Selective release of antioxidant peptides and minerals from fermented SC-CO2-defatted Spirulina

This study aimed to develop an integrated process for the valorization of defatted spirulina ( Arthrospira platensis ) by combining supercritical carbon dioxide (SC-CO 2 ) extraction with targeted lactic acid bacteria (LAB) fermentation. Specifically, SC-CO 2 (25.0 MPa, 50.0 °C, 16.0 mL/min, and 60.0 min) was used to defat Spirulina to obtain the protein-rich substrate as SC-CO 2 defatted spirulina (SC-D- Sp ) for the production of bioactive peptides (BPs), which will be fermented with 5 % Lactiplantibacillus plantarum (LP) and 5 % Lactiplantibacillus casei (LC). A significant microbial growth (up to 2029.3 × 10 6 CFU) and metabolic activity were observed after LAB fermentation. The fermentation solids and supernatants were separated after fermentation, and the protein (using the DUMAS method), bioactive peptides (analyzed by LC-MS/MS TOF), minerals (measured by ICP-MS), and total antioxidant capacity (TAC) were evaluated. Most of the protein remained in the fermentation solids, regardless of whether the LAB strain was used. Nevertheless, LAB fermentation significantly ( P < 0.05) enhanced the production of antioxidant bioactive peptides such as EL, GA, and KP, as well as the enhancement in TAC of the fermented supernatants. In parallel, higher levels of Mg and K were found in the fermented supernatants, while Fe and Zn remained in the fermented solids. In this study, the LAB fermentation in SC-D- Sp could enhance the recovery of valuable high-value-added compounds, including the increasing performances in antioxidant peptides and minerals. The LAB fermentation in SC-D- Sp poses the possibility of future application in developing novel functional ingredients and sustainable marine resources.