IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Red wine astringency and the influence of wine–saliva aggregates on oral lubrication

Red wine astringency and the influence of wine–saliva aggregates on oral lubrication

Abstract

Oral tribology receives growing attention in the field of food sciences as it offers great opportunities to establish correlations between physical parameters, such as the coefficient of friction, and sensory perceptions in the human mouth. One important aspect is astringency produced by wine, which can be described as the sensation of dryness and puckering in the mouth, specifically occurring between the tongue and the palate after swallowing. Results obtained have contributed to important advances in trying to mimic oral conditions and astringency determination by lubrication tests (Brossard et al., 2021; Brossard et al., 2016). However, these results revealed complex and specific interactions between tannins and saliva proteins with or without the precipitation of the complex (Brossard et al., 2021; Rossetti et al., 2009; Cala et al., 2012; Brossard et al., 2016). In addition, astringency sub-qualities are affected not only the presence of particles, but also by their shape, size and texture (Brossard et al., 2021).
The latter presents a significant challenge in predicting astringency and mimicking oral conditions when tasting. Likewise, variations in the tribometers used and working conditions like tribopairs, contact load and sliding speed, make the comparison of different studies more difficult. This work aims at shedding some light on recent advances trying to correlate physical measures, such as the friction coefficient of oral tribology, with prevailing theories on underlying physiological causes for sensory perception of wines. Friction coefficient was evaluated using different experimental conditions including contact load, and sliding speed, using model wines and wines with different sensory astringency. Results of this work on the friction coefficient suggest that both soluble and insoluble aggregates could be responsible for oral lubrication modulation. A mechanism for astringency intensity and its sub-qualities that illustrates the role of the aggregates is proposed. The model for astringency takes into consideration not only the presence of the particles (shape, size and texture) but also its movement within the oral cavity. These aggregates could be sensed and modulate the friction coefficient, increasing or decreasing oral lubrication. Findings of this work propose an effect of aggregates on sensory perception and opens the possibility to explore their effect on oral lubrication.

References

 

Brossard, N., Cai, H., Osorio, F., Bordeu, E. & Chen, J. (2016). Oral tribology study of astringency sensation of red wines. Journal of Texture Studies, 47, 392–402.
Brossard, N., Gonzalez‐Muñoz, B., Pavez, C., Ricci, A., Wang, X., Osorio, F., Bordeu, E., Paola Parpinello, G. and Chen, J., 2021. Astringency sub‐qualities of red wines and the influence of wine–saliva aggregates. International Journal of Food Science & Technology, 56(10), pp.5382-5394.
Cala, O., Dufourc, E.J., Fouquet, E., Manigand, C., Laguerre, M. & Pianet, I. (2012). The colloidal state of tannins impacts the nature of their interaction with proteins: the case of salivary proline-rich protein/procyanidins binding. Langmuir, 28, 17410–17418.
Rossetti, D., Bongaerts, J.H.H., Wantling, E., Stokes, J.R. & Wil- liamson, A.-M. (2009). Astringency of tea catechin: More than an oral lubrication tactile percept. Food Hydrocolloids, 23, 1984–1992

DOI:

Publication date: June 23, 2022

Issue: IVAS 2022

Type: Article

Authors

Brossard Natalia¹, Madrid Romina¹, Alfaro Gabriel¹, Rosenkranz Andreas¹and Bordeu Edumundo¹

¹Department of Fruit Trees and Enology, Pontifical Catholic University of Chile

Contact the author

Keywords

Wine astringency, tannin–protein aggregates, red wine, oral lubrication

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Impact of climate change on the viticultural climate of the Protected Designation of Origin “Jumilla” (SE Spain)

Protected Designation of Origin “Jumilla” (PDO Jumilla) is located in the Spanish provinces of Albacete and Murcia, in the South-eastern part of the Iberian Peninsula, where most of the models predict a severe impact of climate change in next decades. PDO Jumilla covers an area of 247,054 hectares, of which more than 22,000 hectares

Downscaling of remote sensing time series: thermal zone classification approach in Gironde region

In viticulture, the challenges of local climate modelling are multiple: taking into account the local environment, fine temporal and spatial scales, reliable time series of climate data, ease of implementation and reproducibility of the method. At the local scale, recent studies have demonstrated the contribution of spatialization methods for ground-based climate observation data considering topographic factors such as altitude, slope, aspect, and geographic coordinates (Le Roux et al, 2017; De Rességuier et al, 2020). However, these studies have shown questions in terms of the reproducibility and sustainability of this type of climate study. In this context, we evaluated the potential of MODIS thermal satellite images validated with ground-based climate data (Morin et al, 2020). Previous studies have been encouraging, but questions remain to be explored at the regional scale, particularly in the dynamics of the massive use of bioclimatic indices to classify the climate of wine regions. The results at the local scale were encouraging, but this approach was tested in the current study at the regional scale. Several objectives were set: 1) to evaluate the downscaling method for land surface temperature time series, 2) to identify regional thermal structure variations. We used weekly minimum and maximum surface temperature time series acquired by MODIS satellites at a spatial resolution of 1000 m and downscaled at 500 m using topographical variables. Two types of analyses were performed:

