不同地域嗜热链球菌在发酵乳制作中产关键性风味物质研究

Study on Key Flavor Compounds in Fermented Milk Production of Streptococcus thermophilus Isolated from Different Areas

以来自不同地域的6株嗜热链球菌(Streptococcus thermophilus)为实验菌株,采用固相微萃取与气相色谱-质谱联用技术(SPME-GC-MS)相结合的方法,并结合香气阈值和相对气味活度值(relative odor activity value,ROAV)探讨发酵牛乳中关键性风味物质。结果表明,6株嗜热链球菌发酵乳中共检测出63种挥发性风味物质,包括醛类、酮类、酸类、酯类、醇类、芳香族及烷烃化合物等。其中,双乙酰、乙偶姻、乙醛、2-壬酮等12种挥发性化合物的ROAV值较高(ROAV≥1),对发酵乳总体风味贡献较大。主成分分析和相似度比较分析结果表明,来自同一地域的嗜热链球菌发酵乳中风味化合物之间具有较高的相似性,而不同地域的菌株发酵乳中风味化合物之间相似度较低,说明生长环境压力能够对菌株发酵乳的产香特性产生影响。

The key flavor compounds of fermented milk produced by six strains of S. thermophiles isolated from different regions were analyzed by solid phase microextraction-gas chromatography-mass spectrometry（ SPME-GC-MS） technology,combined with aroma threshold and relative odor activity value（ ROAV）. The results showed that the total of 63 volatile compounds were finally detected in these fermented milk,including aldehydes,ketones,acids,esters,alcohols,aromatics,and hydrocarbon compounds. Among them,12 kinds of volatile compounds,such as diacetyl,acetoin,acetaldehyde,and2-nonanone had higher ROAV（ ROAV≥1）,which contributed greatly to the overall flavor of fermented milk. Principal component analysis and comparative analysis of similarity demonstrated that there was a high similarity among the flavor compounds of S. thermophilus fermented milk from the same area while that from different regions was lower. The results indicated that the pressure of growth environment can exert an influence on the aroma-producing characteristics of the fermented milk of the strain.