Evolution of ochratoxin A content from must to wine in Port Wine microvinification

Abstract

To study the evolution of ochratoxin A (OTA) content from must to wine during the making of Port Wine, grapes from the five most common varieties of Port Wine were harvested and combined in equal percentages in order to perform microvinifications. Three sets of assays were studied: a blank (A), where the most common Port Wine-making process was used; in the second (B), a solution of OTA was added to the initial must; in the third (C), the grapes were aspersed with an inoculating solution of OTA-producing fungi. Samples were collected, in duplicate, on four different occasions throughout the process. The influence of the addition of SO2 to the must was also assessed in each set. The quantification of OTA was based on the standard reference method for wines (European Standard prEN 14133), which includes clean-up via immunoaffinity columns and HPLC with fluorescence detection. The limits of detection were 0.076 microg/l for wine and 0.114 microg/l for must. The method was validated by assessing the precision, accuracy and by obtaining an estimate of the global uncertainty. Overall, the levels of OTA observed during the vinifications dropped by up to 92%, and no grapes used in this work were contaminated naturally.

Removal of Ochratoxin A (OTA) from Naturally Contaminated Wines During the Vinification Process

“…The range of OTA content in wines produced in Europe varied between 0.01 and 3.4 µg/L 4 . Values higher than 0.5 µg/L were reported by several authors 10,26,28,30 . In the winemaking process, OTA must be considered a principal safety hazard and the occurrence of this toxin in wine must be systematically investigated 15 .…”

Mycotoxin Contamination of Beverages: Occurrence of Patulin in Apple Juice and Ochratoxin A in Coffee, Beer and Wine and Their Control Methods

“…During this time the mycotoxin level diminishes, probably due to its adsorption on the Saccharomyces yeast surface, to its interaction with metabolites produced by yeast or its degradation by the lactic bacteria still present in wine [284][285][286]. Grape washing, cooking and pressing can also promote the OTA content drop [53,287]. During vine fruits production, efficient drying and turning over are required because in these stages, moisture and sugar content stimulates Aspergillus section Nigri development and OTA synthesis [288].…”

Occurrence of ochratoxin A in grapes, juices and wines and risk assessment related to this mycotoxin exposure

“…This procedure also provides that the characteristic alcohol level of this beverage is achieved, since the fermentation was terminated. In this way, enological practices influence the concentration of OTA (PIETRI et al, 2001;BELLI et al, 2004;RATOLA et al, 2005;CHIODINI et al, 2006). VALERO et al (2008) found high levels of OTA in wines produced using grapes with excessive degree of ripeness (15.62ng ml -1 ) and fortified wines (27.79ng ml -1 ) elaborated with grape wine distillate.…”