Optimization of compound enzyme–ultrasound extraction of chicory polysaccharides and their effects on the quality of fermented Milk

Chicory polysaccharides (CIP) were efficiently extracted by a compound enzyme-ultrasound method optimized via response surface analysis, achieving a yield of 56.47 %-notably higher than enzyme- or ultrasound-only extraction. Structural analyses (FT-IR, XRD, SEM, DSC, TGA) confirmed that the process preserved CIP integrity while enhancing thermal stability and rheological properties. When incorporated into fermented milk, CIP improved lactic acid bacteria viability, water-holding capacity, and viscosity in a fat-dependent manner, while supplementation at 2-3 % significantly enhanced antioxidant activity during storage. Sensory evaluation and free amino acid/taste activity analyses further showed that 3 % CIP achieved optimal texture, flavor balance, and consumer acceptability. These results demonstrate that CEUE-derived CIP can serve as a multifunctional dairy ingredient, simultaneously improving physicochemical quality, sensory profile, and health-promoting potential of fermented milk.