Chemistry Reference
In-Depth Information
have patented a combination of membrane technology for manufacturing
lactose-free milks (Dunker et al., 2007; Shakeel-Ur-Rehman et al.,2007).The
product is 100% lactose free, has 75% more protein and 65% less sugar than
cows' milk and contains 4 g of hydrolyzed lactose per serving (240 mL).
Recently, patented processes (Tossavainen and Sahlsten, 2003) have been
developed to reduce the lactose in milk to less than 3% and the residual
lactose is hydrolyzed by
-
D
-galactosidase to glucose and galactose in order
to get a sweetness similar to normal milk. These milks are becoming popular
in Europe and America. The reduction of lactose by membrane technologies
or chromatographic processes has resulted in labeling issues with regulatory
authorities. Milk in which lactose is reduced by filtration technology to less
than 2.0% results in a lower cryoscopic value than that of ordinary whole
milk and, even after lactose hydrolysis, the cryoscopy value is lower than
regular cows' milk. The health authorities consider the reduction in cryoscopic
values as adulteration in milk. The popularity of foods with a low glycemic
value has also necessitated the manufacture of milk products with reduced
milk sugar. In Europe, Valio has developed a range of lactose-free and lactose-
reduced dairy beverages using membrane technologies. The products, in which
the level of lactose in milk is reduced by membrane technologies, may be
suitable for diabetic people.
The use of UF concentrates in the manufacture of sweetened condensed
milk has been found to avoid sandiness (Sepra Alverez et al., 1979) as the
condensed milk is low in lactose.
Delactosed high-protein milk powders have been manufactured by use
of ultrafiltration and diafiltration processes (Mistry and Hasan, 1991). The
delactosed milk protein powder has potential in the manufacture of new
products like low-fat yoghurts.
Milk protein concentrate (MPC) is a relatively new dairy ingredient
produced by ultrafiltration of skim milk. The proportion of protein in the
MPC depends on the removal of lactose by ultrafiltration/microfiltration
and diafiltration. The proportion of caseins and whey proteins in the MPC
is similar to that in the original milk but MPC contains little lactose. Due to
the high casein content and low lactose content in MPC, it is an attractive
ingredient for enriching the casein content of cheese milk. MPC80 contains
6.5% lactose compared to 51% in non-fat dry milk (NFDM); the use of
MPC instead of NFDM in cheese milk results in a low residual lactose level
in cheese and reduces the chances of undesirable fermentation during
ripening (Shakeel-Ur-Rehman et al., 2003). The ratio of protein to lactose
is higher in MPC than in condensed milk or NFDM. The use of MPC to
standardize milk for Pizza cheese manufacture results in an increased yield
and less browning.
