ฉันรักแปล
Drying of food consists of three steps, namely pre-drying
processing, dehydration and post-drying handling of the
material. The pre-drying processes depend on the physical
state of the material subjected to drying. Liquids are vacuum
concentrated, treated with enzymes or foamed, while solids
are sulfited, soaked in solutions of different compounds,
dewatered by osmosis, blanched, frozen or treated by high
pressure. Drying of the pre-treated material can be done
under vacuum or at atmospheric pressure. Material undergoing
drying can be heated by surface heating or by
volumetric heating, and it can be stationary or set in motion.
Storage stability of a dry material depends on the state at
which the drying process is finished. The effect of all these
steps on quality of the final product are discussed. It is shown
that to design a process of hot air drying a thorough
understanding of all the operations affecting quality is
needed