酶法提取铁皮石斛多糖工艺优化及对挥发性成分的影响研究

Optimization of Enzymatic Extraction of Polysaccharide Content and Volatile Components from Dendrobium candidum

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.