Wheat and maize starches were phosphorylated with sodium tripolyphosphate (TPS) at 4 different levels of addition. The maximum viscosities of the wheat doughs formed were increased and the dough temperatures decreased as the degrees of substitution of phosphate groups were increased; while for the maize starch the viscosities were increased and the dough temperatures remained constant. The phosphorylated starches (starch/water, 1:10) were subjected to cooking (100 ºC/1 minute), followed by drying (40 ºC/~ 4.0 per cent moisture) and milling (particle diameter, Φ = 0.149 mm) to determine the resistant starch (RS) content. For the lowest degree of substitution of phosphate groups in wheat starch (0.0029), resistant starch content of 30.46 per cent was found, while for maize starch RS content of 24.36 per cent was found. For the highest degree of substitution in wheat starch (0.0127) 46.69 per cent of RS content was found; while for maize starch, RS content of 28.40 per cent was found. According to the results, the increase in the degree of substitution in both cases seems to induce an increase in the resistant starch content, and phosphorylation with TPS was shown to be an excellent method for producing significant quantities of resistant starch in both wheat and maize starch.
wheat starch; corn starch; phosphorylation; rheology; resistant starch
