**4. Processing techniques/methods of cereal grains**

Cereals are been processed in different ways due to their specific characteristics and purpose. Their processing comprises an important part of the food production chain, but it is a complex procedure. The most common cereal processes include dry milling (wheat and rye), pearling (rice, oat, and barley), wet milling (corn and wheat), and malting (barley, corn, and wheat) [19]. However, certain general principles applied to most of them. Cereals undergo several processing stages between harvest, storage and consumption. Processing methods of cereal grains can be divided into two different methods, primary and secondary processing method. Primary processing includes cleaning and grading, hulling, milling and drying while the secondary process is the storage of the cereal grains for further processing.

#### **4.1 Primary processing**

#### *4.1.1 Cleaning and grading*

The first stage in cleaning is threshing, i.e. the removal of grains from the rest of the plant. It involves four different operations: Separating the grain from the panicle; sorting the grain from the straw; graded according to size; winnowing the chaff from the grain. Before cereal processing, the grains should be dried to 10–15% moisture before storage to avoid spoilage of the cereal grains.

### *4.1.2 Hulling*

Grains have an unpalatable huskthat needs to be removed before processing. There are different kinds of de-hulling machines designed for this purpose, depending on the type of cereal grains.

#### *4.1.3 Milling*

This can be achieved using any of these cereal grains mill; Plate mill, hammer mill and roller mill. The type of mill to be used depends on the cereal grains. Roller mills are majorly used industrially due to its high cost and maintenance while hammer mill and plate mill can be used at home and all business scale level.

#### *4.1.4 Drying*

Before storage, the cereals grains should be dried to 10–15% moisture to avoid spoilage of the cereal grains.

#### **4.2 Secondary processing**

#### *4.2.1 Storage*

Dried grains are stored in much quantity until required for processing. The grains should be inspected regularly for signs of spoilage and the moisture content tested. If the grain has picked up moisture, it should be re-dried.
