Hot-Water Solubilities and Water Sorptions of Resistant Starches at 25(degree)C

Resistant starches (RS) were prepared from wheat starch and lintnerized wheat starch by autoclaving and cooling and by cross-linking. Heatmoisture treatment also was used on one sample to increase RS. The experimental resistant starches made from wheat starch contained 10-73% RS measured as Prosky dietary fiber, whereas two commercial resistant starches, Novelose 240 and 330, produced from high-amylose maize starch, contained 58 and 40%, respectively. At 25(degree)C in excess water, the experimental RS starches, except for the cross-linked wheat starch, gained 3-6 times more water than the commercial RS starches, and at 95(degree)C gained 2-4 times more. Cross-linked RS4 wheat starch and Novelose 240 showed 95(degree)C swelling powers and solubilities of 2 g/g and 1%, and 3 g/g and 2%, respectively. All starches showed similar water vapor sorption and desorption isotherms at 25(degree)C and water activities (a(w)) < 0.8. At a(w) 0.84-0.97, the resistant starches made from wheat starch, except the crosslinked wheat starch, showed approximately 10% higher water sorption than the commercial resistant starches.