Wheat Flour provides 350 KCAL (1.47 MJ) per 100
Wheat flour is derived mainly from the en-do sperm (normal)
which contains the polypeptides, gliadin and glutenin; these are collectively
known as gluten and constitute about 12% of the flour.
Gluten is protein which becomes viscous when water is
added to it; thus, a good dough can be made from wheat flour. This property is
not present in rice, bajra or jowar flour. Carbon dioxide can be bubbled into
wheat dough to make a spongy mass suitable for making bread or cake. Bakers use
brewers' yeast or baking powder as a source of carbon dioxide; many Indians make
delicious spongy preparations by fermenting wheat flour with toddy.
The hard Indian wheat contains more gluten than the
Western variety. The gluten content of wheat flour can be greatly reduced, even
to 3% -4% by infestation with weevils.
Gluten is relatively poor in the amino acid lysine which
is necessary for proper growth. If lysine is supplied by other vegetable
proteins, nutrition improves. Pulses, soybean, groundnut, and cotton seed flours
provide a good supplement to wheat; milk is probably the best supplement for
providing the amino acids missing in a pure-wheat diet.
Gluten, and particularly its gliadin fraction, is the
substance responsible for celiac disease (gluten-sensitive enteropathy-see Malabsorption
Syndrome).. Wheat is perhaps the only gluten-containing cereal
eaten in the East, but in the West bread is also made from 'rye' which contains
gluten. Complete exclusion of all gluten-containing preparations from the diet
results in remarkable improvement in celiac disease.
Wheat flour contains 1.7% fat derived from the germ.
Whole wheat flour provides 72% carbohydrates.
Thiamine, riboflavin, and nicotinic acid values diminish
considerably as the extraction rate is increased.
Calcium : Wheat is poor in calcium. Refined flour contains only
20mg calcium per 100g. but this lower content is offset by better absorption.
The best and most inexpensive way of solving the problem of calcium deficiency
in wheat is to add calcium carbonate, 14g to 280 kg flour, as is done in the UK.
The calcium carbonate content should not be less than 235 mg (22.35 mmol as
calcium) and not more than 390 mg (3.9 mmol as calcium) per 100 g flour.
Fortification of wheat flour with calcium is advocated
particularly in areas where milk intake is low and little calcium is available
from other food sources. Indian children showed nearly the same rate of growth
on a daily supplement of 1 g calcium lactate, as on a supplement of 30 g skimmed
milk powder (1 cup milk).
Iron The iron content of whole wheat flour
is high, while
refined flour has considerably less iron. In Britain, regulations require not
less than 1.65 mg (29.5 micromol) iron per 100 g flour; thus, 70% extraction
flour requires the addition of iron. This fulfils the policy of restoration and
not of fortification. However, iron from brown bread is absorbed better than
that from iron-enriched white bread.
Phosphorus Whole wheat flour is rich in phosphorus in
comparison to refined flour. The high content of phosphorus prevents the
absorption of other minerals like iron and calcium.