Formulation of chitosan-oleic acid coating for Kiew Wan tangerine by response surface methodology

Abstract

The coating formulation is an essential factor in maintaining the postharvest quality of tangerines. A common problem found in coated tangerines is off-flavor due to improper coating. The aim of this study was to use chitosan and oleic acid to formulate the most suitable coating for tangerines displayed at room temperature (30±2°C). In order to optimize the formulation, response surface methodology (RSM) with a central composite design was applied. The response effect of chitosan (1-2%) and oleic acid (1-4%) on weight loss, ethanol in juice, and carbon dioxide and oxygen in fruit were investigated. A second order model was used to explain the effect of the dependent variables (weight loss, O2, CO2, ethanol), which were highly significant and produced R2 values in the range from 77 to 92%. The optimum coating formulation for tangerine was found to be 1% chitosan (v/v) and 2.5% oleic acid (v/v), which was based on a composite desirability value of 0.80.