Comparative analysis of chemical composition and bioactive properties of green, honey, and white Chlorella vulgaris hydrolysates

Chlorella vulgaris strains with different pigmentation may differ in composition and bioactivity, but this remains poorly explored for their protein hydrolysates. This study aimed to compare hydrolysates from three C. vulgaris strains (Green, Honey and White) produced by enzymatic hydrolysis and ultrafiltration (<3 kDa), regarding their chemical composition and bioactivity. Green hydrolysates exhibited the highest protein (48.83%) and phenolic (1.44 g GAE/100 g) content, with superior antioxidant (ABTS: 1140.51 ± 18.97; ORAC: 1188.94 ± 83.28 μmol TE/g protein) and ACE-inhibitory (76.98 ± 0.56%) activities, while White hydrolysates showed the lowest values. Ultrafiltration did not enhance bioactivity, indicating hydrolysis alone already generated peptide-rich hydrolysates. Multivariate analysis confirmed phenolics, ABTS and ACE inhibition as main differentiating variables, positioning Green hydrolysates as the most promising. Peptidomic analysis revealed distinct peptide profiles, with the green strain characterised by fewer but more abundant bioactive sequences. These findings highlight C. vulgaris hydrolysates, particularly Green, as promising natural ingredients for food, nutraceutical and cosmetic applications.