Viscosity based quantification of endogenous beta-glucanase activity in flour

摘要

High molecular weight (MW) is a key parameter for cereal beta-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 beta-glucan MW. The depolymerization of a standard beta-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/eta) against degradation time was used to quantify beta-glucanase activity by comparison with slopes obtained with known concentrations of the beta-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 beta-glucanase activity, treatments that can inactivate beta-glucanases in flour, or the development of beta-glucanase inhibitors for the use in e. g. bread making. (C) 2014 Elsevier Ltd. All rights reserved.