Gari Yield and Chemical Composition of Cassava Roots Stored Using Traditional Methods

Abstract

Cassava has gained increased industrial, economic and nutritional importance over the years, because of the multifarious uses of the starch-rich roots. Several storage methods have been proposed for cassava roots due to the physiological deterioration that sets in 2-3 days after harvesting, followed by microbial deterioration 3-5 days thereafter. Nigeria is the largest producer of cassava in the world; with 80% of the production from rural farmers who cannot practice modern storage methods. Furthermore, gari (a major fermented product of cassava root) is an important component of cassava production in Africa. It is therefore imperative to quantify the effects of traditional storage methods being practiced by the farmers on the yield of gari and the chemical composition of cassava roots. Four traditional storage methods (polyethylene bags, jute bags, trench and plastic storage boxes containing sawdust) were used to store fresh cassava roots for 14 days. The roots were evaluated at 7 day intervals for moisture, ash, crude fibre, carbohydrate, pH, TTA, cyanogenic potentials and yield of gari. The result revealed a varied impact of the storage methods on the chemical composition of the root over the holding period. The moisture, carbohydrate, cyanogenic potentials and yield of gari reduced while the ash and crude fibre increased as the holding period increases. The moisture content reduced significantly from 66.52% to 60.15, 61.97, 63.26, and 64.17% for samples stored in polyethylene bag, jutebag, trench and storage box respectively. The sample stored in the plastic storage box had the highest gari yield of 29.9 and 24.2% after 7 and 14 days of storage respectively. While the gari yield from the roots stored in trench and jute bags were 22.8 and 23.4% respectively, after 14 days storage. This was significantly lower than the yield obtained for fresh roots of 31.2%. It could therefore be deduced from the study that storage of fresh cassava roots could be done for a maximum of 7 days using plastic storage boxes and trench containing wet sawdust for gari production.