Brandão Elsa, Santos Silva Mafalda, García-Estévez Ignacio, Mateus Nuno, de Freitas Victor, Soares Susana
REQUIMTE/LAQV, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre S-N, 4169-007 Porto, Portugal.
REQUIMTE/LAQV, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre S-N, 4169-007 Porto, Portugal.
Food Chem. 2017 Aug 1;228:427-434. doi: 10.1016/j.foodchem.2017.02.027. Epub 2017 Feb 8.
Astringency is closely related to the interaction between procyanidins and salivary proteins (SP). The aim of this work was to study the interaction between mucin, a SP responsible for saliva lubricating properties, with different procyanidins (B4 dimer, tetramer (TT) and fractions of oligomeric procyanidins), and the influence of several conditions [pH, ionic strength, procyanidins' mean degree of polymerization (mDP) and different solvents (ethanol or dimethylsulfoxide)] on this interaction by fluorescence quenching and Saturation Transfer Difference (STD)-NMR. For fractions of oligomeric procyanidins, the mucin-procyanidin interaction increased with mDP; however, for pure compounds, procyanidin TT has lower affinity than dimer B4 which could be due to a lower structural flexibility imposed by its complex structure. Furthermore, EtOH and DMSO can disrupt the main driving forces of these interactions, hydrophobic interactions and hydrogen bonds, respectively, lowering significantly the binding constants.
涩味与原花青素和唾液蛋白（SP）之间的相互作用密切相关。本研究旨在通过荧光猝灭和饱和转移差（STD）-核磁共振研究负责唾液润滑特性的SP——粘蛋白与不同原花青素（B4二聚体、四聚体（TT）和低聚原花青素级分）之间的相互作用，以及几种条件[pH、离子强度、原花青素的平均聚合度（mDP）和不同溶剂（乙醇或二甲基亚砜）]对这种相互作用的影响。对于低聚原花青素级分，粘蛋白-原花青素相互作用随mDP增加而增强；然而，对于纯化合物，原花青素TT的亲和力低于二聚体B4，这可能是由于其复杂结构导致的较低结构灵活性。此外，乙醇和二甲基亚砜可分别破坏这些相互作用的主要驱动力——疏水相互作用和氢键，显著降低结合常数。
