Chitosan-Based Coating Incorporated with Chitin Nanofibers for Extension of the Shelf Life of Fruits

Chitin is the second most abundant biopolymer in the world. Herein, deacetylated chitin
nanofibers (dChNFs) through partial deacetylation were initially prepared, and dChNFs were
subsequently added into chitosan (CS) to develop the biodegradable coatings to extend the shelf life
of bananas. The degree of deacetylation and the average diameter of the obtained dChNFs were
29.12 % and 19.49 ± 3.1 nm, respectively. The addition of dChNFs into CS at the ratio of 50:50
decreased the water vapor permeability (WVP) from 4.56 × 10–11 g/m·s·Pa to 3.81 ×10–11 g/m·s·Pa.
Moreover, three different suspensions of CS, dChNFs, and CS/dChNFs were applied as coatings on
Hom–Thong bananas via the dipping technique. The application of the CS/dChNFs coating showed
a significant postponement in the color change of the peel (from green to yellow) to 22 days,
compared to 9 days for uncoated bananas. The weight of the bananas coated with CS/dChNFs
exhibited a weight loss of 26.53 % day–1, which was lower than that of the uncoated bananas
(30.71 % day–1). This suggested that the CS/dChNFs coating would be efficiently used to prolong
the shelf life of bananas, reducing food waste.