Elimination of Aflatoxins B1 and B2 in White and Red Wines by Bentonite Fining. Efficiency and Impact on Wine Quality

Aflatoxins B1 and B2 are two highly toxic mycotoxins that have been sometimes found in wines. Currently, no technological solution is available to reduce or eliminate aflatoxins from wines when they are present. Therefore, this work aims to study the efficiency of already approved wine fining agents like activated carbon, potassium caseinate, chitosan, and bentonite for aflatoxins B1 and B2 removal from white and red wines. It was observed that the fining agents' efficiency in removing aflatoxins was dependent on the wine matrix, being higher in white than in red wine. Bentonite was the most efficient fining agent, removing both aflatoxins (10 μg/L total) from the white wine and 100% of aflatoxin B1 and 82% of aflatoxin B2 from red wine. The impact of bentonite on white wine chromatic characteristics was low (color difference, ΔE* = 1.35). For red wine, bentonite addition caused a higher impact on wine' chromatic characteristics (ΔE* = 4.80) due to the decrease in total anthocyanins, although this decrease was only 1.5 points of color intensity. Considering the high efficiency of bentonite in aflatoxins B1 and B2 removal and despite the impact on red wine color, bentonite is a very good technological solution for aflatoxin removal in white and red wines.