Carboxymethyl cellulose coating regulates cell wall polysaccharides disassembly and delays ripening of harvested banana fruit

Banana is a perishable fruit that ripens and deteriorates quickly after harvest. In this work, we investigated the impact of a dip in carboxymethyl cellulose (CMC) at concentrations of 0.5%, 1.0% and 1.5% on the quality of harvested bananas during storage at ambient conditions of 20 +/- 1 degrees C for a 15-d period. It was noted that 1.5% CMC markedly delayed the occurrence of decay incidence (9%) and suppressed physiological weight loss (6%). The 1.5% CMC treatment suppressed the activities of chlorophyllase, pheophytinase, Mg-dechelatase and chlorophyll (Chl)-degrading peroxidase (POD), which ultimately delayed banana peel color changes by conserving higher total Chl contents and reducing the accumulation of carotenoids. This subsequently resulted in higher L* and a* along with a lower increase in b* values as compared with control. Banana fruit coated with 1.5% CMC exhibited delayed ethylene and respiration peaks in comparison with control. In the same way, 1.5% coating maintained higher firmness and showed higher contents of protopectin, chelate-soluble pectin, sodium carbonate soluble pectin, cellulose and hemicellulose along with lower water-soluble pectin due to reduced activities of cellulase, pectin methylesterase, polygalacturonase and beta-glucosidase. In the same way, postharvest application of 1.5% CMC coating suppressed the increase in total soluble solids (TSS) and showed higher titratable acidity (TA) along with a lower ripening index (TSS/TA ratio) in flesh of banana fruit compared with control. In conclusion, 1.5% CMC application could be an appropriate coating concentration to delay the ripening and rapid softening of harvested bananas stored in ambient conditions.

Automated summary

A dip in 1.5% carboxymethyl cellulose (CMC) can significantly delay decay and soften of bananas. It can suppress the occurrence of decay and physiological weight loss, delaying the color changes of banana peel. The dip treatment can also delay the ethylene and respiration peaks of bananas, maintaining firmness and pectin content of the fruit.