Nutritional profile of cassava
Cassava root is essentially a carbohydrate source. Its composition shows 60-65 percent moisture, 20-31 percent carbohydrate, 1-2 percent crude protein and a comparatively low content of vitamins and minerals. However, the roots are rich in calcium and vitamin C and contain a nutritionally significant quantity of thiamine, riboflavin and nicotinic acid. Cassava starch contains 70 percent amylopectin and 20 percent amylose. Cooked cassava starch has a digestibility of over 75 percent.Cassava root is a poor source of protein. Despite the very low quantity, the quality of cassava root protein is fairly good in terms of essential amino acids. Methionine, cysteine and cystine are however limiting amino acids in cassava root.
Cassava is attractive as nutrition source in certain ecosystems because cassava is one of the most drought tolerant crops, can be successfully grown on marginal soils, giving reasonable yields where many other crops do not grow well. Cassava is well adapted within latitudes 30° north and south of the equator, at elevations between sea level and two thousand meters above sea level, in equatorial temperatures, with rainfalls of fifty millimeters to five meters annually, and to poor soils with a pH ranging from acidic to alkaline. These conditions are common in certain parts of Africa and South America.
Cassava is a highly productive crop in terms of food calories produced per unit land area per unit of time. Cassava productivity is significantly higher than other staple crops. Cassava can produce food calories at rates exceeding 250,000 cal/hectare/day compared with 176,000 for rice, 110,000 for wheat, and 200,000 for maize (corn).
Cassava, like other foods, also has anti-nutritional and toxic factors. Of particular concern are the cyanogenic glucosides of cassava (Linamarin and Lotaustralin). These, on hydrolysis, release hydrocyanic acid (HCN). The presence of cyanide in cassava is of concern for human and for animal consumption. The concentration of these anti-nutritional and unsafe glycosides varies considerably between varieties and also with climatic and cultural conditions. It is therefore important that cassava species grown be carefully selected. Once harvested, cassava must be treated and prepared properly prior to human consumption, or animal consumption.
