title: Selective antimicrobial action of chitosan against spoilage yeasts in mixed culture fermentations.
abstract: The effect of chitosan on Saccharomyces cerevisiae (the yeast that carries out alcohol fermentation), Brettanomyces bruxellensis and Brettanomyces intermedius (contaminants of alcohol fermentations), was investigated. The effect of chitosan was tested on each yeast, as well as on mixed cultivations of S. cerevisiae + B. bruxellensis and S. cerevisiae + B. intermedius. Chitosan enhanced the lag period of both strains of Brettanomyces (80 h for B. bruxellensis and 170 h for B. intermedius with 6 and 2 g/l chitosan, respectively). The growth rate of S. cerevisiae was inversely proportional to the chitosan concentration; the former was 50% when 6 g/l polysaccharide was used. Moreover, in mixed cultivations of S. cerevisiae and Brettanomyces strains, it was found that both B. bruxellensis and B. intermedius failed to grow while growth of S. cerevisiae was not affected (using 3 and 6 g/l chitosan, respectively). An interesting collateral result was that the presence of chitosan accelerated the consumption of glucose in the mixed cultivations (60 h instead of 120 h).
authors.affiliation: Departamento de Ingeniería Química-Bioquímica, Unidad de Investigación en Alimentos (UNIDA), Instituto Tecnológico de VeracruzMiguel Angel de Quevedo 2779, Col Formando Hogar, CP 91860, Veracruz, Mexico.
authors.forename: Leticia
authors.initials: L
authors.lastname: Gómez-Rivas
authors.forename: Blanca I
authors.initials: BI
authors.lastname: Escudero-Abarca
authors.forename: M Guadalupe
authors.initials: MG
authors.lastname: Aguilar-Uscanga
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Hayward-Jones
authors.forename: Patricia
authors.initials: P
authors.lastname: Mendoza
authors.forename: Mario
authors.initials: M
authors.lastname: Ramírez
mesh_terms: D000434:Alcoholic Beverages / Q000382:microbiology*; D001672:Biocompatible Materials / Q000494:pharmacology*; D002686:Chitin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D048271:Chitosan; D005285:Fermentation; D005506:Food Contamination; D008828:Microbiological Techniques; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000254:growth & development; D004718:Saccharomycetales / Q000187:drug effects* / Q000254:growth & development
chemical_list: D001672:Biocompatible Materials; D002686:Chitin; D048271:Chitosan