Edible multilayer coating using electrostatic layer-by-layer deposition of chitosan and pectin enhances shelf life of fresh strawberries

This study aimed to develop an edible multilayer coating by electrostatic layer-by-layer deposition (LbL) of chitosan-pectin biopolymers to extend the shelf life of strawberries. A fixed concentration of chitosan (2% w/v) and varying pectin concentrations (0.25-1% w/v) in an LbL sequence were initially applied to coat on the low-density polyethylene (LDPE) film. The successful assembly of these biopolymers in the LDPE film was confirmed by their zeta potential (chitosan, +43 mV and pectin, -36 to -42 mV) and Fourier transform infrared (FTIR) spectroscopy in the range of 1800-1600 cm(-1) indicating the strong interactions between chitosan and pectin. Chitosan (2% w/v) and pectin (0.25% w/v) had the lowest water vapour permeability (WVP) of 1.86 +/- 0.02 x 10(-9) in gday(-1) m(-1) Pa-1 among all other formulations. The application of the coating on strawberries extended the shelf life (9 days) compared to the control (6 days) at room temperature (25 degrees C) while still retaining the colour, firmness and pH of strawberries. The results obtained illuminate the potential application of safer, ecofriendly and sustainable packaging materials in the food industry.