Functional Enhancement of Whey Protein Isolate by Water-Soluble Polysaccharides from Lanzhou Lily Bulbs

Polysaccharides (LPs) were extracted from Lanzhou lily bulbs using hot water, decolorized with AB-8 resin, deproteinized by Sevage reagent, and precipitated with ethanol. The main monosaccharides were glucose (79.95%), mannose (18.41%), arabinose (0.85%), and galactose (0.80%). FTIR spectroscopy revealed that LPs-WPI interactions altered protein structure, especially in the amide I and II bands. Intrinsic fluorescence peaked at (1%) LPs addition. SEM images showed clear structural changes in WPI after LPs incorporation. Functionally, LPs significantly enhanced the viscosity, antioxidant activity, surface hydrophobicity, and emulsifying capacity of WPI. The LPs-WPI complexes exhibited higher radical scavenging activity than WPI alone, with maximum DPPH and ABTS rates of (87.09%) and (89.24%), respectively. Surface hydrophobicity and emulsification properties varied with LPs content, with the highest EAI observed at (3%). These findings suggest LPs-WPI complexes are promising food-grade materials with enhanced stability and functionality, suitable for application in the food industry.