冷榨和热榨亚麻籽油挥发性成分比较

Comparative research on volatile compounds in cold-﹠hot-pressed flaxseed oils

采用顶空固相微萃取法提取冷榨和热榨亚麻籽油中挥发性成分,借助气相质谱联用技术(GC-MS)分析并比较了挥发性成分相对含量变化。研究发现,冷榨亚麻籽油主要挥发性成分有正己醇、2-丁醇、2-甲基丁醇、戊醇、正己醛、2-乙基呋喃等,其中醇类物质相对总含量可达66%;相比而言,热榨亚麻籽油挥发性成分中醇类物质相对含量下降,出现大量美拉德反应产物糠醛及以吡嗪、吡咯、吡啶为主的芳香杂环类化合物,致使醛类(140℃,25.1%)和杂环类(140℃,41.68%)物质相对含量快速升高,这些特征挥发性成分赋予热榨亚麻籽油浓郁的烤香气味;但据研究这些芳香杂环化合物及其复合物对人体生理机能具有一定的毒理作用,因而影响到热榨亚麻籽油的食用安全性,相比较而言,冷榨亚麻籽油食用更为安全。

Volatile compounds in both cold-﹠hot-pressed flaxseed oil samples were extracted using headspace solid phase micro-extraction（HS-SPME） and analyzed by gas chromatography-mass spectrometry（GC-MS）.The results showed that main volatile compositions in cold-pressed flavor flaxseed oil were 1-hexanol,2-butanol,2-methyl-1-butanol,1-pentanol,hexanal,4-hydroxy-butanoic acid,2-ethyl-furan,and the total relative content of alcohols could reach up to 66%.By contrast,the relative content of alcohols in hot-pressed flaxseed oil volatile compounds dropped quickly,and the characteristic volatile compounds were found to be a lot of Maillard reaction products,such as furfurals,pyrazines,pyrroles,pyridines and so on,the relative content of aldehydes（140 ℃,25.1%） and heterocyclic compounds（140 ℃,41.68%） increased rapidly.The Maillard reaction products formed hot-pressed flaxseed oil unique toasting flavor.But according to research these aromatic heterocyclic compounds and their complexes have toxic effects on human physiological function,thus affects the safety of hot-pressed linseed oil.Thus cold-pressed linseed oil has the characteristics of higher food safety.