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Cassava • The forgotten game changer

By: Charles Benoni Okine
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Cassava can be grown in any part of the country
Cassava can be grown in any part of the country

ITS botanical name is manihot esculenta. It is also known as yuca or manioc. Its starchy roots provide food and income for more than 800 million people worldwide.

In Africa, where consumption is highest, the plant is said to bear smaller yields than its cousins in Asia and South America.

However, African varieties tend to be more tolerant of blights, such as the deadly cassava mosaic disease now spreading across Asia, according to a report published by Biosciences for Farming in Africa (B4FA) last week.

In Ghana, the root tuber is a delicacy. Mention fufu and gari and everyone knows it is mostly from cassava. Popular among the Akan speaking people in Ghana, cassava is also widely planted across the country because it serves many purposes aside being used for the preparation of food.

About 12 years ago, the government launched a major project under a presidential initiative. Farmers were asked to plant more cassava to feed a plant which processed the crop into starch for export. Much as this was laudable and started well, the plant is now defunct.

A myriad of reasons have been adduced for the unfortunate phenomenon but that does not take away the potential of this special crop to create more jobs in the agricultural sector to help increase foreign exchange through exports, among other things.

Uses of cassava
The Food and Agriculture Organisation (FA) of the United Nations says flour produced from the cassava plant, which on account of its low content of noncarbohydrate constituents might well be called a starch, is known in world trade as tapioca flour. It is made into a group of baked or gelatinised products or manufactured into glucose, dextrins and other products.

It is said that the food industries are one of the largest consumers of starch and starch products. In addition, large quantities of starch are sold in small packages for household cooking.

Confectioneries: In addition to the widespread use of dextrose and glucose syrup as sweetening agents in confectioneries, starch and modified starches are also used in the manufacture of many types of candies such as jellybeans, toffee, hard and soft gums, boiled sweets (hard candy). fondants and Turkish delight.

Canned fruits, jams and preserves: Recent advances in these industries include the partial replacement of sucrose by dextrose or sulphur-dioxide-free glucose syrup. This helps to maintain the desired percentage of solids in the products without giving excessive sweetness, thereby emphasising the natural flavour of the fruit.

Monosodium glutamate (MSG): This product is used extensively in many parts of the world in powder or crystal form as a flavouring agent in foods such as meats, vegetables, sauces and gravies. Cassava starch and molasses are the major raw materials used in the manufacture of MSG in the Far East and Latin American countries.

The production of commercial caramel: Caramel, as a colouring agent for food, confectionery and liquor, is extensively made of glucose rather than sucrose because of its lower cost. If invert sugar, dextrose or glucose is heated alone, a material is formed that is used for flavouring purposes but if it is heated in the presence of certain catalysts, the colouration is greatly heightened, and the darker brown products formed can be used to colour many foodstuffs and beverages.

Glucose: According to Whistler and Paschell, Abu Mansur, an Arabian teacher and pharmacologist, about 975 A.D., described the conversion of starch with saliva into an artificial honey. In 1811 Kirchoff discovered that sugar could be produced by the acid hydrolysis of starch. Glucose, or dextrose sugar, is found in nature in sweet fruits such as grapes and in honey.

At present, glucose is usually produced as a syrup or as a solid. The physical properties of the syrup vary with the dextrose equivalent (DE) and the method of manufacture. Dextrose equivalent is the total reducing sugars expressed as dextrose and calculated as a percentage of the total dry substance. Glucose is the common name for the syrup and dextrose for the solid sugar. Dextrose, sometimes called grape sugar, is the D-glucose produced by the complete hydrolysis of starch.

Cassava in animal feed: Cassava is widely used in most tropical areas for feeding pigs, cattle, sheep and poultry. Dried peels of cassava roots are fed to sheep and goats and raw or boiled roots are mixed into a mash with protein concentrates such as maize, sorghum, groundnut or oil-palm kernel meals and mineral salts for livestock feeding.

In many tropical regions, the leaves and stems of the cassava plant are considered a waste product. However, analytical tests have proved that the leaves have a protein content equivalent to that of alfalfa (about 17-20 per cent). Feeding experiments also showed that dehydrated cassava leaves are equivalent in feed value to alfalfa.

Nonfood uses: It has non-food uses. Starch makes a good natural adhesive. There are two types of adhesives made of starches, modified starches and dextrins: roll-dried adhesives and liquid adhesives.

The application of cassava in adhesives continues to be one of the most important end uses of the product. In the manufacture of glue, the starch is simply gelatinised in hot water or with the help of chemicals. For conversion into dextrin, it is subjected separately or simultaneously to the disintegrative action of chemicals, heat and enzymes.

African scientists on cassava
A geneticist at the International Institute of Tropical Agriculture (IITA) in Ibadan, Nigeria, and his colleagues are on a mission to improve cassava.

The project scientists are using genomic data to identify useful traits for breeding cassava varieties that will suit the world’s needs — safeguarding against starvation as the climate warms, populations grow and viruses spread.

When the African plants reach Thailand, scientists there will cross them with cassava varieties adapted to Asia. Then they will screen the resulting offspring for genetic markers that the lead scientist and his colleagues use to predict a plant’s resistance to mosaic viruses, along with 12 other traits — such as leaf colour and the amount of edible starch in each root.

These genetic markers have helped the researchers in Nigeria to breed eight types of cassava that are now growing on test plots across the country. Scientists and farmers will compare them with the best existing cassava varieties in wide use.

Way forward
Despite the importance of the crop and how it can contribute to the growth of Gross Domestic Product (GDP), create jobs and help boost the country’s foreign exchange earnings, it is crucial for the government to place a special focus on the crop and release funds for further research to improve the current varieties and yields.

Through the government’s Planting for Food and Jobs, many people should be encouraged to plant more cassava.

Ghana has a lot of unused arable lands in every part of the country and those can be used to cultivate the crop in real commercial quantities to feed the people, feed the factories and for the export market. What Nigeria is doing is not beyond Ghanaian scientists. They also need more encouragement to improve the varieties in Ghana.

Cassava can be a game changer and, therefore, the potential must not be overlooked.