Hot water extraction of longan polysaccharide assisted by microwave pretreatment
Longan polysaccharide (LPS) has been discovered to have high anti-oxidation and anti-senility activity, while only a few studies about its extraction and chemical structure analysis have been reported.In this paper, longan pulp was pretreated by microwave and then LPS was extracted with hot water.The results of single-factor examination and orthogonal experiments showed that the optimal process parameters for this method were: microwave pretreatment with power 700 W for 60 s, followed by hot water extraction with solid(g)-liquid (ml)ratio of 1∶15 at 100℃ for 7 h with stirring speed of 240 r·min -1.The optimal yield of 9.00 mg·g -1 (dried longan biomass weight) was achieved under these parameters.Ultraviolet spectrum and FTIR analysis showed that LPS was a β type acidic heterosaccharide with pyran and acetyl amino group.