Publication no. C-2004-0420-02R |  VIEW ARTICLE

Prediction of beta-Glucan Concentration Based on Viscosity Evaluations of Raw Oat Flours from High beta-Glucan and Traditional Oat Lines.

Mirela Colleoni-Sirghie (1), Jean-Luc Jannink (2), Igor V. Kovalenko (3), Jenni L. Briggs (1,3,4), and Pamela J. White (1,5). (1) Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011. (2) Department of Agronomy, Iowa State University, Ames, IA 50011. (3) Department of Agricultural & Biosystems Engineering, Iowa State University, Ames, IA 50011. (4) Present address: Thermo Electron Corporation, Madison, WI 53711. (5) Corresponding author. Phone: 515-294-9688. Fax: 515-294-8181. E-mail: <pjwhite@iastate.edu> Cereal Chem. 81(4):434-443. Accepted December 15, 2003. Copyright 2004 American Association of Cereal Chemists, Inc.

Rheological properties of raw oat flour slurries were determined in experimental high beta-glucan (<7.8%) and traditional oat lines (4–5% beta-glucan) grown in two consecutive years. Three different media were used to disperse oat flours: deionized water, silver nitrate solution (to inactivate endogenous enzymes), and alkali solution (to solubilize both water-soluble and water-insoluble beta-glucans). Significant correlations (P < 0.05) between viscosity of slurries and beta-glucan concentration obtained in either deionized water (r = 0.833), silver nitrate (r = 0.940), or alkali (r = 0.896) solutions showed that beta-glucans were the main contributor to oat extract viscosity. The highest correlation was obtained in silver nitrate solution, suggesting that inactivating endogenous enzymes is important to obtain high correlations. Predictive models of oat beta-glucan concentration based on the viscosity profile were developed using partial least squares (PLS) regression. Prediction of beta-glucan concentration based on viscosity was most effective in the silver nitrate solution (r = 0.949, correlation coefficient of predicted vs. analyzed beta-glucans) and least effective in the alkali solution (r = 0.870). These findings demonstrate that the beta-glucan in oat could be predicted by measuring the viscosity of raw flours in silver nitrate solution, and this method could be used as a screening tool for selective breeding.