Co-design and evaluation of spatially explicit strategies of adaptation to climate change in a Mediterranean watershed

Climate change challenges differently wine growing systems, depending on their biophysical, sociological and economic features. Therefore, there is a need to locally design and evaluate adaptation strategies combining several technical options, and considering the local opportunities and constraints (e.g. water access, wine typicity). The case study took place in a typical and heterogeneous Mediterranean vineyard of 1,500 ha in the South of France. We developed a participatory modeling approach to (1) conceptualize local climate change issues and design spatially explicit adaptation strategies with stakeholders, (2) numerically evaluate their effects on phenology, yield and irrigation needs under the high-emissions climate change scenario RCP 8.5, and (3) collectively discuss simulation results. We organized five sets of workshops, with in-between modeling phases. A process-based model was developed that allowed to evaluate the effects of six technical options (late varieties, irrigation, water saving by reducing canopy size, adjusting cover cropping, reducing density, and shading) with various distributions in the watershed, as well as vineyard relocation. Overall, we co-designed three adaptation strategies. Delay harvest strategy with late varieties showed little effects on decreasing air temperature during ripening. Water constraint limitation strategy would compensate for production losses if disruptive adaptations (e.g. reduced density) were adopted, and more land got access to irrigation. Relocation strategy would foster high premium wine production in the constrained mountainous areas where grapevine is less impacted by climate change. This research shows that a spatial distribution of technical changes gives room for adaptation to climate change, and that the collaboration with local stakeholders is a key to the identification of relevant adaptation. Further research should explore the potential of adaptation strategies based on soil quality improvement and on water stress tolerant varieties.

Is wine terroir a valid concept under a changing climate?

The OIV[i] defines terroir as a concept referring to an area in which collective knowledge of the interactions between the physical and biological environment (soil, topography, climate, landscape characteristics and biodiversity features) and vitivinicultural practices develops, providing distinctive wine characteristics. Those are perceptible in the taste of wine, which drives consumer preference and, therefore, wine’s value in the marketplace. Geographical indications (GI) are recognized regulatory constructs formalizing and protecting the nexus between wine taste and the terroir generating it. Despite considering updates, GIs do not consider the nexus as a dynamic one and do not anticipate change, namely of climate. Being climate a fundamental feature of terroir, it strongly impacts wine characteristics, such as taste. According to IPCC[ii], many widespread, rapid and unprecedented changes of climate occurred, some being irreversible over hundreds to thousands of years. Climatic shifts and atmospheric-driven extreme events have been widely reported worldwide. Recent climatic trends are projected to strengthen in upcoming decades, whereas extremes are expected to increase in frequency and intensity, forcing wines away from GI definitions. Geographical shifts of viticultural suitability are projected, often moving into regions and countries different from current ones. Some authors propose adaptation in viticulture, winemaking and product innovation. We show evidence of climate changing wine characteristics in the Douro valley, home of 270-year-old Port GI. We discuss herein resist or adapt stances for when climate changes the nexus between terroir and wine characteristics. Using the MED-GOLD[iii] dashboard, a tool allowing for easy visual navigation of past and future climates, we demonstrate how policymakers can identify future moments, throughout the 21st century under different emission scenarios, when GI specifications will likely need updates (e.g., boundaries, varieties) to reduce climate-change impacts.

Geospatial trends of bioclimatic indexes in the topographically complex region of Barolo DOCG

Barolo DOCG is an economically important wine producing region in Northwest Italy. It is a small region of approximately 70 km2 gross area. The topography is very complex with steep sloped hills ranging in elevation from below 200 m to 550 m. Barolo DOCG wine is made exclusively from the Nebbiolo grape. Bioclimatic indexes are often used in viticulture to gain a better understanding of broader climate trends which can be compared temporally and geographically. These indexes are also used for identifying potential phenological timing, growing region suitability, and potential risks associated with expected climatic changes. Understanding how topography influences bioclimatic indexes can help with understanding of mesoscale climate behaviour leading to improved decision making and risk management strategies. The average monthly maximum and minimum temperatures, the Cool Night Index, the Huglin Index, and the monthly diurnal range (from July to October) were calculated using data from 45 weather stations within a 40 km radius of the Barolo DOCG growing area between the years 1996 and 2019. Linear and multiple regression models were developed using independent variables (elevation, aspect, slope) extracted from a digital elevation model to identify significant relationships. Bioclimatic indexes were then kriged with external drift using independent variables that showed significant relationships with the bioclimatic index using a 100 m resolution grid. The maximum monthly temperatures and the Huglin Index showed consistent significant negative relationships with elevation in all years. The minimum monthly temperatures showed no relationship with elevation but in some months a small but significant relationship was observed with aspect. Due to the lack of a relationship between minimum monthly temperatures and elevation compared to the significant relationship between maximum monthly temperatures and elevation, monthly diurnal range had a negative relationship with elevation.