Assessment of Cassava (Manihot esculenta Crantz) Fermentation and Detoxification Using Previously Cassava-fermented Chips

Aims: This study was aimed as the assessment of dried cassava-fermented chips (DFCC) efficacy in terms of their fermentation acceleration and cyanogens reduction potential.

Study Design: An experimental study design was employed in order to achieve the objective of the study.

Place and Duration of Study: The study was carried out in the Laboratoire de Microbiologie of the University of Yaoundé 1, Cameroon between October 2011 and August 2014.

Methodology: Commercial fermented cassava chips samples were analyzed for their performances to accelerate the retting of cassava roots. The performances of DFCC were determined by periodical measure of the degree of softening of the roots in retting process by penetrometry for 4 days. Further, cassava chips were produced at different fermentation times and assessed for the same properties. Finally, the best fermentation time to obtain cassava-fermented chips capable to reduce efficiently the retting time was determined and chips produced at this time were used after different pre-treatments in order to assess their impact on the fermentation performances and detoxification of cassava roots as compared to spontaneous retting.

Results: Results indicated that DFCC samples collected have high retting performances variability correlated to their fermentation time and microbial concentration. The best DFCC used as cassava retting accelerator (CRA) was obtained after 96h of fermentation (CRA-96). It permitted to reduce the retting time from 71.3±8.5 hours to 35.8±1.4 hours compared to the spontaneous fermentation; and final cyanides contain of 7.86±0.00 ppm corresponding to 98.8% reduction. Optimization assays showed that CRA-96 when soaked for 12 h before use, reduce retting time by 58.5% but did not modify cyanides reduction.

Conclusion: The adoption of the CRA-96h as cassava retting accelerator by cassava fermented by-products producers would be great advantage for them who often only ret for 1-2 days and then get into trouble with large cyanide levels in their flour.