Abstract:
It is reported in the literature that when cleaning whey
protein concentrate fouling layers or gels with highly
concentrated NaOH solutions the cleaning rate is very low.
This phenomenon is particularly evident at pH values above
13.5 and at temperatures below 50°C. Experiments have
been performed on whey gels at the Universities of
Auckland and Cambridge to elucidate the mechanisms
involved in those conditions, as well as for lower pH values.
The results suggest that at pH < 13, the dissolution rate is
controlled by the β-elimination of the intermolecular
disulfide bonds present in the WPC gels. At pH > 13, the
NaOH in the gel is suggested to induce new intermolecular
crosslinks that make the gels more alkali-resistant.
Dissolution experiments with caustic-induced gels show
that the presence of NaOH in whey gels can greatly enhance
their resistance to alkali.
