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 (HS-SPME) method combined with gas chromatography-mass spectrometry (GC-MS). In order to obtain more volatile substances, the extraction conditions were optimized for extracting at 60 ℃ for 30 min using 65 μm 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 (11.25%), 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.