Effects of starch from five different botanical sources on the rheological and structural properties of starch-gluten model doughs

Wheat, corn, tapioca, sweet potato and potato starches were independently mixed into starch-gluten model doughs containing 15% (w/w) vital gluten. Rheological properties, including linear viscoelasticity region, frequency dependence and recovery capacity, were studied by strain sweep, frequency sweep, and creep and recovery measurements. Structural properties were also investigated by measuring the disulfide bonds (-SS-) content, SDS-PAGE and low-resolution H-1 nuclear magnetic resonance. Wheat starch (WS)-gluten dough had the greatest linear viscoelasticity region (0.190%), lowest frequency dependence (0.128) and greatest recovery capacity (67.39%), while potato starch-gluten dough had the smallest linear viscoelasticity region (0.126%), greatest frequency dependence (0.195) and lowest recovery capacity (54.97%). Furthermore, WS-gluten dough showed the highest disulfide bonds (-SS-) content (3.47 mu mol/g), lowest intensity of extracted glutenin bands and highest bond water content (23.20%). This suggested that WS-gluten dough formed stronger starch-gluten interactions compared with those of the other four starch-gluten model doughs.