Subcritical Water Degradation Kinetics of Cornus officinalis Seed Meal and Its Polysaccharide Properties

In this study,Cornus officinalis seed meal was used as raw material to conduct a subcritical water degradation study,and the reducing sugar content of the liquid product was measured at different degradation temperatures and degradation time. The Saeman model was adopted to simulate the analysis,and the degradation kinetics equation was established to obtain the degradation kinetics parameters,and the physicochemical properties of the degraded product were analyzed. The results showed that the Saeman model could better reflect the process of subcritical water degradation of Cornus officinalis seed meal,with the reaction activation energy E_a1 of primary degradation being 29.47 kJ/mol,the reduction sugar activation energy E_a2 being 22.21 kJ/mol,the preexponential factor K₁₀ being 101.49 min^-1,and K₂₀ being 20.28 min^-1.At the degradation temperature of 160 ℃ and the degradation time of 20 min,the reducing sugar with higher yield could be obtained. The monosaccharide analysis showed that the polysaccharide of Cornus officinalis was mainly composed of glucose,xylose,galactose and galacturonic acid,and its total sugar content was as high as 78.82%.Preliminary structural analysis results by scanning electron microscopy and infrared spectroscopy showed that polysaccharides were spherical structures with smooth surface,irregular granule and different particle sizes,and they were pyranoid glycoside ring skeletons. The results of antioxidant activity analysis showed that the polysaccharides of Cornus officinalis had good free radical scavenging ability. At the mass concentration of 1.0 mg/mL,the scavenging rates of DPPH free radical,hydroxyl free radical and ABTS free radical were 85.61%,63.40% and 76.20%,respectively.The results of this experiment provide reference for the further separation and purification of polysaccharides from cornus officinalis seed and the analysis of their physicochemical characteristics and morphological structure.