title: Enzyme-catalyzed phase transition of alginate gels and gelatin-alginate interpenetrated networks.
abstract: The enzyme-catalyzed gel-sol transition of calcium-alginate obtained by internal gelling strategy with the help of an entrapped alginate lyase is described. We show that alginate molecules and enzyme-produced oligoalginates shorten the gel time of physical gelatin gels (5% and 1.5%), probably due to local protein concentration increase. Interpenetrated networks composed of calcium-alginate and of gelatin were obtained only if elongation of gelatin helices inside a pre-existing calcium-alginate network could occur and only for low gelatin concentration (1.5%). The physical gelatin network is almost reversible inside the alginate one. Both networks can be obtained in the presence of alginate lyase, but gel-sol transition of calcium-alginate cannot be obtained in the presence of gelatin.
authors.affiliation: Laboratoire ERRMECe UFR Sciences et Techniques Université de Cergy-Pontoise, 2 avenue Adolphe Chauvin, Pontoise cedex, France.
authors.forename: Bastien
authors.initials: B
authors.lastname: Doumèche
authors.forename: Julien
authors.initials: J
authors.lastname: Picard
authors.forename: Véronique
authors.initials: V
authors.lastname: Larreta-Garde
mesh_terms: D000464:Alginates / Q000737:chemistry* / Q000378:metabolism; D002118:Calcium / Q000737:chemistry; D002384:Catalysis; D004548:Elasticity; D005417:Flavobacterium / Q000201:enzymology; D005780:Gelatin / Q000737:chemistry* / Q000378:metabolism*; D005782:Gels / Q000737:chemistry / Q000378:metabolism; D020723:Glucuronic Acid / Q000737:chemistry / Q000378:metabolism; D006603:Hexuronic Acids / Q000737:chemistry / Q000378:metabolism; D044662:Macrocystis / Q000378:metabolism; D015394:Molecular Structure; D044367:Phase Transition; D011133:Polysaccharide-Lyases / Q000378:metabolism; D012212:Rheology; D014783:Viscosity
chemical_list: D000464:Alginates; D005782:Gels; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D005780:Gelatin; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase; D002118:Calcium