Production of a fermented<i> Arthrospira</i><i> platensis</i> beverage using<i> Lactobacillus</i> spp.: A comprehensive analysis of its angiotensin-converting enzyme activity, bioactive compounds, and bioaccessibility

This study investigates how the chemical composition and bioactive properties of commercial (C) and laboratorygrown (L) Arthrospira platensis are influenced by fermentation with different lactic acid bacteria. The protein content in the L samples (49-70 %) was significantly higher compared to the C samples (27.6-65.6 %). Chlorophyll a (53.34 mu g/L DW), phycocyanin (55.37 mg/L DW), total carotenoids (19.47 mu g/L DW), and antioxidant activity (DPPH and ABTS) reached their highest levels on the 2nd day of fermentation in samples grown in the laboratory and fermented with Lactiplantibacillus plantarum (L-LP) strain. Fermentation also increased the ACE inhibitory potential, with samples fermented with Lactiplantibacillus plantarum (LP) showing the most significant effects. Sixteen phenolic compounds were identified by LC-MS/MS, and novel compounds such as apigenin 6-Cpentosyl-8-C-(2 ''-O-hydroxy feruloyl)-pentoside, tricaffeoyl-glucosyl-glucoside, vanillic-4-sulfate, and quercetin3-O-rutinoside were reported for the first time. In vitro bioaccessibility analysis revealed the superior release of antioxidants and phenolics in L samples during digestion, with the intestinal phase showing the highest values. These findings demonstrate that A. platensis is a promising substrate for enhancing bioactive properties through fermentation.