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Background: Viticulture has adapted foliar applications of biostimulants as a tool to improve crop quality. Recently, nanotechnology has been incorporated as a strategy to reduce the loss of biostimulants and treat nutrient deficiencies. Therefore, the present study aimed to investigate the effect of foliar applications of amorphous calcium phosphate nanoparticles (ACP) doped with methyl jasmonate (ACP-MeJA) and urea (ACP-Ur), individually or together (ACP-MeJA+Ur), on the content of volatile compounds in 'Tempranillo' grapes, compared to the conventional application of MeJA and Ur, individually or in combination (MeJA+Ur)., Results: The results showed that nanoparticle treatments reduced the total C6 compounds and some carbonyl compounds in the grape musts. This is of novel interest because their presence at high levels is undesirable to quality. In addition, some aroma-positive compounds such as nerol, neral, geranyl acetone, β-cyclocitral, β-ionone, 2-phenylethanal and 2-phenylethanol increased, despite applying MeJA and Ur at a lower dose., Conclusion: Consequently, although few differences in grape volatile composition were detected, nanotechnology could be an option for improving the aromatic quality of grapes, at the same time as reducing the required doses of biostimulants and generating more sustainable agricultural practices. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., (© 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

Background: Elicitors induce defense mechanisms, triggering the synthesis of secondary metabolites. Irrigation has implications for a more sustainable viticulture and for grape composition. The aim was to investigate the influence on grape aroma composition during 2019 and 2020 of the foliar application of amorphous calcium phosphate (ACP) nanoparticles and ACP doped with methyl jasmonate (ACP-MeJ), as an elicitor, with rainfed or regulated deficit irrigation (RDI) grapevines., Results: In both growing seasons, nearly all terpenoids, C 13 norisoprenoids, benzenoid compounds and alcohols increased with ACP-MeJ under the RDI regimen. In 2019, under the rainfed regime, ACP treatment increased limonene, p-cymene, α-terpineol, 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN), 2-ethyl-1-hexanol, (E,E)-2,4-heptadienal, and MeJ concentration in comparison with control grapes. In 2020, the rainfed regime treated with ACP-MeJ only increased the nonanoic acid content. Grape volatile compounds were most influenced by season and watering status whereas the foliar application mainly affected the terpenoids., Conclusion: A RDI regime combined with the elicitor ACP-MeJ application could improve the synthesis of certain important volatile compounds, such as p-cymene, linalool, α-terpineol, geranyl acetone, β-ionone, 2-phenylethanol, benzyl alcohol, and nonanoic acid in Monastrell grapes. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., (© 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

Background: The knowledge of volatile compounds concentration in grape berries is very valuable information for the winemaker, since these compounds are strongly involved in the final wine quality, and in consumer acceptance. In addition, it would allow to set the harvest date according to aromatic maturity, to classify grape berries according to their quality and to make wines with different characteristics, among other implications. However, so far, there are no tools that allow the volatile composition to be measured directly on intact berries, either in the vineyard or in the winery., Results: In this work, the use of near-infrared (NIR) spectroscopy to estimate the aromatic composition and total soluble solids (TSS) of Tempranillo Blanco grape berries during ripening was evaluated. For this purpose, the spectra in the NIR range (1100-2100 nm) of 240 intact berry samples were acquired in the laboratory. From these same samples, the concentration of volatile compounds was analyzed by thin film-solid-phase microextraction-gas chromatography-mass spectrometry (TF-SPME-GC-MS), and the TSS were quantified by refractometry. These two methods were used as reference methods for model building. Calibration, cross-validation and prediction models were built from spectral data using partial least squares (PLS). Determination coefficients of cross-validation (R 2 CV ) above 0.5 were obtained for all volatile compounds, their families, and TSS., Conclusions: These findings support that NIR spectroscopy can be successfully use to estimate the aromatic composition as well as the TSS of intact Tempranillo Blanco berries in a non-destructive, fast, and contactless form, allowing simultaneous determination of technological and aromatic maturities. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., (© 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

Background: Grape aromas are formed by a great number of volatile compounds. Methyl jasmonate (MeJ) and urea (Ur) foliar applications have been studied to improve grape quality, but their combined application has never been studied., Results: In both seasons, MeJ application enhanced terpenoids and C6 compounds synthesis, though decreased alcohols content. Moreover, MeJ + Ur treatment reduced benzenoids and alcohols and did not affect C 13 -norisoprenoids content. However, there was no clear effect of these treatments on the rest of the volatile compounds. Multifactorial analysis showed a season effect on all volatile compounds, except terpenoids. Discriminant analysis showed a good separation among samples under treatment criterion. The great effect of MeJ treatment on terpenoids was probably due to this elicitor influencing their biosynthesis., Conclusion: Season has a strong influence on grapes aromatic composition since it affects all volatile compound families except terpenoids. MeJ foliar application enhanced terpenoids, C 13 -norisoprenoids and C6 compounds synthesis, whereas decreased alcohols content; however, MeJ + Ur foliar treatment did not affect C 13 -norisoprenoids and C6 compounds, and decreased benzenoids and alcohols grape compounds. Therefore, no synergistic effect was observed between Ur and MeJ on grape volatile compounds biosynthesis. Foliar application of MeJ seems to be sufficient to improve the aromatic quality of grapes. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., (© 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

Background: Grape nitrogen composition directly affects the development of alcoholic fermentation and also influences the final wine aromatic composition. Moreover, different factors influence grape amino acids composition, such as rate and timing of nitrogen application. The aim of this study was to determine the influence of three doses of urea, applied at two different phenological stages (pre-veraison and veraison), on the nitrogen composition of Tempranillo grapes during two consecutive seasons., Results: Urea treatments did not affect vineyard yield, oenological parameters of the grapes and yeast assimilable nitrogen. However, amino acids concentration in the musts increased at both moments of urea application (pre-veraison and veraison), but the lower urea concentrations and sprayed at pre-veraison improved most of the amino acids in the musts, during two vintages. Moreover, when the year was rainy, the higher dose treatment (9 kg N ha -1 ) applied at pre-veraison and veraison improved the amino acid concentration in the must., Conclusion: Foliar applications of urea could be an interesting viticulture practice in order to increase the amino acids concentration in Tempranillo musts. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., (© 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

