Z Ebadi1, H Ghaisari2, B Tajeddin3, S S Shekarforoush2. 1. Ph.D. Student in Food Hygiene, Department of Food Hygiene and Public Health, School of Veterinary Medicine, Shiraz University, Shiraz, Iran, and Animal Science Research Institute (ASRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran (current address). 2. Department of Food Hygiene and Public Health, School of Veterinary Medicine, Shiraz University, Shiraz, Iran. 3. Agricultural Engineering Research Institute (AERI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
Abstract
Background: Recent research has shown that chitosan has good moisture-absorbing properties at the micro and nanoscale, and seems to be a good candidate for the production of biodegradable moisture-absorbing films. Aims: The aim of this study was to evaluate the properties and antibacterial activity of starch-based microchitosan (MCH) films impregnated with two essential oils (EOs). Methods: MCH films with varying thicknesses were made from cornstarch (6%), microchitosan (1%), glycerol (2.25%), and/or EOs (2%), and their characteristics, including swelling degree (SD), tensile strength (TS), and elongation at break (EB%), were examined. The film structures were confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). To determine the antibacterial activity against Escherichia coli and Staphylococcus aureus, two EOs of Shirazi thyme, garlic, and a mixture of them were used in the experimentation. Results: The EB% and TS had a linear relationship with the thickness of samples and improved by increasing the thickness of films. The XRD pattern showed that the MCH films had an amorphous structure. SEM of the films showed a homogeneous dispersion of MCH in the starch matrix without any porosity. The AFM images showed a simultaneous increase in the thickness of the MCH films and surface roughness. The film was able to absorb water up to 15.78 times its weight in 48 h. The inhibition zone of films containing 2% thyme EO was 42.0 mm for S. aureus and 12.3 mm for E. coli (P<0.05). Conclusion: MCH film containing Shirazi thyme can be described as a moisture-absorbing antibacterial pad and is a new idea for active food packaging to increase the shelf life of foods with fully degradable properties.
Background: Recent research has shown that chitosan has good moisture-absorbing properties at the micro and nanoscale, and seems to be a good candidate for the production of biodegradable moisture-absorbing films. Aims: The aim of this study was to evaluate the properties and antibacterial activity of starch-based microchitosan (MCH) films impregnated with two essential oils (EOs). Methods: MCH films with varying thicknesses were made from cornstarch (6%), microchitosan (1%), glycerol (2.25%), and/or EOs (2%), and their characteristics, including swelling degree (SD), tensile strength (TS), and elongation at break (EB%), were examined. The film structures were confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). To determine the antibacterial activity against Escherichia coli and Staphylococcus aureus, two EOs of Shirazi thyme, garlic, and a mixture of them were used in the experimentation. Results: The EB% and TS had a linear relationship with the thickness of samples and improved by increasing the thickness of films. The XRD pattern showed that the MCH films had an amorphous structure. SEM of the films showed a homogeneous dispersion of MCH in the starch matrix without any porosity. The AFM images showed a simultaneous increase in the thickness of the MCH films and surface roughness. The film was able to absorb water up to 15.78 times its weight in 48 h. The inhibition zone of films containing 2% thyme EO was 42.0 mm for S. aureus and 12.3 mm for E. coli (P<0.05). Conclusion: MCH film containing Shirazi thyme can be described as a moisture-absorbing antibacterial pad and is a new idea for active food packaging to increase the shelf life of foods with fully degradable properties.
Authors: José Antonio Morales-González; Eduardo Madrigal-Bujaidar; Manuel Sánchez-Gutiérrez; Jeannett A Izquierdo-Vega; María Del Carmen Valadez-Vega; Isela Álvarez-González; Ángel Morales-González; Eduardo Madrigal-Santillán Journal: Foods Date: 2019-08-13