functionality of whey protein isolates and hydrolyzed whey proteins

Abstract

The aim of this study was to determine functional properties: solubility, dispersibility, viscosity, emulsifiying, foaming and rheological properties of hydrolyzed whey protein (HWP) and whey protein isolate (WPI). Particle size analysis and specific area of HWP and WPI were performed by «Mie – theory» of «light scatering» using «Malvern Mastersizer X». The results of this analysis have shown that HWP had higher particle size and specific area than WPI.By examing functional properties, it has been established that HWP has higher solubility, dispersibility, emulsifiying properties as well as foam stability (FSI and MFS) compared to WPI. Rheological properties of protein suspensions were determined in 10, 15, and 18 % suspension of proteins (HWP and WPI) by rotational viscosimeter, Brookfiel DV-III at 25°C. Apparent viscosity at 200 s-1 was calculated, using Newtonian law. On the basis of measured shear rate and shear stress, using least squere method, rheological parameters, flow behavior indeks (n) and consistency coefficient (k) were determined according to the Ostwald de Waele model. The highest viscosity was observed in 18% HWP model system while the least viscosity was found in a model system prepared with 10% WPI.