C. Holt et Ds. Horne, THE HAIRY CASEIN MICELLE - EVOLUTION OF THE CONCEPT AND ITS IMPLICATIONS FOR DAIRY-TECHNOLOGY, Netherlands milk and dairy journal, 50(2), 1996, pp. 85-111
Physico-chemical measurements on the native bovine casein micelle have
indicated that the outermost region comprises a diffuse layer of flex
ible hydrophilic polypeptide chains from the C-terminal half of kappa-
casein. By analogy with the steric stabilization theory devised for hy
drophobic colloids, 'the hairy layer' presents a virtually impregnable
barrier against aggregation unless the hairs are removed enzymically
(e. g. renneting) or if the solvent quality is reduced (e. g. ethanol
stability). In acid gelation, the disruption of the core structure of
the casein micelles caused by the dissolution of the colloidal calcium
phosphate is undoubtedly implicated in the loss of stability, rather
than gelation being caused by some simple neutralisation of charges at
the iso-electric point. Tn the other technologically important proces
ses such as acid gelation and heat coagulation of milk, the mechanism
by which the steric barrier is breached, bridged, or otherwise rendere
d ineffective is largely unknown.