Physical modification of various starches by partial gelatinization and freeze-thawing with xanthan gum

Abstract

Aqueous dispersion (40% w/w, dry basis) of different starches (corn, potato, and tapioca), with or without xanthan gum (0.1% w/w, based on starch solids), were partial gelatinizated for 1 h at 5 degrees C above the onset temperatures of starch and cooled (GC), freeze-thawed (FT), and then dried at 60 degrees C. The combined treatments (GCFT) raised the viscosity and shear stability of starch pastes. Among the starches tested, potato starch exhibited the greatest changes in the pasting behavior. In addition, the physical treatments (GCFT) improved the gelation behavior and the stability against repeated freeze-thawing cycles. A minor addition of xanthan gum enhanced the effect of physical treatments, especially on the stabilization of starch gels.