Zhantugulov
T., Bolat E.B.
Kostanai State University named after A. Baitursynov
the Republic of Kazakhstan
Technology
of extrudate production
Extrusion (from late Latin
extrusio — pushing out) — technology of receiving products by forcing of
material liquid melt through forming
output port, discharging.
One of the effective methods of impact on grain
components biochemical indexes is
processing in extruders in which the product is exposed to the action of high pressure and temperature.
Process of extrusion takes less than 30 seconds. During this time the raw
materials manage to pass some processing stages: thermal, sterilization and
disinfecting, grinding and mixing, partial (to 50% from initial) dehydration,
stabilizing, a texturing, expansion and grading.
Fundamentally there are
three processes in extruding: thermal processing of fodder means under
pressure; mechanochemical deforming of the product: "explosion" of
the product in the front edge of percussive. After thermal treatment tastes of
fodder means are improved because of the appearance of aromatic substances,
etc. significantly increases the activity of enzymes in the process of forages
digestibility, and also neutralization of some toxins and destruction of their
producers.
Grain are processed in
the press-extruder at the pressure up to 100 atmospheres and temperature to 120
degrees by C. As a result there even is
the devastation of the spore microflora
and possible populations of bacteria and mushrooms. After that the extruder
produces expanded, porous product in the form of a braid (strand of rope) with
a diameter of 20-80 mm, with mass volume 100-250kg in m3, with humidity of
6-8%.
Along with thermal treatment there are profound changes in nutrients. So
starch is decomposed to dextrins and sugars, proteins are exposed to a
denaturation and forages digestibility
increases at several times. As a result of such complex processing it is
received an extrudate with pleasant bread taste and smell.
Feeding animals with normal
forage can be compared with feeding
animals with candies in a lead envelope — an animal acquires only a
half because all energy is spent on "wrapper" digestion. As a result
here is the case that animals activity is simply supported and paltry surplus
weights and milk yield are received. At extrusive processing of grain and grain
wastes, a half of stomach operation of an animal is carried by the extruder and
therefore forage energy is entirely directed to the construction of animal
organism. The principal source of
carbohydrates in fodder diets of animals is grain forage. More often it is used
grain of cereal cultures: barley, wheat, corn, oats, etc. The big percent of
the fodder grain supplied to farms, has
humidity. The quantity of mold fungi
and aerobic bacteria in such grain quickly increases therefore it becomes
dangerous for animals. Fresh- cut grain even in case of low humidity contains a
huge number of microorganisms. Development of containing in grain mold fungi
and bacteria leads to formation of
toxins either at forage storage, or in animal organism. Availability of
toxins is marked even in the grain exposed to drying with 14% of humidity
Great practical value has a method of disinfecting and preparation of
grain for feeding by its extrusion. As a result of barometric influence caused in the course of extruding, there is
sterilization of grain and inactivation of the toxic substances existing in it.
The extruded forage is almost sterile after 3–4 months storage is kept
in usual warehouse conditions. Even meat-and-bone
meal tankage — the most exposed to bacteriological semination, in case of storage (put into extrudate) doesn't
change the properties.
Extruded forage possesses a range
of advantages which are necessary for
modern animal husbandry keeping:
- it is takes extrudate twice
less, than compound feed;
- it isn't necessary to trouble extruded compound feed, and it can be
simply filled with cold water;
- the dung after feeding of strand of
ropes can be immediately used as fine
organic fertilizer because it has no
chaft and weeds seeds.
It can be introduced into the soil, leaving out a phase where the dung
must "fused".
In case of extrusion under the influence of temperature and pressure
there is a deep transformation of nutrients structure and properties that
allows to make the high-quality product possessing the following properties:
1 . improvement of qualities due to composition homogeneity, unpleasant smell is eliminated, the share of
sugars at the expense of destruction of polysaccharides increases; under the
influence of temperature and pressure there is sterilization of forage,
thereby, improving their sanitarian status;
2 . it is eliminated or significantly decreased the influence of
anti-nutritious factors and their negative impact on animals;
3 . as a result of extrusion it is received more structured forage which
specially fitted and meeting needs of
animals, the negative effect of processing
has been minimized ( vitamins, fats and amino acids destruction) due to
the rapidity of operation, the time period for passing through the extruder is
30 seconds, and under the influence of maximum temperature it is kept only for
5-6 seconds.