基于气相色谱-质谱联用技术分析测定川麦冬块根及须根中可溶性糖组分

Analysis of Soluble Sugars in Ophiopohon japonicus Tuberous Roots and Fibrous roots by Gas Chromatography-Mass Spectrometry

目的建立基于气相色谱-质谱联用技术(GC-MS)分析测定川麦冬块根及须根中多种可溶性糖组分的方法,并结合多元统计分析其可溶性糖组分差异。方法采用优化后甲氧基化-三甲基硅烷化两步衍生法结合GC-MS法测定18批川麦冬块根及须根中多种可溶性糖组分,结合主成分分析(principal component analysis,PCA)、正交偏最小二乘法判别分析(orthogonal partial least squares discrimimation analysis,OPLS-DA)和聚类热图分析等模型统计分析其组分差异,并根据含量换算块根及须根样品甜度值。结果在川麦冬块根和须根样品中鉴定了18种可溶性糖组分,对其中14种进行定量分析,川麦冬块根和须根样品中可溶性糖组分组成基本一致,14种可溶性糖总量平均值也基本一致(块根88.76 mg·g^(-1)vs.须根85.66 mg·g^(-1)),但各组分含量存在一定差异,其中须根中D-(-)-果糖含量较高,而块根中D-(+)-蔗糖较高。多元统计分析结果显示,通过可溶性糖组分测定可显著区分块根和须根。通过换算,块根和须根的甜度值差异较小。结论GC-MS法灵敏度高、精密度好、准确度高,能够将多种结构相似的可溶性单糖和二糖区分开,实现川麦冬块根和须根中多种可溶性糖的准确定性和定量,为麦冬不同部位的可溶性糖组分研究及其进一步开发利用提供了依据。

OBJECTIVE To establish a method based on gas chromatography-mass spectrometry(GC-MS)for simultaneous determination of a variety of soluble sugars in Ophiopohon japonicus tuberous roots and fibrous roots and to analyze the differences in the soluble sugars by multivariate statistical analysis.METHODS The optimized two-step derivatization method of methoxylation-trimethylsilylation combined with GC-MS was used to determine the soluble sugar components in 18 batches of Ophiopohon japonicus tuberous roots and fibrous roots.And the differences in the components were analyzed by multivariate statistical analysis,and the sweetness values of the tuberous roots and fibrous roots samples were converted according to the contents.RESULTS Eighteen kinds of soluble sugars were identified and 14 kinds of them were quantitatively analyzed in the tuberous roots and fibrous roots of Ophiopohon japonicus.It was found that the ingredients of the soluble sugar components in the tuberous roots and fibrous roots of Ophiopohon japonicus were basically the same,and the average of the total contents of the 14 kinds of soluble sugar components were also basically the same(88.76 mg·g^(-1) in tuberous roots vs.85.66 mg·g^(-1) in fibrous roots).However,there were some differences in the contents of the components,and the contents of D-(-)-fructose and in the fibrous roots were significantly higher than those in the tuberous roots,while the contents of D-(+)-sucrose in the tuberous roots were significantly higher than those in the fibrous roots.The results of multivariate statistical analysis showed that tuberous roots and fibrous roots could be significantly differentiated by the determination of soluble sugar fractions.The difference in sweetness values between tuberous roots and fibrous roots was small by conversion.CONCLUSION With high sensitivity,good precision and accuracy,GC-MS is able to distinguish a variety of soluble monosaccharides and disaccharides with similar structures,and realize the accurate characterization and quantification of a variety of soluble sugars in Ophiopohon japonicus,and providing a basis for the study of soluble sugar fractions in different parts of Ophiopohon japonicus and its further development and utilization.