Chemical physics of whey protein isolate in the presence of mucin: From macromolecular interactions to functionality.

Chemical physics of whey protein isolate in the presence of mucin: From macromolecular interactions to functionality. Int J Biol Macromol. 2019 Dec 10;: Authors: Ahmad M, Ritzoulis C, Pan W, Chen J Abstract Oral processing, textural perception and functionality of colloidal foods are strongly influenced by the interactions between the salivary mucins and the food proteins. This work studies the physico-chemical aspects of mixtures of a typical food protein, whey protein isolate (WPI) and mucin. Phase separations result from aggregation between the two components at pH 7 and at pH 3. ζ-potential and fluorimetry data show that electrostatics contribute to entropically-driven interactions at pH 3, while at pH 7, two different non-electrostatic interactions, an entropically-driven and an enthalpically-driven one lead to aggregation and phase separation. Substitution of WPI with increasing mucin concentrations at pH 7 results in a marked increase of the shear viscosity in comparison with pH 3. Mucin enhances the extensional viscosity in a similar fashion, e.g. the incorporation of mucin into a WPI system at 6:4 ratio increases the extensional viscosity ≥ 3-fold (0.27-0.85 Pa s) and ≥2-fold (0.38-0.89 Pa s) at pH 3 and pH 7, respectively. These results indicate a notable increase of the extensional over shear viscosity ratio (Trouton's ratio). The above highlight the effect of the molecular-level interactio...
Source: International Journal of Biological Macromolecules - Category: Biochemistry Authors: Tags: Int J Biol Macromol Source Type: research