Influence of deficit irrigation on grapevine cv. “Touriga Nacional” in Douro region: A metabolomic approach

This study investigated if compositional differences between Shiraz and Cabernet Sauvignon grape varieties could influence the production of yeast-derived compounds. This work was based on the analysis of 40 experimental red wines made in triplicate fermentations from grapes harvested from two consecutive vintages in New South Wales (Australia). Grapes were picked at three maturity stages using berry sugar accumulation as physiological indicator, from nine commercial vineyards located in three different climatic regions (temperate, temperate-warm and warm-hot). A range of 30 yeast-derived wine volatiles including esters and alcohols were quantified by HS/SPME-GC/MS. Ammonia, amino-acids and lipids were analysed in the corresponding grapes. The juice total soluble solids (°Brix) in addition to the wine alcohol and residual sugar levels were also measured. The influence of grape maturity on wine ester composition was also variety dependent, particularly for higher alcohol acetate and ethyl ester of branched acids. This study highlights that varietal differences observed in Shiraz and Cabernet Sauvignon wines involve fermentation-derived compounds irrespective of the site (soil, climate, viticultural practices).

NIR spectroscopy has widely been tested in viticulture as powerful alternative to traditional analytical methods in the field of quality evaluation. NIR instruments have been used for assessing must and wine quality features in several works, but little information regarding their application on whole berries for polyphenol determination is available.

This study investigates how precipitation from November to February during each harvest year, influence the phenolic and isotopic profiles of red wines, particularly focusing on trans-resveratrol, total phenolic compounds, and carbon and oxygen isotopes (¹³C/¹²C and ¹⁸O/¹⁶O).

The wine industry is currently shifting toward more sustainable production systems. There are many reasons for this as the interest of people over climate change and, consequently the wine consumer’s choice toward organic and biodynamic, reduced carbon-footprint, vegan and other environmentally friendly wines. While the viticultural effects of biodynamic and organic practices on wine grapes have been investigated, there is a lack in literature on the general effect on the final quality of wine

Vines are exposed to environmental conditions that cause abiotic stress on the plants (drought, nutrient and mineral deficits, salinity, etc.). Polyamines are growth regulators involved in various physiological processes, as in abiotic plant stress responses. Stressful conditions can modify grape’s composition, and in this work, we have focused on studying the effect of abiotic stress on the composition of polyamines and amino acids in grapes. In addition, the effect of grape variety on these compounds has been studied.