Determination of metallic elements in Chilean wines by atomic absorption spectroscopy and inductively coupled plasma–mass spectrometry

Those previous years, pesticides are often brought to the forefront by media. Questions arose about their toxicity for growers and consumers. Even if a downward trend is underway, the use of pesticides is required to ensure steady quality and quantity of harvests. A large number of active ingredients are authorized but regarding viticulture, mainly insecticides and fungicides are applied, to control pests and diseases and to increase crop yield. Some phytosanitary products, principally fungicides, applied close to the harvest date may frequently be detected in wines.

Wine oxidation is a problem that affects the freshness, the aromatic profile, the colour and also the mouthfeel of the wine. It mainly concerns white wines. Oxygen interactions with wine compounds lead to the phenomena cited above that are responsible for the depreciation of these wines. Barrel aging is a crucial step in the wine process because it allows many modifications as wine enrichment, colour stabilization, clarification and also a slow oxygenation of the wine. Effects of the oak barrel have to be known to prevent oxidation of the wine. We have been interested in the main antioxidant compounds released by oak barrels to the wine and we have developed an innovative method to reach directly these antioxidant compounds at the oak stave surface.

The effects of anthropogenic activities on vineyard (different plant protections) and in winery
(pressing/clarification step, addition of sulfur dioxide) on fungal populations from grape to wine were studied. The studied anthropogenic activities modify the fungal diversity. Thus, lower biodiversity of grapes from organic modality was measured for the three vintages considered compared to biodiversity from ecophyto modality and conventional modality. The pressing / clarification steps strongly modify fungal populations and the influence of the winery flora is highlighted.

The production of red sparkling wines is lower in Spain in comparison with the winemaking of white or rosé sparkling wines. In red sparkling wine processing it is essential to obtain suitable base wines that should have moderate alcohol content, high acidity, good color values, an adequate mouth-feel and a sweet tannin. Grapes for sparkling wine production have to be harvested at low maturity stages, with lower alcohol contents and higher acidities, which will that the phenolic maturity of the grapes is also low, showing green tannins. This paper analyses different treatments in order to minimize these inconveniences: cold maceration-prefermentation and delestage to elaborate the grapes with lower maturity, must nanofiltration, and the partial osmosis of the wines made from grapes with an adequate maturity degree.

In partnership with a Bordeaux property wanting to improve the quality of its second wine, the effects of two factors, American oak barrels and mannoproteins were studied. Their impact on the attractiveness and sweetness of wines were characterized during two successive vintages (2012 and 2013). Vinification took place with a homogeneous batch of Cabernet Sauvignon. The wine was then divided up into various groups of five barrels of French and American oak, new or reused. Analyses of volatile and non-volatile wood compounds were undertaken at four months and eight months of wood ageing, by LC-MS and GC-MS.