Prolamin in barley

Prolamins are the endosperm storage proteins of cereal grains. The prolamins are monomeric polypeptide chains with molecular weights between 30 to 80 kDa depending on the type of cereal. They are rich in proline and glutamine (20 - 55 %).

Prolamins present different names depending on the type of cereal from which are extracted. Prolamins in wheat which are known as gliadins, in barley as hordeins, in rye as secalins, and in oats as avenins are main triggering factor in celiac disease.

Barley prolamins are the main storage protein in the grain, and major protein in barley by-product. The barley prolamins, hordeins as the main storage protein fraction in barley seeds constitute approximately 50–80% of total grain proteins.

Hordeins accumulate in the starchy endosperm cells of developing barley grains, during grain filling. Hordein synthesis proceeds linearly from approximately 10 to 30 days post-anthesis.

Four sub-units are classified based on their electrophoretic mobilities, B-hordein of 35–46 kD, C-hordein of 55–75 kD, γ-hordein of less than 20 kD and D-hordeins of more than 100 kD.

B-hordein consists in the major fraction of hordein (70–80%) and are sulfur-rich. C-hordein it is the second most important fraction (10–20%) and are sulfur-poor. D-hordein considered a protein with high molecular weight (HMW) and γ -hordein (1%–5%) with the smallest polypeptides.

Scientists study the effect of B, C and D hordeins on malting quality of northern European barleys and found that the B fraction had some effect on malting quality through changing adjusting diastatic power.

The hordeins are amongst the triggers of coeliac disease (CD), a well characterized T-cell mediated disorder suffered by approximately 1% of most populations. In coeliac disease the immune system mounts an inappropriate reaction to particular peptide sequences in dietary gluten, reacting as if the gluten molecules were an invading microorganism.
Prolamin in barley

Five classes of common American wheat

Five principle classes of wheat are commonly grown in North America:
Hard Red Winter 
This wheat is grown in large quantities. It has moderately high protein content and used for bread. Hard Red Winter Wheat mostly grown in the central and southern Great plain.

Soft Red Winter Wheat 

Used for cakes and pastries. This wheat grows in the eastern and southeastern states of United States.

Hard Red Spring Wheat 
This wheat has the highest protein content of North American wheat and is used for manufacturing bread. It grows mainly in northern Great Plains.

White Wheat 
This wheat is suitable for pastry flour. It grows in New York, Michigan and the Pacific Coast states.

Durum wheat  
Grow in North Dakota and other northern Plains states.  This is the hardest of the five wheat classes. It is for spaghetti

Five classes of common American wheat

Rye flour

Rye is a cereal grass that is second only to wheat in world popularity for bread baking. It has as strong hearty flavor in bread and as a cereal. Most rye is roller milled, though stone milling on the industrial scale was utilized for rye longer than for wheat into the 1920s in some countries.

Because rye is so hydroscopic, the gain requires less tempering before it is milled. Rye four is a gluten-containing flour although it is lower in gluten than wheat. Whole grain rye flour produces dense but very flavorful breads.

Rye flour is commercially ground to a range of colors and particles sizes and various nomenclature:
*White rye flour
Rye flour that consist only the center of the endosperm is known as white rye flour. Rye flour lacks many of the original nutrients found in the kernel. It is the rye flour with bran and germ removed. This flour is a good choice for these on low fiber diets.

*Light rye flour or cream
Inclusion of small traces of bran in white rye flour makes it into light rye flour or cream. The lightest is nearly white. It has very fine structure and high percentage of starch, with little protein.

*Medium rye flour
If more bran is included in the white rye flour, medium rye flour is obtained which has many of the original characteristics of the rye.

*Dark rye flour
Dark rye flour is sometimes also referred to as whole grain flour.  Dark rye comes from the part of the rye grain closest to the bran. Thus, it is darker than other rye flours and has lower percentage of fine starch particles.

*Rye meal
This is the best term for whole grain rye flour. Rye meal contains the bran, endosperm and germ of the original rye berry; it can be ground to fine, medium or coarse levels.

*Pumpernickel
Coarse, whole grain rye flour is known as pumpernickel. It is also the name of the traditional German bread.

Rye four makes delicious robust bread. It does not, however, respond favorably to commercial yeast, so wheat flour must be added to the dough to enable the yeast to develop.
Rye flour  

Classifications of Wheat

Classifications of Wheat
Whole wheat, consisting of about 13% protein, can contribute considerably to the diet. The flour, made from the whole wheat, is higher in biological value than white flour (made from the endosperm only).

Wheat is perhaps the most popular cereal grain for the production of bread, and cakes and other pastries. Wheat produces a white flour.

In addition, the unique properties of wheat protein alone can produce bread dough of the strength and elasticity required to produce low density bread and pastries of desirable texture and flavor.

There are many verities of wheat. They may be classified as:

• hard red winter wheats,

• hard spring wheat,

• soft red winter wheats,

• white wheats and

• durum wheats.

Winter wheats are planted in the fall and harvested in the late spring or early summer. Spring wheats are planted in the spring and harvested late summer. Hard wheats are higher in protein content and produce more elastic dough than soft wheats.

Therefore, hard wheats are used for breads, and soft wheats are used for cakes. Durum wheats are most used for alimentary pastes (spaghetti, macaroni, etc.) and for the thickening of canned soups.
Classifications of Wheat