Effects of NaCl and CaCl2 on physicochemical properties of pregelatinized and granular cold-water swelling corn starches

The physicochemical properties of drum dried pregelatinized (PG) and granular cold-water-swelling (GCWS) corn starch pastes were determined in the presence of NaCl and CaCl2 (0, 50, 100, 150 and 200 mM). Light micrographs revealed that NaCl roughened the surface of PG starch particles while CaCl2 did not bring about obvious changes on their morphology. In the case of GCWS starch, there were some wrinkles on the surface of starch granules. NaCl increased the wrinkles but CaCl2 softened the surface of granules. GCWS starch had higher water absorption, cold paste viscosity and textural parameters than PG starch and these parameters were enhanced with addition of CaCl2 while NaCl exhibited an opposite trend for all of these factors. The Freeze-thaw (F-T) stability and turbidity of GCWS were also higher than PG starch. In presence of salts F-T stability and turbidity of both modified starches improved and CaCl2 caused more evident changes.