Composición química de la raíz y de la hoja de algunas variedades de yuca Manihot

Abstract

Eight varieties of cassava tubers (Manihot), as well as their dehydrated leafs, were studied to obtain information regarding their use in animal nutrition and on the industrial production of starch. The varieties were grown in Guatemala, 5 of them in a dry subtropical area and the remaining 3 in a dry tropical area. The tubers of each variety were weighed and the quantity of rind was determined. The analysis of both roots and leafs included determinations of moisture, ether extract, crude fiber, protein, ash, and carbohydrate, as well as calcium, phosphorus, iron, and HCN. The percentage of tuber's rind varied between 11.1 and 20.3%, with an average of 16.1 for all varieties. The roots produced, by a simple extraction with water, at least 70% of the total starch of the root. The chemical composition analyses showed that the cassava contains small amounts of protein, but is rich in carbohydrates, specially starch. Thus, it is a good caloric concentrate that can be used in animal feeding, providing that all the hydrocyanic acid contained in the root is eliminated. The root could be also used, with certain economic advantages, in the feeding of dairy cattle and also in ratios for cattle and swine. The rind is relatively rich in the chemical components studied and it could be an important by-product in the starch industry, providing it is detoxified before using it. It could also be used in the feeding of ruminants as ensilage. However, it is recommended that a study be made of the nutritive value of this product by digestibility assays and to determine if the minerals it contains are biologically available for animals. The cassava leaf is relatively rich in protein, ash, calcium and ether extract, it is considered of good nutritive value, but, as indicated before, it must be detoxified before it is used for animal consumption. Hydrocyanic acid concentration was highest in the peel, and lowest in the leaf. There was a large range in HCN concentration between varieties.