 IVES 9 IVES Conference Series 9 Prediction of astringency in red wine using tribology approach to study in-mouth perception

Prediction of astringency in red wine using tribology approach to study in-mouth perception

Abstract

AIM: Astringency is described as a ‘dry puckering‐like sensation’ following consumption of tannins1 that affect consumer preference of foods and beverages, including red wine2. To improve the understanding of astringency, which is a complex interaction due to multiple mechanisms occurring simultaneously, further studies are needed. In this view, oral tribology is considered a useful technique for beverage study to evaluate the thin-film lubrication properties of saliva resulting in oral friction‐related sensations3. The aim of this study was to examine the film behavior of selected protein-based fluids under controlled friction conditions, to understand polyphenol-protein interactions involved in the sensation of astringency.

METHODS: A mini-traction device was self-assembled to evaluate friction during a dynamic process under different test conditions. Moreover, several oenological tannins and red wines were analyzed to relate instrumental and sensory results, and the effect of selected parameters involved in astringency perception (acidity, ethanol, polysaccharides) was investigated.

RESULTS: After a preliminary screening of several proteic fluids based on friction behavior, the addition of oenological tannins at increasing levels showed empirical evidence of linear range of interaction with protein (R2 up to 0.97) with increasing friction values. Results were greatly affected by the botanical origin of tannins, their degree of purity and the tannin-to-protein ratio. The tribological findings were confirmed by the chemical and sensory analysis of red wines, which highlighted the great contribution of phenolic compounds, in particular tannins.

CONCLUSIONS:

The inherent properties of the selected protein-based fluid allow a satisfactory prediction of astringency in wine and future work will focus on friction and film formation across a broader set of conditions to improve the characterization of wine astringency based on tribology-sensory relationship.

DOI:

Publication date: September 22, 2021

Issue: Macrowine 2021

Type: Article

Authors

Andrea Versari , Arianna RICCI, Giuseppina Paola PARPINELLO, Luigi RAGNI, Elena BABINI,

Università degli Studi di Bologna (ITALY),

Contact the author

Keywords

sensory analysis; red wine; astringency; phenolic compounds; tribometry

Citation

Influence of climatic conditions on grape composition of Tempranillo in La Mancha DO (Spain)

The aim of this work was to analyze the variability in grape composition of the Tempranillo cultivar related to climatic conditions, in La Mancha Designation of Origin. Grape composition (sugar content, total acidity, pH, malic acid, and total and extractable anthocyanins) recorded during ripening, were analysed for the period 2000-2019. The weather conditions at daily time scale, recorded during the same period, were also evaluated. The relationships between grape parameters with climatic variables related to temperature and to water deficits, referring different periods between phenological events along the growing cycle, were evaluated using regression analysis. High variability in grape composition was observed in the period analysed. Total acidity varied between 3.7 and 7.3 gL-1 while malic acid varied between 1.2 and 4 gL-1. The extractable anthocyanins ranged between 526 and 972 mgL-1, and total anthocyanins ranged between 922 and 1388 mgL-1, being the lowest values recorded in the hottest year (2017). Total acidity decreased 0.77 gL-1 for an increase of 100 GDD, while malic acid decrease in 0.42 gL-1 for the same GDD increase, being the period between veraison and harvest the one that seemed to have higher influence on acidity. In addition, it was confirmed that increasing water deficits decreased acidity. Total and extractable anthocyanins increased in about 210 and 105 mgL-1, respectively, with an increase of 100 GDD from veraison to harvest, and the increase in water deficits favour the increase of anthocyanins, both total and extractable anthocyanins. Total and extractable anthocyanins concentration increased in 35 and 22 mgL-1 per an increase of 10 mm in the water deficit. These results can be of interest to understand the potential changes that grapes composition may suffer under future warmer climates.

La producción vitivinícola como fuente de impactos positivos en el medio seminatural

Wine is at risk of being labelled as a dangerous health product, based on studies that focus on its alcohol content. However, multiple studies suggest that moderate consumption is healthy. Changing the focus from health impacts to the environmental and socioeconomic impacts that wine companies cause, what can be said?

The use of cation exchange resins for wine acidity adjustment: Optimization of the process and the effects on tartrate formation and oxidative stability

Acidity adjustments are key to microbial control, sensory quality and wine longevity. Acidification with cation exchange resins -in acid cycle- offers the possibility to reduce the pH by exchanging wine cations, such as potassium (K+), for hydrogen ions (H+). During the exchange process, the removal of potassium and calcium ions contributes to limiting the formation of tartrate salts, thus offering an alternative solution to conventional methods for tartrate stability. Moreover, the reduction of wine pH and the removal of metals catalyzers (e.g. iron) could positively impact the wine’s oxidative stability. Therefore, the aims of this work were (a) to optimize the ion exchange process by testing different volumes and concentrations of sulfuric acid (H2SO4) during the acid cycle, (b) evaluate the effects of the ion exchange process on the formation of tartrate salts, and (c) analyze the oxidative stability of the treated wines.

Considerations about the concept of “terroir”: definition and research direction

On exposera la distinction et la relation entre: “Etude des milieux”, “Zonage Petit ou Zonage Technique ou Sub Zonage”, “Grand Zonage”, “Délimitation des zones productives” ex.

Importanza del monitoraggio micro-meteorologico nella caratterizzazione del terroir

Le variabili meteorologiche e micro-meteorologiche ricoprono un importante ruolo sulla risposta vegeto-produttiva della vite e di conseguenza sulla qualità delle produzioni. Utilizzando una rete wireless di sensori sono stati monitorati i parametri meteorologici e micro-meteorologici di 4 vigneti del territorio toscano e in differenti condizioni di gestione agronomica.