Fermented quinoa–chickpea beverages as an emerging plant-based alternative: physicochemical, microbial, and sensory insights

The consumption of plant-based beverages (PBB) has increased markedly in recent years, driven by health, environmental, and allergen-related concerns. Although fortification strategies have been applied to enhance the nutritional functionality of these products, challenges related to composition, stability, and sensory acceptance remain. Fermentation with lactic acid bacteria (LAB) has emerged as an effective approach for improving flavor, texture, and nutrient bioavailability. This study evaluated the physicochemical properties, microbiological quality, antinutritional compounds, and sensory acceptance of quinoa–chickpea beverages fermented with Lactobacillus acidophilus LA-5 at a 1:1 flour ratio. Homolactic fermentation significantly enhanced nutritional quality by improving the essential amino acid profile, and reducing phytolaccagenin and oleanolic acid saponins, while the protein content remained statistically comparable to the unfermented beverage; no significant effect was observed on phytic acid. Fermentation also promoted color stability, characterized by higher L∗ and b∗ values and lower a∗ values, as well as improved viscosity and overall system stability. High viability of LAB (>7.8 log Colony Forming Units (CFU)/mL) after simulated digestion further supported the probiotic potential of fermented beverages. The absence of spoilage and pathogenic microorganisms confirmed the microbiological safety of PBB, likely because of the combined effects of acidification (pH < 3.5) and antimicrobial metabolites produced by LAB. Sensory analysis revealed enhanced aroma, creaminess, and flavor, with sweetness (particularly in coconut-flavored beverages) positively influencing acceptability. These sensory findings were consistent with the physicochemical changes occurring during fermentation. Overall, homolactic fermentation enhances both the functional and sensory qualities of quinoa–chickpea beverages, supporting consumer acceptance and potential commercial viability.