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Pasting and Thermal Properties of Flours from Oat Lines with High and Typical Amounts of β-Glucan

¹Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011. ²Department of Agronomy, Iowa State University, Ames, IA 50011. ³Corresponding author. Phone: 515-294-5980. Fax: 515-294-8181. E-mail: pjwhite@iastate.edu

Experimental oat lines high in β-glucan (6–7.8%) and traditional lines (3.9–5.7% β-glucan) were used to evaluate the effect of β-glucan on pasting (by rapid viscoanalysis) and thermal properties (by differential scanning calorimetry) of oat flours. Significant correlations established between β-glucan concentration and the pasting parameters after amylolysis demonstrated the role of β-glucans in oat pasting. The relative decrease of peak viscosity (PV) observed after enzymatic removal of β-glucans was correlated with β-glucan concentration (r = 0.880, P < 0.010) and reconfirmed their contribution to pasting. A significant increase of PV with β-glucan concentration obtained under conditions of either autolysis (deionized water used for dispersion) (r = 0.89, P < 0.010) or inhibition (silver nitrate solution used for dispersion) (r = 0.91, P < 0.001) might be explained by an increase in water retention capacity caused by the β-glucans. Predictive models of β-glucan concentration based on the whole pasting profile or selected profile regions were developed using partial least squares (PLS) regression.Prediction of β-glucan based on the whole profile obtained in the silver nitrate solution was the most effective (r = 0.93, correlation coefficient of predicted vs. analyzed β-glucans, P < 0.050). No correlations were observed between the thermal properties of oat flours and the β-glucan concentration.