Tools to address the mismatch between technological and phenolic maturity of grapes are needed. Application of elicitors could be an effective alternative. This work compares the effect of the application of methyl jasmonate (MeJ) in conventional form and, as a novelty, in the form of MeJ-doped nanoparticles (ACP-MeJ) on the phenolic composition of Tempranillo grapes. Results showed that, regardless of season, both treatments increased the grape total phenols content. In 2019, most of the anthocyanins, and to a lesser extent the flavanols, increased with the application of MeJ, and several hydroxycinnamic acids increased in the grapes treated with ACP-MeJ, with dose 10 times lower than those of the MeJ conventional. In 2020, anthocyanins were not affected by the treatments, but total flavanols, flavonols, hydroxybenzoic acid, and stilbenes increased after ACP-MeJ application. Thus, foliar application of ACP-MeJ could serve to increase grape phenolic composition, reducing maturity decoupling and the environmental impact., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The measurement of aromatic maturity during grape ripening provides very important information for determining the harvest date, particularly in white cultivars. However, there are currently no tools that allow this measurement to be carried out in a noninvasive and rapid way. For this reason, in the present work, we have studied the use of hyperspectral imaging (HSI)) to estimate the aromatic composition of Vitis vinifera L. Tempranillo Blanco berries during ripening. A total of 236 spectra in the VIS+short wave near-infrared (VIS+SW-NIR) range (400-1000 nm) of intact berries were acquired contactless under laboratory conditions. As gold standard values, a total of 20 volatile compounds were quantified by gas chromatography-mass spectrometry (GC-MS), and the concentration of total soluble solids (TSS) was measured by refractometry. Calibration, cross-validation, and prediction models were built using partial least squares (PLS). Values of R CV 2 ≥ 0.70 were obtained for α-terpineol, p- cymene, β-damascenone, β-ionone, benzaldehyde, benzyl alcohol, hexanal, citral, linalool, 2-phenylethanol, octanoic acid, nonanoic acid, 2-hexenal, 2-hexen-1-ol, (Z)-3-hexen-1-ol, total C 13 norisoprenoids, total C6 compounds, total positive compounds (i.e., the sum of all families except C6 compounds), total benzenoids, and total soluble solids (TSS). Therefore, it can be affirmed that HSI in the VIS + SW-NIR range could be a good tool to estimate the aromatic composition of Tempranillo Blanco grape berries in a contactless, fast, and nondestructive way.

Background: The grape volatile fraction determines to a great extent its aroma, which is one of the most important characteristics influencing wine quality and consumer preferences. Grapevine downy mildew (GDM) is one of the most important and devastating diseases of grapevines worldwide. In this study, the impact on the volatile composition of cv. Verdicchio grapes of classical copper formulations, was compared to that of alternative products. Thus, 11 treatments were foliar applied throughout one grapevine cycle., Results: Most of the volatile compounds present in the grapes were not affected by the treatments used in order to prevent GDM. In the case of the total C 13 norisoprenoids, some differences were found between grapes untreated control and those applied with the grapefruit seed extract. Moreover, the content of alcohols was smaller in grapes from Bordeaux mixture treatment and higher in the samples from chitosan application., Conclusion: Therefore, from the qualitative point of view of the berry, treatment with tested products alternative to copper is recommended, which minimize the environmental and health problems that this heavy metal brings to the soil and in the winery, since it means that their applications did not affect the grape aroma. © 2022 Society of Chemical Industry., (© 2022 Society of Chemical Industry.)

Nowadays, nanoscience is a leading modern science that has a major impact on the food, pharmaceutical, and agriculture sectors. Several nanomaterials show a great potential for use during vine growing and winemaking processes. In viticulture, nanotechnology can be applied to protect vines against phytopathogens and to improve grape yield and quality. Thus, nanotechnology may allow the use of lesser amounts of phytochemical compounds, reducing environmental impact and promoting a more sustainable agriculture. And in winemaking, nanomaterials and nanodevices can be used to control the growth of spoilage microorganisms and to reduce or remove undesirable compounds, such as ethyl phenols (4-ethylphenol and 4-ethylguaiacol), biogenic amines, and tartaric acid, and so on, as well as to facilitate some technological processes (i.e. in wine filtration to eliminate microorganisms). This review summarizes recent studies with applications of nanotechnology in viticulture in order to facilitate agronomic management and optimize grape production and in enology to improve wine quality and safety. © 2021 Society of Chemical Industry., (© 2021 Society of Chemical Industry.)

The study of seaweeds is increasing in viticulture due to their implications on plant protection and grape quality. This trial aimed to study the effects of foliar applications of an Ascophyllum nodosum extract at low (0.25%, v v -1 ) and high (0.50%, v v -1 ) dosages on grape and wine phenolic compounds in 2017 and 2018. In grapes, seaweed biostimulation increased the content of malvidin-3-glc, myricetin-3-glc and myricetin-3-gal in 2017 season. Moreover, both treatments improved the synthesis of trans-piceid and total stilbenes in both seasons. Sensory analysis revealed that 2017 wines had more color than the 2018 wines, which coincided with color intensity parameters. Therefore, seaweed applications to grapevines improved stilbenes content in grapes independently of the season and its effects on the rest of phenolic compounds in grapes and wines depended strongly of season factor., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: The use of nanomaterials for the efficient delivery of active species in viticulture is still an unexplored opportunity. Nitrogen, an essential nutrient for grapevine development and wine quality, is commonly provided in the form of urea. However, the application of conventional fertilisers contributes to nitrate leaching and denitrification, thus polluting groundwater and causing a serious environmental impact. Nanotechnology is offering smart solutions towards more sustainable and efficient agriculture. In the present work, we assessed the efficiency of nontoxic amorphous calcium phosphate (ACP) nanoparticles as nanocarriers of urea (U-ACP) through field experiments on Tempranillo grapevines. Four treatments were foliarly applied: U-ACP nanofertiliser (0.4 kg N ha -1 ), commercial urea solutions at 3 and 6 kg N ha -1 (U3 and U6) and a control treatment (water)., Results: The grapes harvested from plants treated with U-ACP and U6 provided similar levels of yeast assimilable nitrogen, despite the very large reduction of nitrogen dosage. The concentration of amino acids was greater in U-ACP-treated plants than those of the control and U3 treatments and, barring a few exceptions, the values were comparable with those observed in grapes obtained following U6 treatment. Nanofertilisers provided a high arginine concentration in the musts but low proline concentrations in comparison to the U6 treatment., Conclusions: The results of this work show the potential benefits of nanotechnology over conventional practices for nitrogen fertilisation. Significantly, the application of U-ACP allowed a considerable reduction of nitrogen dosage to maintain the quality of the harvest, thereby mitigating the environmental impact. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

