidant capacity, total soluble solids and titratable acidity. The results showed that the amount of calcium in fruit tissue increased only in calcium lactate treatment, and hot water treatment showed a small effect on the trait. The combination of calcium lactate and hot water treatments caused higher effect on maintaining the firmness, controlling weight loss and preserving the quality of fruit when compared to applying each treatment alone. Furthermore, the treatments maintained antioxidant properties of the fruits during cold storage by maintaining the amount of soluble tannin, carotenoid and ascorbic acid contents. Thus, combined treatment of hot water and calcium lactate can be used to enhance antioxidant properties and preserve nutritional quality of persimmon fruits during postharvest storage.