Rheological Properties of Sonicated Guar, Xanthan and Pectin Dispersions

The influence of high intensity ultrasound on the rheological characteristics of guar, xanthan, and pectin dispersions was investigated. Guar 1%, xanthan 1% and pectin 2% (w/v) dispersions were sonicated at varying intensity levels of 3.7, 6.3, 8.1, and 10.1 W/cm2 for 5 min at 25oC. Significant differences were observed in the rheological characteristics of each sonicated hydrocolloid dispersion studied. Sonication affected the consistency index (k), flow behaviour index (n) and complex power law constants (a and b). No recovery was observed in the structure breakdown after a 24-h storage period. Changes in the rheological properties of guar and pectin dispersions were significantly higher than that of xanthan dispersions.