title: Viscosity based quantification of endogenous β-glucanase activity in flour.
abstract: High molecular weight (MW) is a key parameter for cereal β-glucans physiological benefits like decreased serum cholesterol and attenuated post prandial blood glucose. However, the activity of endogenous flour enzymes during bread production results in a decrease of β-glucan MW. The depolymerization of a standard β-glucan solution by different flour extracts (wheat, barley and rye) was followed by measuring the viscosity decrease with a Rheometer. The slope of the inverse viscosity (1/η) against degradation time was used to quantify β-glucanase activity by comparison with slopes obtained with known concentrations of the β-glucanase Lichenase. Results correlated well with depolymerization rates estimated by HPSEC. The viscosity based method is rapid (20 min per sample), accurate (≤6% variation), and a powerful screening tool for identifying flour fractions with low β-glucanase activity, treatments that can inactivate β-glucanases in flour, or the development of β-glucanase inhibitors for the use in e.g. bread making.
authors.affiliation: Nofima, Norwegian Institute for Food, Fisheries and Aquaculture Research, PB 210, N-1431 Aas, Norway. Electronic address: anne.rieder@nofima.no.
authors.forename: Anne
authors.initials: A
authors.lastname: Rieder
authors.affiliation: Nofima, Norwegian Institute for Food, Fisheries and Aquaculture Research, PB 210, N-1431 Aas, Norway. Electronic address: simon.ballance@nofima.no.
authors.forename: Simon
authors.initials: S
authors.lastname: Ballance
authors.affiliation: Nofima, Norwegian Institute for Food, Fisheries and Aquaculture Research, PB 210, N-1431 Aas, Norway. Electronic address: svein.knutsen@nofima.no.
authors.forename: Svein Halvor
authors.initials: SH
authors.lastname: Knutsen
mesh_terms: D004789:Enzyme Activation; D057075:Enzyme Assays / Q000379:methods*; D005433:Flour; D005504:Food Analysis / Q000379:methods*; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D014783:Viscosity
chemical_list: D006026:Glycoside Hydrolases
keywords: Activity; Cereal β-glucan; Molecular weight; Quantification; Viscosity; β-Glucanase