Magnetic field-assisted extraction of Crataegus pinnatifida polysaccharides: Enhanced yield, structural integrity, and antioxidant activity through magnetic field pretreatment

As important functional food ingredients with excellent biological activities, Crataegus pinnatifida polysaccharides (CPPs) are widely applied in the food industry. However, their traditional extraction methods often encounter issues such as thermal degradation and shear damage, which result in the instability of polysaccharide structure and the reduction of biological activity. In this study, a magnetic field-assisted extraction (MFAE) method of CPPs was developed to solve the problems of thermal degradation, shear damage, and decreased bioactivity in conventional polysaccharide extraction. Compared with hot water, ultrasound-assisted, and microwave-assisted extraction, MFAE significantly improved the extraction yield and total soluble sugar content of CPPs. Through AFM, SEM, antioxidant and immunomodulatory identification, magnetic field-assisted extracted CPPs maintained stable triple-helix conformation and unique microstructure, exhibited excellent antioxidant activity, and showed no cytotoxicity toward RAW264.7 macrophages while exerting immunomodulatory effects. This demonstrates that MFAE can effectively protect the structural integrity and biological activity of hawthorn polysaccharides while achieving efficient extraction. The optimal MFAE parameters optimized by response surface methodology were as follows: solid-liquid ratio 1:30.81, magnetic field intensity 93.20 mT, and extraction temperature 92.37 °C, with a predicted extraction yield of 20.90%. This study provides a novel strategy for the high-yield and structure-preserving extraction of bioactive polysaccharides, and offers theoretical basis and technical reference for their development in the field of functional foods.