Comparative transcriptomic analysis of the flavor production mechanism in yogurt by traditional starter strains.

Autor:	Tian H; School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai 201418, People's Republic of China., Huang N; School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai 201418, People's Republic of China., Yao W; School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai 201418, People's Republic of China., Yu H; School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai 201418, People's Republic of China., Yu B; School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai 201418, People's Republic of China., Chen X; Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot 010018, People's Republic of China., Chen C; School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai 201418, People's Republic of China. Electronic address: chenchen@sit.edu.cn.
Jazyk:	angličtina
Zdroj:	Journal of dairy science [J Dairy Sci] 2024 Aug; Vol. 107 (8), pp. 5402-5415. Date of Electronic Publication: 2024 Feb 07.
DOI:	10.3168/jds.2023-24328
Abstrakt:	The synergistic fermentation of milk by Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus is one of the key factors that determines the quality of yogurt. In this study, the mechanism whereby yogurt flavor compounds are produced by a mixture of S. thermophilus SIT-20.S and L. delbrueckii ssp. bulgaricus SIT-17.B were investigated by examining the flavor production, growth, and gene transcription of these strains. The results showed that yogurt produced by a 10:1 mixture of the aforementioned strains had the highest abundance of acetoin, whereas yogurt produced by a 1:1 mixture had the highest abundance of diacetyl and acetaldehyde. In addition, the growth of S. thermophilus SIT-20.S was enhanced in the 10:1 mixture. Transcriptomic analysis revealed differentially expressed genes in the flavor-compound-related pathways of S. thermophilus SIT-20.S and L. delbrueckii ssp. bulgaricus SIT-17.B in yogurts produced by 10:1 and 1:1 mixtures compared with those produced by either strain alone. Mixed fermentations regulated the expression of genes related to glycolysis, resulting in an increase of pyruvate, which is an important precursor for diacetyl and acetoin synthesis. The gene encoding the acetoin reductase (SIT-20S_orf01454) was decreased in S. thermophilus SIT-20.S, which ensured the accumulation of acetoin. In addition, the gene encoding the acetaldehyde dehydrogenase (SIT-20S_orf00949) was upregulated in S. thermophilus SIT-20.S, and the expression of alcohol dehydrogenase (SIT-20S_orf01479; SIT-17B_orf00943) was downregulated in both strains, maintaining the abundance of acetaldehyde. In addition, the gene encoding the NADH oxidase (SIT-17B_orf00860) in L. delbrueckii ssp. bulgaricus SIT-17.B were upregulated, which promoted the accumulation of diacetyl and acetoin. Overall, we characterized the mechanism by which S. thermophilus and L. delbrueckii ssp. bulgaricus synergistically generated yogurt flavor compounds during their production of yogurt and highlighted the importance of appropriate proportions of fermentation starters for improving the flavor of yogurts. (© 2024, The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)
Databáze:	MEDLINE
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