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Structure and composition of corn maize
1. Structure and
Composition of Corn
Presented by.: Atharv. Kurhade (MITU20BTFT0020)
Dept.: Agro-Based Plant Operation
Subject.: Cereals Processing and Technology
MIT SCHOOL OF FOOD TECHNOLOGY, PUNE
2. Introduction
Maize or the scientific name Zea mays and
also the common name corn is the third
most important grain worldwide, after
wheat and rice. It is generally believed that
the earliest form of maize arose from
natural hybridization of two or three
grasses native to Mexico and Guatemala.
4. Additional Info.:
Maize species : [Sturtevant,1899]
o Zea mays indurate (Flint corn) –Most cultivated in India
o Zea mays indentata (Dent corn) – most common in USA
o Zea mays everta (Pop corn) - when they are heated the
pressure built up within the kernel suddenly result in an
explosion and the grain is turned inside out.
o Zea mays saccharata (Sweet corn ) – Sweeter than
other
o Zea mays amylacea (soft corn )
o Zea mays tunicata (pod corn )
o Zea mays ceratinakulesh (waxy corn ) – Produces
starch similar to tapioca
5. Structure of Corn/Maize
o Maize: Botanical name of corn is Zea mays L.
This is the important cereal crop in North
America.
o It apparently originated Mexico. Seed of corn is
much larger than other cereal.
o The corn seed is a single fruit called the
kernel. In includes an embryo, endosperm,
aleurone and pericarp.
o The embryo of maize is relatively larger
(10 – 13 % of grain) than any other cereal
grain.
7. Structure of Corn/Maize
o The pericarp is a thin layer that has protection
role for the endosperm and embryo. Pericarp
adheres tightly to the outer surface of aleurone
layer and thought to impart semipermeable
properties to the corn kernel.
o The pericarp is composed of dead cells that are
cellulosic tubes. Here, pericarp and testa are
fused to form hull.
o Part of germ overlaying the germ is called tip
cap. Industrially, maize is used for manufacture
of starch, sugar syrup, glucose, beer and
alcohol.
8. Structure of Corn/Maize
The maize grain is a small one-seeded fruit called
the caryopsis. In maize grain, the seed coat
(testa) is fused with the fruit wall (pericarp).
Externally, the maize grain is yellow in colour and
somewhat triangular in shape with the following
structures:
o Endosperm: Maize grain consists of two
unequal portions divided by a layer called
epithelium. The bigger portion, the endosperm
which is yellowish or whitish is the food storage
tissue of the grain and is rich in starch. But its
outermost layer contains only protein and is
called aleurone layer.
9. Structure of Corn/Maize
o Seed coat: It is formed of a thin layer
surrounding the whole grain. This layer is made
up of seed-coat and pericarp, i.e. fruit wall.
o Embryo: It consists of one large and shield-
shaped cotyledon. This is also known as
scutellum in the case of maize and other
cereals. The axis of the embryo is embedded in
the scutellum. The axis consists of a plumule at
the upper portion and the radicle at the lower
end. Both radicle and plumule are enclosed in a
sheath called coleoptile and that covering the
radicle are known as coleorhiza.
10. Composition of Corn/Maize
o The composition of maize starch is genetically
controlled.
o In common maize, with either the dent or flint
type of endosperm, amylose makes up 25 to 30
percent of the starch and amylopectin makes
up 70 to 75 percent.
o Waxy maize contains a starch that is 100
percent amylopectin.
o An endosperm mutant called amylose-extender
(ae) induces an increase in the amylose
proportion of the starch to 50 percent and
higher.
o Other genes, alone or in combination, may also
modify the amylose-to-amylopectin ratio in
maize starch
12. Types of Corn/Maize
Different varieties of corn that yield
for agriculture as well many other
purpose. Mostly the corn comes
under listed five types.
o Flint Corn
o Flour Corn
o Dent Corn
o Sweet Corn
o Pop Corn
13. Types of Corn/Maize
Flour Corn:
o Flour corn is oldest corn type that started to
grown up by Americans
o Flour corn is used in baked food items, and it
is very soft, starchy .Primary grown in white
laterally grown in many colors.
14. Types of Corn/Maize
Flint Corn:
o Flint Corn is otherwise called as Indian corn
o The kernels have been bounded by hard shell
and it preserves as well by an ornament with
the range of different colors from white to red
15. Types of Corn/Maize
Dent Corn:
o It is also called as Field Corn
o It used as food product which provides high
starch and low in sugar for humans.
o Most of the maize exporters in india are
yielding Flint corn as well as Dent Corn.
16. Types of Corn/Maize
Popcorn:
o It is one type of flint Corn, the kernels which
also in yellow or white color.
o Initially found in New Mexico.
o It have starchy that covered by hard shell.
17. Types of Corn/Maize
Sweet Corn:
o We eaten sweet Corn freshly as like
fresh vegetables, which is in white or
yellow color
o Sweet corn contains more natural
sugar, when compared to all other Corn
type.
o All other corn contains only 4%sugar
but sweet corn contains 10% sugars
which are all converted into starch
18. Types of Corn/Maize
o Initially the high range of sweet corn
cultivated in US around 119400 acres in
the year of 1996.
19. Additional Info.:
Soil type:
o Maize thrives better on well drained,
sandy-loam to silty-loam soils.
Land Preparation:
o Give four to five ploughings and
planking's to make the seed–bed free
from clods and weeds.
o Use mould board plough ,disc harrow
or cultivator for the 1st cultivation.
20. Additional Info.:
Seed rate:
o Use 7 kg seed for popcorn and 8 kg per
acre for other varieties.
Time of sowing:
o Last week of May to end of June.
Irrigation management:
o Generally, 4 -6 irrigations are required
depending upon rainfall.
21. Fact
Corn and maize are both terms that
reference the same cereal grain. Corn
is primarily used in the North American
English vernacular, whereas Maize
is used in the British English vernacular.
Though the two words are often used
interchangeably, they can have
substantially separate applications.
