植物乳杆菌发酵牛乳挥发性风味物质的解析

Analysis on volatile compounds in milk fermented by Lactobacillus plantarum

利用电子鼻和顶空固相微萃取-气质联用仪(headspace solid-phase microextraction-gas chromatograph-mass spectrometry,HS-SPME-GC-MS)研究了发酵牛乳挥发性风味物质的变化和组成。测定牛乳发酵过程中的p H值,确定发酵时间。结果表明,电子鼻能够灵敏地检测到牛乳发酵过程中气味的变化,主成分分析(principal component analysis,PCA)显示各个样品间差异明显。通过GC-MS在新鲜牛乳和发酵0、2、4、6、8、10、12、14、16h的牛乳中分别检测出36和34、41、36、45、34、34、31、30、29种化合物,主要为烃类、醇类、醛类、酮类、酯类、酸类及其他化合物,其中醛类和酮类化合物的总峰面积和总浓度均较高,是发酵牛乳主要的挥发性风味成分。

The goal of this study was to discuss the change of the volatile substances in milk by fermented Lacto- bacillus plantarum during fermentation, which provided a reference for the research on flavor materials in fermented milk. Electronic nose and headspace solid-phase microextraction-gas chromatography-mass spectrometry （HS-SPME- GC-MS） were used to study the changes and compositions of the volatile substances in fermented milk. And the pH values of fresh milk and fermented milk during fermentation were measured to determine the optimal fermentation time. The results showed that the electronic nose could sensitively detect the changes of volatile flavor from milk dur- ing fermentation processing. PCA results revealed that there were obviously differences among samples. Then the GC- MS analysis indicated that 36, 34, 41, 36, 45, 34, 34, 31, 30, 29 kinds of volatile composition were respectively presented in the milk fermented for 0 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 14 h and 16 h, which mainly included hy- drocarbons, alcohols, aldehydes, ketones, esters, acids and other compounds. Among them, aldehydes and ketones accounted for a higher proportion in total peak area and total concentration, and were the main volatile compounds in fermented milk.