Comparative evaluation of enzymatic, ultrasonic, and deep eutectic solvent extraction techniques for the recovery of bioactive and secondary metabolites from milky ripeness oat grass ( Avena sativa L. )

). In contrast, ultrasound extraction in water or DES achieved lower polysaccharide yields and showed reduced functional activity, while DES-based extraction produced higher amounts of alkaloids and glycosides, highlighting the importance of safety profiling and indicating a need for careful consideration regarding extract safety and downstream purification for food applications. The aqueous fermentation approach offered the advantages of simplicity, and avoided issues related to solvent recovery inherent to DES systems. These findings highlight fermentation-assisted hot water extraction as a scalable and sustainable method for producing oat-derived polysaccharide-rich extracts with potential applications in functional foods and nutraceuticals.