Elsevier

Food Hydrocolloids

Volume 61, December 2016, Pages 695-702
Food Hydrocolloids

Improving functional properties of chitosan films as active food packaging by incorporating with propolis

https://doi.org/10.1016/j.foodhyd.2016.06.001Get rights and content

Highlights

  • Functional properties of chitosan film can be enhanced by incorporating with propolis.

  • Chitosan film containing propolis has better gas barrier and mechanical properties.

  • Chitosan film containing propolis exhibits antimicrobial and antioxidant activities.

  • Propolis incorporated chitosan film has potential to be used as active food packaging.

Abstract

Chitosan films containing 0, 2.5, 5, 10 and 20% w/w propolis extract (PE), high in polyphenols, were developed. The films’ tensile strength, elongation at break, total phenolic content and antioxidant activity increased, while water vapor permeability and oxygen permeability decreased with increasing propolis concentration. Increasing PE concentration resulted in deeper orange color films, as compared to light yellow control films. The ability of the films to inhibit Staphylococcus aureus, Salmonella Enteritidis, Escherichia coli and Pseudomonas aeruginosa was determined using agar diffusion technique. Chitosan films containing PE could inhibit all tested bacteria on contact surface underneath the film discs. Changes in the Fourier Transform Infrared spectra of the films were observed when PE was incorporated, suggesting some interactions occurred between chitosan and propolis polyphenols. The characterization of mechanical properties, oxygen and moisture barrier, and antioxidant and antimicrobial activities revealed the benefits of adding PE into chitosan films and the potential of using the developed film as active food packaging.

Introduction

Recently, research and developments in active food packaging have focused on bio-based functional packaging materials incorporating natural active compounds and ingredients (Leceta et al., 2013, van den Broek et al., 2015, Madureira et al., 2015). Chitosan is a functional biopolymer with intrinsic antimicrobial and antioxidant properties and consequently, it has high potential to be used as an alternative biodegradable active food package (Fernandez-Saiz et al., 2009, Guoa et al., 2015, van den Broek et al., 2015). Bio-based packaging materials with antioxidant and antimicrobial properties have become popular since oxidation and microbial contamination are major problems affecting food quality and safety. Many studies have been conducted on the utilization of plant polyphenols as alternatives to synthetic antimicrobial and antioxidant agents (Evrendilek, 2015, Lores et al., 2015, Madureira et al., 2015, Salvia-Trujillo et al., 2015, Siripatrawan, 2016).

Propolis, the natural resinous substance collected by honeybees from various plant sources, is considered a good source of natural antioxidants and antibacterials (Bankova, 2005). Propolis contains a variety of chemical compounds such as polyphenols (flavonoid aglycones, phenolic acids and their esters, phenolic aldehydes, alcohols and ketones), sesquiterpene quinines, coumarins, amino acids and inorganic compounds (Bankova, 2005, Falcão et al., 2010). Flavonoids (flavones, flavonols and flavonones), aromatic acids and phenolic compounds are the most important active constituents of propolis and appear to be the principal components responsible for the biological activities of propolis samples (Silici & Kutluca, 2005). Propolis has been reported to possess various biological activities, such as antibacterial, antiviral, antitumor, anti-inflammatory, anticancer, antifungal, and antitumoral properties (Falcão et al., 2010). The antimicrobial effects of propolis against Gram-positive (Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus) and Gram-negative (Salmonella Typhimurium, Escherichia coli and Pseudomonas fluorescence) bacteria have been reported (Silici and Kutluca, 2005, Siripatrawan et al., 2013).

As a good source of polyphenols with multiple biological activities, propolis has high potential to be used as an active agent that can be incorporated into films. Limited research on incorporation of propolis to enhance properties of packaging films and coatings has been published. Pastor, Sánchez-González, Cháfer, Chiralt, and González-Martínez (2010) investigated physical and antifungal properties of hydroxymethylcellulose based films containing propolis. Bodini, Sobral, Favaro-Trindade, and Carvalho (2013) studied properties of gelatin films added with propolis, and Torlak and Sert (2013) examined antibacterial effectiveness of chitosan-propolis coated polypropylene film. Nevertheless, research providing functional characterizations, including mechanical properties, oxygen and moisture barrier, structural property, antioxidant activity and antimicrobial property, of chitosan films incorporated with propolis extract (PE) has not been fully documented. Hence, this research aimed to develop and characterize chitosan films with enhanced functional properties for potential use as active food packaging by incorporating chitosan with propolis extract.

Section snippets

Film preparation

Propolis was collected from Nan province in northern Thailand and extracted following the methods of Siripatrawan et al. (2013). Three grams of ground propolis were extracted using 100 ml of 30% ethanol aqueous solution. The solution was extracted at 50 °C in a water bath shaking incubator (New Brunswick Scientific, Edison, USA) at 200 oscillation/min for 24 h and then filtered through Whatman filter paper No. 1. The extract solution was concentrated using a rotary evaporator (Rotavapor R-200,

Water vapor permeability

Chitosan films without propolis had the highest (p ≤ 0.05) WVP among tested films. Addition of propolis reduced (p ≤ 0.05) WVP of the films, but this did not change (p > 0.05) with increasing amounts (Fig. 1).

Polyphenolic compounds may be able to fit into the chitosan matrix and establish interactions such as hydrogen or covalent bonding with reactive groups of chitosan (Siripatrawan and Harte, 2010, Wu et al., 2013). The hydrogen and covalent interactions between chitosan network and

Conclusions

An active film from chitosan incorporated with PE could be achieved with enhanced functional properties. Incorporation of PE into chitosan films improved mechanical and barrier properties, as well as antimicrobial and antioxidant activities. The modification of film properties could be attributed to the interactions between functional groups of chitosan and polyphenols and other constituents of propolis as verified by FTIR analysis. The developed film has potential to be used as antimicrobial

Acknowledgements

The authors thank the National Research Council of Thailand for awarding the research grant (No. 2556NRCT53492). The propolis used in this research was supported by the Science for Locale Project under Chulalongkorn University Centenary Academic Development.

References (39)

Cited by (328)

  • Tannic acid crosslinked chitosan-guar gum composite films for packaging application

    2024, International Journal of Biological Macromolecules
View all citing articles on Scopus
View full text