Effect of polyol plasticizers on the physicochemical, mechanical, and microstructural properties of films from chayote (Sechium edule) peels

Abstract

This study aimed to develop biopolymer films (BFs) from immature chayote [Sechium edule (Jacq.) Sw.] Quelite variety fruit peels using glycerol, sorbitol, and ethylene glycol as plasticizers at three concentrations (0.05, 0.06, and 0.07 mol/L) using the casting method. The BFs were evaluated at two time points (day 1 and day 30 after casting) to assess their performance, stability, and potential food packaging applications. They were homogeneous, continuous, and exhibited colors ranging from cream to light brown, and had an average thickness of 198 μm. The average solubilities in water, acid, and base were 49.57%, 48.51%, and 65.15%, respectively, while the average moisture content across all treatments was 25.52%. The percentage of elongation increased from 4.8% to 6.8% with higher plasticizer concentrations. No significant effects of plasticizer type, concentration, or storage time were observed on tensile strength, with average values of 0.22 MPa. Water vapor permeability (WVP) ranged from 0.72 to 16.07 g·Pa⁻¹·s⁻¹·m⁻²·10⁻⁷, with significant differences among plasticizers. The films displayed a glass transition temperature of 63.29°C and a melting temperature of 154.26°C, indicating a homogeneous and stable matrix. These findings highlight the potential of chayote peel-based BFs as sustainable materials for food packaging applications.