Valorization of Brown Seaweed (Lessonia spicata): Cellulosic Saccharification for the Development of a Functional Fermented Beverage

This study explored the production of a fermented beverage using Huiro negro (<i>Lessonia spicata</i>), a brown seaweed, as a substrate. The cellulosic saccharification (CS) process was optimized via response surface methodology, identifying that the best conditions were 60 U/g of enzyme at 60 °C for 1.9 h, yielding 2.5 g/100 g of reducing sugars. The resulting hydrolysate was fermented with <i>Lactobacillus</i> spp. for 48 h at 30 °C and compared with a non-saccharified control. The beverage's proximate composition, total phenolic content (TPC), flavonoid content (TFC), antioxidant capacity (AC), and <i>Lactobacillus</i> spp. viability over 16 days of storage at 4 °C were assessed. CS-treated samples showed a progressive increase in TPC, reaching 126.59 ± 5.58 mg GA/L, which correlated with higher AC. However, no significant differences (<i>p</i> > 0.05) were observed in TPC and AC between saccharified and non-saccharified beverages. Notably, the CS-treated beverage achieved significantly higher (<i>p</i> < 0.05) <i>Lactobacillus</i> spp. counts (10⁹ CFU/mL) compared to the control (10⁷ CFU/mL), maintaining viability throughout storage. While further research is needed to confirm bioavailability and gut health effects, these findings shows that enzymatic saccharification substantially improves fermentation performance and functional properties in <i>Lessonia spicata</i>-based beverages.