Daqu is a saccharifying and fermenting starter in the production of Chinese Baijiu; its quality directly affects the quality of Baijiu. The production of Daqu is highly environment-dependent, and ...after long-term natural domestication, it is rich in a wide variety of microorganisms with a stable composition, which provide complex and diverse enzymes and flavor (precursor) substances and microbiota for Jiupei (Fermented grains) fermentation. However, inoculation with a relatively stable microbial community can lead to a certain upper limit or deficiencies of the physicochemical properties (e.g., saccharification capacity, esterification capacity) of the Daqu and affect the functional expression and aroma formation of the Daqu. Targeted improvement of this problem can be proposed by selecting functional microorganisms to fortify the production of Daqu. This review introduced the isolation, screening, identification and functional characteristics of culture-dependent functional microorganisms in Baijiu-brewing, the core functional microbiota community of Daqu, and the related research progress of functional microorganisms fortified Daqu, and summarized the fortifying strategies of functional microorganisms, aiming to further deepen the application of functional microorganisms fortification in Daqu fermentation and provide ideas for the flavor regulation and quality control of Baijiu.
To study the difference between the fungal community compositional and fragrance components in medium- and high-Temperature Taorong-type Baijiu Daqu. The microbial communities and fragrance ...components of Taorong-type Baijiu Daqu were analyzed using high-throughput sequencing (HTS) and headspace-solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). With an abundance at the phylum and genus levels greater than or equal to0.01% as the threshold, 3 phyla, Mucoromycota, Ascomycota, and Basidiomycota, were found in both medium- and high-temperature Daqu, but their abundances differed. At the genus level, 15 and 13 genera were recognized. Rhizopus (72.40%) and Thermomyces (53.32%) accounted for the most significant proportions in medium-temperature and high-temperature Daqu, respectively. Medium-temperature Daqu and high-temperature Daqu were found to have 40 and 29 fragrance components, respectively and contained the highest proportions of pyrazines (53.12%) and acids (32.68%). Correlation analyses between microbes and fragrance components showed that Aspergillus, Hyphopichia, Trichosporon, Alternaria were all highly and positively correlated with pyrazines, but the dominant fungal communities were highly correlated with only a few individual acid compounds but not with acid compounds overall. The unique Daqu -making process and environment lead to these differences.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Daqu is an important saccharification starter in the brewing of Chinese Baijiu. The evolution of microbial communities and flavor formation are similar among different batches of Daqu, but the ...drivers of microbial community succession, the composition of functional microbiota, and metabolic pathways are still unclear. To this end, the microbial community succession, physicochemical properties and volatile metabolites dynamic changes and their correlation during the fermentation process of Taorong-type Baijiu Daqu were analyzed. The results showed that the core microbial genera observed in the whole period were Bacillus, Kroppenstedtia, Microbacterium, Thermoascus, Saccharomycopsis, and Apiotrichum. The correlation analysis showed moisture content and acidity drove the evolution of functional microbial communities in the Daqu. Visualized network analysis demonstrated that changes in the relative abundance of functional microbiota such as Bacillus, Kroppenstedtia, Thermomonas, Saccharomycopsis, Thermoascus and Malassezia promoted the difference of metabolism in different stages of Daqu fermentation. PICRUSt2 prediction and volatile metabolite metabolic pathway enrichment analysis showed that the metabolism of Daqu fermenting microorganisms was concentrated on amino acid, carbohydrates and energy metabolism. Our findings will facilitate the standardized production of stable-quality Daqu, and theoretically underlie Baijiu brewing microecological assembly and directional controllable fermentation.
•Dynamic changes of microbial community during fermentation of Taorong-type Baijiu Daqu were detected.•Bacillus, Kroppenstedtia, Thermoascus, Saccharomycopsis, Thermoascus and Malassezia are the functional microbiota in Daqu.•Moisture, acidity and microbial interactions drive the succession of the microbial community.•Microbial metabolism was significantly enriched to amino acids, carbohydrates and energy related metabolic pathways.
To study the difference between the fungal community compositional and fragrance components in medium- and high-Temperature Taorong-type Baijiu Daqu. The microbial communities and fragrance ...components of Taorong-type Baijiu Daqu were analyzed using high-throughput sequencing (HTS) and headspace-solid-phase microextraction-gas chromatography-mass spectrometry (HS–SPME–GC–MS). With an abundance at the phylum and genus levels ≥0.01% as the threshold, 3 phyla, Mucoromycota, Ascomycota, and Basidiomycota, were found in both medium- and high-temperature Daqu, but their abundances differed. At the genus level, 15 and 13 genera were recognized. Rhizopus (72.40%) and Thermomyces (53.32%) accounted for the most significant proportions in medium-temperature and high-temperature Daqu, respectively. Medium-temperature Daqu and high-temperature Daqu were found to have 40 and 29 fragrance components, respectively and contained the highest proportions of pyrazines (53.12%) and acids (32.68%). Correlation analyses between microbes and fragrance components showed that Aspergillus, Hyphopichia, Trichosporon, Alternaria were all highly and positively correlated with pyrazines, but the dominant fungal communities were highly correlated with only a few individual acid compounds but not with acid compounds overall. The unique Daqu -making process and environment lead to these differences.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The traditional Chinese Baijiu brewing process utilizes natural inoculation and open fermentation. The microbial composition and abundance in the microecology of Baijiu brewing often exhibit unstable ...characteristics, which directly results in fluctuations in Baijiu quality. The microbiota plays a crucial role in determining the quality of Baijiu. Analyzing the driving effect of technology and raw materials on microorganisms. Elucidating the source of core microorganisms and interactions between microorganisms, and finally utilizing single or multiple microorganisms to regulate and intensify the Baijiu fermentation process is an important way to achieve high efficiency and stability in the production of Baijiu. This paper provides a systematic review of the composition and sources of microbiota at different brewing stages. It also analyzes the relationship between raw materials, brewing processes, and brewing microbiota, as well as the steps involved in the implementation of brewing microbiota regulation strategies. In addition, this paper considers the feasibility of using Baijiu flavor as a guide for Baijiu brewing regulation by synthesizing the microbiota, and the challenges involved. This paper is a guide for flavor regulation and quality assurance of Baijiu and also suggests new research directions for regulatory strategies for other fermented foods.
