Inmaculada Álvarez’s research while affiliated with University of Valencia and other places

Exploring new field strategies for adapting winegrowing regions to the adverse effects of climate change becomes imperative. This study focuses on the effects of canopy architecture through the trellis systems leaning of North–South oriented vineyard’s rows vertical shoot positioned (VSP) system by 30° towards either the East (ESP) or the West (WSP) as a possible adaptation technique. The trial was conducted over two seasons in a Vitis vinifera L. cv. Bobal vineyard located in Requena (Valencia), eastern Spain, under a temperate-warm climate. The canopy leaning was considered to affect the radiation load and its timing with potential effects on vine physiology and grape metabolism and, consequently, on grape and wine quality. Leaning treatments affected vegetative growth, likely due to slight differences in vine water status. In comparison to VSP and ESP, WSP intercepts more light in the morning, when the photosynthetic capacity of the vines is at its highest. However, this results in a more negative vine water potential, which in turn leads to a reduction in vigour with no impact on yield. Musts from the WSP showed a tendency to increase total acidity compared to VSP, while ESP tended to decrease it. This was likely due to the reduction in temperature within the cluster microclimate in WSP in comparison to the ESP and VSP treatments. In addition, musts from the WSP treatment showed higher colour intensity, anthocyanins and polyphenols, potentially attributable to its more negative potentials, likely due to its more negative potentials, which may have prompted the synthesis of phenolic compounds. Consequently, wines from the WSP treatment displayed higher total acidity and lower pH, as well as higher colour intensity, anthocyanins, and polyphenolic content. In addition, WSP wines had higher concentrations of esters and higher alcohols. The improvements in grape and wine composition are likely due to an increased cluster radiation interception in the morning and reduced heating in the afternoon when VPD is higher. Our findings demonstrate that canopy management by leaning VSP vines towards the West can be a useful technique for adapting grape and wine composition to climate change and provide insights into its physiological basis.

The application of the ultrasound technique (US) in the production of rosé and red wines has demonstrated that the aromatic composition of rose wine can be affected and that it contributes to increasing the color of red wines without increasing the extraction of astringent tannins. The ultrasound treatment has favored the extraction of anthocyanins, which has had an impact on the increase in color density (C.D.) and has allowed greater color stability over time. Moreover, significant differences have been found between the two US systems applied, with continuous treatment being more effective in the extraction of phenolic compounds than pulsed treatment. The application system of the US also affects the aromatic composition of the wines. These results are of interest, as some esters have been described as important odorants in wines.

The aim of this study was to isolate and characterize autochthonous Saccharomyces cerevisiae yeasts from Cabernet Sauvignon grape must and to analyze how they impacted the final characteristics of the wines obtained from the same type of must. This work was carried out in a “Pago” winery located in Requena, Spain. Twenty-two isolates were obtained from grape must. After molecular identification and typing, 11 different strains were determined. Growth-related parameters and metabolic characteristics (glucose and fructose consumption and ethanol, glycerol and acetic acid production) were determined via laboratory-scale fermentations (50 mL) of Cabernet Sauvignon must. From 2 L fermentation batches, the residual sugar, density, ethanol concentration, titratable and volatile acidities, pH and polyphenolic and volatile compounds were determined, as well as the sensory attributes of the produced wines. Differences between strains in the growth and metabolic parameters were observed. Eleven S. cerevisiae strain profiles were characterized to establish which strain or strains of the selected yeasts would produce the highest polyphenolic and aromatic concentrations of the red Cabernet wines made in the “Pago winery”, to then multiply them for their use to make the red wines of this winery.

This work studies the variability of the Saccharomyces cerevisiae present during the spontaneous fermentation of Garnacha grapes’ musts from a “Pago” winery from the east of Spain. The parameters used to select yeast are those related to growth, fermentative behaviour, and the influence on the wine’s aroma and polyphenolic composition. Yeast identification was performed by ITS analysis and typed by Hinfl mDNA restriction profile analysis. Growth and metabolic characteristics of the isolates were determined by laboratory-scale fermentations of sterile Garnacha must, and the composition of the polyphenolic and the volatile compounds, and the sensory attributes of the small-scale produced red wines were determined. Ten S. cerevisiae strains were isolated and characterized. Overall, strain 22H quickly grew, produced wines with moderate ethanol concentrations and low volatile acidity, and obtained the highest colour and aroma scores, plus a high score for sensory attributes.

The aim of this research is to study the possibility of increasing the quality of red wins made with the Monastrell grape variety. A methodology was established to improve the concentration levels of polyphenol and aroma in these wines. Among flavonoids, the copigmenting effect of rutin stands out, and was tested in both winery and field applications. Buckwheat extract (Fagopyrum esculentum), in which rutin is the main flavonoid, may be of interest for viticulture given its biological activity. This paper focuses on researching the effect of applying the prefermentative vegetable extract of buckwheat (Fagopyrum esculentum) on the concentration of polyphenols and aroma compounds in vineyards. Simultaneously, a study was carried out to compare the effect of pure copigment (rutin) when applied in vineyards and cellars. Traditional vinification was done, plus prefermentative cold maceration. The application of buckwheat extract, and rutin extract to a lesser extent, to Monastrell grapes increased the concentration of malvidin and other anthocyanins, and total anthocyanins. After 12-month storage, no differences were observed in the percentage of copigmented, polymerised and free anthocyanin, the total polyphenol concentration, and the tannin quality parameters like DMACH (aldehyde p-dimethylaminoacimaldehyde) and the Gelatin Index. The concentrations of diethyl succinate, 2 phenylethyl acetate, vanillin and ethyl octanoate increased, while other compounds decreased when the copigment was added. The maceration technique followed during the vinification process had very little effect on polyphenolic compounds. The prefermentative maceration slightly increasing the concentration of total polyphenols, but had no effect on the parameters related to colour, anthocyanin concentration, nature of anthocyanins, their binding state or tannin quality parameters. The results showed that cold prefermentation maceration increased the concentration of some volatile compounds, including alcohols and esters, which should be considered important contributors to Monastrell wine aroma. The combination of the applying buckwheat extract and pure rutin together, and prefermentative cold maceration, positively affects the polyphenolic concentration and increases the concentration of quality volatile compounds.

