OENO IVAS 2019 banner
IVES 9 IVES Conference Series 9 Aroma chemical profiles characterization of wines produced with moristel grapes harvested at different time points

Aroma chemical profiles characterization of wines produced with moristel grapes harvested at different time points

Abstract

The wine aroma is constituted by hundred of volatile chemical compounds that depend on many viticultural and oenological factors. One of the most important factors that will unequivocally affect the final wine pro-perties is the grape maturity level. Grape ripening is an extremely complex process, in which the metabolites and precursors concentrations change significantly with time. However, the knowledge of how grape ripe-ning affects wine aroma composition is still quite limited. Nowadays, wineries measure parameters such as sugar, pH, acidity and colorimetric tests to evaluate the degree of maturity of the vintage and decide the harvest data, but these analysis do not take into consideration the aromatic potential of the grape. The objective of the present work is to understand the differences in the aroma chemical profile of Moristel wines from different vineyards harvested at different time points. So, three different vineyards of Moris-tel grape variety in D.O. Somontano were selected, in two consecutive vintages: two in 2016 and one in 2017. Each block was harvested at different time points followed by microvinifications applying the same fermentation protocol. All of them have been elaborated in triplicated. This was assessed by the analysis of major aroma compounds (GC-FID), trace aroma compounds (GC-MS), methoxypyrazines (TD-GCxGC-MS), polyfunctionalmercaptans (SPE GC-MS), volatile sulfur compounds (BR-VSCs) and total acetaldehyde (HPLC-UV/VIS). The most important result is that the grapes harvested at 42 days postveraison, that is the “green” ones, pro-duce wines with high concentration of acetaldehyde and low IPT. Hence, low concentration of polyphenols facilitate the accumulation of this compound. Another reason for these acetaldehyde high concentrations could be problems associated with the lack of reduction factors (NADH or NADPH). This fact is also corroborated with the decreases of branched acid / fusel alcohol and branched ester/fu-sel alcohol ratios during the maturity. These facts can have very important sensory repercussion, the acetaldehyde and fusel alcohol are components of aroma buffer.

Finally, the evolution of certain maturity markers (c-3-hexenol, Y-nonalactona, rotundone) has been also observed, but these target compounds, by themselves, do not seem to have great sensory relevance in the final wines. This study has help to elucidate how grape maturity state contributes to final Moristel wine aroma profile and possible self-life.

Acknowledgements

This work has been funded by the Spanish MINECO (Project AGL2014-59840, RTC 2015-3379 and RTC-2016-4935-2) and partly co-funded by the European Union (FEDER). I.A. has re-ceived a grant from the Spanish FPU programs. Funding from D.G.A. (T53) and Fondo Social Europeo is acknowledged.

DOI:

Publication date: June 9, 2020

Issue: OENO IVAS 2019

Type: Article

Authors

Ignacio Arias, Sara Ferrero-del-Teso, María Pilar Sáenz-Navajas, Purificación Fernández-Zurbano,Blanca Lacau, Jesús Astraín, Cristina Barónv Vicente Ferreira, Ana Escudero

Instituto de Ciencias de la Vid y el Vino (ICVV) (Universidad de La Rioja-CSIC-Gobierno de La Rioja), Carre-tera de Burgos Km. 6, Finca La Grajera, 26007 Logroño, La Rioja, Spain
Laboratorio de análisis del aroma y enología (LAAE). Department of Analytical Chemistry, Universidad de Zaragoza, Instituto Agroalimentario de Aragón (IA2) (UNIZAR-CITA). Calle Pedro Cerbuna, 12, 50009 Zaragoza

