In this article we will discuss about the quality considerations of sorghum.
Grain Colour:
In general, white grain sorghum is preferred in the country. Most preferred variety in sorghum growing tract of south India is M 35-1 (Maldandi), which is white and shiny. Ethiopians prefer brown grain containing greater amount of tannins.
Grain Weight:
Bold grains with 3.0 to 3.5 g 100-1 grain are, generally, accepted. Higher the grain size and weight, the greater is its susceptibility to mould.
Grain Shape and Pericarp:
Round and oval grains are preferred due to mechanical milling advantages. Beaked and flat grain types are usually selected out, in preference to oval and round types. A thinner pericarp is preferred in India. However, traditional African dehulling prefers thick pericarp.
I. Nutritive Value:
Nutritive values of different sorghums, generally, do not differ significantly. Average chemical composition of sorghum grain has been given in Table 2.6.
Protein:
There is wide variation in protein content of sorghums ranging from 7 to 26 per cent with an average of 10.3 per cent. The alcohol soluble fraction of protein known as kafirin ranges from 40-60 per cent. It is of poor quality with low amino acid and lysine content. It is also relatively deficient in arginine, glycine, tyrosine and methionine. In general, hybrids have lower protein content than the self-pollinated varieties.
Tannin:
Protein availability is limited in sorghum cultivars with high amounts of polyphenols compounds known as tannins. It has been suggested that tannin content of more than 1.0 per cent catachin equivalent results in lower protein availability and lower digestibility of dry matter.
II. Processing:
Dry Milling:
Application of modern grain processing methods have greatly expanded the uses of grain sorghums in USA. Dry milling system separates the kernel into bran, germ and endosperm. Endosperm constitutes 82-85 per cent, germ 8-12 per cent and bran 8 per cent.
Wet Milling:
It starts with hydration, softening of kernels and removal of soluble substances. Milling is then carried out in water slurry in a number of steps to produce each grain component germ, starch, glutene and fibre.
In India, traditional milling consists of soaking the grain in water for an hour or two, draining the water completely and processed in mortar and pestle until the barn separates from endosperm. Flour prepared from bran-removed grain (pearled grain) can be used for different preparations.
III. Sorghum Food Products:
Traditionally, whole grain may be ground into flour or pearled before grinding by hand. Sorghum food products vary from country to country.
Immature Grain:
Dimpled, sugary sorghums are used in India. Grain in hard dough stage is parched or roasted while still green.
Boiled:
Harvested mature grain is dehusked in mortar and pestle to remove the bran. The pearled grain is then boiled in water for consumption as in the case of rice.
Porridge:
Sorghum is consumed as porridge in all sorghum countries. Dehulled grain is ground into flour, course or fine added to boiling water. The product is porridge, stiff enough to mould without being sticky or crumby. This product is called sankati in India, ugali in east Africa, mafo in Somatix, genfo in Ethiopia, asida in Sudan and tuwo in Nigeria.
Leavened Bread:
Much of the grain sorghum in African countries is consumed as bread. It is prepared by mixing flour, water and yeast containing starter mix.
Unleavended Bread:
Breads made without yeast are popular in Nigeria. Roti is unleavended bread made from sorghum and consumed extensively in India. Chapati is also popular in India.