Wheat Grain Quality

WHEAT GRAIN QUALITY CONTROL
WHEAT GRAIN QUALITY:

• Wheat grain (Triticum aestivum L.) is the world's
leading agricultural source of energy, protein and
fiber;
• It belongs to a family Graminaea and genus
Triticum and can be categorized into three main
classes
• hard,
• soft and
• durum
• Wheat quality can best be described in terms of
end-user, nutritional quality, milling, and
baking and rheology quality.’
• In general wheat needs to be sound, clean, well
mature, free from foreign material and damaged
WHEAT QUALITY
• In general wheat quality can be divided into
three main groups
• botanical (species and varieties),
• physical and
• chemical characteristics
• Botanical Criteria of Quality in botanical terms,
wheat quality can be described as falling into
the following two main criteria /
(i) species and
(ii) varieties
Physical criteria
• Physical characteristics of wheat quality
includes, grain weight, hardness, grain
size and shape, vitreousness and color
• Physical properties of grain such as
wheat play a very important role in the
quality of the grain & in final products
such as flour
• Main physical properties that influence
quality of wheat are test weight,
hardness, grain size and shape,
vitreousness and color.
Test weight(TW)
• TW of wheat is considered the most common
and easiest way to quantify wheat
• It is an important quality factor in wheat
grading as it gives rough estimates of flour
yields
• The basic factors that affect the TW of wheat
are kernel size and shape, kernel density,
maturity of wheat, anseases and actual wheat
variety
Hardness
• The hardness of wheat endosperm is critical in
determining the suitability of wheat for various
end products and influences the processing and
milling of wheat
• It is the common characteristic used by millers
and trader to classify wheat
• In term of hardness wheat can be classified as
either hard or soft
Color
• In terms of color, wheat is classified into two
classes (i.e. red wheat and white wheat)
• Hard red winter wheat is considered superior
and commonly used for bread flour production,
• While white wheat are usually used for cake,
chapattis, and pasta (macaroni),
• Each types of wheat has different properties
such as taste, baking quality and milling
yields
Vitreousness
• Wheat vitreousness is an optical property used
by many countries to grade or quantify durum
wheat
• Based on vitreouness, wheat can be classified
into three main classes: vitreous, mealy and
piebald
• Vitreous wheat differs from non-vitreous by
kernel appearance (starchy and opaque);
• vitreous wheat are considered better quality
than non-vitreous kernels, because of higher
quality semolina protein, nice color and
uniform coarser granulation
Chemical (quality) properties of wheat
• A chemical property of wheat includes

moisture contents, protein (gluten) contents,
amylase content and fiber contents
Moisture contents(MC)
• Wheat grain normal harvested at 10-12% MC
• In most countries moisture contents is not part
of grading system, but is the most important
factors affecting quality of wheat grain, hence is
inversely related to dry matter loss
• MC has two significance important in wheat
quality
 too low (too dry) result wheat to break during
storage and handling operation and
 too high will facilitate molds growth which lead to
deterioration
Protein content
• Protein is not part of wheat a grading factors, but
its quantity and quality are the most important
properties in wheat business
• Most buyers and millers need to know the amount
of protein contents of wheat before buys it.
• Wheat contains five different classes of protein; (i)
albumin (soluble in water), (ii) globulin (soluble
in salt solution) (iii) gliadin (soluble in 70%
aqueous ethanol) (iv) proteose and (v) glutenin
(soluble in dilute acid or alkali)
• Other important quality of wheat are milling and
baking quality
Milling quality
• Most of wheat is commercially sold as milled flour or
semolina, hence milling quality is a crucial factor in
wheat trade.
• Milling depends on three main factors
 Size and evenness of kernels- there is a close
correlation with the weight of grain, determined by
thousand-kernel weight,
 Texture of the endosperm- characterized by glassiness
or pearling index and hardness. They influence the
utilization of energy required for milling as well as the
amount of semolina obtained, and
 Percentage ratio of the seed-coat- the larger the kernel
the lower the ratio of seed-coat, and if the layers are not
thicker, then the percentage of the seed-coat will
decreases too, and color of endosperm and seed-coat
Baking quality(BQ)
• BQ is another criterion used to determine the
quality and suitability of Wheat;
• BQ depends on types of wheat uses and processing
conditions, for instance the strong (hard) wheat
are considered of the higher quality & suitable for
bread making, where most of cakes made from
soft wheat flour
• BQ is determined by rheological properties of
wheat flour
• The rheological property of wheat flour is essential
because it determine other physical ch/cs such as
dough (baking) volume & sensory attributes
O U
K Y
AN
T H

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WHEAT GRAIN QUALITY CONTROL

WHEAT GRAIN QUALITY:

• A chemical property of wheat includes

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