Comparative analysis of high-intensity non-thermal physical treatments on the structural and functional properties of Spirulina platensis protein
Junwen Wang, Qinhao Guan, Zhiting Liu, Jiangfei Li, Li Zhou, Qiaoyun Qi, Yue Zhang, Elena Ibáñez, Alejandro Cifuentes, Weihong Lu
Abstract
Spirulina platensis protein (SPP) has attracted attention as a sustainable alternative to conventional proteins. However, its structural and functional performance under different processing conditions remains underexplored. This study investigated the effects of three non-thermal physical treatments-high hydrostatic pressure (HHP, 100-600 MPa), high-intensity ultrasound (HIU, 70-100 % amplitude), and high-speed shear homogenization (HSS, 1.0-2.5 W)-on the structure and functionality of SPP. SDS-PAGE revealed treatment-specific alterations in protein subunits, accompanied by distinct changes in sulfhydryl/disulfide, surface hydrophobicity, intrinsic fluorescence, and secondary structure. HIU induced the strongest structural disruption, characterized by reduced α-helix content, exposure of hydrophobic residues, and a pronounced decrease in particle size and ζ-potential, whereas HHP promoted unfolding at moderate pressures but aggregation at higher levels. HSS primarily reduced particle size with moderate effects on unfolding. Collectively, these results indicate that high-Intensity non-Thermal physical treatments effectively modulate the functional properties of SPP, demonstrating its potential as a protein ingredient for food applications.