Unraveling the difference in flavor characteristics of dry sausages inoculated with different autochthonous lactic acid bacteria

Exploring the regulation of metabolic changes mediated by different combined starter cultures on the characteristic flavor compounds and quality of Sichuan-style fermented sausages

Comprehensive 2D gas chromatography-mass spectrometry (GC × GC-MS) and non-targeted metabolomics were used in this study to systematically investigate the effects of various fermentation agent combinations on the quality characteristics of Sichuan-style fermented sausages. The results indicate that the inoculation of the combined starter culture significantly improves the sensory score and texture characteristics of Sichuan-style sausages, with the overall acceptability score increasing from 77.6 to 79.9-82.9. Furthermore, substantial improvements were observed in key texture parameters, particularly in hardness (increased from 9050.34 g to 10,625.40-16,633.95 g) and chewiness (elevated from 2231.33 g to 2327.23-4505.71 g). Additionally, it reduces both pH values (from 5.86 to 5.83-5.71) and moisture content (from 31.84 % to 31.72-28.99 %). The combined starter culture facilitates the degradation, transformation, and metabolism of proteins and lipids in the sausages, resulting in the production of more metabolites and volatile flavor compounds. In addition, the combined starter culture may promote the release of flavor substances in the sausage spices, thereby enhancing the overall flavor quality. Compared to the control group, the combined starter culture F, comprising Debaryomyces hansenii, Lactobacillus curvatus, Staphylococcus carnosus, and Staphylococcus vitulinus, significantly increased the levels of 60 volatile flavor substances, such as linalool, β-myrcene, and 3-methyl-1-butanol, in the sausages. The combined starter culture F enhanced the levels of 73 secondary metabolites, including beneficial amino acids, organic acids, fatty acids, and others, demonstrating its superior effectiveness in improving the quality characteristics of Sichuan-style fermented sausages.

Effect of pulsed electric field pretreatment synergistic mixed bacterial agent fermentation on the flavor and quality of air-dried goose meat and its molecular mechanism

In this study, the effect of pulsed electric field (PEF) pretreatment synergistic mixed bacterial agent (Lactiplantibacillus plantarum PDD-1 and Lactococcus lactis subsp. lactis JCM5805) fermentation on the flavor and quality of air-dried goose meat and its molecular mechanism were investigated. The results showed that PEF combined with the mixed bacteria fermentation increased activity of monoamine oxidase (232.57 U/mg protein), decreased TBARS (0.3 mg/kg) and TVB-N (15.75 mg/100 g) content, and the hardness and chewiness in air-dried goose. The improvement in flavor due to the synergistic fermentation following PEF pretreatment was primarily attributed to increased levels of aromatic compounds such as Heptanal (green, sweet), (Z)-3-Hexenyl acetate (green fruity), 3-(methylthio)-propanol (onion, bouillion-like note), alongside decreased levels of off-flavor compounds like methyl phenylacetate and 5-methyl-2-acetylfuran, as determined by the e-nose and GC-IMS. Colony counts and high-throughput sequencing demonstrated that Lactococcus and Staphylococcus predominated as the primary bacterial species, with different bioma onion, bouillion-like note rkers present in different air-dried goose groups. This is of strategic importance to develop the unique flavor and quality guarantee of air-dried goose.

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.

Characterization of Fusarium venenatum Mycoprotein-Based Harbin Red Sausages

Fusarium venenatum mycoprotein is an alternative, nutritious protein source with a meat-like texture. Here, F. venenatum mycoprotein-based Harbin red sausage was developed and characterized. The study focused on the effect of mycoprotein on the quality of red sausages, which were evaluated in five groups of red sausages based on nutrient content, differential scanning calorimetry (DSC), and gas chromatography-ion mobility spectrometry (GC-IMS). The results showed that increasing the component of mycoprotein in red sausage increased the protein and volatile organic compound content but decreased the water and ash content. There was no significant difference (p > 0.05) between red sausage with 25% added mycoprotein and traditional red sausage in terms of redness and thawed water component, but the protein component was higher, the flavor substances were slightly richer, and the consumer preference was higher. These results suggest that moderate amounts of mycoprotein can improve nutritional value and maintain sensory quality, but that higher levels of substitution can adversely affect preference. This study highlights the potential of mycoprotein as an artificial meat that can strike a balance between improved nutritional value and sensory acceptability.