Contact the author

Keywords

Wine aroma, maturity, acetaldehyde, reduction factors

Tags

IVES Conference Series | OENO IVAS 2019

Citation

Related articles…

Mapping and tracking canopy size with VitiCanopy

Understanding vineyard variability to target management strategies, apply inputs efficiently and deliver consistent grape quality to the winery is essential. However, despite inherent vineyard variability, the majority are managed as if they are uniform. VitiCanopy is a simple, grower-friendly tool for precision/digital viticulture that allows users to collect and interpret objective spatial information about vineyard performance. After four years of field and market research, an upgraded VitiCanopy has been created to achieve a more streamlined, technology-assisted vine monitoring tool that provides users with a set of superior new features, which could significantly improve the way users monitor their grapevines. These new features include:
• New user interface
• User authentication
• Batch analysis of multiple images
• Ease the learning curve through enhanced help features
• Reporting via the creation of colour maps that will allow users to assess the spatial differences in canopies within a vineyard.
Use-case examples are presented to demonstrate the quantification and mapping of vineyard variability through objective canopy measurements, ground-truthing of remotely sensed measurements, monitoring of crop conditions, implementation of disease and water management decisions as well as creating a history of each site to forecast quality. This intelligent tool allows users to manage grapevines and make informed management choices to achieve the desired production targets and remain profitable.

Upscaling the integrated terroir zoning through digital soil mapping: a case study in the Designation of Origin Campo de Borja

homogeneous zones by intersecting several partial zonings of major factors that influence vineyard growth. Each of them follows specific process from their corresponding disciplines. Soil zoning specifically refers to a Soil Resource Inventory map that has traditionally been generated by conventional soil mapping methods. These methods have shortcomings in reaching fine cartographic and categorical details and involve significant expenses, which undermines their applicability. A new framework named Digital Soil Mapping has introduced quantitative models by statistical techniques to establish soil-landscape relationships and is able to provide intensive scale cartography.

In the present study, a microzoning at 1:10.000 scale is generated from an initial zoning, where the conventional soil map with polytaxic map units is replaced by a new one from digital techniques that disaggregates them. The comparison between the zonings considers a quantitative evaluation of capability for each Homogeneous Terroir Unit by means of the Viticultural Quality Index and its categorization based on its distribution by map. The spatial intersection of both maps gives rise to a confusion matrix in which the flows of class variations after the substitution are assessed.

The results show a five-fold increase in the number of Homogeneous Terroir Units identified and a larger differentiation among them, evidenced by a wider range in the capability index distribution. Both elements are accompanied by an increase in the detection of areas of higher potential within previously undervalued uniform zones.These features are a direct effect of the improvements brought by Digital Soil Mapping techniques and would verify the advantages of their implementation in the Integrated Terroir zoning. Eventually, such new highly detailed terroir units would benefit precision viticulture and sustainable management practices.

Effect of multi-level and multi-scale spectral data source on vineyard state assessment

Currently, the main goal of agriculture is to promote the resilience of agricultural systems in a sustainable way through the improvement of use efficiency of farm resources, increasing crop yield and quality under climate change conditions. This last is expected to drastically modify plant growth, with possible negative effects, especially in arid and semi-arid regions of Europe on the viticultural sector. In this context, the monitoring of spatial behavior of grapevine during the growing season represents an opportunity to improve the plant management, winegrowers’ incomes, and to preserve the environmental health, but it has additional costs for the farmer. Nowadays, UAS equipped with a VIS-NIR multispectral camera (blue, green, red, red-edge, and NIR) represents a good and relatively cheap solution to assess plant status spatial information (by means of a limited set of spectral vegetation indices), representing important support in precision agriculture management during the growing season. While differences between UAS-based multispectral imagery and point-based spectroscopy are well discussed in the literature, their impact on plant status estimation by vegetation indices is not completely investigated in depth. The aim of this study was to assess the performance level of UAS-based multispectral (5 bands across 450-800nm spectral region with a spatial resolution of 5cm) imagery, reconstructed high-resolution satellite (Sentinel-2A) multispectral imagery (13 bands across 400-2500 nm with spatial resolution of <2 m) through Convolutional Neural Network (CNN) approach, and point-based field spectroscopy (collecting 600 wavelengths across 400-1000 nm spectral region with a surface footprint of 1-2 cm) in a plant status estimation application, and then, using Bayesian regularization artificial neural network for leaf chlorophyll content (LCC) and plant water status (LWP) prediction. The test site is a Greco vineyard of southern Italy, where detailed and precise records on soil and atmosphere systems, in-vivo plant monitoring of eco-physiological parameters have been conducted.

