物理改性淀粉与脂肪酸的络合有利于抗性淀粉的生产。然而,缺乏有关超声处理(UC)对淀粉复合物的结构和性质以及稳定化的分子机理的影响的信息。这里,研究了UC前后淀粉-脂肪酸复合物的多尺度结构和体外消化特性,探讨了淀粉和脂肪酸的稳定机理。结果表明,淀粉-脂肪酸复合物的理化性质和多尺度结构随脂肪酸类型的不同而显著变化。UC后淀粉-脂肪酸复合物的溶解度和溶胀力明显下降(P<0.05),这促进了淀粉与脂肪酸的结合。XRD结果表明,加入脂肪酸后,淀粉-脂肪酸复合物显示典型的V形复合物。此外,淀粉-脂肪酸复合物的复合指数显着增加,改进的短程有序性和增强的热稳定性。然而,脂肪酸本身的结构和性质的差异导致UC对玉米淀粉-棕榈酸的多尺度结构没有显着改善。在消化率方面,尤其是UC后的配合物结构更紧凑,这增加了酶消化的难度,从而减缓了消化过程。DFT计算并结合FT-IR分析表明,氢键和疏水相互作用等非共价相互作用是配合物形成的主要驱动力,具有结合能(月桂酸,-30.50,-22.14和-14.10kcal/mol的肉豆蔻酸和棕榈酸),分别。分子动力学模拟进一步证实了包合物形成和稳定化的分子机理。这项研究对于通过控制加工条件来调节淀粉食品具有重要意义,并提供了有关脂肪酸在淀粉复合物调节中的作用和结合机制的重要信息。
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.