 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

Under-row low competitive herbaceous cover: A sustainable alternative to herbicide in vineyards

Weeds are undesirable plants in agroecosystems as they compete with the crop for essential resources such as light, water and nutrients, compromising the final yield and its quality.

High throughput winter pruning weight estimation based on wood volume evaluation

There is currently a real need to improve and speed-up phenotyping in experimental set-ups to increase the number of modalities studied. Accurate information acquisition on plant status with high-throughput capacity is the main appeal of on-board systems.
A proximal sensing camera for a proxy of winter pruning weight was tested. We estimated the shoot volume of the vine by image analysis using algorithms that integrate the local shoot section area estimate along the shoot skeleton obtained by a morphological distance transform.
The study was carried out on the GreffAdapt experimental vineyard in Guyot simple training and a canopy management using vertical trellising. The planting density is 6250 vines/ha with a row spacing of 1.6×1m. Five scions grafted onto 55 rootstocks are present and the combination rootstock×scion is different every five plants.

Impact of canopy management on thiol precursors in white grapes: a six-year field study

The mechanisms behind thiol precursor accumulation in grapes remain incompletely understood, nor are the ways in which they can be improved by agronomic practices. A six-year field trial studied the physiological response of the Swiss white cultivar Vitis vinifera Arvine, rich in varietal thiols and precursors, to canopy management, i.e. leaf removal and canopy height.. Five treatments were set up in a randomized block design to assess the impacts of 1) pre-flowering LR (i.e. pre-flowering or full-flowering stages) and 2) compensating for the leaf area removed in the cluster zone by increasing the trimming height (i.e. 100 or 150 cm canopy height), compared with a non-defoliated control treatment.
Intensive pre-flowering LR severely reduced yield potential (–47% on average) and reduced the concentration of 3-mercaptohexanol precursors (P-3MH) in the must (–21%; p-value < 0.10).

Wine shaking during transportation: influence on the analytical and sensory parameters of wine

According to OIV reports, annual world wine consumption fluctuated around 240-245 mln hL over the past decade. The general market globalization has led to the situation when almost half of the consumed wine is exported to other countries. Of this volume, more than 60 mln hL are bottled still and sparkling wines.

Harnessing biodiversity to improve grapevine rootstock adaptation to drought

Drought is one of the most challenging threats for viticulture because of its impact on reducing yield and on the composition of grapes.