Macrowine 2021
IVES 9 IVES Conference Series 9 Maturation under different SO2 environments: the impact on amino acid and volatile profile for two white wines

Maturation under different SO2 environments: the impact on amino acid and volatile profile for two white wines

Abstract

EU countries are in the top 16 of the world’s wine producers. To respond to a public health concern, caused by SO2 excessive exposure, EU has required a warning in the products indicating that sulphites are present if concentrations are higher than 10mg/L and its reduction or replacement whenever possible. This additive is used as a preservative agent in the winemaking process, due to its antioxidative and antimicrobial properties[3]. Wine aroma depends on many factors, being grape variety and winemaking process that most contributes to volatile organic composition (VOC) found in wines where amino acid composition, due to their biosynthetic products play an important role. Also, during wine ageing VOCs can change depending on many factors such as temperature, pH or oxidation process[4]. In this work, the impact of different doses of SO2 (added after alcoholic fermentation) was evaluated on wine VOCs over time and amino acids content after 3 months over lees.

HS-SPME-GC/MS was used to identify and semi-quantify VOCs, and HPLC-DAD was used for amino acids quantification. Two white wines were studied: one varietal (Antão Vaz; AV) and one blend (BL) of Portuguese varieties. After being kept for 3 months over lees, wines were bottled and VOCs and amino acids were analysed after 3 and 6 months.

A total of 83 compounds were tentatively identified,70 compounds in monovarietal wine and 73 in the blend wine. The chemical functional groups observed were esters, alcohols, carboxylic acids, aldehydes and 12 miscellaneous compounds. When a Principal Component Analysis (PCA) was performed on VOCs semi-quantification of each wine it is observed that PCA plots present different trends throughout the factors under study. In Antão Vaz was attain lower samples distinction for different SO2 doses on sample with 3 and 12 months. However, for the evolution time of 6 months, samples were well separated. In this case, both factors seem to influence the distribution of samples with a similar weight. For the blend wine, a worse distribution of the samples was observed for evolution time of 3 and 6 months. This indicates that they might be more sensitive to SO2 doses and evolution time when compared with Antão Vaz wines. Regarding amino acids profile it was observed that maturation on lees lead to an increasing concentration of AA. However, Antão Vaz was more influenced by the SO2 doses applied.

DOI:

Publication date: September 13, 2021

Issue: Macrowine 2021

Type: Article

Citation

Related articles…

Exploring the contributions of terroir factors on berry quality of cvs. Cabernet-Sauvignon and Merlot (Vitis vinifera L.) at the Eastern Foothills of the Helan Mountains region of China

Terroir leaves its mark on the accumulation of flavours in grape berries, triggering biochemical re-actions and ultimately shaping wine styles.

De novo Vitis champinii whole genome assembly allows rootstock-specific identification of potential candidate genes for drought and salt tolerance

Vitis champinii cultivars Ramsey and Dog-ridge are main choices for rootstocks to adapt viticulture in semi-arid and arid regions thanks to their distinctive tolerance to drought and salinity. However, genetic studies on non-vinifera rootstocks have heavily relied on the grapevine (Vitis vinifera) reference genome, which difficulted the assessment of the genetic variation between rootstock species and grapevines. In the present study, this limitation is addressed by introducing a novo phased genome assembly and annotation of Vitis champinii. This new Vitis champinii genome was employed as reference for mapping RNA-seq reads from the same species under drought and salt stresses, and for comparison the same reads were also mapped to the Vitis vinifera PN40024.V4 reference genome. A significant increase in alignment rate was gained when mapping Vitis champinii RNA-seq reads to its own genome, compared to the Vitis vinifera PN40024.V4 reference genome, thus revealing the expression levels of genes specific to Vitis champinii. Moreover, differences in coding sequences were observed in ortholog genes between Vitis champinii and Vitis vinifera, which therefore challenges previous differential expression analyses performed between contrasting Vitis genotypes on the same gene from the Vitis vinifera genome. Genes with possible implications in drought and salt tolerance have been identified across the genome of Vitis champinii, and the same genomic data can potentially guide the discovery of candidate genes specific from Vitis champinii for other traits of interest, therefore becoming a valuable resource for rootstock breeding designs, specially towards increased drought and salinity due to climate change.

For a phenomenology of terroir. A consumers’ perspective

This study investigates the notion of terroir by applying a phenomenological approach, focusing on the subjective experience of consumers. We will consider how terroir is described by consumers in order to gauge their subjective viewpoint and understand their way of describing and defining this spatiality.

Influenza del sito di coltivazione nella espressione aromatica del Moscato liquoroso di Pantelleria

ln 1997, twenty six cultivation sites of cv. Muscat of Alexandria different for pedological conditions, altitude and exposition were selected through ail Pantelleria isle. ln each site, described and classified according to USDA Soil Taxonony and FAO Soil Classification methods, grapes, collected at technological ripening, were microvinificated, following a standard procedure which allowed to obtain the naturally sweet wine DOC Moscato di Pantelleria. Wines, five months after vinification, were analysed by gaschromatography.