Cyanide and aflatoxin loads of processed cassava (Manihot esculenta) tubers (Garri) in Njaba, Imo state, Nigeria

Abstract

Objectives: The present study sought to investigate the role of palm oil, in conjunction with the duration of fermentation, on cyanide and aflatoxin (AFT) loads of processed cassava tubers (Garri). Materials and Methods: Matured cassava (Manihot esculenta Crantz) tubers were harvested from three different locations (Akunna, Mkporo-Oji and Durungwu) in Njaba Local Government Area, Imo State, Nigeria. The cassava tubers were processed into Garri according to standard schemes with required modifications and measured for cyanide content using titrimetric methods. Samples of Garri for determination of AFT levels were stored for 30 days before the commencement of spectrophotometric analysis. Results: Cyanide content of peeled cassava tubers was within the range of 4.07 ± 0.16-5.20 ± 0.19 mg hydrocyanic acid (HCN) equivalent/100 g wet weight, whereas the various processed cassava tubers was within the range of 1.44 ± 0.34-3.95 ± 0.23 mg HCN equivalents/100 g. For the 48 h fermentation scheme, Garri treated with palm oil exhibited marginal reduction in cyanide contents by 0.96%, 3.52% and 3.69%, whereas 4 h fermentation scheme is in concurrence with palm oil treatment caused 4.42%, 7.47% and 5.15% elimination of cyanide contents compared with corresponding untreated Garri samples (P > 0.05). Levels of AFT of the various Garri samples ranged between 0.26 ± 0.07 and 0.55 ± 0.04 ppb/100 g. There was no significant difference (P > 0.05) in AFT levels among the various samples in relation to their corresponding sources. Conclusion: The present study showed that the 48 h fermentation scheme for Garri production caused significant (P < 0.05) reduction, but did not obliterate the cyanide content of cassava tubers. Conversely, the 48 h fermentation scheme promoted the elevation of AFT levels, but was relatively reduced in Garri samples treated with palm oil.