A comparative study of the gelation properties of whey protein concentrate and whey protein isolate

Abstract

The present paper describes a comparative study of the gelation properties of whey protein concentrate (WPC) and whey protein isolate (WPI). Penetration measurements as well as rheological studies revealed that the strength of heat-induced gels prepared with WPI was higher than with WPC. In addition, gels with WPI were clearly more elastic than WPC gels. The storage modulus of WPI and the storage and loss moduli of WPC increased with increasing frequency, while the loss modulus of WPI revealed no clear dependence on the frequency, resulting in a greater decrease in the loss angle of WPI with increasing frequency. The superior gelation properties of WPI were mainly due to the higher -lactoglobulin content as well as to lower fat, lactose and phospholipid contents. However, in this paper it is also discussed whether the low contents of glycomacropeptide, non-protein-nitrogen and proteose peptone in WPI may partly explain the superior gelation properties of these protein products. WPI were more sensible to an increase in the ionic strength (0.1-0.3% NaCl) than WPC, resulting in clearly stronger gels with WPI than with WPC. In the pH ranges of 2-3 and 7-8, elastic and translucent gels could be prepared using WPI, while their gel-forming properties were low between pH 4 and 5. The strongest gels, turbid, but still elastic, were prepared with WPI at pH 6. whey protein concentrate / whey protein isolate / gelation properties - (WPC) (WPI) WPI WPC