Impact and correlation of fermentation temperature on the bacterial community, flavor characteristics, and proteolysis of Harbin dry sausages

Proteins undergo degradation to produce peptides and free amino acids, which in turn promote the production of volatile compounds with important contributions to the taste and aroma. This study investigated the effect of fermentation temperatures (8, 15, and 25 °C) on the bacterial community, flavor profile, and protein degradation of Harbin dry sausages. The physical and chemical properties were improved at 25 °C compared with 8 and 15 °C. Staphylococcus xylosus increased with the increase in fermentation temperature, whereas Latilactobacillus sakei decreased. The degree of protein degradation increased, and the content and proportion of taste peptides and free amino acids increased. Similarly, a higher fermentation temperature led to an increase in volatile compounds, such as aldehydes, alcohols, and esters. In conclusion, there is an inseparable relationship between proteolysis and microbial proteases. The fermentation temperature of 25 °C best contributed to the sensory quality and flavor characteristics of Harbin dry sausages.

Function-driven high-throughput screening and isolation of ester-producing strains for glutinous rice wine fermentation

Ester-producing strains are of great importance for enhancing the quality and flavor profiles of alcoholic beverages. However, traditional methods for screening ester-producing strains are labor-intensive and time-consuming, significantly impeding the development of alcoholic beverages industry. In this study, we selected five brands of Jiuqu to cultivate within different media, results showed that XB (Jiuqu) incubated with malt extract medium possessed the highest ester-producing capability, with the identification of 27 esters at the concentration of 31.44 ± 2.17 mM. Subsequently, fluorescence-activated cell sorting (FACS) was used to screen and isolate the living fungal cells which accounted for 42.80 % of total cells, followed by cultivation utilizing a culturomics approach. High-throughput screening (HTS) assays using 4-Methylumbelliferyl acetate (4-MA) were utilized to evaluate the ester-production potentials of 960 selected strains. The top10 highest ester-producing strains were sequenced, and all were identified as Saccharomyces cerevisiae, Cyberlindnera fabianii, and Wickerhamomyces anomalus. Eventually, three microbial strains were co-incubated with rice wine starter to improve the nutritional and flavor properties of glutinous rice wine. Compared to the control group, Cyberlindnera fabianii could increase reducing sugar content, up to 0.33 ± 0.01 g/mL, and significantly decrease the concentration of bitter amino acids by 55.83 %, resulting in a final concentration of 32.29 ± 1.51 mg/L. Furthermore, the glutinous rice wine with Cyberlindnera fabianii showed 38 distinct ester compounds at the content of 16.22 ± 0.51 mM, which was superior to the control group (30 ester compounds at the concentration of 11.89 ± 1.39 mM). The diversity and concentrations of flavor components, such as alcohols, aldehydes, and ketones, were also enhanced. Our findings would contribute to advancing the rapid screening of ester-producing strains, as well as providing a theoretical basis for improving the quality of glutinous rice wine.

Coinoculation of autochthonous starter cultures: A strategy to improve the flavor characteristics and inhibit biogenic amines of Harbin dry sausage

The effects of separately coinoculating Lactiplantibacillus plantarum S8 (LP) with Staphylococcus carnosus L8 (LP + SC), Pichia kudriavzevii M6 (LP + PK), and S. carnosus L8 and P. kudriavzevii M6 (LP + SC + PK) on the flavor characteristics and biogenic amines (BAs) production in Harbin dry sausages were investigated. The coinoculated sausages exhibited higher free amino acids (FAAs) content than the noninoculated and LP sausages. Moreover, inoculated dry sausages exhibited lower BA contents (174.45, 239.43, 190.24, and 206.7 mg/kg for the LP, LP + SC, LP + PK, and LP + PK + SC sausages, respectively) than the noninoculated sausage (339.73 mg/kg). Meanwhile, the LP + PK and LP + SC + PK sausages had the highest contents of esters (996.70 μg/kg) and alcohols (603.46 μg/kg), respectively. A sensory evaluation demonstrated that the LP + SC + PK sausage had the highest fermented odor and the lowest fatty odor. Pearson correlation analysis revealed that FAAs were correlated with most key volatile compounds and BAs. This study provides new insights into flavor development and BA inhibition in dry sausages through coinoculation.

