EFFECT OF PREHARVEST AND POSTHARVEST APPLICATION OF CHITOSAN COATING ON STORAGE QUALITY OF NECTARINES

Nectarine is a climacteric fruit and exhibits increased ethylene production, respiration rate, changes in fruit texture, colour, aroma and other biochemical and physiological attributes during ripening. It has a limited storage life depending upon the cultivar. The coating of fruit with edible materials has been reported to act as a barrier to moisture and oxygen during postharvest handling and storage. Different compounds have been used as coating materials in fruits including alginate, cellulose, chitosan, chitin, lipids, milk protein, starch and wax with varying success towards extending shelf life and maintaining fruit quality. Chitosan coating had the potential to inhibit decay and hence prolong the storage life of a variety of produce including strawberries, tomatoes, citrus fruit, peaches, pears and kiwi fruit. In this study biodegradable coatings, based on chitosan, were applied to nectarine, 'Diamond Ray', in order to find environmentally friendly, healthy treatments with which better preserve fresh fruit quality and safety during postharvest cold storage. Physicochemical properties (weight loss, °Brix, titratable acidity, colour and texture) were determined throughout cold storage. The effects of three chitosan applications were investigated: (1) preharvest(10 g L−1), (2) pre- and postharvest (10 g L−1), (3) postharvest (10 g L−1) (4) control (no chitosan application). Preharvest chitosan-treated nectarines were firmer and had higher soluble solids content than control ones. Also pre and postharvest application fruits showed high soluble solids content and texture values and the highest titratable acidity. Hence it can be concluded that chitosan in preharvest treatments has the poten¬tial to preserve valuable attributes and prolong the shelf-life of nectarines, presumably due to its property to inhibit the postharvest ripening and senescence processes.