wheat

Structure of wheat. 

Wheat is used most commonly because of its insoluble protein called gluten. Gluten gives elasticity and extensibility to any product in which it is used. The other grain which has gluten is Rye.  There are different type of wheat.

1.            Hard wheat  -        Up to 14% protein

2.       Soft wheat   -        Up to 8% protein

3.       Medium wheat-     Up to11% protein

Wheat is a cereal grass of the genus tritium and is basically made of 3 parts:

1.   Bran                -        15%

2.   Germ               -        2.5%

3.   Endosperm      -        82.5%

Structure of Wheat

BRAN: This is the pericarp or the outer coat surrounding the fruit and it is made up of several layers that serve to protect the embryo. The bran is rich in B vitamins and minerals and contributes significantly to the fibre content in wholegrain flour.

GERM: What is commonly called the germ is the embryo. If placed in the right conditions the embryo will germinate into a new plant. The embryo is a rich source of B vitamins, oil, vitamin E and natural plant fat. It is often removed during milling because the fat causes rancidity during flour storage. However because the Wheat germ is nutritionally valuable it is often sold separately or added to other products.

ENDOSPERM: This is the primary site of starch and protein storage and the fraction of the grain that when the grain is milled, gives rise to white flour. The endosperm is typically 60-80% starch and 5-15% protein with some lipids and minerals associated with these compounds.

Milling Process: Wheat can be milled in two ways.

1.    Stone milling

2.    Roller Flour milling

3.    1.  Stone Milling:

This process was done by our ancestors manually and still present in certain houses in the villages.  It is a very rich and nutritive flour. The flour is ground with the help of the circular stones that have grooved edges placed one on top of the other to help in the milling process. The stone on top is rotated and the wheat is feed through the center, there by breaking the kernel into flour.  The flour extracted by stone milling is termed as whole meal flour.

2. Roller Flour Milling:      

This has originated in Switzerland.  Milling is usually done mechanically.  This enables different types of flour according to the size and composition to be collected during the milling process. 

Before the wheat is milled it is to be graded and blended as per requirement after which it undergoes the following process:

1.    It is leant and conditioned.  Conditioning is done by soaking the wheat kernels which helps to soften the grain. It also helps to remove bran and germ easily.

2.    It is then broken between fluted, grooved rollers which breaks of the bran and germ. The endosperm is powdered coarsely. This is known as semolina.

3.    The coarse flour passes through reduction rolls which has smooth surface and grinds flour into very fine particles.

4.    Flour vary in colour and strength after it is bleached and oxidized to mature it.

Storage of flour:

1.    It should be stored in a   well ventilated room.

2.    The temperature should be between 60º F to 70º F

3.    The relative humidity should be about 60%

4.    The storage rooms walls should be treated with high gloss mould resistant paint

5.    Whole meal flour or whole wheat flour can be stored for about 2 months where as refined flour can be stored for about 4 to 6 months.

Types of Flour:

Type’s flour depends on percentage of extraction.  Extraction rate means a percentage of wheat kernels that goes to make the flour.

TYPE OF FLOUR	PARTS OF THE GRAIN INCLUDED	EXTRACTION RATE
Whole meal flour	Whole grain (endosperm, germ, bran)	100%
Wheat meal flour (brown flour)	Endosperm, germ and some grain	80 – 95%
Refined flour	Endosperm	72 – 75%