Does dextran molecular weight affect the mechanical properties of whey protein/dextran conjugate gels?

Abstract

Maillard reaction (MR) is one of the most studied methods to improve the functional properties of<br />proteins so as to turn them into better food ingredients. The mechanical properties of whey protein<br />isolate (WPI)/dextran (DX) mixed and conjugate (obtained by MR) gels were investigated. Dextrans with different molecular weight (MW: 6, 40 and 70 kDa) and various concentrations (3.6, 7.2 and 10.8% w/w) were studied. WPI/DX conjugates were obtained by controlled dry heating (60 C and 0.63 aw for 5 days). A decrease in the content of free amino group and an increase in colour parameters of WPI/DX conjugate systems revealed that MR had a higher progress for the lowest DX molecular weight and for the highest DX concentration. The mechanical properties (at the fracture point) of WPI/DX mixed gels were affected by DX concentration. On the other hand, unlike mixed gels, WPI/DX conjugate gels showed no fracture under the test conditions (80% deformation).