Optimization of the extraction process for polysaccharides from Cistanche and their molecular weight distribution

A simple and efficient method for extracting Cistanche polysaccharides was obtained and used to extract four Cistanche polysaccharides. The molecular weight, distribution and polysaccharide mass fraction of the four Cistanche polysaccharides were measured by High performance size exclusion chromatography-multiangle laser light scatter-refractive index detector (HPSEC-MALLS-RID) and differences between the four Cistanche polysaccharides were determined. The results of a single factor test and an orthogonal test showed that the best process parameters for extracting Cistanche polysaccharides used a mixture of enzyme (4%), a ratio of complex enzyme (cellulase∶pectinase) 1∶1, ultrasonic power at 350 W (40 kHz), for 20 min, enzymolysis temperature of 50 ℃, and pH 6. The average yield of three repeated extractions was 5.14%, the mass fraction was 90.78%, the comprehensive index was 47.96%, and the RSD = 1.51%, indicating good reproducibility. The four Bossica Cistanche polysaccharides are all spherical structures but their molecular weights and distributions differ. The optimized compounded enzyme combined with ultrasonic extraction increases the yield of Cistanche polysaccharides. It is a simple, convenient, economical and environmentally friendly extraction method, which lays the foundation for future polysaccharide research.