Integrating eco-friendly approaches to produce protein extracts and hydrolysates with antioxidant properties from Microchloropsis gaditana

In recent years, microalgae have emerged as sustainable alternatives to conventional animal-based proteins and powerful sources of bioactive peptides. This study aimed to develop an eco-friendly workflow using ultrasounds and green solvents to extract proteins from Microchloropsis gaditana and enzymatically produce antioxidant hydrolysates. The ultrasound method yielded comparable protein amounts to the traditional approach, reducing extraction time (1 vs. 5 h) and using a greener solvent (water vs. 5 % NaOH). The enzymatic solutions Fla-vourzyme (R) and Alcalase (R) successfully produced protein hydrolysates with up to 70 % hydrolysis, depending on the hydrolysis time. Regarding biological activity, the protein extract and certain hydrolysates (Flavourzyme (R) after 2 h and Alcalase (R) after 8 h of hydrolysis time) showed promising antioxidant effects, as these substances significantly suppressed the intracellular reactive oxygen species (ROS) levels in HCT 116 cells under H2O2- induced stress. The proteomic analysis uncovered up to 288 proteins, in which antioxidant activity-related proteins and the protein Histone H2A were identified, suggesting a potential correlation with the observed biological activity. Thus, this multidisciplinary approach sheds light on the green production of protein extracts and hydrolysates from microalgae and presents an integrated process for producing antioxidant extracts, holding significant promise as potential ingredients for functional foods and nutraceuticals.