Postharvest treatments of banana (Musa acuminata cv. 'Grand Nain', AAA) during cold and ripening temperatures with chitosan and chitosan nanoparticles to alleviate chilling injury and maintain antioxidant activity

Banana (Musa acuminata cv. 'Grand Nain') is prone to chilling injury (CI) during cold storage, which limits extended storage and shelf life. In this study, we investigated the postharvest application of chitosan (CS) and chitosan nanoparticles (CSNPs) on the CI and quality of unpacked banana fruits during and after cold storage. CSNPs were synthesized using sodium tripolyphosphate (STPP), and analyzed using a Fourier infrared spectrophotometer (FT-IR) and a scanning electron microscope (SEM) to assess the changes in the functional groups and surface morphology. Reacting CS with STPP did not result in changes in the functional groups present but the size and morphology of CS were altered. For the treatments, banana fruits were dip coated in 0.5% (wt/vol) CS and 1.5 g/L CSNPs separately for 2 min in the presence of 1% Tween 80. The fruits were stored at 10 +/- 2 degrees C or the optimal storage temperature of 14 +/- 2 degrees C with relative humidity 85-90% for a 20-day period but subsets were transferred from cold storage on 5-day intervals to a storage rack to ripen at 22 +/- 2 degrees C. The CI index, firmness, hue angle (H degrees), weight loss, total antioxidant activity (TAA) and total phenolic contents (TPC) were measured at each interval. Untreated fruits were used as a control. Application of CS or CSNPs reduced CI and weight loss but increased firmness, hue angle, TAA and TPC relative to the control samples. These results affirm that CS and CSNP applications maintain banana fruit quality by alleviating CI symptoms throughout cold and ripening temperatures.

Automated summary

The postharvest application of chitosan and chitosan nanoparticles can alleviate chilling injury and weight loss, while increasing firmness, hue angle, total antioxidant activity, and total phenolic contents in banana fruits. These applications maintain the quality of bananas.