Effect of chitosan-palm stearin edible coating on the post harvest life of star fruits (Averrhoa carambola L.) stored at room temperature

This study was conducted to develop an edible coating containing combined hydrophilic (chitosan) and hydrophobic (palm stearin) components which demonstrated gas barrier and moisture barrier properties, respectively, to prolong the post harvest life of star fruits (Averrhoa carambola L.). The emulsions of chitosan (C) and palm stearin (S) were prepared by using different ratios of C:S which were 1:0, 1:1, 1;2, 1:3, 2:1, 3:1 and 0:1. Viscosity of emulsions was studied. The physicochemical properties of coated star fruits were also evaluated in terms of weight loss, firmness, visual appearance, oxygen concentration, carbon dioxide concentration and ethylene concentration during storage at room temperature (26-28°C) for 18 days. The results obtained showed that coating reduced weight loss, maintained firmness and appearance, slowed down the production of respiratory gases and reduced ethylene production. The most recommended coating for star fruits was C:S of 1:1 ratio as it showed good water barrier and gas barrier properties and could extend the post harvest life of star fruits up to 20 days as compared to the control samples which had a post harvest life of 12 days.