Background: Seaweed application has been defined as a novel technique capable of improving the content of secondary metabolites in berries. There is limited available information about its effects on must and wine volatile composition. This field trial aimed to study the effects of biostimulation to Tempranillo grapevines through an Ascophyllum nodosum fertilizer applied at a low dosage (Ld) and high dosage (Hd) on must and wine volatile compounds over two seasons., Results: Ld treatment scarcely affected must and wine volatile compounds in both seasons. Hd foliar application increased the content in musts of several individual terpenoids, C 13 norisoprenoids, esters, benzenoids, alcohols, carbonyl compounds and C6 compounds in 2018. Must yeast assimilable nitrogen conditioned the production of wine volatile compounds., Conclusion: These results suggest that seaweeds applications can act as elicitors in Tempranillo, triggering the synthesis of several compounds by the plant in musts during a season with a high rainfall and relative humidity. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

The grape and wine aroma is one of the most determining factors of quality, therefore the study of their volatile composition is a very important topic in vitiviniculture. The range of concentrations in which many of these compounds are found is quite low, in concentrations of ng/L; due to this, a sample preparation stage is necessary before doing the chromatographic analysis of the volatile compounds. In this review, the main analytical techniques used for the extraction of volatile compounds in grapes and wines are studied. The techniques presented are liquid-liquid extraction (LLE), solid phase extraction (SPE), solid phase microextraction (SPME), stir bar sorptive extraction (SBSE), and thin film solid phase microextraction (TF-SPME). For each of these techniques, a description was made, and the different characteristics were numbered, as well as their main advantages and disadvantages. Furthermore, from the second technique, a comparison is made with the previous techniques, explaining the reasons why new techniques have emerged. Throughout the review it is possible to see the different techniques that have been emerging in the past years as an improvement of the classical techniques., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The effects of seaweed applications to grapevines on grape and wine volatile composition are currently unknown. The aim of this work was to study the influence of seaweed foliar applications (Ascophyllum nodosum) to a Tempranillo blanco vineyard on grape and wine volatile composition. A low (Ld) and a high dosage (Hd) of the seaweed fertilizer was applied in two consecutive seasons (2017-2018). The most abundant family of varietal volatile compounds in Tempranillo blanco grapes was C 13 norisoprenoid. Hd treatment tended to increase the concentration of certain C6 compounds in grapes in both seasons, whereas Ld application tended to decrease 2-phenylethanol and 2-phenylethanal content in grapes with a season dependence. Season factor affected to the concentration of most of the volatile compounds in grapes due to the differences on rainfall, which affected to the weight of 100 berries and physico-chemical parameters. Yeast assimilable nitrogen (YAN) in musts could have affected the concentration of most of the wine volatile compounds. According to odor activity values (OAV), Tempranillo blanco wines were characterized as floral, fruity, banana, pear, among others aroma compounds., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Recently, A.O.C. Rioja have selected and enlisted the Tempranillo blanco as a new grapevine variety to be cultivated in this area. This is the first report that studies amino acid and ammonium composition of grape juice and wine from Tempranillo blanco. The aim was to study the effect of foliar application of a seaweed extract to a Tempranillo blanco vineyard on must and wine amino acids and ammonium content. The results suggested that Tempranillo blanco behaved as an arginine accumulator variety. Biostimulation after seaweed applications at a high dosage (Hd) to the grapevines increased the concentration of several amino acids in the 2017 season, while scarcely affected their content in 2018. Phenylalanine, precursor of several volatile and phenolic compounds, was increased in both seasons after Hd applications. Season was the most important factor in the variability of the must and wine amino acids concentration, followed by treatment and its interaction., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Seaweeds are defined as novel elicitors in many crops, allowing the synthesis of secondary metabolites to be triggered in different plant tissues. Currently, the phenolic composition of Tempranillo Blanco grapes and wines is unreported. The present study aimed to investigate the effects of an Ascophyllum nodosum seaweed extract applied to Tempranillo Blanco grapevines, at low (Ld) and high (Hd) dosages, on grape and wine phenolic compounds during two consecutive seasons (2017-2018)., Results: The results obtained showed that catechin was the most abundant phenolic compound in Tempranillo Blanco grapes and wines. Season affected the weight of 100 berries and some enological parameters. Catechin and flavonols concentrations in grapes were increased after Hd application to grapevines, independently of season. The concentration of hydroxycinnamic and hydroxybenzoic acids in wines was affected by vintage, probably as a result of oxidation reactions, as well as pinking phenomena, whereas the stilbenes content in wines was conditioned by the affect of cryptogamic diseases in grapes., Conclusion: Seaweeds might act as an elicitor of several phenolic compounds in grapes, enhancing the content of some phenolic compounds in wines. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

Background: Soil and climate are among the most determining factors for the composition of grapes. Among the compounds present in grapes, anthocyanins mainly determine their organoleptic and health-related properties. The purpose of this work was to study the influence of three different soils on the anthocyanin content of Tempranillo grapes (Vitis vinifera L.) from 2016 and 2017 vintages. The soils of the vineyards were classified as Fluventic Haploxerepts (FH), Typic Calcixerepts (TC) and Petrocalcic Palexerolls (PP)., Results: Non-acylated anthocyanins, and those derived from malvidin and peonidin, were the most abundant in grapes, regardless of soil type and year. During the wetter season (2016), the grapes with the highest concentration of total anthocyanins and several of the major anthocyanins were those from TC and PP soils, in which nitrogen availability was lower than that in FH soil. However, during the drier season (2017), no significant differences were observed, although trends similar to those seen in the 2016 season were recognized. Principal component analysis showed a good separation of samples according to the two seasons and to the three soils in each season., Conclusion: In vineyards that resemble each other closely and that are located in a unique mesoclimatic area where similar plant material is used and similar managements practices are applied, soil characteristics, which condition water holding capacity and nitrogen availability for the vines, in conjunction with seasonal conditions, were the factors that predominantly determined the anthocyanin composition in grapes. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

