Macrowine 2021
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

Related articles…

Influence of weather and climatic conditions on the viticultural production in Croatia

The research includes an analysis of the impact of weather conditions on phenological development of the vine and grape quality, through monitoring of four experimental cultivars (Chardonnay, Graševina, Merlot and Plavac mali) over two production years. In each experimental vineyard, which were evenly distributed throughout the regions of Slavonia and The Croatian Danube, Croatian Uplands,

Vineyards and clay minerals: multi-technique analytical approach and correlations with soil properties

Purpose of this research is to quantitatively assess the mineral component of vineyard soils, with particular attention to the mineralogical analysis of clays, which represent an element of high importance in the vineyard culture as well as in general agriculture. An X-ray diffraction (XRD) / thermogravimetric (TG) multi-technique analytical approach was developed, tested on soil samples taken from vineyards around the world. This codified analytical procedure was necessary to obtain precise qualitative and quantitative mineralogical data, globally comparable to distinguish the geopedological identity of the vineyards. Soil samples from vineyards of various locations were analysed, in very different geological conditions. The bulk-rock quantitative phase analysis (QPA) was obtained by the Rietveld method while the detailed composition of the clay-sized fraction was determined by modelling of the oriented X-ray diffraction patterns. The research provided a precise classification of the mineral component of soils, distinguishing the mineral phases of the clays and the so-called mixed-layer clay minerals. We found that the content in mixed layers can be directly correlated with the water retention and the cation exchange capacity ​​of the soil, while the presence of other clayey minerals and phyllosilicates in this research did not affect this CEC parameter, which codes the fertility level of the soils. The study demonstrates that terroir, in particular soils formed in complex or very different geological conditions, can only be effectively interpreted by properly analysing its mineral phases, in particular the mixed-layer clay component. These are characteristic abiotic ecological indicators, which may have specific eco-physiological influences on the plant.

Spatial determination of areas in the Western Balkans region favorable for organic production

In problematic conditions for production of grapes and wine caused by the COVID-19 pandemic and the resulting occurrence of wine surpluses, producers are increasingly turning to the innovative viticulture and winemaking of products that are more appealing to the market and the consumers. On the other hand, consumption of the food safety or organic products, and therefore of organic grapes and wine, is increasingly common in the world, in particular in Europe. The Regional Rural Development Standing Working Group (SWG RRD), as a regional intergovernmental organization gathers actors in the viticulture and winemaking sector from states and territories of the Western Balkans (South-East Europe) in the Expert Working Group for Wine, with the aim of improving viticulture and winemaking in this region through joint activities. In accordance with the aforementioned, the SWG RRD is working on advancing organic production of grapes and wine, and on recognition of specificities of the terroir of wine-growing areas in Western Balkans. In addition, as part of the project “Facilitation of Exchange and Advice on Wine Regulations in Western Balkan Countries” helmed by the German Federal Ministry of Food and Agriculture, in addition to harmonization of relevant legislation with EU regulations, efforts are being invested towards recognition of organic wines. Within activities and project implemented by this organization, expert analyses and scientific research of the terroir of Western Balkans were carried out, and some of the results are presented in this paper.

A multidisciplinary approach to evaluate the effects of the training system on the performance of “Aglianico del Vulture” vineyards

Vineyards are complex agro-ecosystems with high spatial and temporal variability. An efficient training system may counteract the adverse effects of this variability. Moreover, considering the climate change issues, choosing an efficient training system that enhances water use and protects the vines from radiative thermal stress has become a priority for the farmers. A multidisciplinary approach that assesses the soil-crop-yield-wine relationships of vineyards in a distributed and holistic way could bring added knowledge on the behavior of the different training systems. This ongoing research aimed to implement a multidisciplinary approach to study the behavior of “Aglianico del Vulture” grapevines trained with two different systems: a spurred cordon (SC) and an “Alberello in parete” (AL), grown in a high-quality wine production area of Basilicata region (Italy). The approach merged several methods and scales of soil, ecophysiology, must/wine quality, and spectral data collection to assess the influence of the training system. Homogeneous zones (HZs) in both training systems were defined through a procedure based on geomorphological classification, unmanned aerial vehicles (UAV) images analysis, and a traditional soil survey supported by geophysical scanning. During the 2021 season, TDR probes monitored soil water content, while grapevine health status was assessed using eco-physiological measurements (LWP, chlorophyll content, PSII photosynthetic efficiency, LAI, and point-based field spectroscopy). These grapevine in-vivo measurements validated the spectral vegetation indexes (NDVI, RENDVI, CVI, and TVI) derived from the UAV multispectral imagery, which monitored the grapevine status in a distributed and non-invasive way. Grape yield, quality of berries, must and wine were measured to assess the effects of the training systems. The first experimental year results showed the variability of the vineyards and revealed relationships among soil parameters, crop characteristics, and vegetation indices of the SC and AL training systems. This multidisciplinary study could bring new insights into the vineyard training system’s effects on grape yield and wine quality.

Assessing the relationship between cordon strangulation, dieback, and fungal trunk disease symptom expression

Grapevine trunk diseases including Eutypa dieback are a major factor in the decline of vineyards and may lead to loss of productivity, reduced income, and premature reworking or replanting. Several studies have yielded results indicating that vines may be more likely to express symptoms of vascular disease if their health is already compromised by stress. In Australia and many other wine-growing regions it is a common practice for canes to be wrapped tightly around the cordon wire during the establishment of permanent cordon arms. It is likely that this practice may have a negative effect on health and longevity, as older cordons that have been trained in this manner often display signs of decay and dieback, with the wire often visibly embedded within the wood of the cordon. It is possible that adopting a training method which avoids constriction of the vasculature of the cordon may help to limit the onset of vascular disease symptom expression. A survey was conducted during the spring of two consecutive growing seasons on vineyards in South Australia displaying symptoms of Eutypa lata infection when symptomless shoots were 50–100 cm long. Vines were assessed as follows: (i) the proportion of cordon exhibiting dieback was rated using a 0–100% scale; (ii) the proportion of canopy exhibiting foliar symptoms of Eutypa dieback was rated using a 0–100% scale; (iii) the severity of strangulation was rated using a 0–4 point scale. Images were also taken of each vine for the purpose of measuring plant area index (PAI) using the VitiCanopy App. The goal of the survey was to determine if and to what extent any correlation exists between severity of strangulation and cordon dieback, in addition to Eutypa dieback foliar symptom expression.