Macrowine 2021
IVES 9 IVES Conference Series 9 Relationship between chemical parameters of tannins and in-mouth attributes of grape phenolic fractions

Relationship between chemical parameters of tannins and in-mouth attributes of grape phenolic fractions

Abstract

AIM: Establish relationships between taste and mouthfeel properties of grapes and tannin-related chemical parameters.

METHODS: Tempranillo Tinto and Garnacha Tinta grapes were harvested from distinct blocks in different dates; each sample collection date was separated by one week. Grapes were destemmed and macerated in 15% of ethanol for one week. The polyphenolic fraction (PF) of samples was submitted to solid phase extraction on C18 cartridges and recovered with ethanol. PFs were reconstituted in wine model and their taste and mouthfeel properties were characterised by rate-K-attributes methodology. In parallel, concentration (TC) and activity (TAc) of tannins as well as the concentration of tannins linked to anthocyanins (T-A) were determined using HPLC-UV–VIS.

RESULTS: Garnacha PFs show significatively lower values for TAc, TC and the concentration of polymeric pigments (T-A) than Tempranillo PFs. On the one hand, for the Garnacha PFs, TAc and TC present significant and positive correlations with the three dry-related terms evaluated (i.e.: “dry”, “dry on the tongue side” and “dry palate”). Besides, TC also shows negative correlations with “silky” and “watery” atributes and the concentration of polymeric pigments presents a positive correlation with the overall dry-related term: “dry” and a negative relationship with “fleshy”, “silky” and “gummy”. On the other hand, Tempranillo PFs do not present significant sensochemical correlations, which could be attributed to the fact that the chemical parameters of the PFs evaluated present a small variability inducing none significant sensory differences.

CONCLUSIONS:

The presented approach enables to have a representative pool of phenolic fractions of grapes. Significant correlations between mouthfeel terms such as “dry”, “silky”, “watery”, “fleshy”, “silky” and “gummy” and the chemical parameters measured are observed.

DOI:

Publication date: September 22, 2021

Issue: Macrowine 2021

Type: Article

Authors

Sara, Ferrero-Del-Teso , María-Pilar, SAENZ-NAVAJAS, Vicente, FERREIRA,  FERNANDEZ-ZURBANO, 

Institute of Grapevine and Wine Sciences (UR-CSIC-GR). La Rioja, Spain. University of Zaragoza, IA2, Spain.  Purificación, 

Contact the author

Keywords

mouthfeel, tannin activity, tannin concentration

Citation

Related articles…

EVALUATION OF A SEAWEED EXTRACT OF RUGULOPTERYX OKAMURAE AGAINST ERYSIPHE NECATOR IN GRAPEVINE

Powdery mildew, caused by Erysiphe necator, is a widespread disease that causes high economical losses in viticulture. The main strategy to control the disease is the recurrent application of sulphur based phytochemical compounds. However, in order to reduce their accumulation in the environment and promote the sustainability of the sector, the European Commission has applied restrictions to the number of pesticide treatments and the maximum quantity of fungicides to be applied in viticulture. Seaweeds, in particular macroalgae, are marine resources rich in sulphated polysaccharides with bio-protective potential for the plant, representing an environmentally-friendly alternative approach for sustainable wine production.

Discrimination of white wines by Raman spectroscopy coupled with chemometric methods

France is the largest exporter of wine in the world. The export turnover is estimated at 8.7 billion euros in 2017 for 13 million hectoliters sold. This lucrative business pushes scammers to increase the value of some low-end wines by cheating on their appellations, quality or even their origins. These facts lead to losing 1.3 billion euros each year to the European Union’s wine and spirits companies.

Depletion Of Vine-Shoots Phenolic Composicion After Being Used As An Enological Tool For Wine Differentiation

Pruning vine-shoots are a viticulture waste that have been traditionally poorly exploited in relation to its chemical minority composition related to phenolic and volatile compounds. In this line, toasted vine-shoots supposes a proposal of enological tool to use to modulate the chemical and sensorial profile of wines. From a phenolic point of view, when vine-shoots are used during winemaking mainly influence to increase the flavanols and stilbenes content, mostly trans-resveratrol, as also an increasing in the sweet tannins and decreasing the green character and total anthocyanins, changing the violet for garnet colour.

Photoselective shade films affect grapevine berry secondary metabolism and wine composition

Grapevine physiology and production are challenged by forecasted increases in temperature and water deficits. Within this scenario, photoselective overhead shade films are promising tools in warm viticulture areas to overcome climate change related factors. The aim of this study was to evaluate the vulnerability of ‘Cabernet Sauvignon’ grape berry to solar radiation overexposure and optimize shade film use for berry integrity. A randomized complete block design field study was conducted across two years (2020-2021) in Oakville, Napa Valley, CA, with four shade films (D1, D3, D4, D5) differing in the percent of radiation spectra transmitted and compared to an uncovered control (C0). Integrals for gas exchange parameters and mid-day stem water potential were unaffected by the shade films in 2020 and 2021. By harvest, berries from uncovered and shaded vines did not differ in their size or primary metabolism in either year. Despite precipitation exclusion during the dormant season in the shaded treatments, yield did not differ between them and the control in either season. In 2020, total skin anthocyanins (mg/g fresh mass) in the shaded treatments was greater than C0 during berry ripening and at harvest. Conversely, flavonol concentrations in 2020 were reduced in shaded vines compared to C0. The 2020 growing season highlighted the impact of heat degradation on flavonoids. Flavonoid concentrations in 2021 increased until harvest while flavonoid degradation was apparent from veraison to harvest in 2020 across shaded and control vines. Wine analyses highlighted the importance of light spectra to modify wine composition. Wine color intensity, tonality and anthocyanin values were enhanced in D4 whereas antioxidant properties were enhanced in C0 and D5 wines. Altogether, our results highlighted the need of new approaches in warm viticulture areas given the impact that composition of light has on berry and wine quality.

A.O.C. huile d’olive de Nyons et olives noires de Nyons

A.O.C. huile d’olive de Nyons et olives noires de Nyons