Effects of microfluidization on the functional properties of xanthan gum

The effects of microfluidization on xanthan gum were studied by flow behaviour, hydration rate, water uptake and molecular weight determinations. The effect of pressure and number of passes on the xanthan solution produced a decrease in all these functional properties. Consequently the thickening and, stabilizing properties were reduced. We argued that the high shear, turbulence forces and cavitation involved in the microfluidization process produced ordered-disordered conformational transition (by opening of the molecule) and polymer degradation. The opening of the molecule occurred first, followed by polymer degradation due to mechanical stress. Differences observed in viscosity between treated xanthan dispersion and their spray-dried powders is associated with reorganisation of xanthan aggregates during heating and cooling, which occurred in spray-drying, but these phenomena do not change the high pressure effect on the biopolymer. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.