Daqu is an essential starter for baijiu brewing in China. However, the microbial enrichment and metabolic characteristics of Daqu formed at different fermentation temperatures are still unclear.
...High-throughput sequencing technology and the non-targeted metabolomics were used to compare the microbial communities and metabolites of Taorong-type high-temperature Daqu and middle-temperature Daqu. In this study, the relationship between microorganisms and metabolites was established.
The study found that the composition and metabolites of the microbial community differed due to the difference in Daqu-making temperature. The bacterial diversity of Taorong-type high-temperature Daqu was higher than that of middle-temperature Daqu, while the fungal community diversity of Taorong-type middle-temperature Daqu was higher than that of high temperature Daqu. A total of 1,034 differential metabolites were screened from the two types of Daqu, and 76 metabolites with significant differences were detected (
< 0.001 and variable importance in projection (VIP) > 1.15). Tetraacetylethylenediamine is the metabolite with the largest differential fold among the 76 differential metabolites, which can be used as a potential marker metabolite of high-temperature Daqu.
This study helps elucidate the microbial assembly mechanisms and functional expression under different processing conditions through a further understanding of the composition and metabolic profile differences of different types of Daqu microflora in Taorong-type baijiu.
In this study, a fortified Daqu (FF Daqu) was prepared using high cellulase-producing Bacillus subtilis, and the effects of in situ fortification on the physicochemical properties, flavor, active ...microbial community and metabolism of Daqu were analyzed. The saccharification power, liquefaction power, and cellulase activity of the FF Daqu were significantly increased compared with that of the traditional Daqu (CT Daqu). The overall differences in flavor components and their contents were not significant, but the higher alcohols were lower in FF Daqu. The relative abundance of dominant active species in FF Daqu was 85.08% of the total active microbiota higher than 63.42% in CT Daqu, and the biomarkers were Paecilomyces variotii and Aspergillus cristatus, respectively. The enzymes related to starch and sucrose metabolic pathways were up-regulated and expressed in FF Daqu. In the laboratory level simulation of baijiu brewing, the yield of baijiu was increased by 3.36% using FF Daqu.
•Inoculating high-yield cellulase Bacillus subtilis to make fortified Daqu.•Bioturbation of functional strains improved the quality of Daqu.•Bioturbation affected the microflora, enzyme spectrum and metabolic of Daqu.
Pomegranate is a kind of fruit with low temperature sensitivity. Abnormal low temperature can easily lead to chilling injury, which negatively impacts the appearance of fruit, accelerates browning ...and deterioration, as well as seriously reduces the consumption quality and commodity value of pomegranate. This study was carried out to determine the effect of methyl jasmonate on chilling injury of pomegranate during low temperature storage. The result showed that methyl jasmonate treatment effectively maintained edible quality of pomegranate, suppressed the polyphenol oxidase activity and the development of chilling injury index, and inhibited the decline of total phenol content and the increase of malondialdehyde content and cell membrane permeability. In addition, methyl jasmonate could also enhance the disease resistance of fruit by increasing the content of soluble protein, and effectively maintain the integrity of epidermal cell structure and tissue structure. Overall, the conclusion of this paper is that methyl jasmonate can be used as an effective means to suppress chilling injury in postharvest storage of pomegranate.
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•Combined 1-MCP and sterilizing medium is an effective preservation technology.•1-MCP + O3 treatment effectively delayed the softening and senescence of fruit.•1-MCP + O3 treatment ...could induce resistance of fruit at earlier shelf storage.•1-MCP + O3 could maintain brighter color attributes of peaches during shelf life.•At the end of storage, 1-MCP + O3 maintained the best integrity of flesh tissue.
Physiological senescence and quality deterioration of peach after harvest were the restrict factors of peach shelf quality. As an ethylene inhibitor, 1-Methylcyclopropene (1-MCP) can effectively dealy fruit ripening and senescence, and improve storage quality. However, studies showed that the effect of fruit preservation by only using 1-MCP is unsatisfactory. Therefore, in this study, 1-MCP combined with sterilizing medium including ozone, TiO2 photocatalytic and epsilon-polylysine (ε-PL) was applied for enhancement of preservative ability with safety and pollution-free. The flow microcirculation was used for enhancing the effect of sterilizing medium. Results showed that all these three treatment methods can enhance the shelf quality of peach fruit. Among them, the combination treatment of 1-MCP and ozone played a more active role in inhibiting decay, respiration, ethylene production, decline of nutrients such as organic acids and soluble solids. Moreover, it maintained bright color value and cell integrity of peach fruit. In addition, the combined treatment of 1-MCP and ozone had significant effects on inducing resistance in fruit and slowing down membrane lipid peroxidation. In conclusion, 1-MCP combined with ozone was an effective method to delay the senescence and improve the storage shelf quality of fruit, which is beneficial to the guidance of production practice and has potential application prospects in fruit preservation.
