of powders’ properties, such as flowability, wettability, flavour,
colour, etc., is very important for many applications. Even more and
more biologically active substances are used in various industries
because of their beneficial functional properties and effects on the
environment and human health.
coating process of materials can be employed to enhance, time or tune
the effect of functional ingredients and additives, or for extended
drug release applications.
process consists of two steps: sprayed coating solution, through a
nozzle, on the particles; evaporate the solvent, in order to obtain a
coating layer onto particles surface.
the traditional coating process based on organic solvent, the solvent
needs to be recovered due to environmental pollution. Coating processes
with aqueous dispersions are time and energy consuming caused by the
low concentration of coating polymer and large amounts of water which
need to be evaporated.
coating is not really a new technology. It had been applied in
chemical, aeronautical, metallic, wood and paper industries mostly for
coating or recovering woods, metals or any desired surface by paints,
varnishes, different polymers or precious metal to protect them against
corrosion or to reinforce them. Its application to food area is quite
recent and is still in its infancy.
particle coating, consists in coating relatively large particle size
(core material or host) with fine particles (guest). The adhesion of
these particles is made using mechano-chemical treatment or using
plasticizer. The using of plasticizer is particularly indicated to coat
particles that are relatively soft and very sensitive to heat and can
be deformed by severe mechanical forces.
to solvent and water based coating the dry coating method is favourable
regarding environmental friendliness, safety and cost. It might be a
very suitable coating method in order to coat foods and drugs which are
sensitive to organic solvents or water.