Differences between Kazak Cheeses Fermented by Single and Mixed Strains Using Untargeted Metabolomics

Abstract

Mixed fermentation improves the flavor quality of food. Untargeted metabolomics were used to evaluate the impact of mixed fermentation and single-strain fermentation on the volatile and non-volatile compound profiles of Kazak cheese. Lacticaseibacillus paracasei SMN-LBK and Kluyveromyces marxianus SMN-S7-LBK were used to make mixed-fermentation cheese (M), while L. paracasei SMN-LBK was applied in single-strain-fermentation cheese (S). A higher abundances of acids, alcohols, and esters were produced via mixed fermentation. Furthermore, 397 differentially expressed non-volatile metabolites were identified between S and M during ripening. The flavor compounds in mixed-fermentation cheese mainly resulted from ester production (ethyl butanoate, ethyl acetate, ethyl octanoate, and ethyl hexanoate) and amino acid biosynthesis (Asp, Glu, Gln, and Phe). The metabolites were differentially expressed in nitrogen metabolism, D-glutamine and D-glutamate metabolism, phenylalanine metabolism, D-alanine metabolism, and other metabolic pathways. The amount of flavor compounds was increased in M, indicating that L. paracasei SMN- LBK and K. marxianus SMN-S7-LBK had synergistic effects in the formation of flavor compounds. This study comprehensively demonstrated the difference in metabolites between mixed-fermentation and single-strain-fermentation cheese and provided a basis for the production of Kazak cheese with diverse flavor characteristics.

Exploring the Effect of Milk Fat on Fermented Milk Flavor Based on Gas Chromatography–Ion Mobility Spectrometry (GC-IMS) and Multivariate Statistical Analysis

“…In S25%, aldehydes, alcohols, and other components accounted for 5.97%, 11.2%, and 1.06% of the total component content, respectively. Ketones in fermented milk mainly come from the β-oxidation of fatty acids [ 28 ], and the aroma of ketones becomes more intense as the carbon chain lengthens and the branched chain increases. According to previous studies, 3-hydroxy-2-butanone and 2-heptanone are sources of a creamy aroma in fermented milk.…”

Comparative genomic analysis of Lacticaseibacillus paracasei SMN-LBK from koumiss

“…Comparative genomics is an effective technique to explore the changes in genomic information that occur during interspecies and intraspecies evolution ( Wassenaar and Lukjancenko, 2014 ; Huang D. et al, 2020 ). Our previous studies showed that SMN-LBK has good fermentation characteristics and probiotic properties and the ability to tolerate ethanol and ameliorate liver injury caused by ethanol in rats, but the underlying mechanism has not been clarified ( Guo et al, 2020 ; Li et al, 2022 ). Moreover, SMN-LBK has been used in commercial yogurt fermentation as an auxiliary starter, which has extremely high research value and commercial prospects.…”