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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.

[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, We thank the Gobierno de La Rioja for financial support provided to the project P.R. 03/14‐07/15. E. P. Pérez‐Álvarez and T. Garde‐Cerdán thank the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) for predoctoral and doctoral support. We also express our gratitude to Ricardo Leza for providing the vineyard site in which the present study was conducted.

Most of the compounds of interest in oenology to elaborate red wines are found in grape skins. These molecules are principally phenolic compounds, and also, and aromatic compounds known as primary or varietal compounds. Red wine composition depends on the initial grape composition, which is a function of variety, cultivation factors as well as the winemaking techniques. Improving the extraction of these compounds in winemaking is one of the most important questions for the wine industry, especially in red wine elaboration. It is therefore important to investigate alternative techniques to traditional ones that are less time-consuming and more energy efficient, while maintaining, optimizing or improving the quality of extraction and the organoleptic properties of red wines. Actually, in red wines long macerations are carried out with the aim of extracting more anthocyanins and tannins from the skins. Pulsed electric fields (PEF) offer significant advantages in the extraction of compounds of red grape skins, including the previously cited compounds. In the last decade, a high number of papers have been published about this topic. However, the advantages in the extraction of the PEF treatment depends on the treatment applied, grape variety, and maturation state. The purpose of this review is to collect the results obtained during this time to know the best way to apply this technology to red wine elaboration. On the other hand, PEF could be a potential tool in microorganism inactivation. PEF is described as one of the most promising non-thermal methods for inactivating microorganisms in food and wine. The main difference with respect to PEF extraction processes is the largest energy needed to inactivate microorganisms and also the different responses between microorganisms. Research highlights in this field so far are still unclear. For this reason, one of the purposes of this review was to define the most relevant parameters of PEF treatment aimed to inactivation as the moment of application, and the sensitivity of the microorganisms. © 2016 Nova Science Publishers, Inc.

Grapes and wines are one of the most important sources of anthocyanins in the nature. Anthocyanins play a key role in wine quality since they are the main responsible for the color of both red grapes and wines, influencing then on consumers' preferences. Moreover, numerous studies indicate the potential effect that this family of phenolic compounds may have due to their potential health benefits such as antioxidant activity, antiobesity and antidiabetic properties, cardiovascular protection, and chemoprevention and cancer protection. Anthocyanin content in grapes is in part genetically determined but many other aspects also contribute to the final anthocyanin profile, including climate or soil factors. Moreover, during winemaking these compounds are subjected to many changes, resulting in the formation of new pigments which will determine the final color of wines. Due to the important benefits of anthocyanins, some tools have been developed in order to increase their concentration in both grapes and wines. Some of the approaches have been established with the aim of promoting the primary synthesis of these compounds in the vineyard while others have targeted the extraction of anthocyanins in a later stage in the cellar. Among viticultural practices, some strategies have proven to be very promising, such as leaf removal or elicitors application, which have been able to increase the content of not only anthocyanins, but also of other phenolic compounds. On the other hand, cold maceration, enzymes and new technologies such as ultrasounds and pulsed electric fields (PEF) offer significant advantages in the extraction of anthocyanins and other polyphenols before oenological processing. In particular, as regards the speed of the process, the maceration of red wine can be shortened by up to three days. For these reasons, this work is structured as follows: First we revise the main anthocyanins found in grapes and wines. Secondly, we study several strategies to increase the anthocyanin synthesis by the grapevine. And finally, we discuss different technologies to improve anthocyanin extraction from grape skins during winemaking. © 2015 by Nova Science Publishers, Inc. All rights reserved.