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.
Authors: Brossard Natalia1, Madrid Romina1, Alfaro Gabriel1, Rosenkranz Andreas1 and Bordeu Edumundo1
1Department of Fruit Trees and Enology, Pontifical Catholic University of Chile
*corresponding author: ndbrossa@uc.cl
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.
Keywords: Wine astringency, tannin–protein aggregates, red wine, oral lubrication
