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.
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.
Heike
H
Möller
Stéphane
S
Grelier
Patrick
P
Pardon
Véronique
V
Coma
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