Physicochemical properties of wheat-canna and wheat-konjac composite flours.

Abstract

Physicochemical properties of composite flours made of wheat from low to high protein contents and canna or konjac at different levels of substitution (0, 25, 50, 75, and 100%) were prepared and analyzed. Compared to that of wheat flour alone, increasing levels of canna inclusions significantly increased the amount of resistant starch (RS) but decreased the protein content of composite flours. This substitution did not alter the total starch (TS), amylase and amylopectin contents of these mixtures. Changes in physicochemical properties were also observed in wheat-konjac composite flours. Increasing amounts of konjac flour decreased the TS, amylase, amylopectin, and protein content of the mixtures, but increased the amount of RS. Substitution of wheat flour with 75% of canna or konjac flours in HPWC (High Protein Wheat-Canna), HPWK (High Protein Wheat-Konjac), and LPWK (Low Protein Wheat-Konjac) increased the swelling power of these mixtures at 80 and 90°C. In general, substitution of wheat flour with up to 50% of canna or konjac flours did not cause any other observable decline. In addition, the substitution of wheat flour with canna or konjac flours increased the gelatinization temperature of all composite flours.