Evaluation of factors affecting barrier, mechanical and optical properties of pectin-based films using response surface methodology

Emulsion coatings were formulated and films were developed using pectin as the basic structural component. Preliminary experiments were carried out to determine the proper type and concentration of pectin, lipid and plasticizers in the film. The effects of pectin, beeswax and sorbitol concentration on water vapor permeability (WVP), mechanical properties and opacity of the films were evaluated using the response surface methodology. WVP increased by pectin and sorbitol concentration and was decreased by beeswax concentration. Mechanical properties were mainly affected by pectin and sorbitol concentration. Increasing the amount of pectin and decreasing the sorbitol concentration increased tensile strength (TS) and modulus of elasticity (EM), while elongation at break (EB) increased by increasing both pectin and sorbitol concentration. Beeswax was the most influential factor that affected opacity, which increased with increasing beeswax concentration. Models developed for WVP, EB, EM and opacity had high coefficient of multiple determination (R-2) values (> 0.87) and significant F values. The model for TS had a slightly lower R-2 of 0.81.