Page 39 - Handbook on Food Fortification in Kenya

PREMIX ADDITION MECHANISMS

There are general principles by which the feeders control the
amount of premix addition to the maize flour or wheat flour:

Gravimetric Addition: - Gravimetric addition involves
measuring the weight of material to be added on a
continuous basis. All feeders can be made into “loss in
weight” feeders. The rate at which this weight drops
with time indicates the true addition rate.

Volumetric Addition: - Volumetric addition is similar
to using a cup or spoon to measure out ingredients.
This is based on the principle that the volume of the
material being added has a set weight when handled in
a uniform manner. The minimum error of measurement
for volumetric addition is +/±2%.

There are two premix addition systems used for maize flour and
wheat flour fortification; continuous and batch.

PREMIX ADDITION SYSTEMS - CONTINUOUS

In continuous systems the grains just before milling. There
premix is metered continuously are two continuous processes,
during the milling process either micro-feeders and dosifiers.
into the flour stream or into the

39 | FOOD FORTIFICATION HANDBOOK