International Journal of Food Research
ISSN: 2056-9734
Vol. 6(2), pp. 18-28, June 2019
doi.org/10.33500/ijfr.2019.06.003

High physical properties of cashew nut shell biochars in the adsorbtion of mycotoxins

Abderahim Ahmadou^1,2,4*, Alfredo Napoli³, Noel Durand^1,2 and Didier Montet^1,2

¹Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), UMR QualiSud, 73 rue Jean-François Breton, 34398 Montpellier Cedex 5, France.
²Qualisud, Université de Montpellier, CIRAD, Montpellier SupAgro, Université d'Avignon, Université de La Réunion, Montpellier, France.
³Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), UR Biowoeb, 73 rue Jean-François Breton, 34398 Montpellier Cedex 5, France.
⁴Institut Polytechnique Rural de Formation et Recherche Appliquée (IPR/IFRA) de Katibougou, Annexe de Dar-salam Bamako, Mali.

*To whom correspondence should be addressed. E-mail: abderahim.ahmadou@cirad.fr.

Received 26 March, 2019; Received in revised form 23 April, 2019; Accepted 29 April, 2019.

Keywords:
Biochar, Mycotoxin, Adsorption, Aflatoxins, Ochratoxin A.

Biochars were produced from cashew nut shell by pyrolysis on tubular oven at 400, 600 and 800°C. They were then analyzed and characterized (CHN, volatiles and pH); and were tested at different pH (4.15, 6.54 and 9.05) under different adsorption conditions (filtration and stirring) for their ability to capture aflatoxins and ochratoxin A (OTA). Above 25 mg of biochar in 5 mL of water-methanol mixture containing the mycotoxins (aflatoxins and OTA), all biochars adsorbed up to 100% of the aflatoxins at all pH (4.15, 6.54 and 9.05) and under all conditions (filtration or stirring) and pyrolysis temperature. Biochars also showed no effect on aflatoxins adsorption. Great differences were observed for the adsorption rates of OTA in function of the studied conditions. The adsorption efficiency of biochar for OTA increased with the increase of the pyrolysis temperature, which increases the specific surface area. The method used (filtration or stirring) had a strong influence on the adsorption rate, ranging from 29% by filtration up to 52% for 1000 mg of a biochar in 5 mL of water-methanol solution; and stirring increased the adsorption rate. In general, pH had less effect on the adsorption rate of OTA (2-5%). OTA best adsorption rate was observed for biochar produced at 800°C. The affinity between biochars and aflatoxins is very strong because at the same experimental conditions and equal masses, biochars adsorb more aflatoxins than OTA (5 times more).

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