Aro et al., 2010. Livest. Res. Rural Dev., 22 (11)
A study of cassava tuber wastes (CTW) produced by a cassava starch-processing factory in Ondo State of Nigeria was made in which the types and quantity of these wastes were determined. This study revealed that five different types of CTW are produced on a daily basis and are subsequently discharged into the immediate environment. These categories of wastes with the corresponding quantities (fresh weight basis) produced by the factory are: the cassava starch residues (CSR) or pomace (17 metric tonnes/day), cassava peels (CAP) (5 metric tonnes/day), cassava effluent (CAE) (15.4 metric tonnes/day), cassava stumps (CAS) (8 metric tonnes/day) and cassava whey (CAW) (1.51 metric tonnes/day).
The proximate composition of samples collected in respect of these five types of wastes showed that moisture was highest in CAW (96.7%) and lowest in CAS (64.1%). Crude fibre was highest in CAP (29.6%) but was not detected in the whey (CAW). The CAS had the highest content of fat (5.35%) while it was not detected in CAW. Protein was highest in CAP (4.20%) and lowest in CSR (1.12%). Ash content was highest in CAP (7.47%) and lowest in CAW (1.88%). The nitrogen free extractives (NFE) were highest in CAW (95.7%) and lowest in CAP (55.5%).
The analyses of the anti-nutritional factors revealed that cyanide, phytate, oxalate, tannins, saponins and total alkaloids were highest in CAW (61.1mg/kg), CSR (15,926mg/kg), CAE (674mg/kg), CAP (3.90%) and CAS (0.15% and 0.52%) respectively while CAP had the highest content of Potassium (269mg/kg), Calcium (121mg/kg), Magnesium (236mg/kg), Sodium (261mg/kg) and Phosphorus (3233mg/kg). Iron content was highest (16.2mg/kg) in CAE. Copper (10.8mg/kg) and Selenium (1.27mg/kg) were highest in CSR while Manganese (0.43mg/kg) was detected only in CAP. Molybdenum, Cobalt and Arsenic were not detected in any of the cassava tuber waste samples.
These analyses revealed that CTW have appreciable levels of nutrients that could be tapped for beneficial use. The levels of anti-nutrients in some of them are below the normal toxic level but could still be reduced or removed through methods designed for such. Also the various options available for protein enrichment of these wastes could be explored in a bid to convert these wastes to wealth.