Influence of the concentration of locust bean gum on the gelling ability of whey peptic hydrolysates

Abstract

The gelling ability of whey proteins can be changed by limited hydrolysis and by the presence of other components such as polysaccharides; depending on the environmental conditions it can either be improved or impaired. In this work the effect of LBG on the heat-set gelation of aqueous whey protein hydrolysates (10 % w/w) from pepsin was assessed at pH 7.0 by small deformation rheology. Whey protein concentrate (WPC) and hydrolysates with a degree of hydrolysis (DH) of 1.5, 2.5 and 4.9 % were used. Different LBG concentrations were tested: 0, 0.1, 0.3 and 0.55 % (w/w). The behaviour of gels from whey proteins or whey protein hydrolysates towards the presence of LBG was very similar. The evolution of the viscous and storage moduli followed the general behaviour reported for many biopolymer heat-set gelation processes including whey proteins gelation. The increase in the LBG concentration generally led to a decrease in the gel strength. However, for whey proteins a small amount of LBG (0.1 %) leads to a big enhancement in the gel strength probably due to an increase in the protein concentration of the protein enriched phase. Further increases in the LBG concentration led to a decrease in the gel strength. The gelation process is very sensible to environmental conditions and to processing and often leads to rather coarse data. The factorial planning used allowed validating conclusions using fewer experiments than those needed if no planning had been used, while still getting statistical significance out of the results. However, as many factors are involved, the modelling of the process was not straightforward.