INVESTIGATION OF BETA-LACTOGLOBULIN GELATION IN WATER ETHANOL SOLUTIONS/

The critical concentrations for P-lactoglobulin gelation at pH 7 and 8 in 50% ethanol solutions (v/v) were established. Then, the gelation k inetics at 25 degrees C were followed by dynamical rheological methods and Fourier transform infrared spectroscopy. The gelation process was faster at pH 7 compared to pH 8. After 3 min, the infrared spectra of BLG in 50% ethanol solution indicated that the percentage of alpha he lix was higher at pH 8 than at pH 7. Alcohol-induced aggregation of BL G was characterised by the formation of intermolecular hydrogen bonded beta-sheet structures for the two pH values. The final gel structures were also investigated by small-angle neutron scattering. The data ob tained on the molecular, mesoscopic and macroscopic levels showed that the kinetics of gelation were pH dependent contrary to the spatial ar rangements of the aggregates in the final structures. (C) 1998 Elsevie r Science Ltd. All rights reserved.