Use of Agave Bagasse and Lactococcus lactis in Sourdough Production: Drying Effects on Bioactive Compounds

The wastage of by-products generated in the food industry is an issue that should be addressed by determining a second use for these products, with sourdough fermentation being the most popular technology used. The aim of this research was to evaluate the impact of adding agave bagasse (AB) and <i>Lactococcus lactis</i> NRRL B-50307 to sourdough that was later used in the formulation of bread rolls. Five treatments were tested: B1: wheat flour; BI2: wheat flour inoculated with <i>L. lactis</i> (1 × 10⁶ CFU/mL); C10: wheat flour + AB (10% <i>w</i>/<i>w</i>); T5: 5% AB + wheat flour inoculated with <i>L. lactis</i> (1 × 10⁶ CFU/mL); and T10: 10% AB + wheat flour inoculated with <i>L. lactis</i> (1 × 10⁶ CFU/mL). Sourdoughs were back-slopped daily for 6 days, dried in a climatic chamber, reactivated, and left to ferment for 24 h. Samples of each treatment of dried and reactivated sourdough were collected and tests for antioxidant activity (DPPH and ABTS), total amino acid content (OPA), and phenolic and flavonoid content were performed. Phenolic compounds and flavonoids decreased when the sourdough was dried (1.5 to 2.0 mg/g of quercetin); however, an increase in bioactive compounds was observed after reactivation, with the treatments with AB recording the highest values (2.5 mg/g). The DPPH and ABTS tests showed that T10 had the highest activity (25% and 23%, respectively). The OPA results showed an increment in amino acid content (2.0 mg lysine/g), indicating proteolysis. The fermentation curves showed that leavening time was achieved after 600 min of fermentation. AB addition did not affect the viscosity of the sourdough rolls. Sourdough with added AB and <i>L. lactis</i> provided a novel approach to achieve more sustainable baked goods. The drying process decreased the sourdough's bioactive compounds, which were recovered after reactivation.