牦牛曲拉源乳酸菌的产香性能比较

Comparison of the Aroma-Producing Performance of Lactic Acid Bacteria from Qula as the Residue of Yak Milk after Ghee Making

以6株牦牛曲拉源乳酸菌为研究对象,采用固相微萃取-气相色谱-质谱联用技术检测分析发酵乳中的挥发性风味物质,结合相对气味活度值确定发酵乳中关键性风味物质,比较菌株的产香性能差异。结果表明:共鉴定出60种挥发性风味物质,且不同乳酸菌菌株发酵产生的关键性风味物质的组成及含量存在明显差异。菌株G1产2-庚酮能力强;菌株G1和Q1产生异戊醇与己酸能力强;菌株G2产乙偶姻、糠醇和2-十三酮能力显著高于其他菌株;菌株G4产乙酸和丁酸能力较强。主成分分析结果也表明不同乳酸菌的产香性能存在差异。研究结果可为牦牛曲拉源乳酸菌的应用提供理论依据。

In this study,solid phase microextraction combined with gas chromatography-mass spectrometry(SPME-GCMS)was used to detect and analyze the volatile flavor substances in milk fermented with each of 6 strains of lactic acid bacteria isolated from Qula.The key flavor substances were determined by relative odor activity value(ROAV).The results showed that a total of 60 volatile flavor substances were identified in this experiment,and the compositions and contents of key flavor substances produced by the isolated strains were significantly different.Strain G1 had strong ability to produce 2-heptanone;strains G1 and Q1 possessed strong ability to produce isoamyl alcohol and caproic acid;the ability of strain G2 to produce acetoin,sterol and 2-tridecanth was significantly higher than that of the other strains;strain G4 produced acetic acid and its ability to produce butyric acid was strong.The results of principal component analysis also showed that there were differences in the aroma-producing performance of the 6 strains.The research results can provide a theoretical basis for the application of lactic acid bacteria isolated from Qula.