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Overview
Sweet and
condensed milk (or sweetened condensed milk) is produced when
sweetened milk is condensed to half its volume by removing part of
the moisture in a vacuum evaporator. In order to ensure its
preservation, sugar is added either at the beginning or during the
concentration process. The high content of sugar in the resulting
product increases the osmotic pressure to such a level that most of
the microorganisms are destroyed. Thus, no sterilization takes place
after canning or packaging.
Sweet and
condensed milk has a shelf life of approximately 12 months provided
storage conditions are cool and dry. It is used largely as the most
popular source of milk solids for the sugar confectionery industry.
Composition
Sweet and
condensed milk is whole milk, partly skimmed milk or skimmed milk
from which approximately 50 percent of the moisture has been removed.
It must contain no less than 28 percent milk solids and 8 percent
milk fat if whole milk was the raw material. The condensed skimmed
milk must not contain more than 0.3 percent fat. It must contain
added sugar, dextrose, glucose, glucose solids or lactose in any
combination. Vitamin D may be added, but the addition of vitamin A is mandatory.
Typical
composition for
Whole Sweet
and Condensed Milk
|
Sugar (sucrose) |
41.0 - 45 % |
|
Moisture |
31.0% |
|
Milk sugar (lactose) |
10.5% |
|
Fat |
8.0% |
|
Proteins |
6.0 - 8.0% |
|
Ash |
1.5% |
The
microbiological quality of the raw material for condensed milk is
basically the same as required in the manufacture of ordinary milk
products. The sugar concentration in the water phase must not be less
than 62.5 percent or more than 64.5 percent. This saturated
environment acts as a preservative so bacterial and mold growth can
be controlled. At the latter level, the sugar solution reaches its
saturation point and some sugar will then crystallize freely. If the
crystals are too large, they impart an undesirable sandy texture.
Microcrystalline lactose is therefore added to act as a seed,
controlling the dimension of lactose crystals in such a small size
that they cannot settle or be detected by taste.
Characteristics
Appearance:
Sweet and condensed milk is yellowish in colour and has a creamy and
viscous appearance.
Storage: Sweet
and condensed milk can normally be stored for about three months at a
temperature of 0-15.C. Humidity of storage areas should be controlled
below 50 percent to avoid the corrosion of the metal can. Inversion
of the cans is a practical way to minimize the separation of fat and
other constituents and to prevent the product from forming a surface
cream line during extended storage. Prolonged storage (depending on
storage conditions) may cause spoilage by sugar-fermenting yeasts,
defects such as age thinning and age thickening. Swollen or blown
cans indicate fermentation and spoilage and should not be used.
Various uses
Sweet and
condensed milks are used by the confectionery industry typically in
caramel, toffee and fudge manufacture as well as in various desserts,
ice cream, sauces, cake icings and bakery.
Functional properties
Several
desirable properties are achieved by incorporating condensed milk in
product formulations. In fact, it is like adding whole milk in a
sweet concentrated form. Consequently, the added sugars and the major
components of milk, i.e. milk fat, proteins and lactose, will provide
the following functional benefits:
|
Functional Property |
Mode of Action |
|
Water binding/ Hydration |
The water
retention capacity of milk proteins and lactose produces better
texture in food products and helps to maintain their keeping
qualities and shelf life. |
|
Browning/Colour |
Lactose
and proteins react with other sugars during baking, boiling or
cooking. The Maillard browning and caramelization of the sugars in
condensed milk is of obvious importance for colour and flavour development. |
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Emulsification |
Milk
proteins act at the oil/water interfaces to form and stabilize fat
emulsions. They contribute significantly to the emulsification of
fats and give body, texture and mouthfeel to the final product. |
|
Gelling/Thickening
|
Milk
proteins and lactose show high water holding capacity that influences
viscosity through thickening and gelling. |
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Flavouring/Creaming
|
Milk fat
possesses a unique flavour which is widely exploited in the
manufacture of products known for their richness and quality in taste
and texture, which cannot be achieved with other fats. |
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