Enhancing nattokinase stability through synergistic interactions:Construction and mechanism analysis of multi-level...

A hierarchical encapsulation system was engineered through the integration of hydrophobic primary microcapsules within a calcium alginate matrix to enhance the oral bioavailability of nattokinase (NK), a functional enzyme susceptible to gastric degradation. The structural and interactional properties of the resulting fig-like gel beads (CA-WNK-s) were systematically characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), confirming the successful encapsulation and revealing interactions between the polysaccharide matrix and the embedded components. The composite system exhibited a high encapsulation efficiency of 97.18 ± 0.14% and a loading capacity of 27.26%. It also demonstrated exceptional functional performance, retaining 94.89 ± 1.14% of enzymatic activity after 2 h in simulated gastric fluid and enabling sustained release in intestinal conditions. Molecular docking simulations identified hydrogen bonding as the primary interaction mechanism between NK and the wall materials, providing molecular-level insight into the system's stability. The hierarchical architecture significantly enhanced the acid and thermal resistance of NK. This study presents a viable strategy for addressing the stability challenge of NK during oral delivery, leveraging the synergistic effects of a hierarchical encapsulation approach. This strategy offers both a novel and promising approach for enhancing the oral bioavailability of enzymatic proteins and valuable insights for the development of novel antithrombotic functional products.