顶空固相微萃取法分析龙须菜干品中的挥发性成分

采用顶空固相微萃取技术(HS-SPME)对干龙须菜(Gracilaria lemaneiformis)中挥发性成分的萃取条件进行了优化,并结合气相色谱-质谱法(GC-MS)进行了成分鉴定分析。结果表明,顶空固相微萃取的最佳萃取条件为利用65 m PDMS/DVB萃取头在60 ℃萃取30 min;经GC-MS分离和鉴定,共检测出87种挥发性成分,其中醛类化合物28种,相对百分含量为75.62%,酮类化合物14种,相对百分含量为10.49%,另有烃类17种,醇类10种,羧酸类5种,酯类5种,其他含硫、含碘及杂环化合物8种,其相对百分含量分别为5.17%、1.65%、5.41%、0.49%和0.74%;相对百分含量较高的物质主要有 己醛(19.99%)、2-庚烯醛(11.25%)、辛醛(7.95%)、反-2-辛烯醛(6.95%)、1-辛烯-3-酮(6.23%)、反-2-癸烯醛(6.01%)、壬醛（4. 43%)、反-2-壬烯醛(4.37%)、庚醛(4.11%)、206-壬二烯醛(3.79%)、203-辛二酮(3.15%)等。总体上看,醛、酮等羰基类化合物和烃类化合物对龙须菜的风味贡献比较大。

Analysis of volatile compounds of dried Gracilaria lemaneiformis by HS-SPME method

The volatile compounds of Gracilaria lemaneiformis were analyzed using headspace solid phase micro-extraction (HSSPME) method combined with gas chromatography-mass spectrometry (GC-MS). In order to obtain more volatile substances, the extracti on conditions were optimized for extracting at60 ℃ for 30 min using 65 m PDMS/DVB SPME Fiber Assembly. A total of 87 volatile compounds were isolated and identified by GC-MS, including 28 aldehydes, 17 hydrocarbons, 14 ketones, 10 alcohols, 5 acids, 5 esters and 8 others. Among these volatile flavor compounds, the relative percentage content of aldehydes was the highest (75.62%), followed by ketones (10.49%), acids (5.41%), hydrocarbons (5.17%) , alcohols (1.65%), ester (0.49%) and others (0.74%). The high-ranking compounds according to the relative percent content from high to low were hexanal (19.99%), (Z)-2-heptenal (11.5%), octanal (7.95%), (E)-2-octenal (6.95%), 1-octen-3-one (6.23%), (E)-2-decenal (6.01%), nonanal (4.43%), (E)-2-nonenal (4.37% ), heptanal (4.11%), (E0Z)-206-nonadienal (3.79%), 203-octanedione (3.15%), etc.. Generally, carbonyl compounds, especially aldehydes and ketones, and hydrocarbons compounds make greater contribution to the flavor of G. lemaneiformis.