Physiological, morphological, and biochemical changes in grand nain banana fruits under different storage conditions

Banana (Musa spp.) fruits are sensitive to chilling, and can develop damage symptoms such as peel discoloration and irregular ripening when stored at non-ideal low temperatures. The objectives of this study were (1) to investigate the behavior of mature-green fruits of the Grand Nain banana cultivar during storage at 20 and 5 °C in an attempt to generate practical information for improved postharvest handling processes; (2) to identify symptoms of chilling damage when exposed to 5 °C during storage; and (3) to examine the physiological, morphological, and biochemical changes induced by high and low temperatures and their associations with ethylene treatment. Fruit treated with ethylene ripened more quickly, the peel turned yellow, and it’s eating qualities improved. This led to a rapid loss of firmness, starch, and chlorophyll, as well as an increase in carotenoids. Among the chemical parameters, the total soluble solids (TSS) and sugar contents increased, whereas the vitamin C content and titratable acidity decreased during storage in all the treated and untreated banana fruits. Cold storage of bananas at 5 °C resulted in chilling damage, characterized by browning of the pulp and dark brown discoloration of the peel. These symptoms gradually increased with increasing storage time. The untreated fruits with ethylene treatment were more affected than the treated fruits. The chilling effect was reflected in increased membrane permeability, as evidenced by increased relative electrolyte leakage from the peel tissue. However, bananas stored at 20 °C presented no symptoms of chilling damage.