Using enzymes to improve whey protein gelation.

Researchers at the Royal Veterinary and Agricultural University (Department of Dairy and Food Science, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark) have utilized enzymes to optimize the gelation properties of whey proteins. Data on intrinsic viscosity, measured by capillary viscometry, have yielded insight into changes in molecular weight during the initial stages of hydrolysis. Investigators tracked the gel point and subsequent gelation. Early tests show that pH strongly influences the thermal gelation process after initial hydrolysis using an enzyme isolated from Bacillus licheniformis.

At pH 3, the whey protein isolate (WPI) gels appear finely-stranded in terms of structure. Gelation takes place in a manner similar to thermal gelation without hydrolysis. At pH 5 and pH 7, thermal gelation at 90 C creates aggregated gels, which are similar to gels formed by hydrolysis at 40 C, without the use of heat.

Hydrolysis at 40 C before gelation has no effect on the final gels. It appears that the hydrolysis that occurs during heating is the decisive factor. Hydrolysis with the enzyme at greater than 40 C exhibits optimum gelation, especially at 70 C to 75 C. At this point, rapid gelation leads to strong, white and translucent gels.

Other research is focusing on gaining a basic understanding of the behavior of whey proteins. The idea is to improve recovery methods so as to enhance or retain functional properties relevant to the use of the proteins as food ingredients. Investigators are applying analytical and physical techniques along with recent theoretical advances to comprehensively study the aggregation, denaturation and gelation of whey proteins, principally beta-lactoglobulin. They intend to interpret the results using the growing body of information on molecular structure.

Investigators also intend to develop models of whey protein gels using polymer science. They want to relate molecular structure to aggregate and gel formation and to the viscoelastic properties of the gels. Further information. On gelation: Jeanette Otte; phone: [phone]; fax: + 45 35 28 31 90; email: [e-mail]. On functional properties: Carl Holt, M.R.G., Hannah Research Institute, Ayr, KA6 5BL, U.K.; phone: [phone]; fax: [phone]; email: [e-mail].