Effect of clarification process on the removal of pesticide residues in white wine

Presence of pesticides in wine is of great concern, due to their extensive use in viticulture. Seven clarifying agents (activated carbon, bentonite, polyvinylpolypyrrolidone, gelatin, egg albumin, isinglass, and casein) were examined in removing pesticides from white wine, fortified with single solutions and mixtures of pesticides. Solid phase extraction followed by GC-ECD was performed to analyse pesticide residues. The order of decreasing adsorbent effectiveness was: activated carbon 64% > egg albumin 23% >= gelatin 22% > PVPP 17% >= casein 16% > bentonite 8%. Isinglass showed 22% removal at the highest permitted concentration. The effect of the type of the clarifying agent and pesticide's chemical structure and properties (octanol-water partition coefficient and water solubility) on pesticide removal was studied. Distinct behavior is exhibited by each clarifying agent. Adsorption is increased by increasing hydrophobicity and decreasing hydrophilicity of pesticides. The removal of each pesticide from its single solution is generally higher than that from its mixtures, revealing the antagonistic and synergistic effects. (C) 2016 Elsevier Ltd. All rights reserved.