铁皮石斛具有重要的药用价值, 但其资源有限, 因此对其充分开发和利用具有重要的意义。本文利用α-L-鼠李糖苷酶辅助提取铁皮石斛多糖, 通过对酶解温度、酶解时间及加酶量三个因素进行优化, 提高铁皮石斛多糖提取率; 结果显示, 在酶解温度为40 ℃、酶解时间为1 h、加酶量为2.5%时, 多糖提取率为38.4%, 而不加酶处理多糖提取率仅为21.7%, 酶法处理大大增加了铁皮石斛的多糖提取率。同时, 运用顶空固相微萃取技术结合气相色谱质谱联用仪(HS-SPME-GC-MS)分析比较α-L-鼠李糖苷酶对铁皮石斛挥发性成分的影响; GC-MS分析表明, 铁皮石斛加酶处理前后共发现31种挥发性成分, 主要成分均为己醛、1-辛烯-3-醇、异薄荷醇和3-辛烯-2-酮, 并且醛类化合物在加酶处理前后的样品中相对含量均最高, 且加酶处理后产生6种新的挥发性成分。该研究结果表明α-L-鼠李糖苷酶的使用可显著增加对铁皮石斛多糖提取率, 并为铁皮石斛挥发性成分的研究和开发利用提供一定的参考依据。

Dendrobium candidum has important medicinal value, but with limited resources, so it has great significance to its full development and utilization. In this study, the extraction of polysaccharide from Dendrobium candidum was assisted by α-L-rhamnosidase. The extraction rate of Dendrobium candidum polysaccharide was improved by optimizing three factors, including temperature, time and enzyme quantity. The results showed that the polysaccharide extraction rate reached the maximum (38.4%)at 40 ℃, 1 h with 2.5% enzyme quantity and 21.7% without enzyme treatment. At the same time, the effects of α-L-rhamnosidase on the volatile constituents of Dendrobium candidum were analyzed by HS-SPME-GC-MS. GC-MS analysis indicated that 31 kinds of volatile components were found and the main constituents were hexanal, 1-octen-3-ol, isomenthol and 3-octen-2-one. The relative content of aldehydes in the sample were the highest and 6 kinds of new volatile components were produced after enzyme treatment. The results showed that α-L-rhamnosidase has a positive effect on the extraction rate of polysaccharide from Dendrobium candidum, which provides a basis for the research and application of Dendrobium candidum polysaccharides, also gives some references for the research and development of the volatile components of Dendrobium candidum.