Physical Properties, Antioxidant and Antimicrobial Activity of Chitosan Films Containing Carvacrol and Pomegranate Peel Extract

Chitosan-based active films were developed by incorporation of carvacrol (10 g/L), pomegranate peel extract (PPE, 10 g/L) and carvacrol + PPE (10 g/L of each) and their physical, antioxidant and antimicrobial properties were investigated. Incorporation of carvacrol and carvacrol + PPE into the films significantly decreased the water vapor permeability, tensile strength and percentage of elongation at break. Incorporation of carvacrol, PPE and carvacrol + PPE into the films decreased the transparency, but significantly increased the total phenol content and antioxidant activity. All the films, with the exception of PPE-incorporated film, exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus. In addition, the antibacterial activity against Staphylococcus aureus of the film incorporated with carvacrol + PPE was moderately higher than that incorporated with carvacrol or PPE alone, suggesting a synergistic action between carvacrol and PPE.

Effect of Palm or Coconut Solid Lipid Nanoparticles (SLNs) on Growth of Lactobacillus plantarum in Milk

This study was performed to investigate the effect of palm or coconut solid lipid nanoparticles (PO-SLNs or CO-SLNs) on growth of Lactobacillus plantarum (L. plantarum) in milk during storage period. The PO or CO (0.1% or 1.0%) was dispersed both in distilled water (DW) and ultra high temperature milk (UHTM), and subsequently emulsified with Tween(®) 80 by ultrasonication (30% power, 2 min). Increase in particle size and encapsulation efficiency (EE%) in DW was observed with an increase in oil concentration, whereas a decrease in ζ-potential of SLNs was noted with an increment in oil concentration. Moreover, the CO-SLNs exhibited relatively smaller particle size and higher EE% than PO-SLNs. The CO-SLNs were found to be more stable than PO-SLNs. Higher lipid oxidation of PO or CO-SLNs in UHTM was observed during the storage test, when compared to PO or CO-SLNs in DW. However, there was no remarkable difference in lipid oxidation during storage period (p>0.05). In the growth test, the viability of L. plantarum in control (without PO or CO-SLNs in DW) exhibited a dramatic decrease with increasing storage period. In addition, viability of L. plantarum of PO or CO-SLNs in UHTM was higher than that of SLNs in DW. Based on the present study, production of SLNs containing PO or CO in UHTM is proposed, which can be used in lactobacilli fortified beverages in food industry.

Use of herbs, spices and their bioactive compounds in active food packaging

Natural additives obtained from herbs and spices are being increasingly used in the food packaging industry.

Antimicrobial and mechanical properties of β-cyclodextrin inclusion with essential oils in chitosan films

Chitosan films incorporated with various concentrations of the complex of β-cyclodextrin and essential oils (β-CD/EO) were prepared and investigated for antimicrobial, mechanical, and physical properties. Four bacterial strains that commonly contaminate food products were chosen as target bacteria to evaluate the antimicrobial activity of the prepared films. The incorporation of β-CD/EO significantly increased the antimicrobial activities of the chitosan films against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, and Listeria monocytogenes. It was also found that tensile strength (TS) of chitosan film was significantly increased with the incorporation of the β-cyclodextrin and 0.75% essential oils complex. The elongation at break (EB) decreased with the increasing concentrations of essential oils. Inclusion of the complex of β-cyclodextrin and 0.25% essential oils also significantly decreased water vapor permeability (WVP) of chitosan films. Our results suggest that chitosan films containing β-CD/EO could be used as active food-packaging material.

Active and intelligent packaging systems for a modern society

Active and intelligent packaging systems are continuously evolving in response to growing challenges from a modern society. This article reviews: (1) the different categories of active and intelligent packaging concepts and currently available commercial applications, (2) latest packaging research trends and innovations, and (3) the growth perspectives of the active and intelligent packaging market. Active packaging aiming at extending shelf life or improving safety while maintaining quality is progressing towards the incorporation of natural active agents into more sustainable packaging materials. Intelligent packaging systems which monitor the condition of the packed food or its environment are progressing towards more cost-effective, convenient and integrated systems to provide innovative packaging solutions. Market growth is expected for active packaging with leading shares for moisture absorbers, oxygen scavengers, microwave susceptors and antimicrobial packaging. The market for intelligent packaging is also promising with strong gains for time-temperature indicator labels and advancements in the integration of intelligent concepts into packaging materials.

Inhibitory effects of chitosan coating combined with organic acids on Listeria monocytogenes in refrigerated ready-to-eat shrimps

Chitosan and organic acids are natural preservatives with proven antimicrobial efficacies. This study investigated the effects of chitosan coating combined with organic acids on inhibiting Listeria monocytogenes in ready-to-eat (RTE) shrimps during storage at 4°C. Cooked shrimps inoculated with L. monocytogenes were coated with 0.5 and 1 % chitosan solutions in combination with 2 % organic acids (acetic, citric, lactic, and malic acids) for 5 min and then stored at 4°C for 16 days. Bacterial counts, pH, and sensory properties were analyzed every 4 days. The results indicated that the antimicrobial effects of chitosan were significantly enhanced (P < 0.05) when it was combined with 2 % acetic, citric, lactic, or malic acid. Chitosan at 1 % combined with 2 % acetic acid was the most effective treatment, which caused a 5.38-log CFU/g bacterial reduction after 16 days in comparison with the controls. Transmission electron microscopy further confirmed the enhanced antimicrobial effects of the combination of chitosan and organic acids. Such combined treatments also maintained the sensory properties of RTE shrimps. The use of chitosan coating combined with organic acids significantly lowered (P < 0.05) the pH values of RTE shrimps compared with the use of chitosan alone. Therefore, we conclude that chitosan coating combined with acetic acid could be a promising antimicrobial method to prevent the proliferation of L. monocytogenes in RTE shrimps with extended shelf life.

Characterization of Antioxidant Chitosan Film Incorporated with Pomegranate Peel Extract

A novel antioxidant chitosan film incorporated with pomegranate peel extract (PPE) (0, 1%, 2%, and 3% (w/v)) was developed. The mechanical property, water vapor permeability, total phenolic content and antioxidant activity of the films were investigated. Fourier transform infrared (FTIR) spectra revealed that good interactions occurred between functional groups of chitosan with PPE. The flexibility and water vapor barrier property were improved by incorporation with PPE. Films containing PPE had higher total phenolic content and showed better antioxidant activity. These results suggest that chitosan films incorporated with PPE can be useful for meat preservation.

Physical Properties and Antibacterial Activity of a Chitosan Film Incorporated with Lavender Essential Oil

Chitosan-based films containing lavender essential oil (LEO) (0, 0.5%, 1.0%, 1.5% (v/v)) were prepared to evaluate their physical and antibacterial activities. In order to study the impact of the incorporation of LEO into chitosan matrix, the solubility, mechanical property, water vapor permeability, and antibacterial activity of the films were investigated. Fourier transform infrared chromatography (FTIR) was carried out to explain structure–property relationships. Results showed that the solubility and water vapor permeability of the chitosan-based film decreased by LEO incorporation. Films containing LEO showed better mechanical property. FTIR spectra demonstrated good interaction between functional groups of chitosan with LEO. With the concentration of LEO increased from 0 to 1.5 %, the inhibitory zone of four bacterial strains (Escherichia coli, Staphylococcus aurous, Bacillus magaterium, Bacillus subtilis) increased. It can be concluded that chitosan films containing LEO can be used for development of active food packaging materials.