Effects of Lactobacillus plantarum C7 and Staphylococcus warneri S6 on flavor quality and bacterial diversity of fermented meat rice, a traditional Chinese food

The Antioxidant Capacity and Flavor Diversity of Strawberry Wine Are Improved Through Fermentation with the Indigenous Non-Saccharomyces Yeasts Hanseniaspora uvarum and Kurtzmaniella quercitrusa

The production of strawberry wine is an effective strategy for addressing the significant economic losses caused by strawberry spoilage. In recent years, there has been an increase in consumer demand for quality and flavor diversity in fruit wines. Therefore, it is necessary to develop novel strawberry wine products. In this research, we assessed and analyzed the influences of fermentation with Hanseniaspora uvarum, Kurtzmaniella quercitrusa, and Saccharomyces cerevisiae under four fermentation conditions on the fermentation kinetics, organoleptic characteristics, chemical compositions, antioxidant capacities, and flavor profiles of strawberry wines. Strawberry wines fermented with the indigenous non-Saccharomyces yeasts H. uvarum and K. quercitrusa showed higher 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-Azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) free-radical-scavenging capacities and significantly different flavor profiles compared to strawberry wines fermented with S. cerevisiae. In addition, adjusting the initial soluble solids contents of strawberry juices and fermentation temperatures positively affected the quality and flavor profiles of strawberry wines fermented with the H. uvarum and K. quercitrusa strains. Under the condition of 18 °C-20 °Brix, strawberry wine fermented with K. quercitrusa presented the highest antioxidant capacity, with enhanced flavor diversity and color intensity. It is worth noting that K. quercitrusa can be an alternative yeast for producing high-quality strawberry wine with a distinct floral aroma.

Insights into the flavor contribution, mechanisms of action, and future trends of coagulase-negative staphylococci in fermented meat products: A review

During fermentation, meat is pre-treated and cured to cultivate a diverse microflora, resulting in fermented meat products with distinctive flavors. Coagulase-negative staphylococcus holds a crucial role in all fermented meat products, contributing to the breakdown of proteins, carbohydrates, and fats, and the creation of flavor compounds. Fermentation technology has important research value and significance in fermented meat products. The optimization and improvement of flavor by CNS can be achieved by regulating the fermentation environment, initial microflora and processing conditions. The review explores the ways in which coagulase-negative staphylococci contribute to the flavors in fermented meat products. The mechanism of flavor substance formation and means of regulation in coagulase-negative staphylococci were also investigated. The review concludes by summarizing future development trends and drawing conclusions.

Microbiota dynamics and metabolic mechanisms in fermented sausages inoculated with Lactiplantibacillus plantarum and Staphylococcus xylosus

Lactiplantibacillus plantarum and Staphylococcus xylosus are common starters for fermented sausages. Several studies have demonstrated the impact of these two strains on the quality of fermented sausages. However, the mechanism underlying the effects of these two microorganisms on co-cultivation in sausages remains unclear. This study aimed to investigate the effects of inoculation with various combinations of starters on the microbial communities and metabolic profiles of fermented sausages. High-throughput sequencing revealed that, during sausage fermentation, Firmicutes was the dominant bacterial phylum, and the primary microorganisms were Lactococcus, Staphylococcus, Lactobacillus, and Pseudomonas. On the last day of fermentation, the highest abundance of Staphylococcus was observed in the co-inoculation group. Furthermore, inoculated fermentation effectively inhibited the growth of pathogenic and spoilage bacteria. Metabolomic analysis of the four groups of samples identified 208 metabolites in positive ion mode and 109 in negative ion mode. A total of 31 differential metabolites were identified (P < 0.05, variable importance in the projection >1.5), primarily benzene and substituted derivatives, carboxylic acids and derivatives, and fatty acyls. Five crucial differential metabolites (subaphylline, naringenin, 1-hexadecanol, beta-alanyl-L-lysine, and 3'-AMP) were identified as potential biomarkers for fermented sausages. Key differential metabolite metabolic pathways indicated that L. plantarum YR07 dominated in metabolite regulation during sausage fermentation, and S. xylosus Y-18 downregulated the fatty acid degradation pathway, which also affected the metabolism of fermented sausages. Co-cultivation of the two bacteria exhibited a synergistic effect on the metabolism of the fermented sausages. This study offers further insights into improving the quality of fermented sausages, thereby establishing a theoretical foundation for the production of excellent fermenters.

