Natural Chemistry Research Group, Department of Chemistry, University of Turku, FI-20014 Turku, Finland.
Materials Chemistry Research Group, Department of Chemistry, University of Turku, FI-20014 Turku, Finland.
Molecules. 2023 Jul 13;28(14):5370. doi: 10.3390/molecules28145370.
Food, feed and beverage processing brings tannins into contact with macromolecules, such as proteins and polysaccharides, leading to different chemical and physical interactions. The interactions of tannins with proteins are well known but less is known about the affinity of tannins to polysaccharides. We used bacterial cellulose from as a model compound to investigate how tannins and cellulose interact by adsorption measurements using UPLC-DAD. We also explored how the structure of tannins influences these interactions. The model tannins included nine individual structurally different hydrolysable tannins (HTs) and eight well-defined proanthocyanidin (PA) fractions with different monomeric units, mean degree of polymerization and both A- and B-type linkages. Tannins were found to have both strong and weak interactions with bacterial cellulose, depending on the exact structure of the tannin. For HTs, the main structural features affecting the interactions were the structural flexibility of the HT molecule and the number of free galloyl groups. For PAs, prodelphinidins were found to have a higher affinity to cellulose than procyanidins. Similarly to HTs, the presence of free galloyl groups in galloylated PAs and the flexibility of the PA molecule led to a stronger interaction. Adsorption measurements by UPLC-DAD proved to be a sensitive and rapid tool to evaluate the affinity of tannins to cellulose.
食品、饲料和饮料加工使单宁与蛋白质和多糖等大分子接触，导致不同的化学和物理相互作用。单宁与蛋白质的相互作用是众所周知的，但单宁与多糖的亲和力知之甚少。我们使用细菌纤维素作为模型化合物，通过使用 UPLC-DAD 的吸附测量来研究单宁和纤维素如何相互作用。我们还探讨了单宁的结构如何影响这些相互作用。模型单宁包括 9 种结构不同的可水解单宁（HTs）和 8 种结构明确的原花青素（PA）级分，它们具有不同的单体单元、平均聚合度以及 A 型和 B 型键合。单宁与细菌纤维素之间存在强相互作用和弱相互作用，具体取决于单宁的精确结构。对于 HTs，影响相互作用的主要结构特征是 HT 分子的结构灵活性和游离没食子酰基的数量。对于 PAs，原儿茶醛比原花青素更易与纤维素结合。与 HTs 类似，在酰化 PAs 中存在游离没食子酰基和 PA 分子的灵活性会导致更强的相互作用。UPLC-DAD 的吸附测量被证明是一种灵敏且快速的工具，可用于评估单宁与纤维素的亲和力。
