Effects of tannin addition on physical properties of whey protein-containing gelatin gels

Abstract

  In order to identify applications for the effective reuse of whey protein, we have been examining the usefulness of whey protein isolate (WPI) in model gelatin gels. In this report, we analyzed the effects of tannin on the properties of the model jelly, as tea powder or fruit juice, which are often added to jelly, may contain tannin.
  Addition of tannin into the clear gelatin gel produced an opaque and soft jelly. In contrast, addition of tannin into WPI-containing gels had little effect on their transparency, but increased viscosity. On HPLC analysis, greater polymerization was seen in the WPI-containing with tannin added at 100 mg%. Under these conditions, gels showed the highest rupture properties among the model jellies. The hot wire method also showed a reduction in gelation time and an elevation in gelation temperature in samples containing higher tannin levels.
  Addition of WPI thus prevents the deterioration of gelatin gels, even at high tannin levels. This may provide a useful application for the use of whey protein.