Volatile Compounds of Sucuk, a Dry Fermented Sausage: The Effects of Ripening Rate, Autochthonous Starter Cultures and Fat Type

The aim of this study was to determine the effects of ripening rate (slow or fast), usage autochthonous starter cultures (control-spontaneous fermentation, Lactiplantibacillus plantarum GM77, Staphylococcus xylosus GM92 or L. plantarum GM77 + S. xylosus GM92) and type of fat (beef fat-BF, sheep tail fat-STF and BF+STF) on the volatile compounds of sucuk (a Turkish dry fermented sausage). A total of 74 volatile compounds were identified, including groups of aliphatic hydrocarbons, aldehydes, ketones, alcohols, sulfide compounds, esters, aromatic hydrocarbons, nitrogenous compounds, acids and terpenes in sucuk. Slow ripening resulted in significant increases in the abundance of ethanol, acetic acid, ethyl acetate, acetoin and diacetyl. A similar situation was determined for a mixed culture (L. plantarum + S. xylosus). Correlation analysis showed that the effects of slow ripening and mixed culture use were more pronounced in terms of volatile compound content. Although the effect of fat type on volatile compounds was quite limited compared to other factors, correlation analysis showed that STF had a different volatile compound profile.

The Opportunistic Pathogen Staphylococcus warneri: Virulence and Antibiotic Resistance, Clinical Features, Association with Orthopedic Implants and Other Medical Devices, and a Glance at Industrial Applications

In recent decades, the risk of developing opportunistic infections has increased in parallel with the ever-increasing number of people suffering from chronic immunosuppressive diseases or undergoing prosthetic surgery. Staphylococcus warneri is a Gram-positive and coagulase-negative bacterium. Usually found as a component of the healthy human and animal microbiota of the skin and mucosae, it can take on the role of an opportunistic pathogen capable of causing a variety of infections, ranging from mild to life-threatening, not only in immunocompromised patients but even, although rarely, in healthy people. Here, in addition to a concise discussion of the identification and distinguishing features of S. warneri compared to other staphylococcal species, a systematic overview of the findings from case reports and clinical studies is provided. The paper highlights the virulence and antibiotic resistance profiles of S. warneri, the different clinical contexts in which it has proven to be a serious pathogen, emphasizing its ability to colonize artificial prosthetic materials and its tropism for musculoskeletal and cardiovascular tissues. Some original data on orthopedic implant infections by S. warneri complement the discussion. Finally, from a different perspective, the paper addresses the possibilities of industrial exploitation of this bacterium.

The quality characteristics and microbial communities of three components in traditional split-fermented red sour soup

Red sour soup is a Guizhou specialty condiment made by the natural fermentation of tomatoes and chili. In this study, three components (tomato acid, chili acid, and tomato and chili mixed acid) of split-fermented red sour soup were explored to compare the quality characteristics and microbial communities in the middle and late fermentation stages. The titratable acidity of mixed acids was lower than that of tomato acid and chili acid in the middle stage, but it was significantly increased in the late stage. The cell viability of lactic acid bacteria was mostly higher than that of yeasts during the whole fermentation. Also significantly increased in the late stage of fermentation were sensory scores and the signal intensity of sour substances. However, the signal intensity of both bitter and salty substances decreased, and the total amount of free amino acids was reduced. In addition, the antioxidant capacity of the samples and the dominant microorganisms were different between the two fermentation stages, Lactobacillus and Kazachstania were the key common genus of the different components of split-fermented red sour soup. It is anticipated that this study would provide us an insight into the quality characteristics and microbial communities of split-fermented red sour soup.

