Development and characterization of biodegradable films based on Pereskia aculeata Miller mucilage

Abstract

Ora-pro-nobis mucilage (MOPN) is a polysaccharide extracted from the leaves of Pereskia aculeata Miller (Cactaceae family), and is composed of the biopolymer arabinogalactan. The aim of this study was to evaluate the viability of MOPN-based films supplemented with glycerol. The films were developed using the casting technique in five treatments: 1.5% MOPN with 20% glycerol (w/w), 1.5% MOPN with 25% glycerol, 1.8% MOPN with 22.5% glycerol, 2.0% MOPN with 20% glycerol, and 2.0% MOPN with 25% glycerol. The films were characterized according to their rheological, optical, mechanical, thermal, and water vapor permeability (WVP) properties. The film-forming solution presented shear thinning and elastic behavior (G'>G"). Films with 1.5% MOPN and 20% glycerol presented greater elongation (46.10%), higher puncture strength 13.8 N, and lower WVP (8.288 g water·mm·day−1·m-²·kPa−1) than the other evaluated films. Glycerol acted as a cross-linking agent, increasing the bond between the MOPN chains, generating more rigid films. These films presented two glass transition temperatures, below 0 °C and around 60 °C. Thermogravimetry indicated that MOPN contributes to better thermal stability of the films. MOPN is a promising alternative for the use of biodegradable and/or edible packagings, and the best formulation studied was 1.5% MOPN and 20% glycerol.