A model for viscosity reduction in polysaccharides subjected to high-pressure homogenization

Three polysaccharides (alginate, K-carrageenan, xanthan) dispersed in water and exhibiting Newtonian or pseudoplastic (Power Law) flow properties were subjected to high-pressure homogenization (0 to 300 MPa) and one to five homogenization cycles. An exponential decay in viscosity was observed in the three processed polysaccharides due to both homogenization pressure and number of homogenization cycles. A 75-85% viscosity reduction and a viscosity plateau was reached after the polysaccharide dispersions were subjected to a sufficient homogenization pressure and/or number of homogenization cycles. A modified exponential decay model was proposed to describe a sudden reduction in viscosity and the observed constant minimum viscosity values after sufficient homogenization. The model was adjusted by minimizing the sum of squared differences between observed and modeled viscosity values. The model exhibited good correlation coefficient with experimental observations for the three polysaccharides tested (r > 0.98) and error analysis showed negligible fixed errors (bias) and normally distributed random differences between experimental and modeled viscosity values. PRACTICAL APPLICATIONS Polysaccharides are extensively used to modify textural properties of fluid and semi-solid foods. For a given polysaccharide, texture will be greatly affected by molecular weight. This manuscript shows the effect of high pressure homogenization on viscosity reduction for the polysaccharides alginate, K-carrageenan and xanthan gum. High-pressure homogenization offers the potential to be used for the manufacture of polysaccharides with targeted viscosity properties.