Chemistry Reference
In-Depth Information
V.2.3.
Reduction of Lactose in Milk by Chromatographic Methods
Chromatography processes use charged resins to separate proteins and
other charged ions in milk from lactose. The proteins and charged ions bind
to oppositely charged resin while lactose does not bind and passes directly
through the system. Milk from which lactose is to be separated is passed
through a column containing cation exchange resin (Harju, 1989). The cation
exchange resin is balanced in such a way that an ionic balance is obtained with
milk. After balancing the resin, skim milk or concentrated milk is passed
through the bed. The lactose fraction is eluted at the bottom of the bed, while
the protein and mineral fraction is eluted with the help of water in another
stream. The main disadvantages of chromatographic processes are that they
are time-consuming and involve expensive equipment.
V.3.
Conclusion
Awareness about lactose intolerance has considerably increased in past dec-
ade, so has the market for lactose-free milks. Conversion of lactose in ordinary
milk by treatment of
-galctosidase results in high levels of sweetness which
may be unacceptable to many consumers. Reducing lactose in fluid milks by
chromatographic or membrane technology followed by conversion of residual
lactose by
-galctosidase to its constituent monosaccharides has helped
manufacturers to provide a fluid milk with a genuine taste of milk; however,
the products are expensive and there are some concerns about labeling the
products as ''milk''. The chromatographic method of lactose removal is
too expensive and has not found widespread use in industry. Although removal
of lactose from fluid milks by membrane technology increases the price by
about 20-30%, it is still a method of choice for most of the manufacturers to
provide a lactose-free milk with a genuine taste of milk. This has helped many
consumers to again drink milk who had otherwise stopped drinking milk.
References
Dunker, J., McCloskey, M. and Gomez, T. 2007. Dairy compositions and method of making. US
patent US 7169428B2.
Fennema, O.R. 1996. Food Chemistry, 3rd edn, Marcel Dekker, Inc. New York.
Flatz, G. 1987. Genetics of lactose digestion in humans. Adv. Hum. Gen. 16, 1-77.
Grandison, A.S., Glover, F.A. 1997. Membrane processing of milk. In Modern Dairy Technology,
2nd edn., Vol. 1 (R.K. Robinson, ed.), pp. 273-311, Chapman & Hall, London.
Harju, Y. 1989. Process for the specific separation of lactose from milk. US patent 4820348.
