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quality characteristics of raw material: the biologically active ingredients -
vitamins, organic acids, trace elements, etc. The shelf life of canned KVI -
exposure to dry fast recovery products. (in water at room temperature for 20 -
35, at 50 ° C - 10 - 20 minutes) is 1.5 g. in cardboard and more than 3 years -
vacuum-packed. Ascorbic acid reduced only 4 - 8, whereas during defrosting
berries more than 10 times.
In recent years, the market is dominated by two dryers type vacuum
chambers - with cyclic and contact heating. The cyclic cameras first made the
product heating, and then vacuum it. This whole process is repeated several
times until the product dries. This heat transfer material is produced by
convective way, and in vacuum chambers with contact heating - plate.
Microwave - drying. One of the promising trends in the intensification of
drying is the use of electromagnetic energy of ultrahigh frequency (UHF). For
microwave - heating characteristic rapid increase in temperature inside the
product, whereby there occurs an excessive vapor pressure relative to the
pressure medium. This gradient sharply intensifies the drying process as well as
the transfer of vapor occurs as by molecular diffusion and by filtering through
the pores and capillaries of the product. This type of transfer in the microwave -
heating suppress other types of transport. In recent years, attention is paid to use
in technological processes microwave currents.
This is explained as follows: - high absorptive power of the
electromagnetic field of microwave products of plant and animal origin, which
are quite damp cloth;
- The ability to bring the speed of light and highlight the power per unit
volume that is not available to any of the traditional ways of energy supply; -
The implementation of contactless selective heating and obtain the desired
temperature distribution in the product, including the self-regulating heating
mode; - Instantaneous switching on and off of the heat exposure, which provides
heat Radiant mode and high precision heat control; - Practically 100%
conversion efficiency of the microwave - in the thermal energy, released in the
heated material, the low energy losses in the working chambers; - Use in dried
arrangements inherent nature of transporting large volumes of liquid along the
fibers.
From the analysis concluded that the best option is a combined drying,
consisting of pre-ozone - air product processing and subsequent microwave -
vacuum drying.
The first stage of the laboratory tests vacuum microwave drying process of
minced beef with its ozone pretreatment demonstrated that the drying time
during this process was reduced by 10% in comparison with the microwave -
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