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University of Arizona (1995)

Reduction of aflatoxins in African peanut and peanut products

Mahdi, Salah Aldin

Titre : Reduction of aflatoxins in African peanut and peanut products

Auteur : Mahdi, Salah Aldin

Université de soutenance : University of Arizona

Grade : Doctor of Philosophy (PhD) 1995

Résumé
Naturally-contaminated roasted peanuts containing approximately 1500 ppb total aflatoxins were ground and cooked with water to simulate the preparation of a typical African sauce. The peanut sauce was prepared by mixing 200 g. ground peanuts with 700 ml of water, then bringing the mixture to a boil. Five minutes after the peanut sauce began to boil under slow heat, hydrogen peroxide at 0 %, 1 % or 5 % was added in combination with other food additives and the mixture was cooked for 30 minutes. Additives used were : 2 % sodium bicarbonate (NaHCO₃) ; 2 % ammonium bicarbonate (NH₄CO₃) ; 2 % sodium hydroxide (NaOH) ; ammonium persulfate [(NH₄)₂S₂O₈] and 2 % ammonium hydroxide. For analysis two methods of aflatoxin extraction were used. The AOAC-approved CB method produced a stable emulsion with sauces treated with sodium and ammonium hydroxide, so that extraction was not possible. The second, more successful method used methanol extraction. Both TLC and HPLC were used for aflatoxin analysis. Cooking alone reduced aflatoxins B₁, B₂ and G₂ to half or more of the original values, but no significant reduction was observed for aflatoxin G₁. Although cooking with food additives further reduced aflatoxin, none of the chemicals alone or in combiI.ation with hydrogen peroxide were successful in eliminating aflatoxins from the peanut sauce. However, the peanut sauce treated with sodium bicarbonate and 1 % hydrogen peroxide had the aflatoxins reduced to nearly the 20 ppb FDA action level.

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