Effects of different mixed starter cultures on microbial communities, taste and aroma compounds of traditional Chinese fermented sausages

The aim of this study was to investigate and compare the effects of different mixed starter cultures (Lactiplantibacillus plantarum and Staphylococcus simulans) on the bacterial communities and flavor of fermented sausages. The results indicated that native starters grew well in fermented sausages and became dominant at the end of ripening. Among them, Lactobacillus spp. had the highest relative abundance, followed by Staphylococcus spp. In addition, the inoculation of the mixed starters promoted the formation of taste and aroma compounds that contribute to the overall flavor of the fermented sausages. Among them, the L. plantarum CQ01107 + S. simulans CD207 (CCA) treatment was found to have the highest umami amino acid, nucleotide, lactic acid, fatty acid and ketone contents (P < 0.05), as well as excellent sensory properties. In conclusion, the CCA starter may be a desirable starter culture to enhance the flavor of fermented sausages.

The Contribution of Microorganisms to the Quality and Flavor Formation of Chinese Traditional Fermented Meat and Fish Products

Guizhou sour meat and sour fish, Chaoshan fish sauce, Sichuan sausage and bacon, Cantonese sausage, Jinhua ham, and Xinjiang air-dried beef are eight representatives of Chinese traditional fermented meat and fish products (FMFPs), which are favored by Chinese consumers due to their high nutritional value and quality. The quality of the spontaneously fermented Chinese traditional FMFP is closely correlated with microorganisms. Moreover, the dominant microorganisms are significantly different due to regional differences. The effects of microorganisms on the texture, color, flavor, nutrition, functional properties, and safety of Chinese traditional FMFPs have not been not fully described. Additionally, metabolic pathways for flavor formation of Chinese traditional FMFPs have not well been summarized. This article describes the seven characteristic Chinese traditional FMFPs and correlated dominant microorganisms in different regions of China. The effects of microorganisms on the texture, color, and flavor of Chinese traditional FMFPs are discussed. Furthermore, the metabolic pathways of microbial regulation of flavor formation in Chinese traditional FMFPs are proposed. This work provides a theoretical basis for improvement of Chinese traditional FMFPs by inoculating functional microorganisms isolated from Chinese traditional fermented foods.

Enhancement of fermented sausage quality driven by mixed starter cultures: Elucidating the perspective of flavor profile and microbial communities

The metabolic activities of microorganisms play a crucial role in the quality development of fermented sausage. This study investigated the effect of inoculation with different combinations of starter cultures (Lactiplantibacillus plantarum YR07, Latilactobacillus sakei L.48, Staphylococcus xylosus S.14, and Mammaliicoccus sciuri S.18) on the quality of sausages. Inoculation with mixed starter cultures promoted protein degradation to generate amino acids and the conversion to volatile compounds, which enhanced the flavor development in fermented sausages. The bacterial community analyses demonstrated that the inoculation of mixed starter cultures could inhibit the growth of spoilage and pathogenic bacteria, thereby reducing the total content of biogenic amines. The correlation analysis between the core bacteria and characteristic volatile compounds revealed that fermented sausages inoculated with Lactobacillus and coagulase negative staphylococci exhibited significant positive correlations with the majority of key characteristic volatile compounds. In four treatments, inoculation with L. plantarum YR07 and M. sciuri S.18 greatly promoted the formation of characteristic volatile compounds (3-hydroxy-2-butanone, hexanal, and 1- octen-3ol). Therefore, the combined inoculation of L. plantarum YR07 and M. sciuri S.18 is promising to enhance fermented sausage's flavor profile and safety.

