DESCRIPTION
Sweetened condensed milk (SCM)
Figure 16.4 below shows a process line for sweetened condensed milk
manufactured from fresh milk. Before evaporation, the fat and solids-non-fat
values of the milk have been standardised to
predetermined. The milk has also been heat treated to destroy micro-organisms
and enzymes which could cause problems and to stabilise
the protein complex. Heat treatment is also important to the development of
product viscosity during storage, and is particularly important in the case of
sweetened condensed milk. The addition of sugar is a key step in the
manufacture of sweetened condensed milk, as the shelf life of the product
depends on its osmotic pressure being sufficiently high. A sugar content of at
least 62.5% in the aqueous phase is required. Two methods are used for addition
of sugar:
•Addition of dry sugar before heat treatment
•Addition of sugar syrup in the evaporator
The stage at which the sugar is added affects the viscosity of the end product.
The evaporator is usually of the multistage falling-film type. When sugar is
added in the evaporator, the syrup is drawn into the evaporator and mixed with
the milk at the half-way stage of the process. Evaporation then continues until
the required dry matter content has been reached. The dry matter content is
checked continuously by determining the density of the concentrate.
Sweetened condensed milk must be cooled after evaporation. This is the most
critical and important stage in the whole process. The water in the condensed
milk can only hold half the quantity of lactose in solution. The remaining half
will therefore be precipitated in the form of crystals. If the surplus lactose
is allowed to precipitate freely, the sugar crystals will be large and the
product will be gritty and unsuitable for many applications. It is consequently
preferable to control the crystallisation of lactose
so that very small crystals are obtained. The required crystallisation
is accomplished by cooling the mixture rapidly under vigorous agitation,
without air being entrapped. The cooled condensed milk is pumped to a storage
tank where it is kept until the following day to allow the crystallisation
process to be completed.
Sweetened condensed milk should be yellowish in colour
and have the appearance of mayonnaise. Traditionally, it is packed in cans,
which in this case must be cleaned and sterilised
before filling as no sterilisation takes place after
canning. Nowadays it is also possible to pack sweetened condensed milk in
aseptic paperboard packages. The product is also packed in big barrels, holding
about 300kg, for supply to large-scale users.
BENEFIT
1.Opportunity to realize products with
customized recipes.
2.Opportunity to produce more than one product
with the same processing line.
3.Wide customization of the final product.
4.Maximum yield, minimum production waste.
5.Highest energy savings thanks to the most advanced technologies.
6.Complete line supervision system through monitoring of every process phase.
7.Recording, visualization and printing of all daily production data.
CONSTRUCTION FEATURES
Working
capacity
from 5 tons/d up to 100 tons/d
Products - Sweetened
condensed milk
- Evaporated milk without sugar
- Condensed milk in varied package:
Can,
aseptic paperboard packages,
big
barriers; etc.