From grape to wine: Fate of ochratoxin A during red, rose, and white winemaking process and the presence of ochratoxin derivatives in the final products

Abstract

The presence of ochratoxin A (OTA) in wine is mainly due to the contamination of grapes by Aspergillus carbonarius and A. niger, still in the vineyard or at stages prior to winemaking. Throughout winemaking process, although there is a reduction in OTA levels, modified mycotoxins may also be formed. In fact, modified mycotoxins are compounds that normally remain undetectable during the conventional analysis used for the parent toxin. In this context, the current study aimed to evaluate the effect of grape variety and winemaking steps on OTA fate as well as the formation of modified ochratoxins. White, rose and red wines were prepared from Muscat Italia, Syrah and Touriga Nacional varieties, respectively. OTA was determined during different steps of winemaking by UHPLC-ESI-MS/MS. Identification of ochratoxin derivatives was performed using tandem MS experiments. A reduction of 90.72, 92.44 and 88.15% in OTA levels was observed for white, rose and red wines, respectively. Among the sought targets, the following ochratoxin-derived candidates were identified: ochratoxin β, ochratoxin α methyl ester, ochratoxin B methyl ester, ochratoxin A methyl ester, ethylamide ochratoxin A, ochratoxin C and ochratoxin A glucose ester. These results indicate that the formation of ochratoxin derivatives leads to an underestimation of total mycotoxin levels in wine and, therefore, the inclusion of techniques for multi-mycotoxins detection should be considered.