Isolation of non-starch polysaccharides from bulb of tiger lily (Lilium lancifolium Thunb.) with fermentation of Saccharomyces cerevisiae

This study involved the development of the method for removing proteins impurities from lily non-starch polysaccharides (NSP) with fermentation of Saccharomyces cerevisiae, which was different from Sevag and trichloroacetic acid methods. We optimized the extraction conditions of NSP; meanwhile, the optimal deproteinization conditions were determined. Firstly, a Plackett–Burman design was utilized to evaluate the effects of variables on the NSP yield and the ratio of protein removed (RPR). Lily bulb powder, temperature, pH and KH2PO4 exerted significant effects on NSP yield (P < 0.05), whereas lily bulb powder and pH had significant effects (P < 0.01) on RPR. Subsequently, these four factors were optimized using response surface analysis. The analysis revealed that the optimum conditions were 60.0 g/L lily bulb powder, 1.50 g/L KH2PO4, pH4.8 and temperature 26.9 °C. In the verification experiments, the experimental NSP yield of 8.81 ± 0.18% and RPR of 91.71 ± 0.08% perfectly matched with the predicted values (8.99% for NSP yield and 91.70% for RPR), which verified the practicability of this optimum strategy.