Negligible effects of tryptophan on the aflatoxin adsorption of sodium bentonite.

MAGNOLI A.P; COPIA P. ; MONGE M.P.,; MAGNOLI C.E,; DALCERO A.M; CHIACCHIERA S.M.

FOOD ADDITIVES AND CONTAMINANTS. PART B - SURVEILLANCE COMMUNICATIONS

TAYLOR & FRANCIS LTD

Año: 2014 vol. 31 p. 2063 - 2070

1939-3210

The main objective of this study was to evaluate the competitive adsorption of tryptophan (Trp) on adsorption capacity of aflatoxin B1 (AFB1) by a sodium bentonite (NaB) from Argentine, simulated gastrointestinal conditions of monogastric animals. The Trp adsorption isotherm shows a high affinity between the adsorbent and the amino-acid at to assayed pH. A significant decrease in the surface excesses at saturation was observed in the presence of KCl, being 6 times lower of the value found in the absence of KCl. On the other hand, Trp adsorption kinetic show that adsorption is extremely fast and the desorption studies demonstrate that adsorption processes was reversed. The AFB1 adsorption isotherms on NaB with and without Trp were S-type explained by the FFG model, show a high affinity the NaB by AFB1. The highest surface excess at saturation was observed in absence of Trp. This result shows the partial occupation of the adsorption sites of bentonite by Trp, this could result in decreased ability of NaB to protect the animal against the severe mycotoxicoses. This fact has practical implications, since if the Trp was captured in the gastrointestinal tract of poultry, this would be released as its concentration with decrease in gastric fluids besides, capturing Trp by NaB not be important since the viewpoint of amino bioavailability.