Textural and Rheological Properties of Oat Beta-Glucan Gels with Varying Molecular Weight Composition.

The impact of oat beta-glucan concentration and molecular weight (MW) on gel properties was investigated. Mixed MW gels/viscous solutions at 3, 4, and 5% beta-glucan with high molecular weight (HMVV):low molecular weight (LMW) ratios of 0:100, 25:75, 50:50, 75:25, and 100:0 were evaluated. The 100:0 and 50:50 gels had the lowest tan delta values. The 50:50 gels had the highest storage moduli (G'), whereas 100:0 solutions did not gel. Peak melting temperature (T-p) was highest for 0:100 gels and decreased with the addition of HMW beta-glucan. Hardness, at 40% compression, increased with concentration, and 25:75 and 50:50 gels were hardest at each concentration. Ordered microstructure, apparent in 0:100 gels, diminished with HMW beta-glucan addition. Glucose addition resulted in lower tan delta values and firmer, harder gels compared to gels without glucose. Thus, the textural properties and melting profiles of beta-glucan gels can be manipulated by adjusting the ratios of molecular weight fractions or addition of sugar for different applications.