西藏开菲尔发酵乳中挥发性风味物质分析

采用顶空固相微萃取结合气相色谱-质谱联用技术对两种不同地理来源西藏开菲尔粒的发酵乳中挥发性化合物进行检测,并结合化合物的阈值计算香气活力值(odor activity value,OAV)。结果表明,两种发酵乳中共鉴定出挥发性化合物30种,酸类和醇类在两种发酵乳中均占优势。两种西藏开菲尔粒的产挥发性风味物质能力存在差异,发酵乳B中挥发性化合物的种类和总含量均高于A。酯类是两种发酵乳中最重要的香气贡献化合物,辛酸乙酯在两种发酵乳中香气贡献最高。不同类别化合物对两种发酵乳的总香气贡献存在差异,醇类对发酵乳A的总香气贡献高于B,酯类、酸类和酮类对发酵乳B的总香气贡献高于A。

Analysis of Volatile Flavor Compounds in Tibetan Kefir Milks

Headspace solid phase microextraction combined with gas chromatography-mass spectrometry was applied for the detection of volatile compounds in Tibetan kefir milks fermented with two Tibetan kefir grains of different geographical origins,and the odor activity values(OAVs)were calculated based on threshold values of compounds.The results showed that a total of thirty volatile compounds were identified,acids and alcohols were dominant in all samples.The ability to produce volatile flavor compounds of the two Tibetan kefir grain varieties was different,the total kinds and content of volatile compounds in kefir milk B were higher than in A.Esters were the most important aroma contributing compounds in the two kinds of kefir milk,ethyl octanoate possessed the most important aroma contribution for all samples.The total aroma contribution of different classes of compounds for the two kinds of kefir milk was different;the total aroma contribution of alcohols was higher for kefir milk A than B,the total aroma contribution of esters,acids and ketones was higher for kefir milk B than A.