The present work studies the effect of adding catechin and plant extract rich in catechin, Camellia sinensis (green tea) extract, on the volatile and polyphenolic composition of red wines made from Monastrell grapes. The aim of this research is to study the way to increase the red wine quality made with Monastrell variety of grapes. In one of them, the green tea extract was applied to grapes in vineyards 10 days before harvest. In another, catechin was applied to vineyards in the same way, and finally, catechin was applied during grape processing. Each trial was fermented by traditional vinification and prefermentative maceration for 5 days prior to alcoholic fermentation. A simple ANOVA analysis was used to evaluate if the application of copigments and winemaking techniques influenced wine composition. In addition, a multifactorial ANOVA was used to study the copigment treatment effect x winemaking technique interaction. Wine polyphenolic and volatile composition were analysed 12 months after fermentation. The application of green tea extract and catechin to vineyards increased (13%–16%) the concentration of anthocyanins in relation to the control to a greater extent when the initial polyphenolic concentration of grapes was lower. The volatile concentration rose when copigments (green tea extract and pure catechin) were applied to vineyards, in particular, hexyl acetate, ethyl octanoate and vanillin. The application of techniques like prefermentative maceration enhances the effects of copigments added to vineyards. The combination of the application of green extract or pure catechin with prefermentative cold maceration, had positive effects increasing polyphenols and volatile compounds concentration.

This work studies the effect of applying rosemary extract and caffeic acid on the polyphenolic and aromatic composition of Monastrell wines, as well as the influence of traditional winemaking or incorporating prefermentative maceration. For this purpose, three treatments were carried out in triplicate. In one of them, rosemary extract was applied on the clusters 10 days before harvest, caffeic acid was applied in the same way in another, and, finally, this acid was applied to grape before crushing. Each treatment was run by both traditional vinification and vinification with prefermentative maceration. After making wines, they were monitored for 12 months after fermentation. The application of rosemary extract, and that of caffeic acid but to a lesser extent, increased the color, the concentration of anthocyanins, and the percentage of polymerized anthocyanins, while prefermentation maceration gave rise to wines with a higher concentration of condensed tannins and polyphenols. Applying rosemary extract and caffeic acid in the vineyard also increased the concentration of esters and other compounds that favor wine aromatic quality, which was also enhanced by prefermentative maceration.

The effect of preparing the commercial yeast prise de mousse S. cerevisiae IOC 18-2007 on the second fermentation kinetics of a Macabeo white base wine was evaluated. The influence of yeast preparation on the final “Cava” sparkling wines was determined. The medium glucose, peptone, yeast extract (GPY medium), and the characteristic classic pied de cuve procedure were used to prepare the inoculum, which was placed besides a tirage liqueur inside bottles in which a second fermentation took place by the “traditional method”. The fermentation kinetics were similar for the first 60 days regardless of the employed yeast inoculum preparation. In both cases, glucose was exhausted and a few grams of fructose remained on day 30. The ethanol concentration after 60 days was the same in all of the wines. The sparkling wines inoculated with the GPY-grown yeasts showed higher titratable acidity, lower total polysaccharide and protein contents, and greater foamability (HM) and foam stability (HS). Regarding volatile compounds, these wines contained higher esters, fatty acids, higher alcohols, and γ-butyrolactone. Differences in the wine’s visual and flavor attributes were not significant no matter what inoculum was used. However, the aroma score was significantly higher in the wines inoculated with the pied de cuve-prepared yeasts.

Background and Aims To achieve both the control of the undesirable yeasts and the improvement of the characteristics of Merlot ‘Pago’ wines, Saccharomyces cerevisiae yeast diversity was investigated in a spontaneous ‘Pago’ Merlot fermentation from the Utiel-Requena region (Spain). Isolates of S. cerevisiae were characterised by a holistic procedure using the same Merlot grape must from which they were isolated. Methods and Results Yeasts were identified by internal transcribed spacer analysis and typed by HinfI mDNA restriction analysis. Growth and metabolic characteristics of the isolates were determined by laboratory-scale (50 L) fermentations of Merlot must and the composition of the polyphenolic and the volatile compounds and the sensory attributes of the wines were determined. Twelve S. cerevisiae strains were isolated and characterised. Strains 2E, 4A, 7A and 7F had better growth characteristics. Strains 9C and 7F produced wines of good intensity and colour quality, marked intensity and aroma quality, fruity character and better overall quality. Strain 9C displayed poor growth. Conclusions Strain 7F combined good growth characteristics and produced Merlot wines with the best colour, aroma and flavour characteristics during microvinifications. Significance of the Study Characterisation of S. cerevisiae made entirely in Merlot grape must allowed the influence of yeast strains on the final characteristics of commercial-scale Merlot ‘Pago’ wines to be more accurately deduced.