Evolution of grape aromatic composition in cv. Ugni blanc

Aromas are one of the key points in food analysis since they are related to character, quality and consequently consumer acceptance. It is not different in the winery industry, where the aromatic profile is a combination of viticultural and oenological practices. Based on the development of more aromatic clones and on the potential to produce sparkling wines at Caldas, in the southern region of Minas Gerais (Brazil) (21°55´S and 46°23´W, altitude 1,100m), the aim of this work was the determination of volatile compounds in six different clones of Chardonnay grape berries to better understand which compounds add bouquet to the wine, and additionally comprehend the impacts of the edaphoclimatic and annual conditions on the improvement of grape-growing and winemaking practices.

Winemaking generates significant amounts of by-products, such as grape pomace and wine lees, which are primarily used for distillation and composting.

Sulfites (SO2) addition during winemaking is a widespread practice worldwide. This addition is realized at different steps of the winemaking due to the antimicrobial and antioxidant capacity of SO2. In a context of understanding white wines oxidative stability, knowledge about the impact of SO2 on the wine molecular diversity, especially compounds involved in the antioxidant capacity of wine, appears to be very important. In recent years, some studies have shown that SO2 can react with a large number of wine compounds resulting in the formation of numerous adducts. The diversity of compounds involved is important including in particular pyruvic acid, 2-keto-glutaric acid, glyceraldehyde, sugar, phenolics compounds but also amino acids or peptides. Moreover Roullier-Gall et al. have shown using FT-ICR-MS analysis that the molecular composition of wines remains impacted by addition of SO2 to the must (0, 4 and 8 g/hL SO2), several years after winemaking. Indeed, wines made from protected must (8g/hL SO2) contain a larger diversity of CHOS and CHONS compounds than wines made from unprotected must (0 g/hL SO2). The study of the impact of glutathione addition on the sensory oxidative stability has further shown that CHOS and CHONS compounds (amino acids, aromatic compounds and peptides) are markers of the antioxidant metabolome of white wines. This suggests that CHOS and CHONS compounds arise from SO2 adducts formation but also from a protecting effect of SO2 on the antioxidant metabolome of white wines.

The present paper reports the development of an optimized method for simultaneous analysis of
8 biogenic amines (Histamine, Methylamine, Ethylamine, Tyramine, Putrescine, Cadaverine, Phenethylamine, and Isoamylamine). It is based on a method developed by Gomez-Alonso et al. in 2007.

Atmospheric CO2 levels have been rising continuously since the industrial revolution, affecting crop physiology, yield and quality of harvest products, and grapevine is no exception [1]. Most of previously reported studies used potted plants in controlled environments, and explored grapevine response to relatively high CO2 levels, 700 ppm or more. The vineyardFACE, established in Geisenheim in 2012, uses a free air carbon dioxide enrichment (FACE) system to simulate a moderate (ambient +20%) increase in atmospheric CO2 in a vineyard planted with cvs. Cabernet-Sauvignon and Riesling grafted on rootstock 161-49 Couderc and SO4, respectively.