气相色谱-嗅闻-质谱分析浅色麦芽、焦香麦芽及黑麦芽中香气成分

Identification of aroma-active compounds in pale malt,caramel malt and black malt by GC-O-MS

通过采用同时蒸馏萃取和固相微萃取技术，结合气相色谱-嗅闻-质谱进行麦芽风味的定性分析，包括浅色、焦香、黑麦芽3种，采用现行保留指数和美国国家标准与技术局化学（The National Institute of Standards and Technology，NIST）数据库能够定性出100种以上。通过采用峰后强度法结合气相色谱-嗅闻-质谱嗅闻出61种化合物，探明3类麦芽中共有物质及各自特有的重要致香物质。风味轮显示2种萃取的定性结果差异较小，能够真实反映出其香气物质。采用芳香萃取物稀释分析法针对同时蒸馏萃取麦芽萃取液进行深入剖析，确定出高达40种的主要关键香气物质贡献强度。对3类麦芽所有化合物进行定性分析并归类，发现醛类比例在10．3％～48．5％；含氮杂环化合物对其浅色麦芽、焦香麦芽香气贡献小，但对黑麦芽香贡献极显著，高达11％；含氧杂环类对焦香、黑麦芽香贡献突出，分别为7．9％、4．4％。醇、酮、酯、苯、其他类对麦芽香贡献较小。此外，麦芽制备中的热处理程度越强，醛、含氧杂环、含氮杂环、酮类数量和含量都不断递增，而醇类不断减少。

Flavor compounds in barley malt were identified using simultaneous distillation extraction （SDE） and solid phase micro extraction （SPME） techniques combined with gas chromatography-olfactometry-mass spectrometry （GC-O-MS）. Using the linear retention indices and the NIST database, more than 100 compounds were identified in pale malt, caramel malt and black malt. 61 compounds were sniffed out by post peak intensity method combined with GC-O-MS. Identical substances and their unique important aroma substances in three types of malt were detected. Results from Flavor wheel showed that qualitative difference between two extractions was small. It could indicate malt aroma substances. The degree of 40 key eompounds contribute to malt was determined by aroma extract dilution analysis （AEDA）. All compounds in three types of malt were analyzed and classified. The results showed that proportion of aldehydes was between 10.3% and 48.5%. Contribution of nitrogen heterocyclic compounds to the aroma flavor of light malt, caramel malts was small, but was very significant to that of black malt up to 1 1%. Oxygen-containing heteroeyclie compounds had signifieant contribution to caramel malt and black malt, which respectively reached 7.9% and 4.4%. Contribution of alcohols, ketones, esters, benzene and other compounds was small. Furthermore, the number and contents of aldehyde, oxygen heteroeyclie compounds, nitrogen heterocyclic compounds and kctones constantly increased with heat treatment, while aleohols constantly decreased.