WHEAT

WHEAT

Flour is the principal raw material used in the manufacture of bread, cakes, cookies & pastries. It provides bulk & structure to these products.

Flour indicates any foodstuff which is finely powdered e.g. rice flour, soya flour; corn flour etc. when there is no specific indication of the type of flour then it refers to refined wheat flour.

Wheat grows in almost every part of the world, except in extreme climatic conditions. However wheat flourishes best in temperate regions & the best quality comes from the American & Canadian borders under the names Manitoba ,Minnesota hard winter etc. The other countries producing wheat are China, India, Australia, Iran, Turkey, U.K etc.

The commercially grown species of wheat are:

Triticum Vulgare

Triticum Durum

Triticum compactum -Suitable for bread.

-Suitable for spaghetti pasta, macaroni etc.

-Suitable for cake-making.

The wheat berry is made up of three parts-

Bran, Germ & Endosperm.

Bran: it is the outer covering of the kernel & consists of 5 layers:

Epidermis

Epicarp

Endocarp

Epidperm or Testa

Aleurone or Ceralin layer.

The first 3 layers are protective layers. The 4th layer Testa contains the coloring matter that gives color to the wheat e.g. red, amber etc. the 5th layer of Aluerone cells contains the protrase enzyme & has a softening effect on the flour protein. Bran is rich in vitamin B & dietary fibre. The sharp edges of bran fragments have a cutting action on gluten strands, reducing the gas retention power of the dough.

Germ or Embryo:

The germ of wheat consists of 3 parts:

Scuttelum

Plumule

Radical

The germ is that part of the kernel that becomes the new wheat if the kernel is sprouted. In the early stages the berry is incapable of obtaining food needed for the growth of the new plant, so all the nourishment is packed in the germ.

Endosperm:

The endosperm is the starchy part of the kernel after the bran & germ is the kernel after the bran & germ is removed. It contains numerous compartments of cellulose & these are tightly packed with starch cells which are round or slightly oval in shape. In the spaces between them are found many other substances like soluble & insoluble proteins, fat, sugar, moisture & minerals.

The characteristics of the flour depend on the variety of wheat from which it is milled, the location & growing conditions.

For the production of strong wheat a hard winter & a hot ripening period is ideal. Nitrogen is the most important element in the protein molecule & is obtained from soil. According to the availability & solubility of nitrogen, the quality & quantity of protein will vary in the wheat & flour.

Some of the principal types of wheat are- Northern spring, Manitoba, Hard winter, Red winter, Pacific, Durum etc.

Types of flour:-

Whole wheat flour: - has a dark color, it consists of all parts of the grain i.e. bran, germ & endosperm. This flour has a characteristic flavor. As this flour contains the germ (oil) it will have a storage life of only 6-8 weeks.

Straight flour: - is flour from the entire endosperm. Because it contains the part nearer the bran as well as the whiter interior, the color of straight flour is darker in color than patent.

Patent flour: - is milled from the inner part of the endosperm. Patent flour made from hard wheat is a strong flour of excellent quality & light cream color. Patent flour has 11% - 13% protein content.

Clear flour: - the portion of the endosperm from the outer part of the endosperm nearer the bran thus is darker in color.

Cake flour: - is weak or low gluten flour made from soft wheat it has a very soft, smooth texture and pure white color. Cake flour is used for cakes & other delicate baked goods that require low gluten content.

Pastry flour – is also weak or low gluten flour, but is slightly stronger than cake flour. It has a creamy white color. Pastry flour is used for pie-dough, cookies, and muffins.

All- purpose flour: - medium quality flour which can be used for any type of baked items.

Self- rising flour: - is white flour to which baking powder (2%) & salt has been added.

High-ratio flour: - this is highly bleached, finely milled flour, made from wheat having good quality proteins. The fine milling increases the absorption properties of flour while chlorination increases the acidity & renders the starch more soluble making it possible to have a faster set in the oven & thus minimizing the possibility of escape of leavening gas. Mostly used in cake- making.

Other flours:

Rye flour: - contains some proteins but these do not form gluten.

MILLING

There are two distinct methods of milling wheat – stone milling and roller milling.

Stone mills are still in use. From them we get the best whole meal. It consists of two circular stones lying on one top of the other. The one at the bottom remains stationary while the other stone revolves upon it. The faces of the stone are roughened up so that the grooves in them grip and cut into the berries as two rough surfaces pas over it. Cleaned wheat enters the hole in the center called the runner, trickles down and finds its way between the stones. During this process the grain is crushed into flour.