Optimization of hot-water extraction of polysaccharides from dried longan pulp using response surface methodology

Hot-water technique was applied for polysaccharides extraction from dried longan pulp,and the effects of processing parameters on extraction efficiency was optimized using response surface methodology(RSM).Three independent variables were investigated,including the ratio of water to raw material(mL/g),extraction time(min) and rotation rate(r/min).A quadratic polynomial mathematical model with good correlation was constructed and employed to the optimization.The optimiaed extraction conditions were determined as:the ratio of water to raw material as 45,extraction time of 4.5h,and rotation rate of 191 r/min,under which the experimental extraction yield of crude longan polysaccharides was(0.413±0.013)%.