Universidade do Minho. Departamento de Engenharia Biológica (DEB)
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