Influence of Penicillium lanosum and Staphylococcus equorum on Microbial Diversity and Flavor of Mianning Hams

Mianning ham is a traditional meat product in China. In this experiment, solid-phase microextraction-gas chromatography (SPME-GC-MS) and high-throughput sequencing were used to study the effects of adding Penicillium lanosum and adding the mixture of Penicillium lanosum and Staphylococcus equorum on the flavor and microbiology of Mianning ham. The results showed that the addition of the ferments resulted in an increase in the abundance of both the dominant bacterial phylum (Thick-walled Bacteria) and the dominant fungal phylum (Ascomycota). The variety of volatile flavor substances and key flavor substances increased after adding fermentation agents. A free amino acid analysis showed that hams from the Penicillium lanosum and Staphylococcus equorum group had significantly higher umami flavor amino acids than the control group and Penicillium lanosum group. Therefore, inoculation with Penicillium lanosum and Staphylococcus equorum favored the dominant bacteria and flavor of Mianning ham.

New insights into the dominance of mixed fermentation of Staphylococcus cohnii and Staphylococcus saprophyticus in Chinese bacon: Complete genomic and comparative genomic perspectives

Previous studies have demonstrated that Staphylococcus cohnii WX_M8 and S. saprophyticus MY_A10 significantly enhanced the flavor of Chinese bacon in a mixed fermentation. However, due to the complexity of the processing, the contribution of the bacteria is deceptive when investigating only the phenotypic changes at the time of fermentation. In order to clarify the metabolic mechanisms of mixed fermentation, a technological characterization, whole genome and comparative genomics analysis, and metabolites were approached in this study. Results showed that differences in tolerance characteristics existed between WX_M8 and MY_A10. And the genomes of both the two strains consisted of one chromosome and four circular plasmids. Their genome sizes were 2.74 Mp and 2.62 Mp, the GC contents were 32.45% and 33.18%, and the predicted coding genes (CDS) were 2564 and 2541, respectively. Based on the annotation of gene functions and assessment of metabolic pathways in the KEGG database, WX_M8 and MY_A10 strains were found to harbor complete protein degradation and amino acid metabolic pathways, pyruvate and butanol metabolic pathways, and isoleucine metabolic pathways, and their diverse enzyme-encoding genes superimposed the metabolic functions, whereas the alcohol dehydrogenase genes, adh and frmA, achieved complementary functions in the production of esters. Comparative genomics analysis revealed a diversity of encoding genes of aminotransferases and a greater metabolism for sulfur-containing amino acids, aromatic amino acids, and branched-chain amino acids in the mixed fermentation of strains WX_M8 and MY_A10. Metabolites analysis showed that MY_A10 focused on the production of soluble peptides and free amino acids (FAAs), while WX_M8 focused on volatile organic compounds (VOCs), resulting in a significant enhancement of the flavor of Chinese bacon when the two were mixed fermented. This result may provide direction for strains WX_M8 and MY_A10 to be used as starter cultures and targeted to regulate flavor.

Insight into the autochthonous bacterial strains as starter cultures for improving the flavor profiles of dry-cured duck: Changes in microbial diversity and metabolic profiles

The purpose of this study was to reveal the effect of inoculating autochthonous bacterial strains (Lactobacillus and Staphylococcus simulans) on the flavor profiles, microbial community, and metabolites, and to elucidate the potential mechanism of flavor formation in dry-cured duck. The results indicated that the inoculation of bacterial strains could improve the amount of lactic acid bacteria and Staphylococcus and reduce the counts of Enterobacteria. There was a significant difference in flavor profiles between samples inoculated with different strains. Hexanal-D, acetone, 3-methyl-1-butanol-D, thiophene, hexanal-M, propanal, pentanal, (Z)-2-penten-1-ol and ethanol-D were the potential biomarkers. A total of 70 differential metabolites were screened and identified. Amino acid metabolism and lipid metabolism were the key pathways for the production of flavor and metabolites in dry-cured duck. The results of this study will improve our understanding of the mechanism of flavor formation regarding the inoculation of autochthonous starter cultures.

