Melatonin enriched chitosan coating prolonged shelf life and preserved postharvest qualities of ambiently stored banana

Banana, the cheapest energy boosting fruit, is globally consumed for its abundance in carbohydrates, fibre, minerals, particularly potassium, vitamins and phenolic compounds. Bananas are most frequently stored and traded in ambient conditions in many tropical developing countries. However, this leads to high perishability with low shelf life. Therefore, in the present experiment, Melatonin, a natural substance found to delay ripening and fruit senescence, has been used along with Chitosan, a biodegradable biopolymer, found to maintain postharvest quality, inhibit microbial growth and extend shelf life; in sole and in combination for evaluating response on quality and storability of banana cv. Vaibalhla (Tall Cavendish; AAA) at ambient condition (Temperature: 26±30C; Relative Humidity: 75±6%) in the Postharvest Research Laboratory, Department of Horticulture, Aromatic and Medicinal Plants, Mizoram University, Aizawl-796004, India during April-May, 2022. The nine postharvest treatments, viz., T1: Melatonin (MLT) 200 µM, T2: MLT 500 µM, T3: Chitosan (CH) 1%, T4: CH 1.5%, T5: MLT 200 µM + CH 1%, T6: MLT 500 µM + CH 1%, T7: MLT 200 µM + CH 1.5%, T8: MLT 500 µM + CH 1.5% and T9: Control (water dipped) were used in the present study with five replications following a complete randomised design. Results manifested that the MLT+CH combined application in mature green banana had maintained better fruit quality and shelf life during storage. Fruits treated with MLT 200 µM + CH 1% (T5) had minimum weight loss (9.87%), high fruit firmness (21.45/Ncm2), excellent skin colour (L: 87.67, a: 12.16, b: 62.97) with delayed accumulation of TSS (11.150Brix), total sugar (11.76%) and gradual breakdown of starch (2.12%) due to slow down ripening of fruits up to 12 days after storage (DAS). This combined treatment had retained high ascorbic acid (16.96 mg/100 g), phenolics (0.49 mg GAE/g), antioxidant activity (41.36% inhibition DPPH), with minimum fruit decay (8.33%) and thus recorded maximum shelf life (17.20 days) against the control (10.60 days). Therefore, MLT 200 µM + CH 1% was proved to be a favourable approach for long preserving physicochemical qualities while extending shelf life under ambient storage.