Cross-Over Application of Algerian Dairy Lactic Acid Bacteria for the Design of Plant-Based Products: Characterization of and for the Formulation of Quinoa-Based Beverage.

The food industry constantly seeks new starter cultures with superior characteristics to enhance the sensory and overall quality of final products. Starting from a collection of Algerian dairy (goat and camel) lactic acid bacteria, this work focused on the exploration of the technological and probiotic potential of (VR81 and LVT1) and R12 strains isolated from raw camel milk and fermented milk, respectively. These bioactive strains were selected for their high performance among ten other LAB strains and were used as starter cultures to develop a novel and nutritionally enhanced dairy-like plant-based yogurt using quinoa ( Willd) as a raw matrix. The strains were evaluated for their antagonistic effects against , , , , , and , resilience to acidic and osmotic challenges, and tolerance to gastrointestinal mimicking conditions (i.e., pepsin and bile salt). Their aggregation and adhesion profiles were also analyzed. Furthermore, and were tested in single and co-culture for the fermentation and biocontrol of quinoa. The strains exhibited probiotic properties, including a high potential for biocontrol applications, specifically against and (20 mm diameter zone with the neutralized cell-free supernatant), which disappeared after protease treatment, suggesting that bioactive peptides might be responsible for the observed antimicrobial effect. Additionally, they demonstrated resilience to acidic (pH 2) and osmotic challenges (1M sucrose), tolerance to gastro-intestinal conditions, as well as good aggregation and adhesion profile. Furthermore, the strains were able to produce metabolites of interest, such as exopolysaccharide (yielding up to 4.7 mg/mL) and riboflavin, reaching considerable production levels of 2.5 mg/L upon roseoflavin selection. The application of and as primary starters (both in single and co-culture) for fermenting quinoa resulted in effective acidification of the matrix (ΔpH of 2.03 units) and high-quality beverage production. in vivo challenge tests against showed the complete inhibition of this pathogen when was included in the starter, either alone or in combination with . Both species also inhibited and filamentous fungi. Moreover, the co-culture of mutant strains of R12d and VR81d produced riboflavin levels of 175.41 µg/100 g in fermented quinoa, underscoring their potential as starters for the fermentation, biopreservation, and biofortification of quinoa while also displaying promising probiotic characteristics.