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Mérignac, France

Prida A.,British Petroleum | Chatonnet P.,Laboratoire Excell
American Journal of Enology and Viticulture | Year: 2010

Barrel-aged wine is a complex mixture and its olfactory perception results from the interaction of many flavors. To estimate the role of oak-derived flavor compounds, it is necessary to consider odor activity values (OAV) and to perform a correlation study to assess the impact of flavor compounds on the flavor attributes. Twenty Spanish and French wines, each aged in different types of barrels, were studied using both sensory (descriptive) and chemical (GC-MS) analysis. Paired-sample t-tests were used to assess whether there were systematic differences in the concentrations of oak-derived compounds between wines aged in different barrels and evaluated differently in the sensory tests. Regardless of their low OAVs, furanic compounds (furfural, furfuryl alcohol, and 5-methylfurfural) increased the ''overall oak'' intensity rating and decreased the ''fruity'' intensity rating. It is hypothesized that these compounds indirectly impacted the respective intensities. The presence of cis- and trans-whisky lactones, eugenol, and vanillin increased the intensity rating of the vanilla/pastry descriptor, while furfural and 5-methylfurfural diminished it. Regardless of the volatile phenols (guaiacol, 4-methylguaiacol, eugenol) described as smoky and spicy in their pure state, no reliable links were found between these compounds and the respective sensory descriptors in wines. Samples described as having higher olfactory persistence were richer in relatively high-boiling wood compounds, such as trans- and cis-whisky lactone, maltol, eugenol, and vanillin, than their paired samples, explaining their retronasal persistence.© 2010. Source

Agency: Cordis | Branch: FP7 | Program: BSG-SME | Phase: SME-1 | Award Amount: 1.35M | Year: 2011

Cork taint refers to a common fault in wine, associated with the presence of haloanisole compounds (particularly, 2,4,6-trichloroanisole or TCA) in large enough concentrations - above 3 ng/l, to degrade the sensorial attributes of wine. Cork taint affects as much as 5% of the bottled wine in Europe, and results in annual losses of 700M. Cork stoppers are the main TCA contamination source. Even though cork stoppers are already treated in the cork manufacturing plant to prevent cork taint, recontamination occurs unavoidably as a result of the presence of chlorophenolic and other non-biodegradable chemicals in the environment, which are transformed into anisole compounds by metabolic reactions related to the presence of fungi. Currently, there is not any effective technology in the market to grant the absence of haloanisoles in cork stoppers. This project aims at developing a new TCA decontamination method that will be easily adapted and integrated in-line into any existing wine bottling line. The technology has already been tested at the laboratory scale, and has demonstrated its effectiveness to degrade TCA, in spite of the high chemical stability of this chemical. By performing this treatment immediately before sealing the wine bottles, the risk of recontamination will be virtually eliminated. Through a group of SMEs in the consortium, it is foreseen that this technology will be industrialized and commercialized within a short period after the completion of the project. The availability of this technology will benefit thousands of Europan small and medium size wineyards, which will be able to further improve the quality of their products, and avoid costs associated with unsatisfied customers.

Chatonnet P.,Laboratoire Excell | Boutou S.,Laboratoire Excell | Plana A.,Laboratoire Excell
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2014

This research determines the concentrations of various phthalates in French wines and grape spirits marketed in Europe or intended for export. Dibutyl phthalate (DBP), diethylhexyl phthalate (DEHP) and butyl benzyl phthalate (BBP) were the most frequently detected compounds in the wines analysed. While only 15% of the samples examined contained quantifiable concentrations (> 0.010 mg kg-1) of DEHP and BBP, 59% of the wines contained significant quantities of DBP, with a median value as high as 0.0587 mg kg-1. Only 17% of the samples did not contain any detectable quantity of at least one of the phthalates and 19% contained only non-quantifiable traces. In the spirits analysed, DBP (median = 0.105 mg kg-1) and DEHP (median = 0.353 mg kg-1) were the substances measured at the highest concentrations, as well as the most frequently detected (90% of samples). BBP was present in 40% of the samples at an average concentration of 0.026 mg kg-1. Di-isobutyl phthalate (DiBP), which is not permitted in contact with food, was found in 25% of the spirits tested. According to the specific migration limits (SML) for materials in contact with food, slightly more than 11% of the wines analysed were non-compliant, as they exceeded the SML for DBP (0.3 mg kg-1); just under 4% were close to the SML for DEHP. Concerning spirits, 19% of the samples analysed were considered non-compliant to the SML for DBP and nearly 7% were close to the SML for DEHP. The aged grape spirits analysed were often excessively contaminated with DiBP, which is not permitted to be used in contact with food (> 0.01 mg kg-1). A study of various materials frequently present in wineries revealed that a relatively large number of polymers sometimes contained high concentrations of phthalates. However, the epoxy resin coatings used on vats represented the major source of contamination. © 2014 Taylor & Francis. Source

Chatonnet P.,Laboratoire Excell | Fleury A.,Laboratoire Excell | Boutou S.,Laboratoire Excell
Journal of Agricultural and Food Chemistry | Year: 2010

This study identifies a previously isolated bacterium as Rhizobium excellensis, a new species of proteobacteria able to form a large quantity of 2-methoxy-3,5-dimethylpyrazine (MDMP). R. excellensis actively synthesizes MDMP from l-alanine and l-leucine and, to a lesser extent, from l-phenylalanine and l-valine. MDMP is a volatile, strong-smelling substance detected in wines with cork stoppers that have an unpleasant "corky", "herbaceous" (potato, green hazelnut), or "dusty" odor that is very different from the typical "fungal" nose of a "corked" wine that is generally due to 2,4,6-trichloroanisole (TCA). The contamination of cork by MDMP is not correlated with the presence of TCA. It appears possible that R. excellensis is the microorganism mainly responsible for the presence of this molecule in cork bark. However, other observations suggest that MDMP might taint wine through other ways. Oak wood can also be contaminated and affect wines with which it comes into contact. Nevertheless, because 93% of the MDMP content in wood is destroyed after 10 min at 220 °C, sufficiently toasted oak barrels or alternatives probably do not represent a major source of MDMP in most of the cases. Due to MDMP's relatively low detection threshold estimated at 2.1 ng/L, its presence in about 40% of the untreated natural cork stoppers sampled at concentrations above 10 ng/cork suggests that this compound, if extracted from the stoppers, may pose a risk for wine producers. © 2010 American Chemical Society. Source

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