Structural, rheological, pasting and textural properties of granular cold water swelling maize starch: Effect of NaCl and CaCl2

Abstract

In this study granular cold water swelling (GCWS) starches were subjected to 0, 50, 100, 150 and 200 mM NaCl and CaCl2 and their effects on microstructure, rheological, pasting, and textural properties were determined. SEM images revealed that NaCl decreased the thickness of GCWS starch paste cell walls while, CaCl2 resulted in formation of denser and more homogenous pastes. The atomic force microscopy (AFM) results showed that NaCl increased the surface wrinkles of starch granules but CaCl2 reduced the roughness of starch granule surface. Zeta potential measurements showed both salts reduced the negative values and CaCl2 was more effective than NaCl. The steady shear measurements showed the shear thinning behavior of the samples. Starch pastes incorporated with NaCl had lower consistency coefficient (K) and apparent viscosity. However, the CaCl2 containing samples were more viscous. The pasting and textural parameters were increased by the increase of CaCl2 but decreased with NaCl.