Optimization of Microwave Assisted Aqueous Two Phase Extraction of Lily Polysaccharides and Its Structure Characterization

To obtain lily polysaccharides efficiently and characterize the structure of polysaccharides, the polysaccharides from lily was extracted by using microwave-assisted aqueous two-phase extraction in this paper. The best extraction process was determined by single factor experiment and orthogonal experiment. The crude extract of lily polysaccharides was purified via DEAE-52 and Sephadex G-100 column chromatography in turn to obtain a single fraction (LP2-SG). The molecular weight and monosaccharide composition of LP2-SG were determined by high performance gel permeation chromatography and gas chromatography, respectively, and then its structure was preliminarily characterized. The results showed that the optimum extracting parameters to achieve the highest yield of polysaccharides 10.15%±0.11% from lily by microwave-assisted aqueous two-phase extraction was obtained under the microwave power of 400 W, ammonium sulfate mass fraction of 20%, ethanol volume fraction of 50%, and solid-to-liquid ratio of 1:30 g/mL. LP2-SG with a molecular weight of 530.51 kDa was composed of mannose, glucose, and galactose with a molar ratio of 11.63:29.85:8.46. LP2-SG has no characteristic absorption at 260 nm and 280 nm, and it had typical infrared absorption characteristics of polysaccharides. The results of this study provide an important reference for the efficient extraction and deep development of lily polysaccharides.