A quality comparison for Xiecun Huangjiu with different aging stages based on chemical profile, aroma composition and microbial succession

The Xiecun Huangjiu (XCHJ), an exemplary representation of North Huangjiu, exhibits a distinct and invigorating aroma predominantly formed during its aging period. In this study, we observed dynamic changes in 16 key aroma compounds by gas chromatography-mass spectrometry (GC-MS) during the aging of XCHJ, with compounds such as phenethylalcohol, isoamylalcohol, benzaldehyde, and ethylbenzoate initially increasing and then decreasing. Ultra-Performance Liquid Chromatography (UPLC) detected nineteen amino acids, with total content ranging from 1901.45 to 3764.45 mg/L. High-throughput sequencing indicated that Pseudomonas, Ochrobactrum, Moesziomyces and Aspergillus et al. were abundant in aged XCHJ. Totally, 4 bacteria and 8 fungi exhibited strong associations with aroma compounds production. Physicochemical properties were primarily interacted with Pseudomonas, Aspergillus, Pseudeurotium, Thermomyces, Bacteroides and Blautia. Furthermore, co-occurrence network analysis highlighted significant interactions between Pantoea, Rhodotorula, Monascus, and amino acids. These findings provide valuable insights for the regulation of aroma in aged XCHJ.

Comprehensive analysis of flavor formation mechanisms in the mechanized preparation Cantonese soy sauce koji using absolute quantitative metabolomics and microbiomics approaches

Based on the widespread application and under-research of mechanized preparation Cantonese soy sauce koji (MP), absolute quantitative approaches were utilized to systematically analyze the flavor formation mechanism in MP. The results indicated that the enzyme activities increased greatly during MP fermentation, and 4 organic acids, 15 amino acids, and 2 volatiles were identified as significantly different flavor actives. The flavor parameters of MP4 were basically identical to those of MP5. Furthermore, microorganisms were dominated by Staphylococcus, Weissella, and Aspergillus in MP, and their biomass demonstrated an increasing trend. A precise enumeration of microorganisms exposed the inaccuracy of relative quantitative data. Concurrently, Staphylococcus and Aspergillus were positively correlated with numerous enzymes and flavor compounds, and targeted strains for enhancing MP quality. The flavor formation network comprises pathways including carbohydrate metabolism, lipid metabolism and oxidation, and protein degradation and amino acid metabolism. In summary, the fermentation period of MP can be substantially shortened without compromising the product quality. These findings lay the groundwork for refining parameters in modern production processes.

Staphylococcus inoculation enhances the sensorial attributes of Chinese bacon by coordinating the composition of flavor compounds through amino acid metabolism

In this study, we aimed to uncover the potential underlying mechanisms of the flavor modulation of Chinese bacon by Staphylococcus. To that end, taste-enhancing S. cohnii WX-M8 and S. saprophyticus MY-A10 screened from Chinese bacon were used to investigate the effects of their individual and mixed fermentations and their synergistic fermentation with Lactobacillus plantarum BL-1 on the sensorial attributes, physicochemical properties, microbial diversity, and volatile compounds (VOCs) of Chinese bacon. Our results revealed that S. cohnii WX-M8 and S. saprophyticus MY-A10 significantly increased a* (redness) and Aw and reduced thiobarbituric acid reactive substances (TBARS) when fermented in a mixture. Moreover, they promoted the formation of esters, aldehydes (especially straight-chain aldehydes), and phenolic compounds through pathways related to amino acid metabolism, enhancing sensorial attributes. While synergistic fermentation with L. plantarum BL-1 resulted in an improved a* (redness) of Chinese bacon, and the increased microbial metabolism of the carbohydrate and lipid metabolic pathways, the increase in TBARS and the higher content of acidic volatiles, led to a change in the composition of the flavor substances. The advantage of co-fermentation of Staphylococci in sensory attributes can be attributed to their capability to metabolize amino acids and associates. These findings provide insights into the role of Staphylococcus as a starter in regulating bacon flavor.

The combination of high-throughput sequencing and LC-MS/MS reveals the mechanism of Staphylococcus inoculation on bacterial community succession and taste development during the processing of dry-cured bacon

BACKGROUND

To understand the mechanism of co-inoculation of Staphylococcus vitulinus and Staphylococcus xylosus (SX&SV) on taste quality of dry-cured bacon, physicochemical parameters, microbial community, metabolite compositions and taste attributes were investigated during the processing of dry-cured bacon with Staphylococcus inoculation. The potential correlation between core bacteria and metabolites was evaluated, and the metabolic pathway of key metabolites was further explored.

