Physicochemical Properties, Digestibility, and Multiscale Structure Evolution of Quinoa Starch During <i>Lactobacillus rhamnosus</i> Fermentation

ABSTRACT Quinoa fermentation has gained attention for its prebiotic‐enhancing ability, and the protein changes after fermentation have been investigated. Starch is the most abundant nutritional components of quinoa, but fermentation impact on quinoa starch remains unclear. This study investigated how Lactobacillus rhamnosus fermentation of quinoa flour affects starch physicochemical and digestive properties, along with changes in multiscale structure. The results revealed that after fermentation, the water solubility and swelling power increased significantly, along with notable alterations in thermal properties, pasting characteristics, and shear resistance. The amylopectin (AP) content was decreased, particularly in short AP chains (DP ∼6 to 12). The short‐range ordered structure increased, and starch crystallinity decreased. After fermentation, the α‐1,6 glycosidic bond in quinoa starch decreased. These results collectively indicate that short‐chain AP in quinoa starch was preferentially degraded by LGG. Furthermore, fermented quinoa starch exhibited a slight accelerated digestion rate, but no significant change in rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) content was observed. This study elucidates the effects of lactic acid bacteria fermentation on the multiscale structure and properties of quinoa starch. The findings provide valuable insights into the processing and utilization of quinoa‐based products.