Dairy products and milk-based food ingredients - Natural Food Additives, Ingredients and Flavourings - page 433

Coffee whiteners
The production of coffee whiteners, or non-dairy creamers, is a little more
complex, partly because of the ingredients and additives used in the formulation,
and because of the aggressive environment in which whiteners are required to
perform. Coffee whiteners are based on glucose solids or maltodextrin (usually
with a dextrose equivalent (DE) of 25-30%), hydrogenated vegetable fats with
melting points in the range 35-40°C (higher melting points would give a greasy
mouthfeel), sodium caseinate, emulsifi ers (diglycerides (E471) and polyphosphates
(E450)), fl avour, colour and acidity regulators (citrates (E331/E332)). A stable
emulsion is produced during homogenisation, mainly by the interaction of sodium
caseinate and emulsifi ers at the interface between fat globule surfaces and the
surrounding aqueous phase. Acidity regulators prevent the destabilisation of the
emulsion when coffee whitener is added to hot acidic coffee and the release of
free fat as oil droplets on the coffee surface, which would be seen as a defect.
During manufacture, fat-fi lled milk powders must be processed suitably to
allow fat to cool and crystallise before packaging. The fat in concentrates fed to a
spray dryer will be liquid (a necessity if homogenisation is to be effective) at the
point of atomisation and will remain so until the powder cools. If the powder is
packaged without cooling, heat energy will initially be lost, but as the fat
crystallises the temperature will rise due to the release of latent heat of
crystallisation. This can disrupt the emulsion and bind powder particles as a solid
mass. Milk powders that contain fat are often spray-dried using a two-stage or
multi-stage process. In a two-stage process most of the water in the feed
concentrate is removed in the main drying chamber. The powder passes from the
main chamber to a series of external vibro-fl uidised beds (usually two or three),
which permit the agglomeration of the powder particles and the removal of
remaining water, as well as the cooling and crystallisation of fat. The powder is
then suitable for packaging. Agglomerated milk powders can be easier to handle
in food manufacture as they have a reduced tendency to create dust and
agglomeration enhances both cold and hot water dispersability. The cold water
dispersability of milk powders can be improved by spraying a layer of soya
lecithin over the surface of powder particles following fi rst stage drying to
improve wetting.

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Whey powders
Whey powders are used as food ingredients in many applications, from chocolate
and sugar confectionery, bakery, soups and sauces, baby foods, etc., with different
types used in different foodstuffs. The standard whey powder product is anhydrous
whey powder made from sweet whey, the by-product of cheesemaking where
acidifi cation is not excessive and pH is 6.3-6.5 (e.g. emmental and gruyere
production). Sweet whey is evaporated to 60-70% solids to supersaturate lactose
and fl ash cooled to 30°C, at which point α -lactose crystals form. Further cooling
to 15°C causes the mutarotation of β -lactose to α -lactose and some 75-80% of the
lactose crystallises. The whey concentrate can then be spray-dried. Some of the
lactose (up to 20%) remains in the amorphous state, which is hygroscopic. Whey