title: Effects of tyrosinase and laccase on oat proteins and quality parameters of gluten-free oat breads.
abstract: Effects of a Trichoderma reesei tyrosinase (TYR) and a Trametes hirsuta laccase (LAC) on breadmaking performance of gluten-free oat flour were investigated by SDS-PAGE analysis of oat protein fractions, large deformation rheology, and microscopy of the doughs, as well as on the basis of specific volume and firmness of the gluten-free breads. TYR induced the formation of higher molecular weight proteins in the SDS-PAGE assay. Microscopical analysis showed more intensive protein aggregation in the TYR-treated dough than in the dough without TYR. TYR also increased the firmness of the dough, which was assumed to be because of the cross-linking of oat globulins. LAC did not affect the oat globulins. TYR alone, or together with a commercial Thermomyces lanuginosus xylanase (XYL), increased significantly the specific volume of the gluten-free oat bread. A combination of TYR and XYL also increased the softness of the bread, whereas a combination of LAC and XYL improved the specific volume but did not affect the softness of oat bread. The results thus indicate that cross-linking of oat globulins by TYR, especially with the addition of XYL, was beneficial for improving the texture of gluten-free oat bread.
authors: VTT Technical Research Centre of Finland, 02044 VTT, Finland. laura.flander@vtt.fi
authors: Laura
authors: L
authors: Flander
authors: Ulla
authors: U
authors: Holopainen
authors: Kristiina
authors: K
authors: Kruus
authors: Johanna
authors: J
authors: Buchert
mesh_terms: D018554:Avena / Q000737:chemistry*; D001939:Bread / Q000032:analysis*; D002384:Catalysis; D003296:Cooking; D005656:Fungal Proteins / Q000737:chemistry*; D005983:Glutens / Q000032:analysis*; D042845:Laccase / Q000737:chemistry*; D014442:Monophenol Monooxygenase / Q000737:chemistry*; D010084:Oxidation-Reduction; D010940:Plant Proteins / Q000737:chemistry; D055454:Trametes / Q000201:enzymology*; D014242:Trichoderma / Q000201:enzymology*
chemical_list: D005656:Fungal Proteins; D010940:Plant Proteins; D005983:Glutens; D042845:Laccase; D014442:Monophenol Monooxygenase