Agriculture Reference
In-Depth Information
with water is not an issue. As with direct heat transfer processing it is usual to
stabilise the whey proteins by preheating before sterilisation.
Whichever method is used to process UHT milk, the sterilised product must be
aseptically packaged. Various aseptic milk packaging systems are used throughout
the world including, for example, the system developed by Tetra Pak. This is
based on the concept of form-fi ll-seal packaging and the use of laminated
paperboard packaging materials.
17.3.2 Liquid milk products: fl avoured milk
Flavoured milks contribute to the milk-based beverage market by providing
products targeted mainly at children and young people. These products offer an
alternative to carbonated beverages and greater nutritional value. As with most
dairy products the principal ingredient in fl avoured milks is milk. A fl avoured
milk may be made from whole milk, or have a modifi ed fat content (e.g. based on
skimmed or semi-skimmed milk). Its fl avour and colour will determine through
formulation a given product image and the consumer perceptions the image is
intended to evoke. For example, a strawberry-fl avoured milk based on a blend of
skimmed milk (76% of product) and whole milk (18% of product) can be
formulated to give the impression of strawberries by use of a natural strawberry
fl avour and natural beetroot red colour. Natural colourings are increasingly used
by food manufacturers, often at the request of supermarket buyers. Alternative
fl avourings such as banana and chocolate are popular with consumers. The former
may be achieved using β -carotene to create yellow, while reduced fat cocoa
powder will give chocolate brown and contribute chocolate fl avour.
Other ingredients and additives often used in fl avoured milks are sugar, which
provides sweetness, modifi ed maize starch to increase viscosity and contribute
benefi cially to the perception of texture and mouthfeel, and stabilisers, such as
carrageenans, guar gum and xanthan gum. Carrageenans are polysaccharide
extracts of red seaweed (e.g. Chondrus crispus ) found off the coast of Ireland and
also other species. The polysaccharide in carrageenans comprises repeating
galactose units joined by alternating α -1-3 and β -1-4 glycosidic linkages. Three
forms of carrageenan are commonly used in dairy products:
￿ ￿ ￿ ￿ ￿
Iota ( ι ) form - produces soft gels in the presence of calcium
Kappa ( κ ) form - reacts with milk proteins and potassium ions, producing
strong gels
Lambda ( λ ) form - does not gel but increases product viscosity and is used to
thicken.
Carrageenans are classifi ed under the European Union's additive numbering
system as E407.
Like carrageenans, guar gum (E412) is used to increase viscosity and thicken
some dairy products. Guar gum is a galactommanan polysaccharide comprised of
a chain of mannose units (1-4 linked β - D -mannopyranose) with galactose side
groups (1-6 linked α - D -galactopyranose). Mannose and galactose are present in
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