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Rheological properties of hydrocolloids and high pressure treated whey proteins model solutions

The effect of two hydrocolloids addition: carboxymethylcellulose (CMC) and guar gum on the rheological properties of whey protein concentrate (WPC) and whey protein isolate (WPI) model solutions, were studied. Before hydrocolloids addition (0.5 w/w) WPC and WPI were pre-treated with high pressure (300 and 600 MPa, holding time of 5 minutes). The viscosity measurements were done using rotational rheometer at temperature 20 0C. The obtained results have shown that hydrocolloids addition caused increase in viscosity of model solutions prepared with both high pressure treated and native whey proteins. Intensity of applied high pressure influenced the viscosity change. 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 pressure treated whey proteins, the apparent viscosity decreased with intensifying of the high pressure pre-treatment. For WPC the decrease from 18 mPa s (300 MPa) to 15 mPa s (600 MPa) were obtained, while for WPI model solutions viscosity were in range of 16 mPa s (600 MPa) to 19 mPa s (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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