RESUMO
During the course of the EU H2020 OLEUM project, a harmonized method was developed to quantify volatile markers of the aroma of virgin olive oil with the aim to support the work of sensory panel test to assess the quality grade. A peer validation of this method has been carried out, with good results in terms of analytical quality parameters. The method allows the quantification of volatile compounds by SPME-GC with two possible detectors, flame ionization detector and mass spectrometry, depending on the technical facilities of the labs applying this method. The method was optimized for the quantification of 18 volatile compounds that were selected as being markers responsible for positive attributes (e.g. fruity) and sensory defects (e.g. rancid and winey-vinegary). The quantification is carried out with calibration curves corrected by the internal standards. Additionally, a protocol is provided to prepare the calibration samples. This procedure enhances reproducibility between labs since one of the main sources of errors is the application of different procedures in calibration.
RESUMO
Toasting Quercus sp. oak wood is one of the key stages in manufacturing barrels intended for aging wines and spirits. During this operation, the increase in temperature causes variable modifications in the physical structure and, more importantly, the chemical composition of the wood. Polycyclic aromatic hydrocarbons (PAH) are high-risk molecules likely to be formed during toasting of the wood and later extracted by wine or spirits in direct contact with the barrel. In the context of an analysis of all potential sources of risk associated with the manufacture of barrels for winery use [prevention policy defined using a Hazard Analysis Critical Control Point (HACCP) approach], we carried out a preliminary study to provide a more accurate assessment of potential risks related to the presence of PAH in cooperage and winemaking. Wood toasted to different levels under different conditions, as well as wines aged in barrels made using different methods, was analyzed by gas chromatography and mass spectrometry (GC-MS) for the identification of the main PAH present, quantification of each of the molecules extracted, and estimation of any possible toxicological risks, via a comparison of values with those measured in other types of food. The results clearly showed that the heating processes associated with barrel production actually resulted in the formation of various molecules in the PAH family. However, only a minority of the target PAH presented high toxicity, particularly carcinogenic potential. Because of the specific toasting process used, benzo[a]pyrene, the best-known, and one of the most dangerous, contaminants, was not significantly present in toasted barrel wood. In view of the PAH concentrations in wood and the low solubility of these compounds, their extraction in wine is apparently relatively slow and limited. Finally, comparing the overall PAH concentrations, and particularly those of the most toxic compounds, with estimated absorption from food or the environment, we found it was obvious that the contribution of toasted barrels to the total amount was extremely low and should not, therefore, be considered a major health concern.