Full Length Research Paper

Effect of processing conditions on cyanide content and colour of cassava flours from West Africa

Franck Hongbété^1,3, Christian Mestres²*, Noël Akissoé¹ and  Mathurin Coffi Nago¹

¹Centre Régional de Nutrition et d’Alimentation Appliquées, CERNA-UAC/FSA, 01 BP 526 Cotonou, Bénin.

²CIRAD/UMR QualiSud, TA 70/16, 73 rue J. F. Breton, 34 398 Montpellier Cedex 5, France.

³Faculté d’Agronomie, Université de Parakou, BP 123 Parakou, Bénin.

*Corresponding author. E-mail: christian.mestres@cirad.fr. Fax: +33 467614444.

Accepted  22  December, 2008

   Abstract

The evolution of cyanide content and colour were monitored during the processing of lafu, traditional flour and improved flour from five cassava cultivars from Benin. In addition, the total phenol, polyphe-noloxidase (PPO), peroxydase (POD) and linamarase activities were assessed. The processing of cassava in lafu and improved flour proved superior for producing safe and white non-fermented and fermented cassava flours with total cyanide mean values of 16.6 and 11.4 mg HCN/kg, db and DE values of 9.2 and 12.1, respectively. Detoxification appeared to be only linked to processing, in particular to the size reduction level of cassava roots, regardless of the initial cyanide level and the linamarase activity of the fresh roots. Cassava flour yellowness was closely linked to the phenol content (r = 0.95) that decreased after steeping and pressing. The PPO and POD activities did not appear to be linked to flour discoloration.

Key words: Manihot esculenta, cassava processing, cyanide, colour, total phenol, polyphenoloxidase, peroxydase, linamarase.