State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei 230036, China; Joint Research Center for Food Nutrition and Health of IHM, Anhui Agricultural University, Hefei 230036, China.
State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei 230036, China.
Food Res Int. 2024 Sep;191:114711. doi: 10.1016/j.foodres.2024.114711. Epub 2024 Jun 27.
The complexation of physically modified starch with fatty acids is favorable for the production of resistant starch. However, there is a lack of information on the effect of ultrasonication (UC) on the structure and properties of starch complexes and the molecular mechanism of the stabilization. Here, the multi-scale structure and in vitro digestive properties of starch-fatty acid complexes before and after UC were investigated, and the stabilization mechanisms of starch and fatty acids were explored. The results showed that the physicochemical properties and multi-scale structure of the starch-fatty acid complexes significantly changed with the type of fatty acids. The solubility and swelling power of the starch-fatty acid complexes were significantly decreased after UC (P < 0.05), which facilitated the binding of starch with fatty acids. The XRD results revealed that after the addition of fatty acids, the starch-fatty acid complexes showed typical V-shaped complexes. In addition, the starch-fatty acid complexes showed a significant increase in complexing index, improved short-range ordering and enhanced thermal stability. However, the differences in the structure and properties of the fatty acids themselves resulted in no significant improvement in the multi-scale structure of maize starch-palmitic acid by UC. In terms of digestibility, especially the complexes after UC were more compact in structure, which increased the difficulty of enzymatic digestion and thus slowed down the digestion process. DFT calculations and combined with FT-IR analysis showed that non-covalent interactions such as hydrogen bonding and hydrophobic interactions were the main driving force for the formation of the complexes, with binding energies (lauric acid, myristic acid and palmitic acid) of -30.50, -22.14 and -14.10 kcal/mol, respectively. Molecular dynamics simulations further confirmed the molecular mechanism of inclusion complex formation and stabilization. This study is important for the regulation of starchy foods by controlling processing conditions, and provides important information on the role of fatty acids in the regulation of starch complexes and the binding mechanism.
物理改性淀粉与脂肪酸的络合有利于抗性淀粉的生成。然而，关于超声（UC）对淀粉络合物结构和性能的影响以及稳定化的分子机制的信息却很缺乏。在此，研究了 UC 前后淀粉-脂肪酸络合物的多尺度结构和体外消化特性，并探讨了淀粉和脂肪酸的稳定化机制。结果表明，淀粉-脂肪酸络合物的物理化学性质和多尺度结构随脂肪酸的类型而显著变化。UC 后，淀粉-脂肪酸络合物的溶解度和溶胀能力显著降低（P<0.05），这有利于淀粉与脂肪酸的结合。XRD 结果表明，添加脂肪酸后，淀粉-脂肪酸络合物呈现出典型的 V 形络合物。此外，淀粉-脂肪酸络合物的络合指数显著增加，短程有序性提高，热稳定性增强。然而，由于脂肪酸本身结构和性质的差异，UC 对玉米淀粉-棕榈酸络合物的多尺度结构没有显著改善。在消化方面，特别是 UC 后的络合物结构更紧密，增加了酶解的难度，从而减缓了消化过程。DFT 计算和结合 FT-IR 分析表明，氢键和疏水相互作用等非共价相互作用是形成络合物的主要驱动力，结合能（月桂酸、肉豆蔻酸和棕榈酸）分别为-30.50、-22.14 和-14.10 kcal/mol。分子动力学模拟进一步证实了包合络合物形成和稳定化的分子机制。本研究对于通过控制加工条件来调节含淀粉食品具有重要意义，并为脂肪酸在调节淀粉络合物和结合机制中的作用提供了重要信息。
