Application of pyrazine-producing Bacillus in the production of Maotai-flavor Baijiu in Tianjin

Abstract:

[Background] Pyrazines are closely related to the flavor of Maotai-flavor Baijiu. [Objective] To screen out the Bacillus strains with high yields of pyrazines for Baijiu production and provide a basis for improving the quality of Maotai-flavor Baijiu. [Methods] After primary screening and secondary screening, strain J1 with a high yield of pyrazines was screened out from 50 strains of Bacillus in the brewing process of Maotai-flavor Baijiu. The strain was identified by 16S rRNA gene sequencing. The conditions of pyrazine production by this strain were optimized by single factor and orthogonal experiments. Finally, the fermentation performance of the strain was evaluated by simulated fermentation and in-situ fermentation. [Results] Strain J1 was identified as Bacillus amyloliquefaciens. The optimum fermentation conditions were as follows: inoculum concentration of 10⁷ CFU/mL, Saccharomyces cerevisiae to J1 ratio of 1:100, inoculation of J1 two days after inoculation of S.cerevisiae, and the fermentation temperature raised to 50 ℃. Under these conditions, the content of pyrazines reached 322.48 mg/L. The simulation experiment showed that the strain J1 produced rich pyrazines. The content of pyrazines in the Baijiu obtained by in-situ fermentation was 480.87 mg/L, which was about 10 times that of the control group. [Conclusion] This study can provide a basis for improving the quality of Maotai-flavor Baijiu.

Key words:Maotai-flavor Baijiu;pyrazines;Bacillus sp.;in-situ fermentation