 IVES 9 IVES Conference Series 9 Anthocyanins in tannat wines rapidly evolve toward unidentified red-coloured pigments

Anthocyanins in tannat wines rapidly evolve toward unidentified red-coloured pigments

Abstract

AIM: To assess the relationship between the reported low-stability of Tannat colour during wine storage and its pigment composition and evolution

METHODS: Twenty wines were elaborated under experimental conditions over two vintages, 2015 and 2016, eight corresponding to Tannat, and six to Syrah and Marselan. Wines were stored in darkness under cellar temperature conditions. Anthocyanins and tannins were quantified by spectrophotometric methods as well as by HPLC-DAD-ESI-MSn. Analysis were made three months after the end of winemaking, and twelve and twenty-four months later.

RESULTS: At three months, the pigment content determined by HPLC (spectrophotometer) ranged between 190-240 mg/L (370-665 mg/L) in Tannat, 200-320 mg/L (420-470) in Marselan and 100-305 (220-340) in Syrah. Colour intensity was between 17-28 AU in Tannat, 15-17 in Marselan and 10-16 in Syrah. From the second analytical date on, Tannat wines registered the lowest HPLC/spectrophotometer anthocyanin quotient, tendency increasing with wine age. Besides, Tannat wines presented much higher decreases of the HPLC anthocyanin content between analytical dates than the observed in Marselan and Syrah. This was independent from the type of pigment considered. Moreover, the unresolved HPLC broad peak was also of a higher relative magnitude in Tannat wines. This could not be explained by the tannin contents or pH measured in the wines. Spectrophotometric anthocyanin results did not show such differences among cultivars, neither in the proportion of SO2 bleachable pigments. Tannat wines showed as well the highest colour intensity decreases through time.

CONCLUSIONS

The result suggests that in Tannat wines, anthocyanins may evolve rapidly towards polymeric pigments that would still have red-bluish hues but would be less stable. These findings could be behind the low colour stability reported in literature for Tannat wines, and could be a starting point for future research.

DOI:

Publication date: September 14, 2021

Issue: Macrowine 2021

Type: Article

Authors

Guzmán Favre

Faculty of Agronomy, Universidad de la República, Av. Garzón 780. C.P., 12900 Montevideo, Uruguay ,Sergio, GÓMEZ-ALONSO, Regional Institute of Applied Scientific Research (IRICA), University of Castilla-La Mancha, Avda. Camilo José Cela S / N, 13071 Ciudad Real, Spain. José, PÉREZ-NAVARRO, Regional Institute of Applied Scientific Research (IRICA), University of Castilla-La Mancha, Avda. Camilo José Cela S / N, 13071 Ciudad Real, Spain. Diego, PICCARDO, Faculty of Agronomy, Universidad de la República, Av. Garzón 780. C.P., 12900 Montevideo, Uruguay Gustavo, GONZÁLEZ-NEVES, Faculty of Agronomy, Universidad de la República, Av. Garzón 780. C.P., 12900 Montevideo, Uruguay

Contact the author

Keywords

colour stability and evolution, derived pigments, tannat, syrah, marselan

Citation

First characterization of Torrontés Riojano in la Rioja, Argentina: impact of pruning intensity on vine vigor and grape production

Pruning is one essential vineyard management activity whose main purpose is to regulate plant growth and vigour, modulating berry size, and consequently, wine quality. In Chilecito, La Rioja Province, Argentina, Torrontés Riojano stands as the only autochthonous variety for winemaking, yielding golden and aromatic berries and distinctive muscatel-tasting wines. This white cultivar, resulting from the natural cross between Moscatel de Alejandría x Criolla Chica, is traditionally trained in “parral” (horizontal trellis system), aimed to manage vigorous canopies. This project constitutes the first study on the influence of pruning intensity on Torrontés Riojano growth habit and berry quality.

Establishment of a geodatabase ‘for the characterization of the viticultural “terroirs” of “canton de Vaud” (Switzerland)

La caractérisation objective des terroirs viticoles est nécessaire pour mieux comprendre les relations existantes entre les sols, la plante et la qualité de la production vinicole. Dans le cadre d’une recherche sur les terroirs viticoles du canton de Vaud – Suisse, un géorépertoire pédologique et agronomique a été conçu et réalisé.

Integrating RO concentrate in viticultural irrigation for sustainable urban water reclamation

Grapevines (Vitis vinifera L.) require precise irrigation to maintain yield and quality, and the increasing use of reclaimed desalinated water for irrigation raises concerns about the accumulation of reverse osmosis concentrate (ROC), a high-salinity byproduct with no sustainable disposal solution.

Diagnosis of soil quality and evaluation of the impact of viticultural practices on soil biodiversity in a vineyard in southwestern France

Viticulture is facing two major changes – climate change and agroecological transition. In both cases, soil quality is seen as a lever to move towards a more sustainable viticulture. However, soil biological quality is little considered in the implementation of viticultural practices. Gascogn’Innov (2017-2022) is an Operational Group funded by the European Innovation Partnership for Agriculture. As such, it brings together winegrowers from the south-west of France, scientists, advisors and technicians, around a project focused on viticultural soil biological functioning and the design of technical routes more respectful toward soil heritage. To achieve this, the project aims to acquire references on the impact of viticultural practices on soil biology from a dynamic way, and to test a methodology to integrate information provided by the soil bioindicators to manage farming systems. A set of indicators of soil biological quality are evaluated in the project: microorganisms (bacteria and fungi abundance and diversity), fauna (abundance and diversity of nematodes and earthworms), physico-chemical characteristics, soil structure assessment and degradation rate of organic matter. Based on a network of 13 plots that have been subject to an initial diagnosis in 2017, several agronomical practices to restore soil fertility are experimented to redesign the cropping system (for instance plant cover, organic matter inputs, reduction of herbicides, mineral fertilizers). System redesign was made in collaboration by winegrowers and an interdisciplinary group of experts (agronomists, biologists). Several indicators are measured on vine and soil at each vintage to assess vine health and productivity. At the end of the project (2021), a final diagnosis was carried out. Gascogn’Innov allowed to create a regional database on the quality of wine-growing soils, which permitted to evaluate the effect of practices according to soil types. Especially, decreasing the intensity of tillage and increasing the duration and diversity of grass coverage tends to increase the abundance of all the organisms studied. This project confirmed the value of soil biological quality indicators to drive the sustainability of practices, but also highlighted the key-role of expertise, in both agronomy and soil biology, to help winegrowers understand and appropriate their soil quality diagnoses.

Evaluation of intravarietal variability and selection for tolerance to downy mildew: The case of Antão Vaz variety in Portugal

Antão Vaz is a Portuguese white grapevine variety grown mainly in the wine-growing regions of Southern Portugal, particularly in the Alentejo, Lisbon and Setúbal peninsula regions. It is a very vigorous and productive variety, giving the wines a strong identity. It needs heat and sunlight and prefers deep and dry soils, which makes it tolerant to scald caused by the high summer temperatures of Southern Portugal. However, this variety is very susceptible to downy mildew, caused by plasmopara viticola, a very destructive disease in years with rainy springs.