Study On The Drying Process Of Rosa Roxburghii And The Effect Of Drying On The Active Components And Activity

Rosa roxburghii Tratt.is a rosaceous pear of the family Rosaceae.Vitamin C and SOD in Rosa roxburghii are easy to be affected by temperature,so drying is one of the important factors affecting the quality of Rosa roxburghii.In this experiment,the drying process of Rosa roxburghii was studied in order to understand the law of moisture change in drying process and the effect of drying process on the content and activity of active components in Rosa roxburghii.The drying curve of Rosa roxburghii was fitted by 9 kinds of common drying models.RMSE,?² and R² were used as the criteria to evaluate the fit.The linear relationship between model constant and drying temperature was comprehensively analyzed,and the optimum drying model of Rosa roxburghii was selected as Aghbashlo.The moisture diffusion coefficient of Rosa roxburghii at various temperatures is calculated to be 1.623³.246×10^-55 m^2.s^-11 and the activation energy is 40.691 KJ·mol^-1.The optimum extraction technology of vitamin C in Rosa roxburghii was determined by single factor experiment and orthogonal experiment:extraction time of 60 S,liquid-material ratio of 1:35,100 V voltage.The stability,repeatability,precision and recovery rate of the system were investigated by the relative retention time of vitamin C chromatogram and the RSD value of relative peak area in HPLC chromatogram.The optimum chromatographic conditions for the determination of vitamin C in Rosa roxburghii were as follows:detection wavelength:242nm,Flow rate:1.0 mL·min^-1,mobile phase:methanol:0.1%phosphoric acid=2:98,temperature:25?.The dynamic curves of the contents of vitamin C,flavonoids and SOD in Rosa roxburghii with drying time were obtained by using the method of chemical kinetics and the determination of the active components in Rosa roxburghii during the drying process.The antioxidant activity of water extract of Rosa roxburghii in vitro was studied by DPPH and ABTS free radical scavenging assay.The results showed that the antioxidant activity of fresh Rosa roxburghii was the best.In vitro,50%and 70%ethanol extracts of Rosa roxburghii had no antibacterial activity against Enterococcus faecalis,Candida albicans,Proteus albicans and mutants.The bacteriostatic activity of staphylococcus aureus was higher than that of Escherichia coli,and the antibacterial activity of fresh product was the highest,and the antibacterial activity decreased gradually with the increase of drying temperature.