Cereals:
Cereals form the major source of food.
The composition of cereal grains varies greatly due to
The genetic makeup of the plant
Soil factors
Climatic factors
Cultural practices
Cereals include rice, wheat, maize, sorghum, barley, etc
They comes under the family gramineae, i.e grass family.
Chemistry of cereal crops deals about chemical constituents :
Carbohydrates
Fats
Proteins
Ash
Nutrients like Ca,P
Vitamins
Toxins
Cereals are the major part of Indian diet so also known as staple foods.
The 80% percent of the dry matter in grains is carbohydrate, mainly the starch therefore, they are considered as the main energy providing crops.
Cereals provide 350 kcal of energy per 100 grams to the body.
Cereals contain 6-12% of protein
The whole grain form of cereal is more nutritious than milled one as it contains greater levels of B-complex vitamins, dietary fibre and essential fatty acids.
Cereals low in proteins.
High in Nitrogen Free Extract which includes the carbohydrates such as starch, dextrin, soluble sugars.
Starch constitutes more than 90% of NFE.
Grains, hulls and bran – rich in cellulose, pentosans and ash constituents.
germ or embryo – higher oil content, crude protein, sugar and minerals.
Endosperm – starch.
Abundant constituent of cereal plant system (80-95%).
With maturity water content decreases in plant.
CARBOHYDRATES:
Generally cereals rich in carbohydrates.
It ranges from 70-80%.
83% of total dry matter of wheat, barley, rye, maize, sorghum
and rice and 79% of oats.
Carbohydrates in cereal grains include more than 90% of starch.
Dextrin occurs in small amounts.
Bran chiefly contains pentosans and some cellulose and lignin.
Germ tissues have sucrose.
PROTEINS:
Cereal proteins are simple proteins in composition.
Conjugated proteins like nucleoproteins are concentrated mostly in the germ.
The simple proteins yield α- amino acids on hydrolysis.
Among simple proteins, cereal grains found to have
1) water soluble proteins (albumins)
2) salt soluble proteins (globulins)
3) alcohol soluble proteins (prolamines)
4) acids and alkali soluble proteins (glutuleins)
In cereals 6-12%
2. Cereals:
Cereals form the major source of food.
The composition of cereal grains varies greatly due to
The genetic makeup of the plant
Soil factors
Climatic factors
Cultural practices
Cereals include rice, wheat, maize, sorghum, barley, etc
They comes under the family gramineae, i.e grass family.
3. Chemistry of cereal crops deals about chemical
constituents :
Carbohydrates
Fats
Proteins
Ash
Nutrients like Ca,P
Vitamins
Toxins
4. Cereals are the major part of Indian diet so also known as staple
foods.
The 80% percent of the dry matter in grains is carbohydrate,
mainly the starch therefore, they are considered as the main energy
providing crops.
Cereals provide 350 kcal of energy per 100 grams to the body.
Cereals contain 6-12% of protein
The whole grain form of cereal is more nutritious than milled one as
it contains greater levels of B-complex vitamins, dietary fibre and
essential fatty acids.
5. Cereals low in proteins.
High in Nitrogen Free Extract which includes the
carbohydrates such as starch, dextrin, soluble sugars.
Starch constitutes more than 90% of NFE.
Grains, hulls and bran – rich in cellulose, pentosans and ash
constituents.
germ or embryo – higher oil content, crude protein, sugar and
minerals.
Endosperm – starch.
6. Abundant constituent of cereal plant system
(80-95%).
With maturity water content decreases in plant.
Water
7. CARBOHYDRATES:
Generally cereals rich in carbohydrates.
It ranges from 70-80%.
83% of total dry matter of wheat, barley, rye, maize, sorghum
and rice and 79% of oats.
Carbohydrates in cereal grains include more than 90% of starch.
Dextrin occurs in small amounts.
Bran chiefly contains pentosans and some cellulose and lignin.
Germ tissues have sucrose.
8. PROTEINS:
o Cereal proteins are simple proteins in composition.
o Conjugated proteins like nucleoproteins are concentrated
mostly in the germ.
o The simple proteins yield α- amino acids on hydrolysis.
o Among simple proteins, cereal grains found to have
1) water soluble proteins (albumins)
2) salt soluble proteins (globulins)
3) alcohol soluble proteins (prolamines)
4) acids and alkali soluble proteins (glutuleins)
o In cereals 6-12%
9. Prolamines are the characteristics of grass family.
Cereal proteins are poor in one or more essential amino acids.
Zein – maize protein lacks lysine and trptophan.
Wheat protein poor in lysine and threonine.
proteins:
Rice – oryzenin
Wheat – gliadine and glutenin.
Maize – zeatin
10. LIPIDS:
1- 5% in cereal plant.
Lipids are present in the embryo of seeds.
They include fatty oils, phosphatides like lecithin and sterols
like sitosterols.
Tocopherols ( vitamin E) are found in larger amount in the
unsaponifiable fraction of germ oils.
The iodine value of cereal oils varies from 100 – 125 and they
are classed as semidrying oils.
This is a measure of degree of unsaturation of fats and oils.
11. ENZYMES:
The most important cereal enzyme is amylases.
Other enzymes present in cereals are proteases, lipases,
oxidases.
Also contains fermentation enzymes such as maltases,
diastases, etc.,
12. VITAMINS:
All the cereal grains are fairly rich in vitamin B but low
in vitamin C & D.
The endosperm has the lowest amount of vitamin B.
About 63% of thiamine content of wheat is found in
scutellum.
Golden rice rich in vitamin A, containing carotenoids.
Vitamin A activity in yellow rice is primarily due to
coloring substances “cryptoxanthin”.
13. MINERALS:
Inorganic constituent .
Occurrence- free state, ions, salts, organically bound form.
2- 5%
The dominant ash constituents of cereals are K , P and
Mg.
The other minerals are S, Cl, Ca and Na which are
present in small volumes.
14. Silicon is found to present in higher proportions
in closed cereal grains like rice and barley (4-6%).
The other trace elements are Al, Ca, Cu, Li, Ni, Se,
Sn, Ti and I.
P content is uniformly distributed in different
cereals and in many cases higher than that of Ca.
It is mainly present as Ca or Mg salt of phytic
acid.
15. TOXINS:
Some cereals contains toxins in their
forage:
Sorghum – HCN/ dhurin/ prussic acid
Pearl millet – oxalic acid
16. CRUDE FIBER
Defined as the sum of all those organic components
remain after removal of crude protein, crude fibre,
and nitrogen-free extractives.
insoluble in dilute acid and alkali
represents about 50-80% of cellulose, 10-15% of lignin,
and 20% of the hemicellulose of the original food.
Cereal grains are good sources of water-soluble dietary
fibres.
In cereals crude fibre content used for evaluating
milling efficiency .
17. King - wheat
Queen – maize – backbone of America.
King of coarse cereals – sorghum
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