Effect of activated carbon on ochratoxin A reduction in "Pedro Ximenez" sweet wine made from off-vine dried grapes

The application effect of an activated carbon on Ochratoxin A (OTA) contents was studied in small-scale winemaking trials in musts from sun-dried grapes Pedro Ximenez variety. For this experiment a 2 x 3 x 4 factorial arrangement was used in the same batch, the factors being adsorbent (control and activated carbon), time (1, 2, and 3 h), and adsorbent dose (control, 0.12, 0.24, and 0.36 g/L). Immunoaffinity columns to sample clean-up and enzyme-linked immunosorbent technique were utilized for OTA determination. The two-parameter Freundlich equation was used to evaluate the adsorption data and the K (F) values obtained ranging from 0.11 to 2.68. Activated carbon at 0.24 g/L dose was the most effective treatment to reduce OTA, up 70% in sweet wines. The mean percentages reduction of color parameters (intensity and tone) and total polyphenol index of the wines were 9.8, 3.5, and 4%, respectively. The study demonstrates that this treatment can be successfully applied as a suitable technique to reduce OTA contents of the musts and sweet wines during the early winemaking processes.