Agriculture Reference
In-Depth Information
screw-type conveyer are usually designed to ensure easy
cleaning and sanitation.
easily through a sieve of square aperture size of 1.40-mm
square mesh but of which a maximum 20% of the weight
will pass through a sieve of 0.71-mm square mesh; and (3)
medium desiccated coconut
, of which not less 90% of the
weight shall pass easily through a sieve of square aperture
size of 2.80 mm but of which a maximum 20% of the weight
will pass through a sieve of 1.40 mm square aperture size.
Dehydration of pulverized kernel
In the DC manufacture, different types of dryers are used for
drying. In the early 1980s, tray-type desiccators or dryers
with semiautomatic arrangement for loading and unloading
were used. Presently, in the modern DC plants, fluidized-
bed continuous dryers are used in place of tray-type batch
dryers. As the drying can be done in the continuous mode,
they are faster and more efficient (Kumar et al., 2003). The
operational mechanism of the drying process in desiccators
was indirect heating of the heat exchangers by the flue
gases generated through the combustion of either firewood
or furnace oil. The hot air from the heat exchangers is
blown onto the dryers from bottom to top. After removal
of the water from the wet kernel, the humid air is dispelled
through a chimney. When the inlet and outlet temperatures
of air are 130
◦
and 88
◦
C, respectively, the average drying
temperature inside the dryer is around 88
◦
C. Under these
conditions, the drying process for the removal of kernel
moisture from 43% to 3% normally takes about 45 min
(Fernando and Thangavel, 1984).
Batches of DC reaching desired moisture level would be
ready to determine the outturn. Usually, the outturn or per
nut yield of DC might vary due to factors such as vari-
etal differences, soil fertility and climate. In the industrial
sector, for those operating as coconut producer societies
or cooperatives, the DC outturn per 1,000 nuts is an im-
portant determinant for profit sharing and related matters.
Data collected over the years show that at least 7,000 nuts
would normally be required for 1 metric ton of DC from
tall varieties of coconut in Sri Lanka.
DC packing, storage, and product quality
DC is packaged, transported, and stored in containers that
optimize maintenance of nutritional and organoleptic qual-
ity. For best quality, the product should be stored in a cool,
dry place. The packaging material shall be such that it
protects the product against microbial and other contami-
nations and infiltration of moisture as well. In addition, the
packaging material should not impart any odor or flavor to
the product. The material of choice for packaging DC is
polylaminated Kraft paper bags with inner poly liner; such
material can effectively act as a barrier for moisture, air,
and light.
Generally, the microbiological stability of the finished
products is dependent on the microbial load of the start-
ing material as well as the maintenance of sanitation in the
processing plant. Therefore, the higher colony count in the
end product could be probably reduced by pasteurization as
well as strict sanitary control. The maximum allowable mi-
crobial colony counts in DC are given in Table 9.6. Drying
process not only preserves the product for extended times
and prevent microbial growth, it also offers easy application
in various food products.
Coconut milk, cream, and milk powder
Coconut milk is a white, thick liquid extracted with wa-
ter from freshly grated coconut kernel. Basically, it is an
emulsion containing fat, protein, sugars, minerals, and vi-
tamins. Fat is the most dominant component in coconut
milk, and its content might vary depending on the volume
of the water added during milk extraction. For instance, co-
conut cream obtained without addition of water may have
about 35-37% fat while the milk obtained with a 1:1 mix-
ing ratio would have 15-17% fat (Anon, 1998). Coconut
milk is a relatively less stable emulsion, which, under am-
bient conditions, may break down into two distinct phases:
a heavy aqueous phase and a lighter creamy phase. Owing
to the high content of nutrients, coconut milk may un-
dergo rapid deterioration at room temperature. For short-
term preservation, the milk can be kept in a freezer, while
for long-term preservation, it may need to be stabilized by
additives as well as packed under sterile conditions. Use
of aseptically packaged coconut milk is popular in some
DC grading
Desiccated coconut is graded according to the fineness of
the material to meet the customer requirements. Fine and
medium are the two most popular grades of DC highly
demanded by western countries. As production of DC ex-
clusively in one form might not be practically feasible,
often the finished product may become a mixture of fine
and medium grades. DC in the form of fancy cuts is also
required for certain specific applications. According to the
CODEX standard for desiccated coconut (CODEX, 1991),
DC is classified as (1)
extra-fine desiccated coconut
,in
which no less than 90% of DC shall pass easily through
a sieve with a 0.85-mm square mesh, and furthermore, no
more than a maximum 25% of the weight will pass through
a sieve of 0.50-mm square mesh; (2)
fine desiccated co-
conut
, of which not less than 80% of the weight shall pass
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