In vitro efficacy of mycotoxins' adsorption by natural mineral adsorbents

The paper describes in vitro model for evaluation of natural mineral adsorbents ability to adsorb mycotoxins. Bentonite, diatomite and zeolite were prepared in the Institute for Technology of Nuclear and Other Mineral Raw Materials, Belgrade (Serbia). A total of six mycotoxins: aflatoxin B1 (AFL), ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZON), diacetoxyscirpenol (DAS) and T-2 toxin were tested in vitro. For adsorption experiments crude extracts of mycotoxins, produced in the Department of Microbiology of Bio-ecological Center in Zrenjanin (Serbia), were used. The ability for binding mycotoxins was evaluated in the electrolyte 0.1 M K2HPO4 which pH value was adjusted to 3.0 and 6.9, respectively. Mass ratio of individual mycotoxin and natural mineral adsorbent was 1:5000. The experimental mixtures were incubated for 1 hour on a rotary shaker (185 rpm) at room temperature (22-25 deg C). After incubation the extractions of unadsorbed mycotoxins from the filtrates were performed with organic solvents, and their quantifications were done by thin-layer chromatography (TLC). By the use of TLC method it was noted that bentonite, diatomite and zeolite binded more than 95% of applicated AFL. In the case of OTA only diatomite adsorbed that toxin - adsorption index was 66.67%. Binding of DON has been observed only at pH 3.0 of electrolyte. Its adsorption index varied from 25.00 to 50.00% depending on the type of mineral adsorbent. Effect of electrolyte pH value on the binding of ZON was not so expressed. Its adsorption index ranged from 12.20 to 37.00%. In the case of type A trichothecenes (DAS and T-2 toxin) bentonite, diatomite, and zeolite binded only T-2 toxin. The amount of adsorbed T-2 toxin ranged from 16.66 to 33.33%. The obtained results point out the need for activation or processing of natural mineral adsorbens, especially bentonite and zeolite, in order to increase the efficiency of adsorption of the wider spectrum of mycotoxins.