“Oral” Tribological Study on the Astringency Sensation of Red Wines

Abstract

Astringency is a specific oral sensation dominated by a dryness and puckering feeling and is one of the main quality factors for red wines, teas as well as some fruit products. Various hypotheses have been proposed to explain the mechanisms of the astringency sensation; however which prevails is still unknown. Here we used a tribological system to determine if the astringency is predominantly a physical perception. Mixtures of whole human saliva and typical astringent compounds such as tannins and red wines were evaluated for their lubrication behavior. Friction coefficient was measured over a wide range of lubrication speed. By comparing friction coefficient with human sensory results of astringency, a positive correlation was found. In particular the highest correlation was observed (R 2 5 0.93) at a sliding speed of 0.075 mm/s. Results from this work demonstrate that astringency of polyphenol-rich products is a sensory perception via a physical stimulus and can be quantified using tribology techniques. PRACTICAL APPLICATIONSThere is an increasing interest in sensory astringency, particularly its signaling process in oral cavity and the quantitative assessment of its intensity. This is due to the fact that astringency is an important quality characteristic which strongly influences consumer's acceptability for many polyphenol-rich foods. This research achieved the first experimental approach to sensory astringency determination on red wines by using a tribological technique. Results from this work positively confirm the hypothesis that astringency is a tactile sensation. The method established in this work provides a useful tool for efficient determination of astringent intensity both as industrial quality control and for the prediction of consumer's sensory perception.

Aging‐related changes in quantity and quality of saliva: Where do we stand in our understanding?

“…All nonvolatile food components need to be dissolved in the saliva in order to reach the taste receptors (Neyraud, ). Furthermore, the role of saliva is also implicit in mouth sensations caused by food components, such as astringency that occurs by the complexation of food polyphenols and salivary proteins (Brossard, Cai, Osorio, Bordeu, & Chen, ; Laguna & Sarkar, ; Rutuja, Natalia, & Jianshe, ). Conversely, the effect of concentration changes of inorganic ions might elevate the taste thresholds and decrease supra‐threshold intensities that give an explanation of elderly people suffering from taste aberrations.…”

“…All nonvolatile food components need to be dissolved in the saliva in order to reach the taste receptors (Neyraud, 2014). Furthermore, the role of saliva is also implicit in mouth sensations caused by food components, such as astringency that occurs by the complexation of food polyphenols and salivary proteins (Brossard, Cai, Osorio, Bordeu, & Chen, 2016;Rutuja, Natalia, & Jianshe, 2016).…”

Spectral analysis of the stick‐slip phenomenon in “oral” tribological texture evaluation

“…The tribometer settings used in the present study revealed mostly friction trends in the boundary and mixed regimes, which could be the most important for the prediction of several friction‐related texture attributes (Pradal & Stokes, ). Wine astringency would be predicted around 0.075 mm/s in the boundary regime (Brossard et al, ), even though astringency could often not be related to friction coefficient values in other studies. Fat perception of food hydrocolloids and emulsions would be mainly predicted from 1 to 30 mm/s or higher velocities by the mixed regime friction coefficient (Malone et al, ) in the range of velocities measured between tongue and palate (De Hoog et al, ; Prinz et al, ).…”

“…Several attempts failed to correlate rheological or bulk texture properties with thin‐film related texture attributes (Bourne, ; Stokes et al, ). Friction coefficient values at specific velocities were related to fattiness, smoothness (Kokini, ; Malone, Appelqvist, & Norton, ), creaminess (Morell, Chen, & Fiszman, ; Sonne, Busch‐Stockfisch, Weiss, & Hinrichs, ), and astringency (Brossard et al, ). Sonne et al () demonstrated that in‐mouth creaminess of yoghurt result from a multisensory experience of combined assessments of rheology, particle size, and tribological characteristics.…”

Saliva could act as an emulsifier during oral processing of oil/fat

“…Major glands include sublingual, submandibular, and parotid, whereas minor glands are scattered inside the oral cavity. Saliva is a complex fluid mostly consisting of water (98-99%), and various organic and inorganic substances (1-2%; Aps & Martens, 2005;Edgar, 1992) and enzymes which interact with food components and then affect eating experience (Bridges, Smythe, & Reddrick, 2017;Brossard, Cai, Osorio, Bordeu, & Chen, 2016;Young et al, 2016). Human saliva is normally distinguished into two types, unstimulated saliva (US) and stimulated saliva (SS), the later one being more dominated by secreted products from the parotid glands.…”