Electric birefringence measurements of native, denatured, and renatured xanthan

Abstract

Electric birefringence measurements were performed on three xanthan solutions to determine conformational differences between native xanthan, denatured xanthan (heated in 4 M urea to 90°C and cooled), and renatured xanthan (heated and cooled). The birefringence of samples exposed to pulses of 1000 V for 1 ms were analyzed to determine longest relaxation times and steady-state birefringence. The results showed the following order for steady state birefringence, native > renatured > denatured, and longest relaxation time, renatured > native > denatured. The results are interpreted in terms of helix reformation and aggregation upon renaturing.