Corn (Maize) is one of the staple food for human beings. It is rich in nutritive components such as protein, oil and carbohydrates. With the advancement of technology, corn is finding innumerable food and industrial uses by separation of its components. In the process of wet milling of corn, a number of co-products such as starch, protein powder (corn-gluten meal), corn fibre, corn germ oil and corn-steep liquor are obtained, which can realize the full use of corn.
Corn is processed through wet milling. The process employs the techniques of grinding, screening and centrifugation to separate purified starch from fiber, oil and tightly bound protein.
Starch is the main product of corn milling, which is a very important industrial raw material used extensively in food, in chemical industry, in pharmaceuticals, in paper making and in textiles. More and more products are being developed, based on corn starch and its uses are becoming wider and wider.
Down-stream products of corn starch -
1.
Glucose, maltose dextrin / dextrose, oligosaccharide etc.
2.
Modified starches.
3.
Fermented products like Alcohol, Glycerol, Yeast, Mono-sodium glutamate, Lysine and some amino acids, Citric acid etc.
4.
Starch degrading
plastic etc.
Corn slurry (corn steep liquor) can be used as nutritive additive for fermenting industry in addition to its use in the feed industry after drying upto 50% to replace molasses as a binder and as a nutritive supplement. Corn germ is one of most important by product in corn starch process and can be used to produce corn germ oil, which is high in poly-unsaturated essential fatty acids, with numerous health benefits.
Products & capacity -
|
Production capacity
|
-
|
150 tons of corn per day x
300 days per year
|
|
Products
|
-
|
Corn starch-30,000 tons per
year
|
|
|
-
|
Corn slurry - 3,600 tons per
year
|
|
|
|
(or Corn steep liquor with
dry material content 43%)
|
|
|
-
|
Corn protein powder- 2,400
tons per year (or corn gluten meal)
|
|
|
-
|
Germ cake
|
-
|
2,880 tons per year
|
|
|
-
|
Corn fibre
|
-
|
5,280 tons per year
|
Brief manufacturing process -
1.
Corn cleaning -�
Corn cleaning section will remove impurities such as iron, sand, stone, stem etc.Corn is cleaned
with pre-cleaner, de-stoner and magnetic separator through bucket
elevators.� Clean corn is weighed and
pumped into soaking system with water and H2So3.
2.
H2So3 (Sulfurous acid) preparation
��
H2So3
is prepared by sulphur.� Sulfur is burnt
to� produce� So2,�
which� is� absorbed with absorption tower to produce
sulfurous acid, by two-grade absorption method.� H2So3 preparation equipment is composed of
burning stove, sublimer, cooler, absorption tower, water pump and fan.
3.
Corn soaking and concentration �
The purpose of
soaking is to change the structure and physio-chemical properties of corn
endosperm, to weaken inter-linking strength of corn, and to remove the soluble
materials and restrain the micro-organism from growing.
More than 8 soak
tanks are needed for the process. Soaking time is 48-60 hours.� After soaking, dry material content of
dilute corn slurry is 5 � 9 % with� pH
of 3.9 to 4.1, which is concentrated to corn slurry with 40% dry material
content.
4.
Corn grinding and germ separation �
Corn
after soaking and concentration is transferred to de-stoner and to buffer
hopper.� Corn is then transferred into
first degerm mill, where it is broken into 4 � 6 parts & the content of
complete corn is not more than� 1%.� Here, 75 � 89% germ can be separated.�
