Screening sensory-directed methodology for the selection of non-saccharomyces wine yeasts based on perceived aroma quality

A method of suspect screening analysis to study grape metabolomics, was developed [1]. By performing ultra-high performance liquid chromatography (UHPLC) – high-resolution mass spectrometry (HRMS) analysis of the grape extract, averaging 320-450 putative grape compounds are identified which include mainly polyphenols. Identification of metabolites is performed by a new HRMS-database of putative grape and wine compounds expressly constructed (GrapeMetabolomics) which currently includes around 1,100 entries.

Ellagitannin, anthocyanin and woody volatile composition of Cabernet Sauvignon wines aged in oak barrels for 12 months was evaluated. Depending on the container where malolactic fermentation (MLF) was carried out, two wine modalities were investigated: wines with MLF carried out in stainless steel tanks and barrel-fermented wines. Three toasting methods (medium toast, MT; medium toast with watering, MTAA; noisette) were considered for ageing of each wine modality. Sensory analyses (triangle and rating tests) were also performed. Two-way ANOVA of the raw experimental data revealed that the toasting method and the container where MLF took place, as well as the interaction between both factors, have a significant influence (p < 0.05) on ellagitannin, anthocyanin and woody volatile profiles of Cabernet Sauvignon wines.

An alternative to improve grape quality is the application to the vineyard of elicitors. Although these compounds were first used to increase resistance of plants against pathogens, it has been found that they are also able to induce mechanisms involved in the synthesis of phenolic compounds and some amino acids. However, researches about the influence of elicitors on grape volatile composition are scarcely. Therefore, the aim of this work was to study the influence of methyl jasmonate (MeJ) foliar application on grape aroma composition over three consecutive vintages. MeJ was applied to Tempranillo grapevines at a concentration of 10 mM in 2013, 2014, and 2015 years. Control plants were sprayed with water.

The impact of minute amounts of headspace oxygen on the post-bottling development of wine is generally considered to be very important, since oxygen, packaging and storage conditions can either damage or improve wine quality. This is reflected in the generalised use of inert bottling lines, where the headspace between the white wine and the stopper is filled with an inert gas. This experiment aimed to address some open questions about the chemistry of the interaction between wine and oxygen, crucial for decisions regarding optimal closure. While it is known that similar amounts of oxygen affect different wines to a variable extent, our knowledge of chemistry is not sufficient to construct a predictive method.

Flavonols are a class of flavonoid compounds derived from plant secondary metabolism. There they play different roles like antioxidants, internal regulators and UV screenings. In red wines, flavonols have increasingly received consideration by part of scientific and winemakers according their properties began to arise known. Among these stand out wine colour stabilization and their value as bioactive compounds. In this work the complete series of the acetylated and p-coumaroylated derivatives of the 3-O-glycosides of methoxylated flavonols, namely isorhamnetin, laricitrin and syringetin, have been identified in grapes and their respective wines from Vitis vinifera cv. Tannat.