Comparison of plant and microbial protein particles fabricated by heat-induced aggregation or enzymatic cross-linking: structure, physicochemical properties, and stability.

This study innovatively conducted a systematic comparison of plant and microbial protein particles under two preparation methods, including heat-induced aggregation and enzymatic cross-linking. Specifically, protein particles were fabricated from three distinct protein sources: soybean, mung bean and yeast proteins. We evaluated the effects of holding temperature on heat-induced aggregates and reaction time on enzymatic cross-linking aggregates. The microstructure, particle size, zeta potential, physical stability, and turbidity of the particles produced were then measured and compared. Nanoparticles or microparticles could be produced using both methods, whose dimensions range from 177.3 ± 1.5 nm to 3576.0 ± 16.4 nm. As expected, both the heat and enzyme treatments altered the circular dichroism and fluorescence spectra of the proteins, indicating that conformational changes had occurred. Meanwhile, the two plant-derived globular proteins possess relatively ordered tertiary structures, while the microbial yeast protein has a heterogeneous composition and less ordered structure. These differences also lead to distinct aggregation behavior.