Application of Supercritical Solvent Impregnation for Production of Zeolite Modified Starch-Chitosan Polymers with Antibacterial Properties

Jelena Pajnik,Malgorzata Korzeniowska,Ivana Lukić,Irena Zizović,Milan Gordic,Jelena Dikić,Jelena Asanin,Dusan Misic

doi:10.3390/molecules25204717

Jelena Pajnik, Malgorzata Korzeniowska + Show 6 more

Open Access

https://doi.org/10.3390/molecules25204717

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Journal: Molecules	Publication Date: Oct 15, 2020
Citations: 18	License type: CC BY 4.0

Affiliation: University of Belgrade

Abstract

In the present study, supercritical solvent impregnation (SSI) has been applied to incorporate thymol into bio-composite polymers as a potential active packaging material. Thymol, a natural component with a proven antimicrobial activity, was successfully impregnated into starch-chitosan (SC) and starch-chitosan-zeolite (SCZ) films using supercritical carbon dioxide (scCO2) as a solvent. Experiments were performed at 35 °C, pressures of 15.5 and 30 MPa, and an impregnation time in the range of 4–24 h. The highest impregnation yields of SC films with starch to chitosan mass ratios of 1:1 and 1:2 were 10.80% and 6.48%, respectively. The addition of natural zeolite (15–60%) significantly increased the loading capacity of films enabling thymol incorporation in a quantity of 16.7–27.3%. FTIR and SEM analyses were applied for the characterization of the films. Mechanical properties and water vapor permeability of films before and after the impregnation were tested as well. Thymol release kinetics in deionized water was followed and modeled by the Korsmeyer-Peppas and Weibull model. SCZ films with thymol loading of approximately 24% exhibited strong antibacterial activity against E. coli and methicillin-resistant Staphylococcus (S.) aureus (MRSA).

Highlights

Active packaging is an emerging food technology developed to meet constant worldwide market expansion as well as continuous changes in consumers’ demands [1]
SC Films synthesized SC films were exposed to pure CO2 at a temperature of 50 °C and a pressure of 30 MPa for 4 h
The results revealed that no extractables were present in the preliminary experiments, films exposed pure

Summary

Introduction

Active packaging is an emerging food technology developed to meet constant worldwide market expansion as well as continuous changes in consumers’ demands [1]. Active packaging refers to the improved properties of a packing system designed to provide prolonged shelf life, enhanced quality, and safety of food products [2]. This can be accomplished by the incorporation of active compounds, such as moisture absorbent substances or substances with antimicrobial and antioxidant activity into the food packaging material [2]. One of the most common approaches for packaging films with improved antimicrobial properties is based on the release of active compounds from the packaging material into the close surroundings [3]. Due to stricter standards nowadays in the food industry and the ban on the usage of many substances that were previously allowed in food production [4], natural biodegradable polymers have the advantage of being used for active packaging in comparison to synthetic materials.

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