The pH-dependent interactions in Basil seed gum/whey protein isolate mixed dispersions: A rheology and phase behavior study

In this study, the effect of pH (2.5-7) and Basil seed gum (BSG) concentration (0-0.5) on the phase behavior and rheological properties of BSG/WPI mixed dispersions have been investigated. Phase behavior of the mixtures were dependent on both pH and BSG concentration so that all mixtures containing 0.5% w/w BSG were stable at pH values of 2.5, 4.5, 6 and 7. At 3pH4 no mixures were stable. Indivitual whey protein dispersions (6% w/w) and the mixtures containig 6% w/w WPI and 0.5% w/w BSG showed Newtonian and shear-thining bahaviour, respectively. The best model to fit the flow behavior of the mixtures at pHs 2.5, 6 and 7 was Herschel-Bulkley while at pH 4.5 Carreau model was the best model. The highest viscosity was indicated at pH 4.5. Frequency sweep oscillatory measurements showed that the highest G’ value was for WPI/BSG mixtures at pH 4.5 while the lowest value was related to the mixtures at pH 2.5. Results showed that at the pHs below, above and near the pI of WPI and pKa of BSG can influence the stability and rheological behaviour of BSG/WPI mixed systems

کلیدواژه ها:

Basil seed gum/Whey protein isolate mixed dispersion ، rheology ، phase behavior ، pH