Fjölrit RALA - 22.03.1979, Side 12

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A mixture which has been packaged is svmbolized with a
plus (+)■ The first time it is packaped is indicated bv one
star, the second time by tv’Or, etc.
C. CHOICE OF MATERIALS AND DESCRIPTION OF STUDY
1. Processing Techniques and Raw Materials:
The technique used to produce concentrated whey from the
original skyr whev is called reverse osmosis. The whev is
pressed through dense membranes which the water passes through,
while larger molecules are prevented from doing so. This causes
the osmotic pressure of the liquid to increase and considerable
pressure may be required to overcome it and press the water
through the membrane.
It is possible to control the pore size of the membranes
and thus affect the size of the molecules which will pass
through them. In addition, it is possible to concentrate
the solution to varying degrees and thus produce concentrated
whey containing different amounts of dry matter. For example,
25% concentrated whey is produced by removing 25% of the water.
A 25% filtrate is the liquid which passes through the membrane
when 25% concentrated whey is produced.
Fruit whey is made by mixing together concentrated whev
and fruit juices. The plan is to use only pure pasteurized
juices in this production.
The production technique which has been used at the M.B.F.
is the following:
(1) The whey is separated from the skyr, centrifuged
and pasteurized.
(2) It is filtered by reverse osmosis and part of
the liquid removed.
(3) The concentrated whey is stored for a while or
centrifuged in order to remove as much of the
solid matter (skyr) as possible before mixing.
(4) The whey and fruit juice are mixed together in
the appropriate ratios.
(5) The mixture is heated, i.e. either pasteurized
or receives a short high-temperature treatment.