Characterization of ethylene-vinyl alcohol copolymer containing lauril arginate (LAE) as material for active antimicrobial food packaging

Abstract

• Casting manufacture of antimicrobial film of EVOH 29 and EVOH 44 with lauril arginate. • Transparent, barrier and stable films with promising applicability in food packaging. • Antimicrobial release can be designed to improve efficiency. • The quicker release was obtained with EVOH 29 at high temperature. The aim of this work was to characterize, as packaging materials, antimicrobial films based on two different ethylene vinyl alcohol copolymers (EVOH 29 and EVOH 44) containing 5 and 10% lauril arginate (LAE). The characterization included optical, surface, thermal and barrier properties of the developed films, as well as the release of the agent into aqueous media. The results show that the addition of LAE did not produce relevant changes in optical, but reduced the films’ barrier properties to oxygen and water vapor, especially at high humidity conditions, and improved the wettability of the surface as demonstrated by the significant decrease in contact angle, both effects a consequence of the surfactant properties of the compound. The thermal properties confirmed that the distribution of LAE in the matrix was homogeneous, that the agent induced an antiplasticization effect and reduced the quality and percentage of the crystalline region, and that casting (or coating) is a suitable processing technology to reduce compound degradation. Finally, the release of LAE from EVOH films to water was characterized at 4 °C and 23 °C. This study showed that the agent was fully released into the food simulant from all films, although kinetically LAE diffusion was faster in EVOH 29 and at higher temperature. All these results show that the developed films present excellent functional properties and are able to release the antimicrobial agents suitably, making them promising materials for active food packaging applications.