Analysis of Different Strains Fermented Douchi by GC×GC-TOFMS and UPLC-Q-TOFMS Omics Analysis

Area of Science:

• Food Science and Technology
• Microbiology
• Biochemistry

Background:

• Douchi is a traditional Chinese fermented soybean food.
• Understanding the chemical composition of Douchi is crucial for its quality and characteristics.
• Different microbial strains can influence the flavor and functional properties of fermented foods.

Purpose of the Study:

• To investigate the common and differential flavor compounds and non-volatile components in Douchi fermented by Aspergillus niger, Rhizopus arrhizus, and Bacillus circulans.
• To compare the chemical profiles of Douchi fermented by single strains versus co-fermentation.
• To identify key compounds contributing to the unique flavor and function of Douchi produced by different microbial consortia.

Main Methods:

• Fermentation of Douchi using single strains (Aspergillus niger, Rhizopus arrhizus, Bacillus circulans) and a co-fermentation approach.
• Gas chromatography-gas chromatography-time of flight mass spectrometry (GC×GC-TOFMS) for flavor compound analysis.
• Ultra-performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-Q-TOFMS) for non-volatile component analysis.
• Omics analysis to identify and quantify metabolites.

Main Results:

• Identified common flavor compounds (pyrazines, ketones, alkenes) and functional components (peptides, amines, flavonoids) across different fermentations.
• Determined unique flavor and functional compounds specific to each microbial strain (e.g., Aspergillus niger, Rhizopus arrhizus, Bacillus circulans).
• Observed a significantly higher abundance of flavor substances and non-volatile components in multi-strain fermented Douchi compared to single-strain fermented Douchi.

Conclusions:

• Common and differential compounds contribute to the basic and unique flavor and function of Douchi.
• Multi-strain fermentation enhances the diversity and abundance of flavor and functional metabolites in Douchi.
• The findings provide a valuable reference for researching the flavor and functional substances of Douchi.