Comparative analysis of protein extraction, functional properties, and digestibility of seven microalgae for food...

Microalgae are promising alternative protein sources for functional foods due to their high protein content (22-64 %) and bioactive potential. Seven species were evaluated for extraction efficiency, functionality, digestibility, and bioactivity. An optimized homogenization-ultrasonication method achieved yields from 5.1 % in E. gracilis to 83.6 % in C. vulgaris. Proteins from C. vulgaris and S. platensis showed high solubility, strong foaming, and stable emulsions. Digestibility ranged from 0.66 (C. vulgaris) to 0.81 (N. oculata). After digestion, antioxidant activity improved markedly, with DPPH scavenging rising from 36 % to 90 % in C. vulgaris and from 71 % to 91 % in S. platensis. Both species also reduced lipid accumulation by up to 42 % and triglycerides by 45 % in 3T3-L1 cells. These results highlight their potential as multifunctional ingredients for sustainable food and nutraceutical applications.