不同生长年限滇黄精的挥发性成分及香气特征分析

为比较分析不同生长年限滇黄精挥发性成分及香气特征，采用顶空固相微萃取-气相色谱-质谱联用技术对滇黄精样品挥发性成分进行定性和定量分析，结合相对气味活性值（Relative Odor Activity Value，ROAV）构建香气雷达图，比较其挥发性香气物质差异，并用正交偏最小二乘判别法（Orthogonal Partial Least Squares Discrimination Analysis，OPLS-DA）和随机森林（Random Forest，RF）筛选出标志差异性香气物质。结果表明，从不同生长年限滇黄精样品中共鉴定挥发性成分67种，主要包括酯类（18.39%~63.98%）16种、烷烃类（2.22%~20.85%）15种、醛类（18.31%~35.45%）9种、烯烃类（0.46%~2.33%）8种、醇类（2.50%~6.21%）5种和酮类（0.39%~1.31%）4种。ROAV和香气雷达图表明(E,E)-2,4-壬二烯醛、庚酸乙酯、正己醛对滇黄精香气贡献较大，2年生青草香较突出，3、4、5年生脂肪味较突出，而6年生果香和花香更强烈。OPLS-DA和RF结果表明2-丁基-2-辛烯醛、己酸乙酯、辛酸乙酯、庚酸乙酯、正己醛和(E,E)-2,4-壬二烯醛为标志性风味物质。该研究结果揭示了不同生长年限滇黄精的挥发性成分及香气特征差异，为其综合开发利用提供数据支撑。

Volatiles and Aroma Characteristics of Polygonatum kingianum at Different Ages

To compare the volatiles and aroma characteristics of Polygonatum kingianum at different ages, headspace solid-phase microextraction-gas chromatography-tandem mass spectrometry (HS-SPME-GC-MS) was used to quantitatively and qualitatively analyze the volatiles associated with P. kingianum samples of different age, which were identified using an aroma radar chart based on the relative odor activity values (ROAVs). Orthogonal partial least squares discrimination analysis (OPLS-DA) and random forest (RF) were then used to identify the signature aroma compounds within each sample and a total of 67 volatiles were identified, including 16 esters (18.39%~63.98%), 15 alkanes (2.22%~20.85%), nine aldehydes (18.31%~35.45%), eight olefins (0.46%~2.33%), five alcohols (2.50%~6.21%), and four ketones (0.39%~1.31%). The ROAVs and aroma radar chart indicate that (E,E)-2,4-nonadienal, ethyl heptanoate, and hexanal are the largest contributors to the aroma associated with P. kingianum; two-year-old samples have a strong grassy scent, three-, four-, and five-year-old samples are characterized by fatty aromas, and six-year-old samples have intense fruity and floral scents. The OPLS-DA and RF results show that 2-butyl-2-octenal, ethyl caproate, ethyl caprylate, ethyl heptanoate, hexanal, and (E,E)-2,4-nonadienal are signature aroma compounds in P. kingianum. In summary, this study reveals how the volatiles and aroma characteristics of P. kingianum vary at different ages and is expected to serve in the comprehensive development and utilization of P. kingianum.