Chinese rice wine (CRW), a unique wine species, has a long history in China. Fagopyrum tataricum grain is a kind of high-quality grain with function in health care. The production of CRW wine with F. tataricum grain is beneficial to the development of new rice wine products. The flavor compounds and microorganisms in F. tataricum grain rice wine were studied. One hundred and seven volatile compounds (including 11 kinds of pyrazines that were rarely detected in wine) were detected and eight organic acids were measured. The microecological diversity in the fermentation process of F. tataricum rice wine was studied. It was found that Bacillus was the main bacterial genus, and the unclassfied_O_Saccharomycetales was the main fungi. Correlation analysis between microorganism and flavor compound shown there are 838 correlations. A total of 108 microbial genera maybe participate in the formation of flavor compounds. In addition, fourteen genera included unclassified_O_Saccharomycetales, Lactococcus, Pediococcus, Aspergillus, Cladosporium, Cochliobolus, Sporidiobolus, Pichia and Saccharomycopsis et al. were screened as functional significant microbiota and built correlation with flavor compounds. This work provides a perspective for bridging the gap between flavor compound and microbial community, and advances our understanding of mechanisms in F. tataricum rice wine fermentation.
Huangjiu is a national alcoholic beverage in China. Millet has congenital advantages in development and utilization of nutrient. Brewing Huangjiu with millet can increase the value of millet. Microbial community plays crucial roles in millet Huangjiu fermentation. Flavor compounds reflect the quality and health function of Huangjiu. The flavor compounds of Huangjiu are complex and their formation is closely associated with microorganisms, but the relationship between them during fermentation has been unknown. In this research, this relationship during millet Huangjiu fermentation were deeply investigated. Totally 86 volatile compounds were detected. Bacillus, Weissella, Paenibacillus, Klebsiella, Prevotella was investigated as the dominant microbes through high-throughput sequencing. 537 correlations between major flavor compounds and microbes were established to reflect the dynamic change during millet Huangjiu fermentation. The top five dominant genus of flavor producing microbes were Chryseobacterium, Sporolactobacillus, Psychrobacter, Sphingobium and Anoxybacillus. The content of malic acid and citric acid was gradually improved all through the millet Huangjiu fermentation. Malic acid and citric acid generated from millet Huangjiu fermentation shows healthy properties as liver protection and eliminating fatigue. Our research provides essential information on microbial community succession and the flavor formation during millet Huangjiu fermentation, and beneficial for development of Huangjiu products.
Decoding the aroma composition plays a key role in designing and producing foods that consumers prefer. Due to the complex matrix and diverse aroma compounds of foods, isolation and quantitative analytical methods were systematically reviewed. Selecting suitable and complementary aroma extraction methods based on their characteristics can provide more complete aroma composition information. Multiple mass spectrometry detectors (MS, MS/MS, TOF-MS, IMS) and specialized detectors, including flame ionization detector (FID), electron capture detector (ECD), nitrogen–phosphorus detector (NPD), and flame photometric detector (FPD), are the most important qualitative technologies in aroma identification and quantification. Furthermore, the real-time monitoring of aroma release and perception is an important developing trend in the aroma perception of future food. A combination of artificial intelligence for chromatographic analysis and characteristic databases could significantly improve the qualitative analysis efficiency and accuracy of aroma analysis. External standard method and stable isotope dilution analysis were the most popular quantification methods among the four quantification methods. The combination with flavoromics enables the decoding of aroma profile contributions and the identification of characteristic marker aroma compounds. Aroma analysis has a wide range of applications in the fields of raw materials selection, food processing monitoring, and products quality control.
Higher alcohols (HAs) are abundant compounds that provide important flavors in Huangjiu, but they also cause hangover. Previous studies have shown the production of HAs to be related to yeast, but the correlations between HAs and other microorganisms are rarely reported. In this study, we detected changes in levels of HAs and microbial dynamics during the Huangjiu fermentation process. Relationships were characterized using Pearson’s correlation coefficient. The functional core HA-producing bacteria were selected by bidirectional orthogonal partial least squares (O2PLS). The result showed that 2-methyl-1-propanol, phenethyl alcohol and 3-methyl-1-butanol were the principle HAs present at high levels. Lactococcus and Saccharomyces were predominant at the genus level of bacteria and fungi, respectively. A total of 684 correlations between HAs and microorganisms were established. Five genera were screened as functional core HA-producing bacteria. Our findings might provide some new inspiration for controlling the content of HAs, enhancing international prestige and market expansion of Huangjiu.
Aflatoxin B1 (AFB1) is one of the most harmful mycotoxins, raising serious global health and economic problems. Searching for biological approaches for effective and safe AFB1 degradation is imminent. In our study, Microbacterium proteolyticum B204 isolated from bovine faeces degraded 77% of AFB1 after 24 h, becoming the first reported bacteria from the Microbacterium family to possess AFB1 degradation characteristics. Temperature variation showed little effect on its degradation ratio, demonstrating high thermostability of 75% and 79% after boiling and sterilization, respectively. We suppose that the components playing a key role during this process were proteins, considering the decreased degradation rate caused by Proteinase K. Cell viability detection on HepG2 cells indicated that the degradation products were much less toxic than pure AFB1. Furthermore, B204 cell-free culture supernatant also degraded AFB1-contaminated food, such as peanuts, corn and cheese. These results suggested that this strain with AFB1 degradation properties could be a prospective candidate for application in the food and feed industries.