Effect of the Addition of Acetylated Polysaccharides on the Properties of an Active Packaging Based on Polysuccinimide and Oregano Essential Oil

TL;DR

This study explores how adding acetylated polysaccharides improves the strength and eco-friendliness of food packaging made from a biodegradable polymer and oregano oil.

Contribution

The novel contribution is demonstrating how varying acetylation levels in polysaccharides enhances mechanical and thermal properties of active food packaging.

Findings

Acetylated polysaccharides increased tensile strength, elasticity modulus, and thermal stability of the polymer films.

Water vapor permeability decreased by up to 56.4% with higher acetylation levels.

Antibacterial and antioxidant properties remained unaffected by the degree of acetylation.

Abstract

Polysuccinimide (PSI) is a biodegradable, extended-release polymer with great potential for developing active food packaging. In this study, we prepared PSI films functionalized with oregano essential oil (OEO, 3.5% w/w) and reinforced with acetylated polysaccharides (corn starch and microcellulose from Agave Lechuguilla Torr fibers) with different degrees of substitution (DS; 0.44–1.25) at a constant concentration (22% w/w). Tensile strength (0.86–1.34 MPa), elasticity modulus (0.96–1.65 MPa) and elongation at break (14.16–21.66%) increased (p < 0.05) with DS in the reinforcing materials. The moisture content and solubility decreased from 13.17% to 9.81% and from 45.64% to 38.75%, respectively. With increasing DS, water vapor permeability (WVP) decreased by up to 56.4% compared to the control film (unacetylated polysaccharides). The DS of the reinforcing materials did not affect the antioxidant activity. Antibacterial activity against Escherichia coli and Staphylococcus aureus revealed similar inhibition halos for both bacteria, regardless of the DS. Thermogravimetric and calorimetric analysis showed that reinforcing PSI films with acetylated materials improves thermal stability. The results of this research suggest that PSI, a polymer derived from the thermal polymerization of aspartic acid, has significant potential for the development of eco-friendly active packaging for food products.

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