Effects of Carboxymethyl Cellulose and Chitosan ‘Layer-by-Layer’ Edible Coating

Hadar Arnon, Food Quality and Safety, Agricultural Research Organization, Volcani Center, Bet-Dagan, Israel

A newly developed 'Layer-by-Layer' (LbL) polysaccharide-based coating was applied to citrus fruit (mandarin, orange, grapefruit) as a healthier and eco-friendly alternative to the commercial polyethylene-based wax. Carboxymethyl cellulose (CMC), at a fixed concentration of 1.5% was applied as an internal well adhesive layer and chitosan was applied as an external layer to improve coating performance.  Different concentrations of chitosan (0.5%, 1.0%, 1.5%) were examined to find the optimal LbL edible coating for mandarins model.  In the second stage, the chosen LbL edible coating (1.5% CMC + 1.0% chitosan) was applied at conditions of storage and marketing to simulate the effects of coating on fruit quality. The 1.5% CMC + 1.0% chitosan coating was concluded as the optimal edible coating. This coating provided enhanced gloss and firmness with relatively low accumulation of CO₂ and ethanol.

Overall, we report that a newly developed CMC/chitosan LbL edible coating may be effectively used during postharvest handling of citrus fruit. The coating is homogenous and stable, inexpensive and easy to prepare, does not require use of organic solvents, safe and biodegradable.