Autochthonous Cultures to Improve Safety and Standardize Quality of Traditional Dry Fermented Meats

Traditional dry fermented meat products are obtained artisanally in many countries, where they represent a gastronomic heritage well distinguished from industrial counterparts. This food category is most often obtained from red meat, a food commodity that is under attack because of evidence of increased risk of cancer and degenerative diseases with high consumption. However, traditional fermented meat products are intended for moderate consumption and gastronomic experience, and, as such, their production must be continued, which would also help safeguard the culture and economy of the geographical areas of origin. In this review, the main risks attributed to these products are considered, and how these risks are reduced by the application of autochthonous microbial cultures is highlighted by reviewing studies reporting the effects of autochthonous lactic acid bacteria (LAB), coagulase negative staphylococci (CNS), Debaryomyces hansenii and Penicillium nalgiovense on microbiological and chemical safety and on sensory attributes. The role of dry fermented sausages as a source of microorganisms that can be beneficial to the host is also considered. From the results of the studies reviewed here it appears that the development of autochthonous cultures for these foods can ensure safety and stabilize sensory characteristics and has the capacity to be extended to a larger variety of traditional products.

Non-gene-editing microbiome engineering of spontaneous food fermentation microbiota-Limitation control, design control, and integration

Non-gene-editing microbiome engineering (NgeME) is the rational design and control of natural microbial consortia to perform desired functions. Traditional NgeME approaches use selected environmental variables to force natural microbial consortia to perform the desired functions. Spontaneous food fermentation, the oldest kind of traditional NgeME, transforms foods into various fermented products using natural microbial networks. In traditional NgeME, spontaneous food fermentation microbiotas (SFFMs) are typically formed and controlled manually by the establishment of limiting factors in small batches with little mechanization. However, limitation control generally leads to trade-offs between efficiency and the quality of fermentation. Modern NgeME approaches based on synthetic microbial ecology have been developed using designed microbial communities to explore assembly mechanisms and target functional enhancement of SFFMs. This has greatly improved our understanding of microbiota control, but such approaches still have shortcomings compared to traditional NgeME. Here, we comprehensively describe research on mechanisms and control strategies for SFFMs based on traditional and modern NgeME. We discuss the ecological and engineering principles of the two approaches to enhance the understanding of how best to control SFFM. We also review recent applied and theoretical research on modern NgeME and propose an integrated in vitro synthetic microbiota model to bridge gaps between limitation control and design control for SFFM.

Changes in the Sensory Odor Profile during Chorizo Maturation and Their Relationship with Volatile Compound Patterns by Partial Least Square Regression (PLS)

Odor is one of the most important attributes to determine the overall acceptance of a product. The aim of this investigation is to evaluate the changes in the odor profile and the volatile compounds during thirty-three days of ripening to obtain the pattern of volatile compounds necessary to integrate the odor profile of chorizo (fermented sausage), using Partial Least Squares (PLS). The chili and pork meat odors were predominant during the first five days, vinegar and fermented odors at days twelve and nineteen days, and finally a rancid odor predominated at the end. Only the vinegar, rancid, and fermented odors could be predicted with a good fit model, with the R² coefficient above 0.5, using linear PLS, and the pork meat odor using logarithmic PLS. Each group of volatile compounds interacted in different ways; esters had a positive influence on the vinegar and rancid odors, but a negative on the fermented odor. Some volatile compounds contributed to more than one odor, such as hexanal, ethanol, and ethyl octanoate. This work allowed us to understand the pattern of volatile compounds required to generate some of the specific odors of chorizo; further studies are required to explore the effect of other food components on these patterns of odors.

Effects of sorbitol-mediated curing on the physicochemical properties and bacterial community composition of loin ham during fermentation and ripening stages

In this study, the impacts of loin ham with sorbitol-mediated curing on its physicochemical properties and bacterial community composition during fermentation and ripening were investigated. The salt content, pH, and water activity (a_w) were lower in the sorbitol group than in the control group throughout the fermentation and ripening stages (P < 0.05). In addition, the L* values were higher in the sorbitol group (P < 0.05). Additionally, microbial diversity diminished in all groups as the fermentation and ripening process proceeded, with Lactobacillus turning into the dominant genus in the control group and Staphylococcus and Lactobacillus becoming dominant in the sorbitol group. Pearson's correlation analysis confirmed that the physicochemical properties have been significantly correlated with the bacterial community. In conclusion, sorbitol-mediated curing not only facilitates salt reduction while prolonging the storage period of loin ham, but also improves the distribution of bacterial community in loin ham and enhances its quality.