RESULTS

The values of pH, water activity and adhesiveness were significantly lower in SX&SV, and more than 2.56- and 2.15-fold higher values in richness and overall acceptance were found in SX&SV bacon than in CK bacon. The overwhelming advantage of Staphylococcus was confirmed in SX&SV by high-throughput sequencing. Sixty-six metabolites were identified by liquid chromatography-tandem mass spectrometry, and oligopeptides, amino acid derivatives and organic acids were the key components. Pearson correlation demonstrated that the accumulation of oligopeptides, amino acid derivatives and organic acids were positively correlated with high abundance of Staphylococcus. The pathways of purine metabolism, glutathione metabolism and glutamate metabolism were mainly involved in developing the taste quality of SX&SV.

CONCLUSION

The co-inoculation of Staphylococcus vitulinus and Staphylococcus xylosus enhanced the taste attributes of dry-cured bacon. The present study provides the theoretical reference with respect to regulating the taste quality of fermented meat products by starter cultures of Staphylococcus during manufacture. © 2023 Society of Chemical Industry.

Bacterial microbiota in different types of processed meat products: diversity, adaptation, and co-occurrence

As a double-edged sword, some bacterial microbes can improve the quality and shelf life of meat products, but others mainly responsible for deterioration of the safety and quality of meat products. This review aims to present a landscape of the bacterial microbiota in different types of processed meat products. After demonstrating a panoramic view of the bacterial genera in meat products, the diversity of bacterial microbiota was evaluated in two dimensions, namely different types of processed meat products and different meats. Then, the influence of environmental factors on bacterial communities was evaluated according to the storage temperature, packaging conditions, and sterilization methods. Furthermore, microbes are not independent. To explore interactions among those genera, co-occurrence patterns were examined. In these respects, this review highlighted the recent advances in fundamental principles that underlie the environmental adaption tricks and why some species tend to occur together frequently, such as metabolic cross-feeding, co-aggregate at microscale, and the intercellular signaling system. Further investigations are required to unveil the underlying molecular mechanisms that govern microbial community systems, ultimately contributing to developing new strategies to harness beneficial microorganisms and control harmful microorganisms.

Characterization and application in yogurt of genipin-crosslinked chitosan microcapsules encapsulating with Lactiplantibacillus plantarum DMDL 9010

Microcapsules could improve the protection of probiotics in the lyophilization and gastrointestinal digestion process. The purpose of this study was to prepare Lactiplantibacillus plantarum DMDL 9010 (LP9010) microcapsules by cross-linking chitosan with genipin and to determine the encapsulation efficiency, morphological characterization, storage stability and the application of the microcapsules in fermentation. The results showed that the LP9010 microcapsules embedded in 1.00 wt% genipin cross-linked chitosan were in a uniform spherical shape with a smooth surface and satisfying agglomeration. The LP9010 microcapsules demonstrated the reasonable thermal stability and persistence of biological activity in the range of -20 °C to 25 °C. Additionally, yogurt obtained from the ST + LB + ELP9010 strain formulation with the addition of microencapsulated LP9010 had smaller particles, better taste, and better stability compared with the yogurt obtained from other strain formulations. As detected by GC-MS, the yogurt formulated with ST + LB + ELP9010 as a strain retained more flavor substances and the content of flavor substances was greater than that of the yogurt obtained from other strain formulations. Therefore, genipin cross-link chitosan could be a suitable microencapsulated material for producing yogurt fermentation strains.

Heterogeneity changes of active bacterial community on cigar filler leaves after fermentation based on metagenome

Microorganisms play an important role in cigar fermentation. To further explore the dynamic changes of bacterial community composition, the changes of surface bacterial diversity of cigar filler leaves were investigated in the present study by high-throughput sequencing technology. It was found that the surface bacterial richness was declined after fermentation, and the dominant microorganisms on the surface of cigar filler leaves evolved from Pseudomonas spp. and Sphingomonas spp. before fermentation to Staphylococcus spp. after fermentation. The chemical composition and sensory quality evaluation of cigar filler leaves were closely related to the changes of surface bacterial community. The changes of the dominant surface bacterial community led to the differences of metabolic functions, among which the metabolic pathways such as the synthesis of secondary metabolites, carbon metabolism, and amino acid biosynthesis were significantly different. The results provide a basis for clarifying the roles of bacteria in fermentation of cigar filler leaves.