Light is an energy source and key environmental factor for plants. Out of the different light wavelengths, blue-light is one of the most relevant spectral regions because of its relation to anthocyanins biosynthesis. Among the compounds present in grapes, anthocyanins determine their main organoleptic and healthy properties; while a minimum concentration of ammonium and amino acids is necessary for a desirable development of the alcoholic fermentation. Moreover, amino acids are precursors of several volatile compounds synthetized during the fermentation. The aim of this study was to assess the influence of riboflavin (vitamin B2) applications, at harvest and one week later,to grapevine leaves in combination with post-harvest blue-light irradiation on Tempranillo (Vitis vinifera L.) grape anthocyanins and amino acidscomposition. The combination of blue-light irradiation and two riboflavin doses as well as theseindividual factors affected both grape anthocyanins and amino acidsconcentrations. After one week of storage, anthocyanins concentration diminished when clusters were irradiated with blue-light; while for amino acids content, the trend to increase or decrease is dependent on the riboflavin dose applied in vines and the storage time., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Rootstocks affect vegetative and reproductive parameters of the scion. However, limited knowledge exists on the effects of the adoption of a specific rootstock on grape and wine phenolic composition, which contribute to certain sensory attributes such as color, body and astringency of wine. These compounds are mainly affected by the variety, viticultural management and rootstock. The aim of this work was to study the influence of eight rootstocks on grape anthocyanin content, skin and seed proanthocyanidins and wine chromatic characteristics obtained from Merlot vines., Results: Grapevines grafted onto SO4 rootstock, in general, presented a higher concentration of total proanthocyanidins in skins and seeds compared to the rest of the rootstocks, whereas grapevines grafted onto Gravesac presented a lower concentration of proanthocyanidins in skins and seeds. These differences were found in the wines developed from grapevines grafted onto SO4. Wines from grapevines grafted onto SO4, 140 Ruggeri, Gravesac and 4453 M rootstocks presented, in general, better chromatic characteristics and a higher anthocyanin and tannin content than the rest of the samples., Conclusion: This work gives additional information concerning the influence of rootstock on grape and wine phenolic composition. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

Foliar application of biostimulants (including resistance inducers or elicitors) in the vineyard has become an interesting strategy to prevent plant diseases and improve grape quality on the grapevine. This also represents a partial alternative to soil fertilisation, avoiding some of the negative effects to the environment from leaching of nutrients into the groundwater. The foliar applications that most promote the synthesis of secondary metabolites in grape berries are treatments with nitrogen, elicitors, other biostimulants, and waste from the agricultural industry. However, the impact of their use in the vineyard depends on a number of conditions, including mainly the type of compound, application rate, timing and number of applications, and cultivar. This review thus summarises the influence of biostimulants as foliar applications to grapevines on grape amino acids and their phenolic and volatile concentrations, to define the most important factors in their effectiveness. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

Photosynthetic pigments, including carotenoids are important secondary metabolites, which play a key role in photosynthesis. There is little information about the effects of nitrogen and elicitor applications on chlorophyll and carotenoid concentrations in grapes. The aim of this work was therefore to study the effects of the foliar application of nitrogen sources and elicitors to Tempranillo, Garnacha and Graciano (Vitis vinifera L.) grapevines on chlorophyll and carotenoid contents. The results showed that β-carotene and lutein were the most abundant carotenoids in all the samples, ranging from 1336 and 227 to 7054 and 1382 μg/g, respectively. The applied treatments had greater impact on chlorophyll and carotenoid contents in Tempranillo grapes than in Graciano and Garnacha varieties. The content of chlorophyll was determined by the variety factor, while the concentration of carotenoids was influenced by the interaction of variety and treatment factors, depending on the type of foliar application., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

An alternative to improve grape quality is the elicitor application to the vineyard due its implication to induce defense mechanisms involved in the synthesis of secondary metabolites. There are few studies about the influence of elicitors on grape volatile composition. The aim of this work was to investigate the influence of methyl jasmonate (MeJ) foliar application to Tempranillo grapevines on grape aroma composition over three consecutive vintages. In the first vintage, MeJ treatment improved p-cymene, methyl jasmonate, and hexanal synthesis, and degraded 2-hexen-1-ol acetate, (Z)-3-hexen-1-ol, and n-hexanol. In the second season, the content of several terpenes, β-damascenone, methyl jasmonate, esters, benzenoids and (Z)-3-hexen-1-ol was diminished after MeJ application. In the third vintage, the synthesis of several volatile compounds considered positive contributors for grape aroma was improved by MeJ application. In conclusion, the effect of MeJ foliar application on grape volatile content was mainly dependent on the vintage., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Carignan noir is one of the minor and ancient varieties from the Chilean wine scenario that has had a resurgence as a result of to its rediscovered oenological potential when cultivated under the conditions of the interior dryland area. Under these growing conditions Carignan noir wines stand out as fruit driven and fresh compared to those originating from other growing areas. On the other hand, it is well known that wine aroma composition depends mainly on variety, viticultural management and winemaking. Thus, the present study aimed to investigate the volatile composition of wines from Carignan noir grapes originating from ungrafted and grafted onto País grapevines, in ten sites of the Maule Valley (Chile) during two consecutive vintages., Results: Higher alcohols were the most abundant volatile compounds, whereas ethyl esters and ß-damascenone were the most odoriferous compounds according to their odorant activity value. The dominant factor in Carignan noir wine volatile composition was season, whereas rootstock did not have a significant effect in differentiating the wines. In terms of climate, cold nights during the month prior to harvest correlated with higher linalool, α-terpineol and trans-3-hexen-1-ol content. The biologically effective degree-days index was inversely correlated with isoamyl acetate and 2-phenylethyl acetate content. Huglin's heliothermal and the average mean temperature of the warmest month indices were inversely correlated with ethyl vanillate, ethyl hexanoate and ethyl octanoate content., Conclusion: Site climate conditions were related to the accumulation of certain wine volatile compounds. This information may be useful for devising new Carignan noir vineyard management strategies when aiming to improve wine quality or adjust site selection approaches to maximize grape/wine volatile composition according to wine style. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

