Preparation, characterization, and antioxidant activity of gallic acid grafted purple sweet potato polysaccharide

In this study, alkali-soluble purple sweet potato polysaccharide (PSAP) was conjugated with gallic acid (GA) through a free radical grafting reaction. The GA-g-PSAP conjugate's structure was validated using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The GA content measured in GA-g-PSAP was 13.5 mg GAE per g, and antioxidant assays confirmed that GA-g-PSAP exhibited stronger radical scavenging activity and higher reducing power than native PSAP.