Nutrient Composition and Processing Effects on Cassava Leaf (Manihot esculenta, Crantz) Antinutrients

Abstract

Leaves of 3 genetically improved varieties of cassava plants were harvested and subjected to different processing methods including sun-drying (SND), oven-drying (OVD), steaming (STM), shredding (SHD) and steeping (STP) and a combination of these methods to deliberately reduce the high level of cyanogenic glucosides present in the leaves. A combination of SHD and SND (SHD+SND) seemed to be the most effective technique of reducing the cyanide content. Proximate/mineral composition and gross energy were determined. Particular attention was paid into the determination of hydrocyanic acid (HCN), polyphenols (tannic acid) and phytic acid as they constitute the major anti-nutrients militating against the utilization of cassava leaf in animal nutrition. The leaves contained: crude protein 348.0gkg DM (range: -1 332.0 363.0gkg DM); crude fibre 121.0gkg DM (range: 115.0 127.0gkg DM); ether extract 70.0gkg DM -1 -1 -1 -1 (range: 63.0 75.0gkg DM); ash 69.0gkg DM (range: 63.0 78.0gkg DM) and gross energy 47.0MJkg -1 -1 -1 -1 (range: 46.5 47.2MJkg ). The CLM protein content was high and comparable with some rich conventional -1 protein sources of plant and animal origins used in monogastric feed formulation. The mineral content was high particularly Ca, Zn, Ni and K. The “cyanide scare” associated with acute intoxification when food substances rich in cyanide is ingested at high levels seemed to be obviated by a combination of processing methods (SHD+SND).