Vine foliar applications of phenylalanine (Phe) or methyl jasmonate (MeJ) could improve the synthesis of secondary metabolites. However, there are no reports focusing on the effects of elicitation supported by precursor feeding on must amino acid composition in grapevines. The aim of this research was to study the effect of the elicitation of methyl jasmonate (MeJ) supported by phenylalanine (Phe) as a precursor feeding (MeJ+Phe) and its application individually on must amino acid composition. Results showed that foliar Phe and MeJ treatments decreased the concentration of most of the studied amino acids with respect to the control (p≤0.05). MeJ+Phe treatment did not affect must nitrogen content. Musts obtained from MeJ+Phe showed higher concentration of several amino acids than samples from Phe and MeJ applications. Therefore, other sources of precursor feeding could support elicitation, to improve amino acid composition and be considered as a tool for viticulture., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Elicitors and nitrogen foliar applications to vineyards could regulate grape nitrogen composition, which has an important effect on grape and wine quality. Thus the aim of this research was to study the effect of foliar elicitor treatments, methyl jasmonate (MeJ) and yeast extract (YE), and foliar nitrogen applications, urea (Ur) and phenylalanine (Phe), to Garnacha, Graciano and Tempranillo vines on grape amino acid composition., Results: The results showed that elicitor and nitrogen foliar applications to Garnacha and Tempranillo grapevines decreased the must amino acid concentration. However, Phe application to these two grapevines increased the must Phe content. The treatments applied to Graciano grapevines barely effected the grape amino acid content. According to the percentage of variance attributable, the variety had a higher impact on the must amino acid composition than the treatments and their interaction, except in certain amino acids such as Phe., Conclusion: The influence of elicitor and nitrogen foliar applications to grapevines on grape amino acid concentration was strongly conditioned by the variety. © 2017 Society of Chemical Industry., (© 2017 Society of Chemical Industry.)

Background: Stilbenes have a significant biological activity and are one of the most important non-flavonoid contributors to grape and wine health-related properties. The accumulation of this class of compounds could be favored by viticultural practices such as the application of biostimulants. However, stilbene concentration also depends on several factors, including, for example, grape variety. Therefore, the aim of this work was to study the influence of foliar treatments carried out with elicitors (methyl jasmonate (MeJ) and a commercial foliar spray (YD)) and nitrogen compounds (phenylalanine and urea) on the grape stilbene composition of three varieties: Grenache, Graciano and Tempranillo. An ultra-high-pressure liquid chromatographic methodology was validated for stilbene determination., Results: Results showed that, despite the huge influence of the grape variety, YD significantly improved stilbene composition in Grenache and Graciano, while MeJ increased the stilbene content in Graciano and Tempranillo. As for the nitrogen treatments, phenylalanine significantly increased the stilbene concentration in Graciano, while urea treatment increased it in Tempranillo. However, the application of elicitors had a greater effect than the nitrogen compounds., Conclusion: Overall, the foliar application of the elicitors could be a suitable practice for increasing the amount of stilbenes in grape and, therefore, its nutraceutical properties. © 2017 Society of Chemical Industry., (© 2017 Society of Chemical Industry.)

Nitrogen compounds play a key role on grape and wine quality. Their composition in grapes depends mainly on variety, viticultural management, and terroir, and affects fermentation kinetics and the volatile compound formation. The aim of this work was to study grape and wine amino acid composition of ungrafted or grafted onto cv. País Carignan grapevines growing under rainfed conditions in ten sites of the Maule Valley (Chile). The results showed that proline was the most abundant amino acid in grapes and wines. In general, Carignan noir grapevines grafted over País showed lower grape amino acid content respect to ungrafted vines. Cool night index (CI) was inversely correlated to several amino acids, showing that their plant synthesis or accumulation increased with lower minimum temperatures during the last month before harvest. Truquilemu (Tru) and Ciénaga de Name (Cdn) sites showed the highest concentration for several amino acids and total amino acid content in grapes, which led to a faster alcoholic fermentation., (Copyright © 2017. Published by Elsevier Ltd.)

Nitrogen is an important element for grapevine and winemaking, which affects plant development, grape juice fermentation and has a potential effect in modulating wine quality. The aim was to study the influence of foliar applications of riboflavin (vitamin B2) to vineyard on grape nitrogen composition. This vitamin has a reported capacity to protect different plant species, but its application to favor grape and grape juice quality had not previously been studied. This work reports the oenological properties and the effect on amino acid concentration of grape juices obtained from grapes treated with riboflavin at two different doses compared to control. Results showed that probable alcohol, malic acid, color intensity and hue had significant differences when the riboflavin treatments were applied. Most of the amino acids presented the highest concentrations when the lowest riboflavin dose was used. These results are promising in terms of fermentation development and grape juice nitrogen composition., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Among Chilean varieties, Carignan noir has had a major resurgence due to its rediscovered wine quality potential. For this, the aim of this study was to characterize phenolic composition of grapes grown in six sites from the Maule Valley., Results: The data showed that myricetin-3-glc and catechin were the most important flavonol and flavanol, respectively. Anthocyanin and flavonol composition was correlated with biologically effective degree days, exhibiting a relationship with grape maturity. Flavanol and hydroxycinnamic acid composition was inversely correlated to the average maximum temperature of the warmest month, showing that their synthesis is favored by cooler temperatures during the warmest month., Conclusion: These results have enological and viticultural interest for grape growers as vineyard site selection for this cultivar can confer differentiable attributes in terms of grape composition and quality. On the other hand, understanding the effects of climate on the synthesis of phenolic compounds may be useful for managing the vineyards with the aim of improving grape quality. © 2017 Society of Chemical Industry., (© 2017 Society of Chemical Industry.)

