Chemistry Reference
In-Depth Information
from cows' milk with lactose to produce the first infant formulae in 1867
(Anonymous, 2007a). This has been one of the major uses of lactose since.
The period from 2004 to 2007 has seen a dramatic increase in the price
of lactose from around US$440 to a high of US$2000/tonne and decreasing
later to US$1100/tonne (Affertsholt-Allen, 2008). This price increase is likely
to see a swing in the uses of lactose as it moves from being a low-cost energy
source to a relatively expensive source. For comparison, the cost of sucrose in
2007 fluctuated around US$175/tonne. The reason for the increase in the
price of lactose can be traced back to the market forces of supply and demand.
In this case, the demand has been stimulated by the standardisation of milk
powders. In countries, such as New Zealand, where the lactation of the
national herd is largely synchronised to match seasonal grass availability,
the protein content of milk powder fluctuates markedly throughout the year.
The addition of lactose to standardise protein level is now permitted, pro-
vided that the adjustment does not alter the whey protein to casein ratio of the
milk being adjusted. Standardisation of milk for protein as well as fat levels is
being introduced within Europe also. The result has been a great demand for
lactose causing a worldwide shortage. This effectively means that lactose has
an inherent value approaching that of skim milk powder, rather than being a
substance that has to be disposed of so that it does not cause problems in the
environment due to its high biological oxygen demand (BOD). The price of
lactose is likely to fall again when the supply matches the increased demand,
as has happened by March 2008. At any point in history, there are usually
multiple lactose production projects waiting to be considered by cheese-
producing companies.
Lactose is limited as a food ingredient in that many people around the
world are lactose intolerant (hypolactasia), meaning that their body does not
produce lactase, the enzyme which hydrolyses lactose in the gut into glucose
and galactose, which can be absorbed. Consequently, the lactose passes into
the lower intestine where it provides a ready source of energy for anaerobic
bacteria. These bacteria produce gas as a by-product and this can cause
cramping, flatulence and perhaps diarrhoea.
In the pharmaceutical industry, lactose is used as the main carrier
(about 70% of tablets contain lactose) for drugs because it is not sweet, it is
safe, it is available in highly refined form and it makes good quality tablets. It
has found uses in the industry in a number of different product forms. The
main one is
-lactose monohydrate which can be used as a tablet excipient,
but it can also be finely milled to produce inhaler-grade lactose. Here, the
lactose acts as a carrier for micronised drug materials to reach the lungs. Both
anhydrous lactose (
-lactose) and spray-dried lactose are also used to make
tablets. The form of the lactose is critical for consistent tabletting formula-
tions, and much emphasis is placed on the reproducibility between batches of
