Bioprocessing of Sargassum fusiforme via Lactobacillus Fermentation: Effects on Nutrient Composition, Organoleptic Properties, and In Vitro Antioxidant and Hypoglycemic Activities

<i>Sargassum fusiforme</i> is an abundant source of biologically active compounds that are released during fermentation. However, the effects of <i>Lactobacillus</i> fermentation on the nutrient composition of <i>S. fusiforme</i> have yet to be sufficiently determined. In this study, we used five strains of <i>Lactobacillus</i> to ferment <i>S. fusiforme</i> and examined changes in the bioactive components, volatile compounds, and bioactivities of the fermentation supernatants. Among the assessed strains, fermentation with <i>Lactobacillus delbrueckii</i> promoted significant increases in the total phenolic contents, and fermentation with all strains contributed to reductions in the levels of undesirable volatile compounds associated with the characteristic odor of <i>S. fusiforme</i>. In addition, <i>S. fusiforme</i> fermented using <i>L. delbrueckii</i> showed superior ABTS radical scavenging activity, whereas <i>S. fusiforme</i> fermented using <i>L. plantarum</i> FY03 (PF-3) or <i>L. plantarum</i> FY02 (PF-2) showed enhanced DPPH radical scavenging capacity, and fermentation using <i>L. rhamnosus</i> promoted the highest ferric-ion-reducing power. Moreover, the inhibition of α-glucosidase activity increased by 2.0- to 3.0-fold in fermented <i>S. fusiforme</i>, whereas the inhibition of α-amylase activity was only significantly augmented by the PF-2 and PF-3 strains. These findings highlight the potential health benefits of <i>Lactobacillus</i>-fermented <i>S. fusiforme</i>, particularly the enhanced antioxidant activities and the capacity to inhibit α-glucosidase and α-amylase activities.