Study on the quality formation mechanism of Zao chili with enhanced fermentation by Lactipllantbacillus plantarum 5-1

Zao Chili (ZC) is a traditional fermented pepper, which plays an important role in Chinese cooking. The aim of this study was to elucidate the effect of Lactipllantbacillus plantarum 5-1 on the physicochemical properties, metabolite and microbiota profiling of ZC. The physicochemical factors changed regularly with the fermentation time. In the microbial communities, Lactobacillus, Weissella, Enterobacter, Gibberella, Fusarium, Zygosaccharomyces and Pichia were the dominant genera. 7 kinds of organic acids were detected in the whole fermentation process of ZC, but only 5 kinds changed significantly. Based on the OPLS-DA model with VIP > 1 and ANOVA with P < 0.05, 33 volatile flavor compounds with significant differences were screened out of 89. According to the redundancy analysis (RDA), fungi mainly contributed to soluble solids, while bacteria mainly contributed to pH. Lactobacillus, Weissella, Enterbacter and Zygosaccharomyces may be the potential flavor contributing microorganisms in the fermentation process of ZC by the Spearman correlation coefficient. A total of 11 main metabolic pathways were obtained by KEGG enrichment analysis of 89 volatile flavor compounds and 7 organic acids. Therefore, this study further enhanced our understanding of the flavor quality formation mechanism of Lactipllantbacillus plantarum in ZC, and providing a theoretical basis for improving the flavor quality of ZC.

Correlation and Difference between Core Micro-Organisms and Volatile Compounds of Suan Rou from Six Regions of China

Suan Rou (SR), a traditional fermented meat, is widely favored by consumers due to its unique flavor and characteristics. To study the relationship between the core differential micro-organisms and differential volatile organic compounds (VOCs) of SR from six regions of China, high-throughput sequencing (HTS) and gas-chromatography−ion mobility spectrometry (GC-IMS) technologies were used to analyze the correlation between micro-organisms and VOCs in SR from Xiangxi of Hunan, Rongshui of Guangxi, Zunyi of Guizhou, Jinping of Guizhou, Congjiang of Guizhou, and Libo of Guizhou. A total of 13 core micro-organisms were identified at the genus level. Moreover, 95 VOCs were identified in the SR samples by GC-IMS analysis, with alcohols, aldehydes, ketones, and esters comprising the major VOCs among all the samples. The results showed a strong correlation (|r| > 0.8, p < 0.05) between the core differential micro-organisms and differential VOCs, including four bacteria, five fungi, and 12 VOCs. Pediococcus, Debaryomyces, Zygosaccharomyces, and Candida significantly contributed to the unique VOCs of SR.

Insight into bacterial community profiles of oil shale and sandstone in ordos basin by culture-dependent and culture-independent methods

To promote the exploitation of unconventional oil resources by indigenous microorganisms, the bacterial community profiles of oil shale and sandstone in Ordos Basin were investigated using Illumina Miseq sequencing combined with the culture-based method, which was performed and reported in this literature for the first time. A total of 601 operational taxonomic units (OTUs) were obtained from collected samples, the predominant phylum present in all samples was Proteobacteria (76.96%-93.07%). Discriminatory bacterial community profiles existed in those samples by culture-dependent and culture-independent methods, with variations not only in diversity indices but also in the abundance of bacteria at different genus levels. The dominant genera in cultured sandstone sample (SCB), uncultured sandstone sample (SUB), cultured shale sample (YCB), uncultured shale sample (YUB) were Enhydrobacter (71.62%), Acidovorax (42.44%), Pseudomonas (40.13%), Variovorax (70.02%), respectively. Both sample sources and culturing methods were the principal factors affecting the variation, while the communities' structures were favored primarily by culture-dependent or culture-independent approaches. The high abundance of hydrocarbon degradation-related genes was exhibited in YCB, which reveals a great potential for utilization of the culture-dependent method in shale oil exploitation. This study provided guidance for the exploitation of shale oil and sandstone oil by artificial utilization of indigenous bacteria.