铁皮石斛多糖水解工艺优化及甘露糖含量的测定

优化高温高压辅助硫酸水解铁皮石斛多糖工艺，测定了不同栽培方式的铁皮石斛不同部位多糖及甘露糖含量。利用苯酚-硫酸法测定3种栽培方式的铁皮石斛茎、叶、花多糖的含量；以单因素实验为依据，固定料液比、硫酸浓度，根据中心组合试验设计（Central Composite Design，CCD）原理建立两因素五水平响应面法优化硫酸水解铁皮石斛多糖的温度及时间，采用柱前衍生化-高效液相色谱法测定甘露糖含量。结果表明，以1 mol/L的硫酸溶液为催化剂，料液比1:1.5、水解温度112 ℃（压强0.15 MPa），水解44 min，甘露糖含量达64.35%±0.76%；同一栽培方式的铁皮石斛茎、叶、花多糖、甘露糖含量表现出极显著差异（P<0.01，茎>叶>花），茎的多糖及甘露糖含量分别在29.32%~33.78%、18.17%~21.05%；叶分别在15.91%~17.31%、10.28%~11.11%，花分别在8.37%~8.68%、5.30%~5.75%之间。高温高压辅助硫酸水解铁皮石斛多糖工艺高效可行，铁皮石斛茎、叶、花是制备甘露糖的优质天然资源。

Optimization of Process of Hydrolysis of Dendrobium officinale Polysaccharide and Determination of Contents of Its Mannose

Process of hydrolysis of Dendrobium officinale polysaccharide by high temperature and pressure-sulfuric acid assisted was optimized by response surface method (RSM) according to Central Composite Design (CCD), and polysaccharides of Dendrobium officinale under the conditions of different cultivation were determined by phenol-sulfuric acid method, and the contents of mannose from different parts (stems, leaves and flowers) of Dendrobium officinale were analyzed by pre-column derivation HPLC method. The research showed that the optimum parameters was as follow: Material-liquid ratio was 1:1.5 (mg/mL), concentrations of sulfuric acid was 1 mol/L, hydrolysis temperature was 112 ℃ (0.15 MPa) and hydrolysis time was 44 min. Under optimal conditions, the content of the mannose was 64.35%±0.76% with stem as the test material. The contents of polysaccharide in stems, leaves and flowers of Dendrobium officinale under the conditions of same cultivation were significantly differences (P<0.01, stems>leaves>flowers). And the contents of mannose in the samples was the same as that of polysaccharide. The content of polysaccharide and mannose in the stems were 29.32%~33.78% or 18.17%~21.05%, respectively. And the contents of polysaccharide and mannose in the leaves were 15.91%~17.31% or 10.28%~11.11%, respectively. And the contents of polysaccharide and mannose in the flowers were 8.37%~8.68% or 5.30%~5.75%, respectively. The results indicated that the method was effective and efficient, which could be used for the hydrolysis of Dendrobium officinale polysaccharide by high temperature and pressure-sulfuric acid assisted. And the stems, leaves and flowers of Dendrobium officinale were high-quality natural resources for the preparation of mannose.