Changes of aroma composition of persimmon wine during fermentation
We compared the extract rate of liquid-liquid extraction and solid phase micro-extraction. Aroma composition was analysed by gas chromatography-mass spectrometry. Solid phase micro-extraction extracted more aroma components with better separation than solvent extraction. The change of aroma composition of persimmon wine during the fermentation was also analysed. Results show that in the first stage of fermentation, alkanes and esters were the main aroma compositions, such as 2,6,10-trimethyl dodecane, tetradecane, 2-methyl-decane, hexadecane and ethyl decanoate, with 81.9 percent of total peak area. During fermentation, alkanes decreased, esters gradually increased, and the alcohols and aldehydes generated. At the end of fermentation, alcohols and esters were the main aroma substances such as 1-pentanol, phenylethyl alcohol, ethyl decanoate, ethyl octylate and ethyl laurate.
Aroma components are the main indicators of wine's flavour and characters (1). There are many techniques to extract aroma compounds, such as liquid-liquid extraction, static headspace, dynamic headspace, fractionation, solid phase extraction and solid phase microextraction (2-4). Liquid-liquid extraction is a classical analytical method. Organic solvents such as dichloromethane, diethyl ether, hexane, and pentane are commonly used. Solid phase microextraction (SPME) is based on solid phase extraction, combining headspace absorption. Comparing with other technologies, solid phase microextraction is a simple, sensitive, reproducible method and without organic solvents contamination (5, 6). SPME combined with gas chromatography-mass spectrometry (GC-MS