Recent works showed that elicitation, supported by precursor feeding, could be a strategy to increase phenolic content. However, these studies have never been conducted in viticulture. This strategy could be of greater interest in Garnacha, a grape variety characterized by its low phenolic content. Therefore, this work studied elicitation with methyl jasmonate (MeJ), supported by precursor feeding with phenylalanine (Phe), in order to improve Garnacha grape phenolic content. Results showed that Phe+MeJ treatment did not improve phenolic content to a greater extent than the corresponding individual treatments. Overall, the greatest improvement was obtained with MeJ application, followed by Phe+MeJ; while Phe treatment barely increased phenolic compounds. Consequently, it was not possible to confirm the hypothesis that elicitation by MeJ could be supported by precursor feeding with Phe, when both applied together. This is the first study dealing with this matter under field conditions serving as basis for future works., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Nitrogen plays a key role in the fermentation and secondary metabolites formation. The aim was to study the influence of vine nitrogen applications on grape amino acid composition. Nitrogen sources applied to Tempranillo and Monastrell grapevines were phenylalanine and urea, during two seasons. Results showed that the application of these compounds had little effect on grape amino acid composition, regardless of variety and vintage. This could be due to the fact that vineyards did not present nitrogenous requirements. Thus, variety was the determining factor in Asp, Glu, Gln, Cit, Met, Gly, Gaba, Val, Ile, and Leu while season was the factor that most affected Thr, Arg, Ala, and Lys due its implication on berry ripening. The concentration of the remaining amino acids was influenced by two or three of the factors studied. Therefore, when the vineyard has adequate nitrogen nutritional status, grape amino acid content was determined by variety and vintage., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Vineyard soil management can modify the nitrogen soil availability and, therefore, grape amino acid content. These compounds are precursors of biogenic amines, which have negative effects on wine quality and human health. The objective was to study whether the effect of conventional tillage and two cover crops (barley and clover) on grapevine nitrogen status could be related to wine biogenic amines. Over 4 years, soil NO 3 - -N, nitrogen content in leaf and wine biogenic amine concentration were determined., Results: Barley reduced soil NO 3 - -N availability and clover increased it. In 2011, at bloom, nitrogen content decreased with barley treatment in both blade and petiole. In 2012, nitrogen content in both leaf tissues at bloom was greater with clover than with tillage and barley treatments. Also, total biogenic amines decreased in barley with respect to tillage and clover treatments. There were correlations between some individual and total biogenic amine concentrations with respect to nitrogen content in leaf tissues., Conclusion: Wine biogenic amine concentration can be affected by the grapevine nitrogen status, provoked by changes in the soil NO 3 - -N availability with both cover crop treatments. © 2017 Society of Chemical Industry., (© 2017 Society of Chemical Industry.)

Elicitors play an important role in the defense against pathogens as an alternative to chemical pesticides by increasing secondary metabolites. Their effect on grape amino acid has been little investigated. Thus, the aim of this research was to study the influence of methyl jasmonate (MeJ), chitosan (CHT), and a yeast extract (YE) on grape amino acid composition, through foliar applications to grapevines. The must amino acid concentration was analyzed by HPLC. The results showed that CHT and YE treatments decreased the must concentration of several amino acids, affecting total amino acid content (from 2364 to 1961, and 1818mg/L, respectively). However, MeJ treatment had a slight effect on grape amino acid content, increasing the concentration of Met (from 8.95 to 12.13mg/L) and Phe (from 7.96 to 9.29mg/L). It seems to be that, the resistance induction through CHT and YE treatments results in physiological costs to grapevines associated with a decrease on grape amino acid concentration. Consequently, MeJ applications, as a viticultural practice, could be a better tool than CHT and YE treatments, because did not affect grape amino acid concentration., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Copper fungicide use is limited by the European regulation; therefore, new strategies have been developed to prevent grapevine downy mildew (GDM). However, there is poor information about their effects on grape amino acid composition. This field trial aimed to evaluate the effect on grape amino acid composition of chitosan and of a mixture of laminarin and Saccharomyces extracts (LamE), applied in different strategies with copper hydroxide. The results showed that all the treatments applied to grapevines decreased the concentration of several amino acids. Moreover, treatments that have mostly decreased these compounds are those with copper hydroxide, especially when applied individually. LamE applied individually or alternately with copper hydroxide had the least negative effect on grape amino acid content. These results provide further information about the negative effects of copper on grape quality, which can be reduced when it is used in strategy with LamE or chitosan in GDM control.

Two preharvest treatments (methyl jasmonate or cell wall yeast) of grapevines (Monastrell and Tempranillo) were applied during two vintages (2014 and 2015) to check whether these elicitors enhanced stilbene accumulation in berries at the moment of harvest and in the corresponding wines elaborated with them. The main objective was checking the effect of treatment, variety and year on stilbene composition due to the interesting health-related properties of these compounds in both grapes and wines. The results pointed to inter-varietal and inter-annual differences, and that the treatments generally enhanced the stilbene composition of grapes and, particularly, of wines. The increase was more evident in Monastrell variety than in Tempranillo variety and in their wines more than their grapes during 2014 vintage but not during 2015 vintage., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Nitrogen affects grapevine growth and also yeast metabolism, which have a direct influence on fermentation kinetics and the formation of different volatile compounds. Throughout the grapevine cycle, soil nitrogen availability and grape nitrogen composition can vary because of different factors. Nitrogen foliar applications can contribute toward enhancing grapevine nitrogen status and minimize the problem of leaching that traditional nitrogen-soil applications can provoke. The present study aimed to evaluate the influence of urea foliar applications on grapevine nitrogen status and grape amino acid content. Accordingly, two different doses of urea were applied over the leaves of a 'Tempranillo' vineyard., Results: The highest urea doses affected nitrogen content on blade leaf tissues after veraison. Must amino acid profiles were modified by urea application and some of the compounds increased their concentrations. The effect of year on the increase of must total amino acid concentrations was more important than the effect of the doses applied., Conclusion: Urea foliar applications can be an interesting tool for decreasing grapevine nitrogen deficiencies. This method of nitrogen implementation in the vineyard could avoid sluggish fermentation problems during winemaking, enhance must nitrogen composition, and contribute to improving wine quality. © 2016 Society of Chemical Industry., (© 2016 Society of Chemical Industry.)

