January 2017, Milling and Grain – by Clifford Spencer, Goodwill Ambassador, NEPAD

INTRO: I have practically and directly worked with over 60 different species of crops in my lifetime. This has been achieved as a farmer, nucleus seed producer, commercial crop grower, on-farm miller and consumer of these crops either directly or through the farm livestock to which they have been fed. My farming family’s proud boast is that we provided the Royal Household of HM Queen Elizabeth with a Christmas Turkey when we won the UK national poultry show at Smithfield many, many years ago. We also broke yield and quality records for many of the crops that we grew on our farm. Our family farm also played host to many African visitors when I was a young boy and this harboured a long-term and growing interest in this huge continent, which is now an area of the world rapidly coming to the fore in global affairs and commercial developments.

Seven of the top 10 performing economies in the world today are within the African continent. When I completed studying agriculture at university, my very first act upon returning to the family farm was to install an on-farm laboratory. Even in the UK, given it was the very early 1970s, this was an unusual on-farm facility.

The laboratory was equipped for seed germination/vigour testing and grain analysis in terms of protein in cereals and oil content in oilseeds. So as I excitedly used my specialist Kjeldahl and Soxhlet apparatus I was at that time blissfully unaware in global terms of just how extraordinarily lucky I was in terms of the science and technology at my fingertips. This ability to analyse and immediately relate the laboratory results to the growing of the cereal and oilseed crops themselves proved to be real winner and as a result crop yield and quality constantly and rapidly improved. Also our grain produced proved to be extremely popular with millers and as a result always fetched a good price. That experience persuaded me very early on in my career of the power of science and technology in quality farming and food production and also its commercial benefits.

The Potential of African-grown crops to meet food demand

Several crops being farmed in Africa are of potential interest to the milling industry. These crops have the ability to both boost African farming and with that development, African economic growth. These opportunities will be reviewed on a crop by crop basis for readers of coming publications of Milling and Grain and to act as an easy source of future reference. With its vast land area covering three billion hectares, Africa has 1.3 billion hectares of agricultural land out of which 252 million hectares (19.36 %) is currently arable (2011, FAO). Compare this for instance to the total arable land of the UK of some five million hectares and the potential for food and feed production and its associated industries is clear. Africa is not only the centre of origin, but also a major producer of several cereals like sorghum, pearl millet, finger millet, teff and African rice.

Another major cereal, maize has overtaken these traditional cereals while wheat is widely cultivated in North Africa and in Sudan and Ethiopia. Africa is thus perhaps the great opportunity for millers to realise.

The importance of indigenous African crops Developing this opportunity has two sides as agriculture is the ‘engine for growth’ in Africa. Agriculture employs 65 percent of Africa’s labour force and is responsible for 32 percent of its GDP. With subsistence agriculture currently practiced by majority small holder farmers, yield gaps are high and poor soils, amongst other constraints add to the difficulties for sustainable farming and incomes. Cereals like Sorghum, Millets, Wheat, Maize and Rice are major staple foods of the most population. These cereals are grown over an area of 98.6 m ha producing 162 m tons of grain as per the crop breakdown in the chart below. This month I will briefly describe maize (corn) before moving on in subsequent editions and in more detail to some indigenous African crops of potential interest to millers. An important consideration that perhaps the milling industry needs to carefully consider in the longer term is the type of crop used as feedstock. This is a basic requirement in terms of producing the highest quality crops in and for Africa and is related to whether the crop is a so-called C4 crop. Wheat, for instance, is a C3 crop and as such does not have the outright yield and quality potential in tropical climes as with a C4 crop, particularly so in sub-Saharan Africa. Maize (corn) is a C4 crop as is Sorghum.

To explain the basic difference, C4 plants are more efficient in photosynthesis than C3 plants. C4 plants are able to more efficiently fix carbon in drought, high temperatures, and limitations of nitrogen or CO2, with the more common C3 pathway being more efficient in the other conditions such as temperate climes. C4 plants are generally native to hot, moist or arid non-saline habitats as experienced in the tropics. The C4 pathway occurs in many grasses, sugar cane, maize, sorghum and other native tropical crops such as millet. In technical speak the C4 cycle is the alternate pathway of Calvin cycle (C3 cycle) and takes place during the dark phase of photosynthesis. In the C4 cycle the first stable compound is a four carbon compound (namely Oxaloacetic Acid) hence it is called the C4 cycle. C4 plants show a specific type of leaf anatomy called Krans anatomy. The indigenous African crops I will go on to describe in later articles are all C4 crops so with proper breeding and agronomy have enormous potential. Much work is now taking place in this area by the Consultative Group for International Agricultural Research (CGIAR) and in particular for example in Sorghum by the International Crop Research Institute for the Semi-Arid Tropics (ICRISAT) as well as many of the larger agricultural corporates as their interest in these developing world regions expands.

