Structure formation in protein-polysaccharide mixtures upon pressure treatment

In recent years high hydrostatic pressure has been evaluated as a food proc essing alternative to classical heat treatment. High hydrostatic pressure c an cause changes in protein conformation leading to denaturation, aggregati on and gelification of proteins. In the presence of polysaccharides, e.g. h igh methoxy pectin, denaturation of whey proteins leads to phase separation . Microscopy and rheology were used to describe the behaviour of incompatib le mixtures of whey proteins and high methoxy apple pectin upon combined hi gh pressure and temperature treatment. Room temperature and a pressure grea ter than or equal to 400 MPa, or heating the proteins above their denaturat ion temperature (80 degrees C) at ambient pressure (holding time 10 minutes ), resulted in the formation of polydispersed gelified microparticles. If h igh pressure was combined with higher temperatures (greater than or equal t o 40 degrees C) pectin and whey protein separated into two bicontinuous pha ses.