The low level of -lg denatur-
ation in Milk72, compared to other UHT treatments, and the low
concentration of -lg and -casein in the formed gel suggests that
the formation and release of a -lactoglobulin- -casein complex
was not the main cause of gelation. Most studies on PL in milk have
focussed on -casein as an indicator of proteolysis. In relation to age
gelation, it is important to consider both hydrolysis of S- and of -
caseins. A part of -casein has been shown to be highly mobile in
the caseinmicelle (Dalgleish, 2011) and hydrolysis of -casein could
be responsible for the reported increase in hydrophobicity
(Aroonkamonsri, 1996), while the hydrolysis of S1-casein could be
responsible for loss of micellar integrity, which in combination
could lead to the age gelation of milk. Manji and Kakuda (1988)
suggested gelation to be a two-stage process, which requires
some degree of proteolysis before time-dependent physical-chemical changes lead to the gelation of milk. This could be