Determination of bacterial community and its correlation to volatile compounds in Guizhou Niuganba, a traditional Chinese fermented dry-cured beef
Chan Wang, Hanyu Liu, Laping He, Cuiqin Li
Abstract
This study investigated the bacterial community and volatile components of Guizhou Niuganba (GZNGB), a traditional fermented food of Southwest China. Microbiological analysis of GZNGB based on Illumina MiSeq sequencing technology revealed that Firmicutes (61.97%) and unclassified_Bacteria (25.35%) were the predominant phyla and Staphylococcus (41.58%), unclassified_Bacteria (25.35%), Lactobacillus (13.89%), and Streptophyta (9.2%) were the predominant genera. Additionally, 96 volatile compounds, including hydrocarbons (34.37%), alcohol (21.87%), aldehyde (9.38%), ketone (9.38%), esters (7.29%), acid (7.29%), and other (10.42%) were identified in all NGB samples using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). Principal component analysis (PCA) revealed the variances in volatile compounds among different NGB samples, and the unique flavor of GZNGB was found to be due to the spices, the Strecker amino acids, and lipid oxidation. Spearman's correlation analysis revealed a correlation between VCs and bacterial flora. The synergistic effect of microorganisms imparted flavor to GZNGB to a certain extent; however, it was not prominent. It may be due to high concentrations of spices that could have inhibited microbial metabolism. Besides, it also improved the fermentation process, controlled the type and content of spices, nurtured beneficial microorganisms for intensive inoculation, and inhibited microbial contamination, which is crucial for mechanized production.