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Influence of hydrocolloids addition and high pressure treatments on the rheological properties of whey protein model solutions

The effect of hydrocolloids addition (in amount of 0.5 %) on the rheological properties of whey protein concentrate (WPC) and whey protein isolate (WPI) model solutions were studied. Hydrocolloids used were carboxymethylcellulose (CMC) and guar gum. 10 % WPC as well as WPI solutions were pre-treated with high pressure (300 and 600 MPa/ 5 minutes) and the viscosity measurements were done at 20 0C using rotational rheometer. The results obtained have shown that hydrocolloids addition caused an increase in viscosity of model solutions prepared with both, high pressured and native whey proteins. The apparent viscosity increase were more pronounced when guar gum was added to WPC (increase of 12.5% and 25.4%, for 300 and 600 MPa, respectively), compared with addition of the same hydrocolloid to WPI model solution (increase of 10% and 22%, respectively). When CMC was added to high-pressured whey proteins, the apparent viscosity decreased with intensifying of the high pressure pre-treatment. For WPC the decrease from 18 mPas (300 MPa) to 15 mPas (600 MPa) were obtained, while for WPI model solutions viscosity varied in range of 16 mPas (600 MPa) to 19 mPas (300 MPa). The all samples viscosity profiles obeyed the power law model most closely (r>0.998). Model solution prepared with guar gum exhibited pseudoplastic behaviour, while model solutions with CMC had dilatant properties.

High pressure; hydrocolloids; rheological properties; whey protein isolate; whey protein concentrate

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