Role of Yeast Mannoproteins in the Interaction between Salivary Proteins and Flavan-3-ols in a Cell-Based Model of the Oral Epithelium

Abstract

Astringency is a highly complex sensation which involves multiple mechanisms occurring simultaneously, such as the interaction between flavan-3-ols and salivary proteins (SP). Moreover, astringency development can be affected by the presence of polysaccharides such as mannoproteins (MP). The aim of this work was to evaluate the molecular mechanisms whereby MP could modulate the astringency elicited by tannins, using a cell-based model of the oral epithelium (TR146 cells), and the effect of salivary proteins on these interactions. The binding of flavan-3-ols to oral cells was evaluated by DMACA assay, while the content of unbound flavan-3-ols after the interactions was assessed by means of HPLC-DAD-MS. Results obtained confirm the existence of cell–tannin interactions, that can be partially inhibited by the presence of SP and/or MP. The most significant decrease was obtained in the system containing MPF (38.16%). Both mannoproteins assayed seem to have modulating effect on flavan-3-ol–SP interactions, acting by two different mechanisms: MPF would lead to the formation of SP/MPF/flavan-3-ols ternary soluble aggregates, while MPL seems to prevent flavan-3-ol–saliva interaction by a competitive mechanism, i.e., MPL would reduce cell–tannin interactions, similar to SP. This study suggests that mannoproteins with different compositional characteristics could exhibit preferential interaction with distinct flavan-3-ol families.

Yeast mannoproteins: Organoleptic modulating functions, mechanisms, and product development trends in winemaking

“…The occurrence of HIs is due to the hydrophobic characters of MPs (mainly the proteic part), phenolic compounds (mainly the aromatic and pyranic regions), proteins, and some volatile compounds of high hydrophobicity; meanwhile, the H-bonds are formed mainly between the hydroxyl, carbonyl and amide groups in different compounds (Chalier et al, 2007;Dufour & Bayonove, 1999;Gonçalves et al, 2018;Lubbers et al, 1994b;Manjón et al, 2020Manjón et al, , 2021Mekoue et al, 2016Mekoue et al, , 2023McRae et al, 2010;Poncet-Legrand et al, 2007b;Ramos-Pineda et al, 2022;Rocha et al, 2007).…”

“…The general functionality of MPs that triggers the direct and indirect interactions with sensory active components are similar to other polysaccharides or proteins: direct interactions between MPs and sensory active components are mainly driven by hydrophobic interactions (HIs) and hydrogen bonds (H‐bonds) (Cao et al., 2021; Jones‐Moore et al., 2021; Li et al., 2021; Liu et al., 2020; Zang et al., 2022). The occurrence of HIs is due to the hydrophobic characters of MPs (mainly the proteic part), phenolic compounds (mainly the aromatic and pyranic regions), proteins, and some volatile compounds of high hydrophobicity; meanwhile, the H‐bonds are formed mainly between the hydroxyl, carbonyl and amide groups in different compounds (Chalier et al., 2007; Dufour & Bayonove, 1999; Gonçalves et al., 2018; Lubbers et al., 1994b; Manjón et al., 2020, 2021; Mekoue et al., 2016, 2023; McRae et al., 2010; Poncet‐Legrand et al., 2007b; Ramos‐Pineda et al., 2022; Rocha et al., 2007).…”

“…Typical SPs involved in the astringency elicitation include freely circulating proline‐rich proteins and mucins in the mucosal pellicle that covers the epithelium (Laguna et al., 2017; Mosca & Chen, 2017). Except for the physicochemical interactions, other biological processes flavanols involved in, such as their interactions with oral cells can also elicit astringency (Huang & Xu, 2021; Ramos‐Pineda et al., 2022; Soares et al., 2019) (Figure 2A).…”

“…Competitive mechanism-1: Some MPs can interact with flavanols, to form MP-flavanol complexes and to protect flavanols from interacting with SPs or oral cells. This competitive mechanism is usually found in MPs of high proteic percentages or high-molecular-weight characteristic(Manjón et al, 2020(Manjón et al, , 2021Ramos-Pineda et al, 2022;Rinaldi et al, 2019;Wang et al, 2021b). With the presence of small/medium-molecular-weight MPs, this kind of MP-flavanol interactions may also inhibit the particle size evolution of flavanol aggregates, benefit the colloidal stability of wine and avoid the formation of flavanol aggregates and precipitates(Alcalde-Eon et al, 2019a;Charpentier et al, 2004;Mekoue et al, 2016;Poncet-Legrand et al, 2007a;Riou et al, 2002; al., 2012a) (Figure 2B); b.…”

“…Possible effects of MPs on wine astringency. (A) Elicitation of astringency due to the interactions of flavanols with salivary proteins and oral cells(Huang & Xu, 2021;Ma et al, 2014); (B) the reduction of wine astringency conferred by MPs due to the competitive mechanism-1: MPs interact with some flavanols to decrease the extent of flavanol-SP or flavanol-oral cell interactions(Agorastos et al, 2022;Manjón et al, 2020Manjón et al, , 2021Ramos-Pineda et al, 2022;Rinaldi et al, 2019;Wang et al, 2021b); (C) the reduction of wine astringency conferred by MPs due to the competitive mechanism-2: MPs interact with some SPs to decrease the extent of flavanol-SP interactions(Manjón et al, 2020(Manjón et al, , 2021Wang et al, 2021a); (D) the reduction of wine astringency conferred by MPs due to the associative mechanism: MPs interact with some SPs and flavanols to form soluble ternary complexes that can maintain the lubricity of the oral surface(Manjón et al, 2020(Manjón et al, , 2021Ramos-Pineda et al, 2018Wang et al, 2021b); (E) the reduction of wine astringency conferred by MPs due to the precipitation mechanism: The MP-flavanol complexes precipitate due to their high-molecular-weight and insoluble characteristics, which causes the decrease of flavanols in wines(Manjón et al, 2021;Poncet-Legrand et al, 2007a;Wang et al, 2021b).d. Precipitation mechanism:The flocculant effect can lead to a coaggregation and precipitation of MP-flavanol complexes(Manjón …”