60
(^0 0) r(
.
DAIRY CHEMISTRY AND BIOCHEMISTRY
'Tolerant'
50 fi lactiise perorally
'lntolerdnt'
0 20 4 0 60 80 100
Minutes
Figure 2.34 Examples of the 'lactose intolerance' test.
Enzyme
Enzyme
filter
MI ver
Liquid milk packaging
Further processing 1-1
Figure 2.35 (a) Scheme for manufacture of low-lactose milk using a 'high' level of soluble
8-galactosidase. (b) Scheme for the manufacture of low-lactose milk by addition of a low level
of soluble P-galactosidase to UHT-sterilized milk. (Redrawn from Mahoney, 1997.)
0 treatment with exogenous P-galactosidase, either domestically by the
consumer or the dairy factory, using free or immobilized enzyme; several
protocols for treatment have been developed (Figure 2.35).
Lactose-hydrolysed milks are technologically successful and commer-
cially available but have not led to large increases in the consumption of