Study On Quality Standards And Drying Methods Of Dendrobium Candidum

Dendrobium candidum, also known as Heijie grass, Tiepi orchid, a peren-nial herb from Dendrobium, Orchidaceae family. Modern pharmacological studies have shown that Dendrobium candidum has many medicinal value, such as anti-aging, anti-tumor, decreasing blood sugar and improving immunity, etc.However, there are many questions about the quality of Dendrobium candidum, such as the uniformity of the quality, series of problems such as lack of quality standards and testing means. The producing areas of Dendrobium candidum spread all over more than ten provinces, whether the Dendrobium candidum from different provinces have the same chemical-substance and the same content or not, it is not clearly. The heating temperature and time of the current Dendrobium candidum drying process were not particular, to some extent, thus lead to the quality of Dendrobium candidum could not meet the standards, in order to guarantee the quality of Dendrobium candidum, the drying process need to investigate and research. This dtudy hope to solve those problems.Objective:Supplement Dendrobium candidum quality evaluation index, to compare the content of the chemical composition of samples from different producing areas and evaluate their quality. Rank of samples on the basis of it, s quality, combine with information about geography and climate of produc-ing areas, try to make the relationship between the Dendrobium candidum quality and the condition of the geography and climate clear by Correl-ational analysis method. Study the drying pattern, optimize the dry condition, to give some advice for the drying process and guarantee the quality of the Dendrobium candidum. Methods:1. Set up the DNS method, used the DNS method and phenol-sulfurie acid method to determine the content of polysaccharide. Set up the UV method and HPLC method to determine the content of amino acids and the content of free amino acids. Then made the standard of Dendrobium candidum more comprehensive.2. Studied the process of Dendrobium candidum polysaccharide hydroly-zation, optimized the hydrolyzing conditions, then set up the HPLC method to analyze of monosaccharide compositions in Dendrobium candidum Poly-saccharide. Analysised the Dendrobium candidum sample which from different producing areas.3. Analyzed and assessed the Dendrobium candidum sample which from9producing areas based on the new standard of Dendrobium candidum.4. According to the rank of samples on the basis of it’s quality, com-bined with information about geography and climate of producing areas, then tried to make the relationship between the Dendrobium candidum quailty and the condition of the geography and climate clear by Correl-ational analysis method, to provide the guidance for the artificial cul-tivation of Dendrobium candidum when control the environmental conditions.5. Studied the drying pattern, drying temperature, drying time about the fresh Product. Optimize the dry condition.Results:1.Set up the DNS method. Build the UV method and HPLC method to det-ermine the content of amino acids and the content of free amino acids. This methods are sensitive and accurate with good stability.2. The best process of Polysaccharide hydrolyization was that1.0ml of test sample solution (≈1.5mg polysaccharides), mixed with2.0ml TFA (2.0mol· L-1), heated2h, the temperature is100℃.The producing area is different,the monosaccharide composition is different. Even through the samples from the same producing area, the monosaccharide composition were not consistent.3. The analytical results about the quality of samples from9producing areas showed that the samples from Xilin, Guangxi province and Guanfu Mountain, Fujian province had better quality, the samples from Guang-chang, Jiangxi province and Heyuan, Guangdong province were not well as other samples, their quality was bad relatively.4. The Dendrobium candidum quality and geographical factors had a cert-ain relevance, the relation between quality and the mean annual temper- ature, the temperature difference, annual rainfall, relative humidity, sun-shine time showed a negative correlation;the relation between quality and altitude showed a positively correlation.5. Based of retention rate of the amino acid and polysaccharide> the energy consumption and efficiency, on the premise of water content met the corresponding standards, we tried to choose the drying process that need lower temperature, shorter drying time. The amino acid and poly-saccharide retention rate of samples which adopted gradient heating process was higher than the samples which adopted constant temperature drying process, but the Gradient heating process costed much more time.Conclusion:The content of the chemical composition of samples from different producing areas were compared. Analyzed the correlation between quality of Dendrobium candidum and its growth environment condition;and the drying process was studied and optimiz-ed. Hope that the whole study can give a advisory opinion for the breed selection-. the adjustment of planting environment condition and the drying process.