Studies On Vacuum Belt Drying Process Of Panax Notoginseng Extract

Vacuum belt drying (VBD) process of Panax notoginseng extract was investigated in this paper. The operation parameters of VBD process were studied. Quality evaluation of dried product was also presented. The studies would be contributed to the foundation of technical standards and application rules of VBD technique for Traditional Chinese Medicine (TCM). The major research content is as follows:(1) Optimum conditions of the vacuum belt drying process (VBD) of Panax notoginseng and Radix puerariae lobatae extract were obtained by orthogonal design. The optimum conditions are as follows, the feeding speed is 15 ml/min, the belt speed is 4cm/min, and heating temperature is (105,100℃). Drying temperature and belt speed affecting the drying process outweighed the feeding speed.(2) Five mathematical models were proposed for simulation of vacuum belt drying of Panax notoginseng extract. The Logarithmic model gave better prediction than other models, and satisfactorily described the vacuum belt drying process of Panax notoginseng extract. The effective diffusivity of Panax notoginseng extract varied between 4.86×10^-7 and 11.0×10^-7 m²/s over the drying conditions.(3) A systematic assessment of influence of drying methods on the final properties of dried products was proposed. In this report, Panax notoginseng extract was made into powder by vacuum belt drying (VBD), spray drying (SD), freeze drying (FD), and vacuum drying (VD). Certain chemical and physical properties of the dry matter, such as moisture content, drying time, porosity, density, saponins content, pH value, and hydroxyl radicals scavenging activity, were determined. Drying methods showed some effect on the qualities of dried product to different extent.(4) NIR was used to develop a fast quality assessment method of vacuum belt-dried Panax notoginseng extract. PLS was proposed to model relation between NIR and contents of five major saponins, namely notoginsenoside R₁, ginsenosides Re, Rg₁, Rb₁ and Rd. The result showed that the proposed method is accurate, robust and can be used for quality evaluation of dried products.