Traditional crops such as yam, sorghum, millet and teff have been ground for centuries in Africa, either with a crude mortar and pestle fashioned from a tree stump and branch or by using flat stones or rubbing stones. All these types of grinding systems are still in common use throughout Africa today.

Newer crops, such as rice, maize and cassava, have been introduced in more recent centuries and new milling techniques have followed.

Tackling the electricity shortage

In the mid-nineteenth century, electric motors were invented but this advance towards hammer and plate milling passed large areas of Africa by, due to the lack of electricity on the bulk of the continent. Instead diesel engineered and lower-speed driven mills were installed but even these were limited to availability of fuel and spare parts. This dearth of electricity on the African continent and particularly in sub-Saharan Africa is now starting to be tackled and NEPAD certainly understands the prizes that can be won as it is installed in greater capacity across the continent and higher speed machines can be used in a greater number of regions.

Maize (corn) will be well known to many readers and is a major staple food crop grown in diverse agro-ecological zones and farming systems on the African continent. Indeed it is now the most widely distributed crop in Africa being grown in almost all ecological zones. Highest yields per hectare are registered in Egypt and Indian Ocean countries. It is consumed by people with varying food preferences and socio-economic backgrounds in sub-Saharan Africa (SSA) and its central role as a staple food in that region is comparable to that of rice or wheat in Asia. It is most highly consumed in eastern and southern Africa (ESA).

Sixteen of the 22 countries in the world where maize forms the highest percentage of calorie intake are in Africa. This one crop accounts for almost half of the calories and protein consumed in ESA, and one fifth of the calories and protein consumed in West Africa. An estimated 208 million people in SSA depend on maize as a source of food security and economic wellbeing. Maize occupies more than 33 million hectares of SSA’s estimated 200 million hectares of cultivated land. Considering the low average maize grain yields that are still pervasive in African farmers’ fields, meeting the projected increase demand for maize grain in Africa presents a challenge, but also a huge opportunity.

What can be achieved

Helpfully, there is the contemporary comparison of the highly successful development of this crop in the US and other world regions. This development has taken place over a relative short period of time historically and is an example of just what can be achieved when humans put their mind and science and technology to this challenge. The success of maize bodes even greater developments for the indigenous and largely underdeveloped African crops that will be described in future editions of Milling and Grain. Hammer-milled maize meal is currently the major African product which varies country-by-country. It is a basic product containing all the ground up bran, germ and as a result has a short shelf life with the germ becoming rancid very fast after milling. This same problem affects plate milled and sifted maize meal which having a great deal of ‘powder’ resulting in high adsorption of moisture and fast release of this moisture when cold, giving a layer of water over the ‘pap’ in the morning and turning the porridge sour.

The porridge cooks with a slightly yellow colour although the raw meal may look dazzlingly white. Bran, with a higher water adsorption than endosperm often gives a bloated feeling to the eager eater.

The need for high digestibility meal for human or animal consumption in Africa has never been greater. Palatability and the need to expose the starch in the grain accordingly plus the need for nutritional additives is also crucial. Also avoiding the respiratory problems when fed dry of overmilled flour is important as many people in East Africa prefer a very fine flour to make ‘nzima’ or ‘ugali’, a smooth gruel.

However, other people in Central and West Africa prefer coarser, unshelled flour, which gives more texture to the product.

Whatever the social custom Africa needs good quality maize meal obtained by de-germinating the maize then milling the samp and chips and if a plate or roller mill is used then sifting the meal with the de-germinator or polisher having separated the bran, germ meal and endosperm. In the next issue I will go on to describe lesser known crop opportunities like Sorghum which have been partly developed in other countries and are now set to make a big mark in African agricultural development, energy and nutrition.

by Clifford Spencer, Goodwill Ambassador, NEPAD – NEPAD is the African Union’s New Partnership for Africa’s Development

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