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.