Rheology of sol-gel thermal transition in cowpea flour and starch slurry

A thermal scanning rigidity monitor was used to follow rheological changes during heating of cowpea flour and starch slurries. The gelatinization temperature of cowpea starch was in the range 67-78 degrees C. For cowpea flour, in addition to starch gelatinization, a shallow plateau was observed. The starch gelatinization onset temperature shifted from 67 degrees C for starch to 72 degrees C for 25% cowpea flour that contained 12-15% starch. The modulus (G') of cowpea gels increased with flour concentration according to a power relationship. Rigidity of the cowpea starch and flour gels decreased at temperatures higher than 78 and 87 degrees C, respectively