Wine quality greatly depends on its chemical composition. Among the most important wine chemical compounds, flavonoids are the major contributors to wine organoleptic properties while amino acids have a huge impact on fermentation development and wine volatile profile. Likewise, nitrogen applications are known to have an impact on wine composition. Therefore, the aim of this work was to study the effects of foliar nitrogen applications on wine flavonoid and amino acid composition. The experiment involved five foliar nitrogen applications at veraison time: urea (Ur), urea plus sulphur (Ur+S), arginine (Arg), and two commercial fertilizers Nutrimyr Thiols (NT) and Basfoliar Algae (BA). The results showed that nitrogen foliar treatments decreased wine flavonoid content although the effect varied according to each treatment. This could be related to a low vine nitrogen requirement, since must yeast assimilable nitrogen (YAN) was above acceptable threshold values for all samples. With regard to wine amino acid content, all treatments except for Ur increased its values after the applications. Finally, foliar nitrogen treatments greatly influenced wine composition. Among them, urea seemed to exert the most negative effect on both phenolics and amino acids. In addition, an inverse relationship between wine amino acid content and flavonol concentration was exhibited., (Copyright © 2017. Published by Elsevier Ltd.)

The main aim of this study was to describe the impact of foliar phenylalanine and urea application on grape and must microbial populations. The tool used to perform the ecological study was DGGE conducted with several infusions in non-enriched and enriched liquid media, as well as direct DNA extractions of grapes and musts. A total of 75 microbial species were found in the study. The alpha diversity indices of grape after both foliar nitrogen treatments did not show significant changes in comparison to the control samples, but were modified in some indices in must samples. The phenylalanine must sample was similar to the control, while foliar urea application caused significant changes in microbial diversity and population structure in comparison to the control must. Further research would be necessary to properly predict the impact on winemaking of the effects observed in this study for grape and must microbiota, especially regarding the foliar application of urea., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Over the last few years, considerable attention has been paid to the application of elicitors to vineyard. However, research about the effect of elicitors on grape amino acid content is scarce. Therefore, the aim of this study was to evaluate the influence of foliar application of methyl jasmonate on must amino acid content. Results revealed that total amino acid content was not modified by the application of methyl jasmonate. However, the individual content of certain amino acids was increased as consequence of methyl jasmonate foliar application, i.e., histidine, serine, tryptophan, phenylalanine, tyrosine, asparagine, methionine, and lysine. Among them, phenylalanine content was considerably increased; this amino acid is precursor of phenolic and aromatic compounds. In conclusion, foliar application of methyl jasmonate improved must nitrogen composition. This finding suggests that methyl jasmonate treatment might be conducive to obtain wines of higher quality since must amino acid composition could affect the wine volatile composition and the fermentation kinetics., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Phenolic compounds play a key role in grape and wine organoleptic properties, being therefore a key parameter in wine quality. Elicitor application constitutes an interesting field of research since it is indirectly involved in the accumulation of phenolic compounds. The aim of this study was to compare the effect of the application of three different elicitors on both grape and wine phenolic content. Methyl jasmonate, chitosan, and a commercial yeast extract were applied to the canopy at veraison and one week later. Results showed that foliar treatments carried out with methyl jasmonate and yeast extract achieved the best results, increasing grape and wine anthocyanin content when compared to the control. Moreover, the application of the yeast elicitor also enhanced grape stilbene content. In contrast, the chitosan treatment did not have a substantial impact on the phenolic compounds. The results of this study indicate that methyl jasmonate and yeast extract applications could be a simple practice to increase grape and wine phenolic content., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The aim of this work was to study the influence of foliar applications of different wood aqueous extracts on the amino acid content of musts and wines from Airén variety; and to study their relationship with the volatile compounds formed during alcoholic fermentation. For this purpose, the foliar treatments proposed were a vine-shoot aqueous extract applied in one and two times, and an oak extract which was only applied once. Results obtained show the potential of Airén vine-shoot waste aqueous extracts to be used as foliar fertilizer, enhancing the wine amino acid content especially when they were applied once. Similar results were observed with the aqueous oak extract. Regarding wine fermentative volatile compounds, there is a close relationship between musts and their wines amino acid content allowing us to discuss about the role of proline during the alcoholic fermentation and the generation of certain volatiles., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Phenolic compounds play a key role in the organoleptic properties of wines. Viticultural practices may influence grape and wine phenolic content, thus determining their quality. The objective of this study was to evaluate the effect of foliar applications of phenylalanine and urea, at two different doses, on wine phenolic composition. Grapes were harvested at their optimal technological maturity and their respective wines were elaborated at small scale. Wine detailed phenolic composition was determined. Results revealed that the content of several anthocyanins and flavonols was enhanced by the application of both phenylalanine doses and by the application of the low dose of urea. In contrast, flavanols and non-flavonoid compounds were less affected by the foliar treatments. The findings seem to be related to the time of application, since anthocyanins and flavonols are accumulated after veraison. In conclusion, nitrogen foliar fertilization increased the phenolic content of Tempranillo wines. This could be of interest since anthocyanins and flavonols are associated with wine quality, especially with its color., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Grapevines may require the input of nitrogen to grow and to guarantee an appropriate grape composition. Recently there has been a growing interest in foliar fertilization, which entails a fast and efficient assimilation of the products. The aim of this work was to study the influence of foliar applications of phenylalanine and urea, at two different doses, on grape anthocyanins, flavonols, flavan-3-ols, phenolic acids, and stilbenes. All treatments were applied at veraison and one week later at doses of 0.9 and 1.5 kg N/ha. The results showed that the synthesis of phenolic compounds was favoured by foliar applications of phenylalanine and urea. The application of the lowest dose of urea was the most effective treatment, increasing the content of several anthocyanins and flavonols. Moreover, none of the foliar treatments worsened the grape phenolic composition. In conclusion, foliar application of phenylalanine and especially urea, could be an interesting management tool for improving grape quality and their health-promoting properties., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The importance of phenolic compounds for grape and wine quality has drawn attention to studying different practices with the aim of increasing their content. Cluster application of elicitors is a viticultural practice that has shown promising results in recent years. However, cluster application requires a previous defoliation, which is time-consuming and expensive. In the present study, methyl jasmonate was foliar applied to Tempranillo grapevines in order to study its effect on grape and wine phenolic composition. Methyl jasmonate foliar application increased anthocyanin and stilbene content in both grape and wine, besides enhancing wine flavonol content. This treatment induced the synthesis of 3-O-glucosides of petunidin and peonidin and trans-p-coumaroyl derivatives of cyanidin and peonidin. For stilbenes, trans-piceid content was considerably increased in both grape and wine. The results obtained suggest that methyl jasmonate foliar application could be a simple and accessible practice to enhance grape and wine quality.

