Este trabajo se centró en el desarrollo de envases activos biodegradables con mezclas de poli (ácido láctico) (PLA), poli (etileno-co-acetato de vinilo) (EVA), polietilenglicol (PEG) y quitosano (QUI). Se investigaron las características morfológicas térmicas y mecánicas de las mezclas, así como, al mismo tiempo, la actividad antifúngica del envase. Para evaluar la actividad antimicrobiana de las mezclas PLA/EVA/PEG/QUI, las muestras

Leticia Riboldi Cavalli,Rosmary Brandalise,Jalma Maria Klein,Ivana Greice Sandri

doi:10.33448/rsd-v10i9.16964

Leticia Riboldi Cavalli, Rosmary Brandalise + Show 2 more

Open Access

https://doi.org/10.33448/rsd-v10i9.16964

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Abstract

This work focused on the development of biodegradable active packaging with poly(lactic acid) (PLA), poly(ethylene-co-vinyl acetate) (EVA), polyethylene glycol (PEG) and chitosan (QUI) blends. It investigated thermal and mechanical morphological characteristics of the blends, as the same time, the antifungal activity of the packaging. To assess the antimicrobial activity of the PLA/EVA/PEG/QUI blends, the samples were inserted between slices of bread with no preservative to the evaluation of their shelf life. By comparing between PLA/EVA/PEG, PLA/EVA/PEG/QUI blends and neat PLA was possible to evidence the partial miscibility, decreased glass transition temperature (Tg) by incorporating PEG into the blends, a decrease in ﬂexural strength of 71% and elasticity modulus of 80.4% to PLA/EVA/PEG/2.5QUI blend, as well as an increase in elongation at break of 153% and 392% to impact toughness. A similar behavior was observed to PLA/EVA/20PEG and PLA/EVA/PEG/5.0QUI. The QUI-containing ﬁlm among the bread slices has also inﬂuenced the water activity reduction, and reduced about 35% in the count of molds and yeasts in the slices of bread. Chitosan in mixtures with PLA/EVA/PEG showed potential as a natural antifungal agent in bakery packaging.

Highlights

The development of biodegradable packaging with improved mechanical and barrier properties which will be useful for maintaining the safety and quality of foods is one of the main strategies currently researched (Dhall & Alam, 2020)
The results showed that the compatibilizing agent reacts completely and the chitosan affects the thermal properties of the films decreasing their decomposition temperatures, glass transition temperature (Tg) and melting (Tm) and increase its crystallinity
By comparing the properties of poly(lactic acid) (PLA) to the blends it was possible to observe a decrease in flexural strength of 71.0% and elasticity modulus of 80.4% to the mixture with incorporation the 20 phr polyethylene glycol (PEG) and 2.5 phr QUI(PLA/EVA/PEG/2.5QUI) besides an increase in elongation at break of 153% and 392% to impact toughness

Summary

Introduction

The development of biodegradable packaging with improved mechanical and barrier properties which will be useful for maintaining the safety and quality of foods is one of the main strategies currently researched (Dhall & Alam, 2020). For its application in food packages, it is necessary to modify some of its properties, mainly as regards its fragility attributed to its glass transition and hardness, and its high hydrolysis rate and low O2 and CO2 barrier properties (Armentano et al, 2013; Correa-Pacheco et al, 2020). These PLA limitations might be eliminated to an extent, by blending/compounding with other polymers, plasticizers, or reinforcement fillers. PEG molecules enter into the PLA macromolecules creating a physical interaction in the form of hydrogen bonding (Yuniarto et al, 2016)

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