Chitin and chitosan: Properties and applications

Antimicrobial properties of chitosan and mode of action: A state of the art review

Chitosan, a versatile hydrophilic polysaccharide derived from chitin, has a broad antimicrobial spectrum to which gram-negative, gram-positive bacteria and fungi are highly susceptible. In the current review, three possible and accepted antimicrobial mechanisms for chitosan are presented and briefly discussed. The activity dependence on polymeric molecular weight (MW) and degree of acetylation (DA) are described. The chitosan minimum inhibitory concentrations (MIC) are summarized according to recent data found in the literature. The potential to improve inhibitory growth of bacteria by using water soluble chitosan derivatives is also discussed. The data indicate that the effectiveness of chitosan varies and is dependent on species of target microorganisms.

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A Review of the Antimicrobial Activity of Chitosan

Chitosan based edible films and coatings: A review

This review concerns the applications of some polysaccharides in the domain of biomaterials and bioactive polymers. Natural polysaccharides from different sources have been studied for a long time, and their main properties are summarized in this paper; some of their derivatives obtained by chemical modification are also described. The main polysaccharides currently used in the biomedical and pharmaceutical domains are chitin and its derivative chitosan, hyaluronan and alginates. Alginates are well known for their property of forming a physical gel in the presence of divalent counterions (Ca, Ba, Sr) whereas carrageenans form a thermoreversible gel; these seaweed polysaccharides are mainly used to encapsulate different materials (cells, bacteria, fungi). Other promising systems are the electrostatic complexes formed when an anionic polysaccharide is mixed with a cationic polysaccharide (e.g. alginate/chitosan or hyaluronan/chitosan). An important development of the applications of polysaccharides can be predicted for the next few years in relation to their intrinsic properties such as biocompatibility and biodegradability in the human body for some of them; they are also renewable and have interesting physical properties (film-forming, gelling and thickening properties). In addition, they are easily processed in different forms such as beads, films, capsules and fibres. Copyright © 2007 Society of Chemical Industry

Main properties and current applications of some polysaccharides as biomaterials

Copolymerization of acrylonitrile with ethyl methacrylate—I

Transesterification of Jojoba Oil-Wax Using Microwave Technique

What is an edible packaging? An edible film or coating is simply defined as a thin film of edible material formed and sprayed on foods or food components. This package can be eaten as a part of the whole food product; it is also biodegradable, so if dumped it will disintegrate in reasonable short time. Edible films and coatings offer extra advantages such as edibility, biocompatibility, esthetic appearance, barrier to gas properties, nontoxicity, nonpolluting, and having low cost (No et al. J Food Sci 72(5):87–100, 2007). In addition, biofilms and coatings by themselves are acting as carriers of food additives (i.e., antioxidants, antimicrobials) and have been particularly considered in food preservation due to their ability to extend the shelf life. This chapter will focus mainly on edible films based on chitosan – a wonderful amazing material which is derived from the naturally occurring polymer chitin.

http://link.springer.com/content/pdf/10.1007/978-3-319-03751-6_7-1.pdf

Chitosan -Based Edible Films

Polyester based on bis- (2-hydroxypropyl terephthalate) (BHPT) and maleic anhydride (MA) was prepared and its structure confirmed by spectral analysis. The kinetic of the condensation reaction was investigated at three different temperatures (180–200 °C) in the presence and the absence of p-toluene sulphonic acid (PTSA) as a catalyst. The reaction order was found to be second and third order in the presence and absence of the catalyst, respectively. The activation energy was calculated in both cases and was found to be 15.7 and 145.5 kJ mol−1 in the presence and absence of the catalyst, respectively. The polyester was mixed with styrene monomer, and with methyl ethyl ketone peroxide (0.5 wt.%) as initiator and cobalt naphthenate (0.25 wt.%) as accelerator to obtain a styrenated resin with good mechanical properties. N-phenyl maleimide (NPMI) was also used together with styrene in different ratios to form a copolymer. No pronounced improvement in the mechanical and the thermal properties was found after the introduction of NPMI.

Preparation and Characterization of Polyester Based on bis- (2- hydroxypropyl terephthalate)

Chitosan was grafted with a novel monomer 1-Cyanoethanoyl-4-acryloylthiosemicabazide (CEATS). The graft copolymerization was conducted using potassium persulfate (K2S2O8) and sodium bisulfite (NaHSO3) as redox initiators. The grafted samples were characterized by FTIR spectroscopy, scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. The data may indicate that grafting has occurred at the surface of chitosan. The grafted samples showed high water swelling. The antifungal behavior of chitosan and its graft copolymers was investigated in vitro and it has been found that grafting with CEATS noticeably enhances the antifungal activity.

Maher Z. Elsabee

Papers

Copolymerization of acrylonitrile with ethyl methacrylate—I

Transesterification of Jojoba Oil-Wax Using Microwave Technique

Chitosan -Based Edible Films

Preparation and Characterization of Polyester Based on bis- (2- hydroxypropyl terephthalate)

Grafting of 1-Cyanoethanoyl-4-acryloylthiosemicabazide onto Chitosan and Biocidal Activity of the Graft Copolymers