The influence of six fungicides (famoxadone, fenhexamid, fluquinconazole, kresoxim-methyl, quinoxyfen and trifloxystrobin) on the volatile composition of red wines obtained from inoculated fermentation was studied. Although treatments were carried out under critical agricultural practices (CAP), the residues in the wines were below their maximum residue limit (MRL). Ethyl decanoate was the compound most influenced by these fungicides, while diethyl succinate, decanoic acid, β-ionone, and citronellol concentration were not changed with any of the treatments. The treatment of grapes with trifloxystrobin induced changes in only one volatile compound, and the variation in volatile composition of wines from grapes treated with fenhexamid, fluquinconazole and quinoxyfen compared to control wines was almost negligible invaluable. The treatment with famoxadone influenced more volatile compounds than the other ones, except for wine from grapes treated with kresoxim-methyl, which was the only wine that showed a big change in its aromatic composition., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The aim of this work was to study the influence of foliar application of different nitrogen sources on grape amino acid content. The nitrogen sources applied to Tempranillo grapevines were proline, phenylalanine, urea, and two commercial nitrogen fertilisers, both without and with amino acids in their formulations. All treatments were applied at veraison and one week later. Proline treatment did not affect the must nitrogen composition. However, phenylalanine and urea foliar application enhanced the plants' synthesis of most of the amino acids, producing similar effects. In addition, the spray of commercial nitrogen fertilisers over leaves also induced a rise in grape amino acid concentrations regardless of the presence or absence of amino acids in their formulation. The most effective treatments were phenylalanine and urea followed by nitrogen fertilisers. This finding is of oenological interest for improved must nitrogen composition, ensuring better fermentation kinetics and most likely enhancing wine quality., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The purpose of this paper was to study the effect of pulsed electric fields (PEF) on the stilbene content of three grape varieties. For this purpose, four different PEF treatments were applied using a continuous system over three varieties, Graciano, Tempranillo and Grenache, destemmed and crushed. In addition, the influence of PEF on their physicochemical composition was studied. PEF treatments did not affect the pH or total acidity of Graciano, however, musts from Tempranillo and Grenache had higher pH values and lower total acidity. In the three varieties, all treatments resulted in an increase of potassium content, deeper colour intensity and total polyphenol index and lower tonality, more pronounced in the treatments with higher time and energy. The stilbene content of the must significantly increased with respect to the control. This increase depended on the variety and the treatment applied. Tempranillo increased up 200% the total stilbene concentration, Grenache 60% and Graciano 50%. For the three varieties, the treatment with the highest time and energy was the most effective on the total stilbene extraction. These results indicate that PEF could be a suitable technology for obtaining musts with deeper colour and higher phenolic content, including resveratrol and piceid., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

A method has been developed to analyse the glycosidic aroma precursor of non aromatic red grapes in terms of glucose GG. Due to the matrix interferences, an extract free of glycosylated polyphenols (especially anthocyanins and flavonols) and free glucose has been prepared. Such interferences have been eliminated by combining the use of Oasis MCX SPE and Fehling reagent. The glycosyl aroma precursor's fraction was subjected to an acidic hydrolysis (pH 1, 100°C, 1h), where equimolecular proportions of glucose (glucose GG) were released from their respective aglycones and quantified HPLC-IR. Compared with methods that require detailed analysis of the volatile aglycones, this one is able to estimate with good reproducibility the potential aroma of grapes by the only measurement of glucose GG., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The aim of this work was to study the influence of nitrogen compounds on the formation of volatile compounds during the alcoholic fermentation carried out with 4 nonaromatic grape varieties collected at 2 different maturation stages. To do this, Monastrell, Merlot, Syrah, and Petit Verdot grapes were collected 1 wk before harvest and at harvest. Then, the musts were inoculated with the same Saccharomyces cerevisiae yeast strain and were fermented in the same winemaking conditions. Amino acids that showed the highest and the lowest concentration in the must were the same, regardless of the grape variety and maturation stage. Moreover, the consumption of amino acids during the fermentation increased with their concentration in the must. The formation of volatile compounds was not nitrogen composition dependent. However, the concentration of amino acids in the must from grapes collected 1 wk before harvest can be used as a parameter to estimate the concentration of esters in wines from grapes collected at harvest and therefore to have more information to know the grape oenological capacity. Application of principal components analysis (PCA) confirmed the possibility to estimate the concentration of esters in the wines with the concentration of nitrogen compounds in the must., (© 2011 Institute of Food Technologists®)

Volatile compounds from a commercial aqueous oak extract application to white Verdejo grapevines at veraison have been studied. Treated grapes under two types of formulation (25% and 100%) have been analyzed at the optimum maturation time, and winemaking was then subsequently carried out. The volatile compounds were analyzed by stir bar sorptive extraction-gas chromatography-mass spectrometry. The results suggest that after the grapevine treatments, grapes store the volatiles in the form of nonvolatile precursors, and some of the volatiles are released during the winemaking process, especially six months after the alcoholic fermentation. The sensory analysis shows that wines maintain the typical aroma properties of Verdejo wines at the end of fermentation; but after six months, the wine color is greener and more astringent, and, in terms of aroma, it has wooden notes as if the wine has been aged in oak barrels.