Although the South African market for sorghum malt has declined, sorghum is still important for traditional and lager beer production in parts of Africa such as Nigeria and Zimbabwe.
- Sorghum lager beer’s value lies in the fact that it is gluten-free.
- The market for gluten-free beer is growing, especially where the beer is targeted at those who are allergic to gluten.
- In countries like Nigeria, importation of barley was prohibited and it had to be replaced by sorghum.
- Developing and identifying better cultivars is therefore vital.
The objective of a study by the Agricultural Research Council in South Africa was to identify grain sorghum varieties or inbred lines that can be used in the development programme. More than 100 cultivars and inbred lines were evaluated.
The following cultivars were found to be most suitable because of their high malting quality:
- M12; M13; M14; M22; M23; P4; P66 (all with a white seed colour).
- M15; M28; P19; SA2036; Barnard (all with a red seed colour).
- M59; P28 (both with a brown seed colour).
GRADING AND MARKETING
Grain sorghum is graded according to its malt, fodder and tannic acid content and prices are set accordingly.
The table gives the current class grading:
The following factors are of relevance to the grain sorghum classes:
- Cultivars with a dark-brown pericarp have a bitter taste and are therefore more bird proof.
- The bitter taste is due to tannic acid, which also has a detrimental effect on malting quality and feed value for monogastric animals.
- Some of the cultivars with a dark pericarp could also have good malting quality if the tannic acid were to be neutralised with formaldehyde.
- Tannic acid affects poultry, hence the lower feed value.
Cultivars with good malting quality are characterised as follows:
- The sorghum grain has a red colour and soft endosperm.
- During the malting process enzymes are readily produced and break down the starch into sugars.
- These cultivars have a good so-called diastatic value.
Another aspect of grain quality that could receive more attention in cultivar development in future is a well-developed yellow endosperm.
Yellow endosperm not only provides more vitamin A for the animal, but also produces a yellow fat and deeper yellow-coloured egg yolk – both characteristics that are highly desirable in the poultry industry.
The feed value of grain sorghum is generally similar to maize when used for most types of animals. The only exceptions are the sorghum types with a brown pericarp (bird-resistant bitter types).
As stated above, these are not suitable as feed for monogastric animals. The advantages of maize as opposed to grain sorghum are greater palatability and a higher vitamin A content (yellow maize).
- This article was written by Willy Wentzel and Constance Chiremba and first appeared in Farming SA.