Method for measuring polysaccharide content of medlar extracting solution

Abstract

The invention discloses a method for measuring polysaccharide content of a medlar extracting solution. The method comprises the following steps of (1) pretreating the medlar extracting solution; (2) preparing a reducing sugar and total sugar test solution; (3) preparing a standard curve; (4) preparing a reference solution for the reducing sugar and total sugar test solution; (5) measuring the absorbency of the reducing sugar and total sugar test solution, checking the standard curve, and calculating the polysaccharide content. According to the method, the medlar extracting solution is pretreated through lead acetate, and the deproteinized solution is transparent and clarified and is suitable for measurement of a spectrophotometric method; meanwhile, due to the method for preparing the reference solution, the absorption of a developing agent is avoided, and influence on the pigment of medlar is eliminated. By the measurement method disclosed by the invention, reducing sugar does not need to be removed, and the reducing sugar does not need to be prepared into solid crude polysaccharide for measurement, so that the problem a phenol-sulfuric acid method is easily affected by the reducing sugar is solved, and the safety of operation is improved. The method is quick, high in accuracy and high in repetitiveness, and is suitable for quality control during large-scale industrial production.

Description

technical field [0001] The invention relates to the technical field of chemical analysis of traditional Chinese medicines and their extracts, in particular to a method for determining the content of polysaccharides in wolfberry extracts. Background technique [0002] One of the main bioactive substances in wolfberry is wolfberry polysaccharide. The determination of Lycium barbarum polysaccharide content has very important guiding significance for the extraction process of Lycium barbarum polysaccharide. At present, the commonly used polysaccharide determination methods mainly include chromatography and colorimetry. Chromatography is expensive. Moreover, since the sugars themselves are not sufficiently volatile, they generally need to be converted into volatile derivatives, which makes the operation steps complicated. The cost of colorimetry is relatively low, it is more practical, and it is suitable as a quality control method in the extraction process. Therefore, the na...

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Problems solved by technology

According to literature review, there are two main categories of application objects of this method: the first category is the water extract after removing reducing sugars (Gao Hongxia, Liu Junhai, Li Guanglu. Research on the extraction process of Lycium barbarum polysaccharides. Food and Machinery, 2008, 24( 5):60-62,72.), the disadvantage is that the step of removing reducing sugars takes a long time, and if the reducing sugars are not completely removed, the measurement results will be high; the second type is solid crude polysaccharides (Huang Wenshu, Yang Haiyan, Li Huanrong, etc. Decolorization process of Lycium barbarum polysaccharide. Food Research and Development, 2008,29(3):95-98), the disadvantage is that the preparation of crude polysaccharide requires a longer measurement period, and the determination needs to re-dissolve the crude polysaccharide, May cause turbidity due to insufficient purity of crude polysaccharides, thus affecting photometric determination

At the same time, there are still some problems in the phenol-sulfuric acid method. For example, phenol needs to be redistilled, concentrated sulfuric acid is highly corrosive, and has potential dangers to operators and equipment. Moreover, different operation methods often lead to poor reproducibility of measurement results, or even Can cause polysaccharide carbonization and other phenomena

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