Antimicrobial and physicochemical properties of chitosan-HPMC-based films.
To prepare composite films from biopolymers with anti-listerial activity and moisture barrier properties, the antimicrobial efficiency of chitosan-hydroxy propyl methyl cellulose (HPMC) films, chitosan-HPMC films associated with lipid, and chitosan-HPMC films chemically modified by cross-linking were evaluated. In addition, the physicochemical properties of composite films were evaluated to determine their potential for food applications. The incorporation of stearic acid into the composite chitosan-HPMC film formulation decreased water sensitivity such as initial solubility in water and water drop angle. Thus, cross-linking of composite chitosan-HPMC, using citric acid as the cross-linking agent, led to a 40% reduction in solubility in water. The water vapor transfer rate of HPMC film, approximately 270 g x m(-2) x day(-1) x atm(-1), was improved by incorporating chitosan and was further reduced 40% by the addition of stearic acid and/or cross-linking. Anti-listerial activity of films was determined on solid medium by a numeration technique. Chitosan-HPMC-based films, with and without stearic acid, inhibited the growth of Listeria monocytogenes completely. On the other hand, a loss of antimicrobial activity after chemical cross-linking modification was observed. FTIR and 13C NMR analyses were then conducted in order to study a potential chemical modification of biopolymers such as a chemical reaction with the amino group of chitosan. To complete the study, the mechanical properties of composite films were determined from tensile strength assays.
Möller
Heike
H
Laboratoire de Chimie des Substances Végétales, Centre de Recherche en Chimie Moléculaire, Institut du Pin, Université Bordeaux 1, 351 cours de la Libération, 33405 Talence, France.
Grelier
Stéphane
S
Pardon
Patrick
P
Coma
Véronique
V
D000890:Anti-Infective Agents / Q000494:pharmacology*; D048271:Chitosan / Q000737:chemistry* / Q000494:pharmacology; D003432:Cross-Linking Reagents; D018857:Food Packaging / Q000295:instrumentation*; D065347:Hypromellose Derivatives; D008089:Listeria monocytogenes / Q000187:drug effects / Q000254:growth & development; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000494:pharmacology; D013229:Stearic Acids; D013329:Structure-Activity Relationship
D000890:Anti-Infective Agents; D003432:Cross-Linking Reagents; D013229:Stearic Acids; D065347:Hypromellose Derivatives; C031183:stearic acid; D008747:Methylcellulose; D048271:Chitosan