Abstract:In order to reduce the molecular weight and improve the utilization rate of Auricularia auricula polysaccharides，used β-glucanase for the enzymatic hydrolysis of A.auricula polysaccharides.On the basis of single factor experiment，orthogonal test was designed to determine the optimal conditions of enzymatic hydrolysis.The influences of the four factors on β-glucanase activity were ranked in a descending order of enzyme amount，pH，time，and temperature.The conditions for the degradation were optimized as 700 U/g enzyme，pH5.2，2 h，and 30 ℃，under which the yield of reducing sugars was 42.64 mg/g.The molecular weight was determined by high performance liquid chromatography，and Fourier transform infrared spectoscopy （FT-IR）and ultraviolet spectroscopy were employed to determine the spectroscopic properties.The polysaccharides after enzymatic hydrolysis showed a decrease of 127 912 Da in molecular weight，no variation of the characteristic peaks，and an increase of 3.6% in dissolution rate.