优化HS-SPME-GC-MS方法表征香菇不同成熟阶段的关键挥发性化合物

Optimization of HS-SPME-GC-MS for the Characterization of Key Volatile Compounds in Lentinus edodes at Different Maturity Stages

通过优化的顶空固相微萃取结合气相色谱-质谱联用技术鉴定香菇不同成熟阶段挥发性化合物,并采用气味活性值(odor activity value,OAV)和偏最小二乘判别分析(partial least squares discriminant analysis,PLS-DA)进行分析。结果表明:最佳提取条件为1.0 g香菇样品在50℃提取25 min,解吸3 min;在香菇不同成熟阶段共鉴定出71种挥发性化合物,不同成熟阶段挥发性化合物种类和含量存在显著差异(P<0.05);通过PLS-DA和变量投影重要性(variable importance in projection,VIP)筛选出18种挥发性化合物,可作为区分香菇不同成熟阶段的挥发性生物标志物;OAV结果表明,有16种挥发性化合物为香气活性化合物,其中,1-辛烯-3-醇、3-辛醇、1-辛烯-3-酮、3-辛酮、苯乙醛、二甲基二硫醚、二甲基三硫醚、2,3,5-三硫杂己烷和1,2,4-三硫杂环戊烷同时满足VIP>1和OAV≥1,是香菇不同成熟阶段最重要的差异挥发性化合物。本研究为探究香菇成熟过程中香气形成机制提供一定理论依据。

The volatile organic compounds(VOCs)in Lentinus edodes at different maturity stages were identified by optimized headspace solid-phase microextraction combined with gas chromatography-mass spectrometry(GC-MS)and analyzed by odor activity value(OAV)and partial least squares discriminant analysis(PLS-DA).The results showed that the optimal extraction conditions were as follows:1.0 g of sample was extracted at 50℃for 25 min and then the analytes adsorbed on the fiber were desorbed in the GC-MS injection port for 3 min.A total of 71 VOCs were identified in L.edodes,and there were significant differences in the types and contents of volatile compounds at different maturity stages(P<0.05).Out of these,18 VOCs that could be used as biomarkers to distinguish L.edodes at different maturation stages were selected by PLS-DA and variable importance in projection(VIP).Besides,16 volatile compounds with OAV≥1 were identified.Among these compounds,1-octen-3-ol,3-octanol,1-octen-3-one,3-octanone,benzeneacetaldehyde,dimethyl disulphide,dimethyl trisulphide,2,3,5-trithiohexane,and 1,2,4-trithiohexane showed VIP greater than 1,thus making them the most significant differential volatile compounds among different maturity stages of L.edodes.This study provides a theoretical foundation for understanding the mechanism of aroma formation during the maturation process of L.edodes.