Towards a regional mapping of vine water status based on crowdsourcing observations

Monitoring vine water status is a major challenge for vineyard management because it influences both yield and harvest quality. It is also a challenge at the territorial scale for identifying periods of high water restriction or zones regularly impacted by water stress. This information is of major importance for defining collective strategies, anticipating harvest logistic or applying for irrigation authorisation. At this spatial scale, existing tools and methods for monitoring vine water status are few and often require strong assumptions (e.g. water balance model). This paper proposes to consider a collaborative collection of observations by winegrowers and wine industry stakeholders (crowdsourcing) as an interesting alternative. Indeed, it allows the collection of a large number of field observations while pooling the collection effort. However, the feasibility of such a project and its interest in monitoring vine water status at regional scale has never been tested.

The objective of this article is to explore the possibility of making a regional map of vine water status based on crowdsourcing observations. It is based on the study of the free mobile application ApeX-Vigne, which allows the collection of observations about vine shoot growth. This information is easy to collect and can be considered, under certain conditions, as a proxy for vine water status. This article presents the first results obtained from the nearly 18,000 observations collected by winegrowers and wine industry stakeholders during 2019, 2020 and 2021 seasons. It presents the vine shoot growth maps obtained at regional scale and their evolution over the three vintages studied. It also proposes an analysis of the factors that favoured the number of observations collected and those that favoured their quality. These results open up new perspectives for monitoring vine water status at a regional scale but above they provide references for other crowdsourcing projects in viticulture.

Phenolic composition of Tempranillo Blanco grapes changes after foliar application of urea

Our research aimed to determine the effect and efficiency of foliar application of urea on the phenolic composition of Tempranillo Blanco grapes. The field experiment was carried out in 2019 and 2020 seasons and the plot was located in D.O.Ca Rioja (North of Spain). The vineyard was Vitis vinifera L. Tempranillo Blanco and grafted on Richter-110 rootstock. The treatments were control (C), whose plants were sprayed with water and three doses of urea: plants were sprayed with urea 3 kg N/ha (U3), 6 kg N/ha (U6) and 9 kg N/ha (U9). The applications were performed in two phenological stages, pre-veraison (Pre) and veraison (Ver). Also, each of the treatments was repeated one week later. Control and treatments were performed in triplicate and arranged in a randomised block design. Grapes were harvested at optimum ripening stage. High-performance liquid chromatography was used to analyse the phenolic composition of the grapes. Finally, the results obtained from the analytical determinations – flavonols, flavanols and non-flavonoid (hydroxybenzoic acids, hydroxycinnamic acids and stilbenes) – were studied statistically by analysis of variance. The results showed that, in 2019, U6-Pre and U9-Pre treatments increased the hydroxybenzoic acid content in grapes, and also all foliar treatments applied at Pre enhanced the stilbene concentration. Moreover, U3-Ver was the only treatment that rose flavonol and stilbene contents in the Tempranillo Blanco grapes. In 2020, all treatments applied at Pre enhanced the flavonol concentration in grapes. Furthermore, U3-Pre and U9-Pre treatments increased stilbene content in grapes. Nevertheless, the hydroxybenzoic acid content was improved by U6-Ver and U9-Ver and besides, hydroxycinnamic acid concentration in grapes was increased by all treatments applied at Ver. In conclusion, the lower and highest dose of urea (U3 and U9), applied at pre-veraison, were the best treatments to improve the Tempranillo Blanco grape phenolic composition.