食品科学 ›› 2020, Vol. 41 ›› Issue (10): 117-123.doi: 10.7506/spkx1002-6630-20190418-231

• 生物工程 • 上一篇    下一篇

功能基因分析辅助筛选产双乙酰和乙偶姻乳酸菌

杨铭,郝晓娜,罗天淇,姜云芸,杨贞耐,朱宏,张健   

  1. (1.北京工商大学 北京食品营养与人类健康高精尖创新中心,北京 100048;2.石家庄君乐宝乳业有限公司,河北 石家庄 050221)
  • 出版日期:2020-05-25 发布日期:2020-05-15
  • 基金资助:
    北京市自然科学基金面上项目(6192004);“十三五”国家重点研发计划重点专项(2018YFC1604302-02); 2019年研究生科研能力提升计划项目(19008001616)

Analysis of Functional Genes Related to Production of Diacetal and Acetoin by Lactic Acid Bacteria

YANG Ming, HAO Xiaona, LUO Tianqi, JIANG Yunyun, YANG Zhennai, ZHU Hong, ZHANG Jian   

  1. (1. Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Beijing 100048, China; 2. Shijiazhuang Junlebao Dairy Co. Ltd., Shijiazhuang 050221, China)
  • Online:2020-05-25 Published:2020-05-15

摘要: 研究8 株分离自内蒙古奶豆腐和西藏灵菇的乳酸菌产双乙酰和乙偶姻特性,通过全基因组注释分析,确定各菌株与双乙酰、乙偶姻等风味物质相关的6 个基因。发酵乳双乙酰含量检测显示,嗜热链球菌GST-6、鼠李糖乳杆菌5-1和副干酪乳杆菌N1115的双乙酰产量较高(P<0.05),分别为0.72、0.53 μg/mL和0.47 μg/mL;加入柠檬酸后产量为6.23、5.28 μg/mL和4.47 μg/mL。与基因的关联统计分析结果显示,草酰乙酸脱羧酶基因与双乙酰产量高度相关,Pearson相关系数为0.898(P<0.01),乳酸脱氢酶基因和乙酰乳酸合成酶基因与产量相关性不显著(P>0.05)。乙偶姻产量与6 个功能基因的关系不显著(P>0.05)。气相色谱-质谱法检测各菌株发酵乳的挥发性化合物组成,共检测到24 种挥发性风味化合物,主成分分析显示有机酸、乙偶姻和双乙酰可能是形成菌株特征性风味的主要原因,2-庚酮和2-壬酮对各样品的挥发性风味也有较大贡献。

关键词: 乳酸菌, 双乙酰, 乙偶姻, 功能基因注释, 挥发性风味物质

Abstract: The diacetyl and acetoin production characteristics of eight lactic acid bacteria (LAB) strains isolated from Tibetan kefir and Inner Mongolia dairy tofu were studied. For this purpose, the six key genes related to the production of the flavor compounds including diacetyl and acetoin in the 8 strains were determined using genome-wide annotation analysis. The amounts of diacetyl produced by Streptococcus thermophilus GST-6, Lactobacillus rhamnosus 5-1, and L. paracasei N1115 in fermented milk were 0.72, 0.53 and 0.47 μg/mL, respectively, significantly higher than those produced by five other strains (P < 0.05), and were increased up to 6.23, 5.28 and 4.47 μg/mL, respectively, when citric acid was added to the milk. Correlation analysis showed that the oxaloacetate decarboxylase (OAD) gene was strongly correlated with the yield of diacetyl with Pearson correlation coefficient of 0.898 (P < 0.01), while the lactate dehydrogenase (LDH) and acetyl lactate synthase (ALS) genes were not significantly correlated with the yield of diacetyl (P > 0.05). The relationship between the yield of acetoin and each of the key genes was not significant (P > 0.05). Using gas chromatography-mass spectrometry (GC-MS), a total of 24 volatile compounds were detected in all the fermented milk samples. Principal component analysis showed that organic acids, acetoin and diacetyl were the characteristic flavor compounds of the strains. Heptanone and 2-nonanone were also important volatile flavor compounds.

Key words: lactic acid bacteria, diacetyl, acetoin, functional gene annotation, volatile compounds

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