Assessment Of Nutritional Composition And Cyanogenic Content Of Gari Sold

1.0 Introduction

Cassava is a shrub of the Euphobiaceae, the spurge family, which is a native of South America. However, it is extensively cultivated as an annual crop in tropical and subtropical regions for its edible starchy tuberous root.
Cassava belongs to the genus Manihot esculenta crantz of the natural order Euphobiaceae. It is said to have been introduced from Brazil. Its original home to West Africa was by the early Portuguese explorers. Cassava contains cyanogenic glucosides in the form of linamarin (93%) and to much less extent, Lotaustralin (7%). The amount of cyanogenic glucosides varies with the part of the plants.

Cassava is the most widely grown of the root crops as it is adaptable to a broad range of climatic and soil conditions. Cassava is always processed before consumption on marketing. Cassava is processed to detoxify it and also increase its storage life and facilitate its transport. (Ihekoronye et al., 1985)

Cassava is a major source of carbohydrates that matches the Nigerian population growth. Cassava is diversified into different food products and these products are available all year round thus making cassava an important staple food for many rural households in Nigeria. One of such is garri (Onabolu, 2001).

Garri or garri is a popular West African food made from cassava tubers. The spelling “garri” is mainly used in Nigeria, Cameroon and Ghana. To make garri, fresh cassava tubers are peeled, washed and grated or crushed to produce a mash. The mash is placed in a porous bag and allowed to ferment and dehydrate for one or two days and weighed down with a heavy object or with a hydraulic press while it is fermenting. The dewatered and fermented lump of mash is pulverized, sifted and the resulting semi dried mash is roasted by heating in a pan (Nweke et al., 2002). The resultant granular product which is preferred can be consumed dry or with cold water or reconstructed with hot water to form “dough” which is eaten with soup. (Oluwole et al., 2004)

The safety concern in the quality of garri which is hydrogen cyanide arises from the presence of cyanogenic glucoside which upon hydrolysis produces cyanohydrins that further breaks down to release hydrogen cyanide – a known plant toxin (Bokanga, 1994 ; Ernesto et al., 2000). The traditional developed methods of processing cassava products have been found to be grossly inadequate in the removal of cyanogens, irrespective of whether the roots are from low or high cyanide variety. (Koch et al., 1994; Achinewhu and Owuamanam, 2001).

The safe level of hydrogen cyanide in garri is 10mgHCN/kg, presence of cyanide above this in cassava flour by FAO/WHO (1999), may pose health risk to the consumers. Some of the health conditions associated with cassava meals include: Tropical Ataxic Neuropathy (TAN); (Oshuntokun et al., 1968; Akintowa et al., 1994).

The aim of this work is to carry out the comparative study on the proximate composition and functional properties of conventional garri and garri from chips, so as to know the one which is best for consumption.