Search

One of famous Chinese Baijiu, Gujinggong (GJG) that is produced in Anhui province, belongs to the famous Luzhou-aroma type of Baijiu in regards of its unique flavor characteristics. However, its key aroma-impact volatiles have not been clearly characterized. In this study, a total of 60 aroma compounds of GJG were identified by GC-O and GC–MS, and 35 of them were further recognized as important aroma compounds owing to their OAVs ≥ 1 and sensory evaluation. As a result, its aroma profile was successfully simulated by reconstitution of those 35 and other 11 aroma compounds based on their measured concentrations in the GJG. Moreover, omission test was applied to investigate the effects of the important aroma compounds on the whole aroma profile of GJG. In this context, 9 aroma compounds were confirmed as the key aroma compounds of GJG. [ABSTRACT FROM AUTHOR]

[Display omitted] • The microbial community of SFB workshops microecology were identified. • Enrich the microbial profiles information by high-throughput sequencing. • The microbial composition in the workshop environment has succession in time series. • The bacterial community in brewing environment tends to be stable as the use time increases. The strong-flavor Baijiu (SFB) brewing workshop is a complex ecosystem with diverse microbiomes. As a potential source of microbiomes in fermentation, microbiota in the environmental microecology may affect the quality and flavor of SFB. Here, we report the collection of environmental microecological samples from three SFB workshops with different usage times (named 70a, 30a, and new, respectively). We used 16S rRNA and internal transcribed spacer (ITS) gene amplicon full-length sequencing to explore the microbial community structure in SFB. The SourceTracker tool was used to investigate links among fermentation samples, raw materials, and the environment and decipher the construction process in the workshop indoor environment. Lactobacillus acetotolerans was the most important bacterial genus in Zaopei after fermentation, whereas other types of samples exhibited different prokaryotic community structures. The composition of the fungal community was similar, with Saccharomycopsis fibuligera , Debaryomyces hansenii , Lichtheimia ramosa , Lichtheimia corymbifera , and Pichia kudriavzevii being the most abundant, and were detected in most samples. Further comparison of the microbiota in the workshop environment showed that the diversity of the microbiota in the indoor environment decreased, showing different clustering patterns under the influence of location. With increasing usage time, the contribution of deterministic processes to the assembly of the prokaryotic community increases, and the community structure tends to stabilize, exhibiting its own characteristics. SFB-fermenting resident functional fungi were the major components of the fungal community, and SourceTracker analysis also highlighted the contributions of Zaopei, Daqu, and tool surfaces as fungal sources. This study is the first to comprehensively monitor the microbial profile of the SFB production environment. This research can be extended to involve more complex spontaneous fermentation environment microbiota and has important implications for the control of spontaneous fermentation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The temporal perception of pungency of Baijiu were evaluated by TI and TDS. • Baijiu with different aging times differed in their temporal profiles of pungency. • Pungency differences of Baijiu were related to both intensity and sub-qualities. • TI and TDS supplied more valuable information of temporal differences, which were not identified using static methods. Pungency is increasingly being recognized as an important factor of overall sensory quality, palatability, and consumer preference of distilled spirits. The characterization of pungency is necessary to evaluate the potential sensory quality of distilled spirits. In this study, the temporal profiles of pungency of Baijiu with different aging times were evaluated using time-intensity (TI) and temporal dominance of sensations (TDS) methods, considering both pungency intensity and pungency sub-qualities. TI results indicated significant differences in release rate of pungency during Baijiu consumption. Compared to young Baijiu, old Baijiu tend to show higher release rate of pungency, the areas under the curve and duration of pungency were significantly decreased in old Baijiu. The TDS results showed significant differences in the combination of dominant sub-qualities, as well as in the maximum dominance rates and the dominant duration of sub-qualities among Baijiu. The young Baijiu were mainly characterized by the dominant sub-qualities of "burning" and "numbing", whereas for old Baijiu, "burning", "prickle", and "drying" were dominant. The application of TI and TDS provided dynamic and temporal profiles of pungency to fully characterize pungency differences of distilled beverages. [ABSTRACT FROM AUTHOR]

• Effects of mechanization on microflora and flavor in Baijiu production were studied. • Pichia kudriavzevii was more active than Saccharomyces cerevisiae. • Five core microbes were detected both in metagenomic and metatranscriptomic analyses. • The expression level of 9 genes related to higher alcohol formation were determined. Microorganisms play an important role in the flavor formation of Chinese Baijiu. Mechanization is the way to develop Baijiu. Therefore, it is necessary to study the effects of mechanization on microbial community and flavor in Baijiu production. The microbial communities exhibited differences between two technologies with the fermentation, and the numbers of yeasts and bacteria in new mechanical technology were significantly higher than those in traditional technology at the peak of fermentation. Both metagenomic and metatranscriptomic analyses showed 5 core microorganisms in the fermentation, namely Saccharomyces cerevisiae , Rhizopus delemar , Pichia kudriavzevii , Lactobacillus helveticus , and Rhizopus oryzae. S. cerevisiae was generally regarded to be the most dominant yeast in Baijiu fermentation, but our metatranscriptomic data showed that P. kudriavzevii was more active than S. cerevisiae. These two analyses indicated that higher initiation abundance of S. cerevisiae and P. kudriavzevii and lower initiation abundance of R. delemar and R. oryzae were observed in traditional technology than in new technology, and that Lactobacillus displayed apparent advantages in traditional technology, whereas Lactobacillus and yeast exhibited obvious advantages in new technology at the end of fermentation. In addition to S. cerevisiae, other microorganisms including non-saccharomyces yeasts, molds, and bacteria were involved in higher alcohol formation. This work provides insight into the microbial dynamics and higher alcohol formation, as well as an efficient strategy for process improvement in Baijiu fermentation. [ABSTRACT FROM AUTHOR]

• Two l -cysteine high-producing Bacillus were inoculated in Baijiu fermentation. • l -cysteine content increased after Bacillus inoculation in Baijiu fermentation. • Bacillus inoculation increased 2-furfurylthiol contents in Baijiu. • Bacillus inoculation affected the microbial community structure. 2-Furfurylthiol was an important contributor to the flavor of traditional fermented foods including Baijiu. It is essential to increase 2-furfurylthiol concentration to improve the quality of Baijiu. This study aimed to enrich the content of 2-furfurylthiol in Chinese sesame-flavored Baijiu via two strains we isolated from Baijiu fermentation, Bacillus subtilis LBM 10019 and Bacillus vallismortis LBM 10020, which could respectively produce 56.31 mg/L and 42.81 mg/L l -cysteine, the precursor of 2-furfurylthiol, in sorghum extract. After inoculation of these two strains, the maximal relative abundance of Bacillus increased from 7.48% to 40.38%, the final content of l -cysteine increased by 101.44% in Baijiu fermentation. Moreover, the concentration of 2-furfurylthiol increased by 89.15% in the production. This work provides a novel strategy to improve the quality of Chinese sesame-flavored Baijiu. [ABSTRACT FROM AUTHOR]