The aim of this study was to employ molecular dynamics simulations to elucidate the mechanism involved in amylose–zein complexation and the stability of the molecular conformation of amylose–zein complexes in water at the atomic and molecular levels. The average root mean square deviation and radius of gyration were lower for amylose–zein complexes (1.11 nm and 1 nm, respectively) than for amylose (2.13 nm and 1.2 nm, respectively), suggesting a significantly higher conformational stability for amylose–zein complexes than for amylose in water. The results of radial distribution function, solvent-accessible surface area, and intramolecular and intermolecular hydrogen bonds revealed that the amylose–zein interaction inhibited water permeation into the amylose cavity, leading to enhanced conformational stabilities of the V-type helical structure of amylose and the amylose–zein complexes. Furthermore, the amylose in amylose–zein complexes displayed the thermodynamically stable ⁴C₁ conformation. These findings can provide theoretical guidance in terms of the application of protein on starch processing aiming to improve the physicochemical and functional properties of starch (such as swelling capacity, pasting properties, and digestibility) for developing novel low-digestibility starch–protein products.

This study aimed to slow down starch digestion by encapsulating the starch granule within a firm zein shell via solvent-exchange-induced zein deposition. The zein shell adhered tightly to the granule surface and the shell thickness increased with increasing zein concentration. The average shell thickness of microparticles produced with zein (1%, 2%, and 3% w/v) was 0.54 μm, 0.97 μm, and 1.63 μm, respectively. Thicker zein shells acted as a mechanical barrier limiting heat transfer and water penetration, thus significantly affecting the starch digestibility. The in vitro simulated digestion experiment indicated that CS-3% zein microparticles exhibited an approximately 19-fold higher resistant starch (RS) content compared with native corn starch. These findings demonstrated the potential of the zein acting as a shell material in developing delivery system for controlled starch digestion. Additionally, this study validated antisolvent precipitation as an effective method to construct hydrophilic core/hydrophobic shell delivery systems to encapsulate unstable and hygroscopic compounds.