Tailoring Rheological, Viscoelastic, and Starch Structural Properties in Plant-Based Beverages via Homolactic Fermentation of Quinoa and Chickpea Flour Blends

This study investigated the effects of homolactic fermentation on the rheological, viscoelastic, and starch structural properties of quinoa–chickpea flour-based beverages. Three formulations with increasing proportions of chickpea flour (10, 25, and 50%) were fermented for 10 h with Lactobacillus acidophilus LA-5. Apparent viscosity, deformation capacity, storage modulus (G′), and pasting behavior were measured along with FTIR-based analysis of the starch molecular structure. All fermented samples reached pH values < 4.5 and exhibited improved rheological properties with significant increases in viscosity and storage modulus (G′), particularly in the 50:50 blend. These enhancements were attributed to the synergistic effects of homolactic fermentation and inherent properties of chickpea starch, particularly its high amylose content, large granule size, and long amylopectin chains. FTIR analysis revealed that the short-range molecular order of starches was preserved after fermentation in all beverages, except for the 50:50 blend, as evidenced by the increased degree of order (DO) and double helix (DD) ratios. Overall, these findings demonstrate that integrating chickpea flour and controlled homolactic fermentation is an effective strategy for tailoring the viscosity and stability of plant-based probiotic beverages, providing a theoretical basis for the development of clean-label and functional fermented plant-based systems.