Traditional Fermented Product Research Articles

Odorants Identified in Chinese Dry-Cured Ham Contribute to Salty Taste Enhancement.

Jinhua dry-cured ham (JDH) is a traditional fermented Chinese meat product. We studied the dynamic sensory and emotional profiles of JDHs obtained by five preparation methods and the corresponding release of sodium ions (Na+), potassium ions (K+), and volatile organic compounds (VOCs) during oral processing. The VOCs with salty taste enhancement abilities were screened based on the correlations of VOCs with salty flavor and concentration of Na and K ions with salty flavor. A trained sensory panel evaluated the saltiness enhancements of selected VOCs by using static and dynamic sensory methods. The results revealed that Na+, K+, and selected VOCs were mainly released during 0-10 s of the chewing process. The release of Na+ and K+ in JDH residue samples exhibited consistently decreasing trends, while in saliva, their concentrations increased. The VOCs showing a high correlation with Na+ and K+ and salty flavor have saltiness enhancement abilities in both NaCl solutions and NaCl + MSG mixtures. Odor-induced saltiness was pronounced at low salt concentrations (0.2% NaCl). The investigation demonstrated 16 VOCs exhibiting saltiness enhancement abilities, including 4 pyrazines, 5 acids, 4 sulfur-containing compounds, and 3 other compounds. The sensory evaluation suggested pyrazines and sulfur-containing compounds as good saltiness enhancers. 2-Furfuryl mercaptan significantly enhanced the salty sensation in the NaCl + MSG solutions when compared with MSG alone (p < 0.05). This research provides evidence that certain odorants identified in JDHs exhibit salty-enhancing properties, indicating their potential for salt reduction at the industrial level.

Effect of Capsaicin Stress on Aroma-Producing Properties of Lactobacillus plantarum CL-01 Based on E-Nose and GC-IMS.

Capsaicin stress, along with salt stress, could be considered the main stressors for lactic acid bacteria in traditional fermented pepper products. Until now, insufficient attention has been paid to salt stress, while the effect of capsaicin on the aroma-producing properties of Lactobacillus plantarum (L. plantarum) is unclear. The present study attempted to illustrate the effect of capsaicin stress on the aroma-producing properties of L. plantarum CL-01 isolated from traditionally fermented peppers based on E-nose and GC-IMS. The results showed that E-nose could clearly distinguish the overall flavor differences of L. plantarum CL-01 under capsaicin stress. A total of 48 volatile compounds (VOCs) were characterized by means of GC-IMS, and the main VOCs belonged to acids and alcohols. Capsaicin stress significantly promoted L. plantarum CL-01 to produce alpha-pinene, ethyl crotonate, isobutyric acid, trans-2-pentenal, 2-methyl-1-butanol, 3-methyl-3-buten-1-ol, 1-penten-3-one, 2-pentanone, 3-methyl-1-butanol-D, and 2-heptanone (p < 0.05). In addition, under capsaicin stress, the contents of 1-penten-3-one, 3-methyl-3-buten-1-ol, 5-methylfurfuryl alcohol, isobutanol, 2-furanmethanethiol, 2,2,4,6,6-pentamethylheptane, 1-propanethiol, diethyl malonate, acetic acid, beta-myrcene, 2-pentanone, ethyl acetate, trans-2-pentenal, 2-methylbutyl acetate, and 2-heptanone produced by L. plantarum CL-01 were significantly increased along with the fermentation time (p < 0.05). Furthermore, some significant correlations were observed between the response values of specific E-nose sensors and effective VOCs.

Metagenomic Insights into the Taxonomic and Functional Features of Traditional Fermented Milk Products from Russia.

Fermented milk products (FMPs) contain probiotics that are live bacteria considered to be beneficial to human health due to the production of various bioactive molecules. In this study, nine artisanal FMPs (kefir, ayran, khurunga, shubat, two cottage cheeses, bryndza, khuruud and suluguni-like cheese) from different regions of Russia were characterized using metagenomics. A metagenomic sequencing of ayran, khurunga, shubat, khuruud and suluguni-like cheese was performed for the first time. The taxonomic profiling of metagenomic reads revealed that Lactococcus species, such as Lc. lactis and Lc. cremoris prevailed in khuruud, bryndza, one sample of cottage cheese and khurunga. The latter one together with suluguni-like cheese microbiome was dominated by bacteria, affiliated to Lactobacillus helveticus (32-35%). In addition, a high proportion of sequences belonging to the genera Lactobacillus, Lactococcus and Streptococcus but not classified at the species level were found in the suluguni-like cheese. Lactobacillus delbrueckii, as well as Streptococcus thermophilus constituted the majority in another cottage cheese, kefir and ayran metagenomes. The microbiome of shubat, produced from camel's milk, was significantly distinctive, and Lentilactobacillus kefiri, Lactobacillus kefiranofaciens and Bifidobacterium mongoliense represented the dominant components (42, 7.4 and 5.6%, respectively). In total, 78 metagenome-assembled genomes with a completeness ≥ 50.2% and a contamination ≤ 8.5% were recovered: 61 genomes were assigned to the Enterococcaceae, Lactobacillaceae and Streptococcaceae families (the Lactobacillales order within Firmicutes), 4 to Bifidobacteriaceae (the Actinobacteriota phylum) and 2 to Acetobacteraceae (the Proteobacteria phylum). A metagenomic analysis revealed numerous genes, from 161 to 1301 in different products, encoding glycoside hydrolases and glycosyltransferases predicted to participate in lactose, alpha-glucans and peptidoglycan hydrolysis as well as exopolysaccharides synthesis. A large number of secondary metabolite biosynthetic gene clusters, such as lanthipeptides, unclassified bacteriocins, nonribosomal peptides and polyketide synthases were also detected. Finally, the genes involved in the synthesis of bioactive compounds like β-lactones, terpenes and furans, nontypical for fermented milk products, were also found. The metagenomes of kefir, ayran and shubat was shown to contain either no or a very low count of antibiotic resistance genes. Altogether, our results show that traditional indigenous fermented products are a promising source of novel probiotic bacteria with beneficial properties for medical and food industries.

Nutraceutical potential of traditional fermented soybean (Hawaijar)

Fermentation not only reduces the toxins but also it is an excellent processing method for improving nutritional and functional properties of soybean due to the increased content of small bioactive compounds. The NEH region of India also has similar traditional fermented soy products. ACE inhibitory activity was found to increase during fermentation and exhibited higher ACE inhibition percent in starter culture strain (H) than starter culture strain (S) of both the soybean used (local small variety and JS-335). Fermentation of soybean with different micro-organisms improve the bio-functional properties due to the increase in free isoflavones and peptides.

Comparative analysis of the effect of fermented derivatives from Bactrian milk on the gut microbiome

Background:The gut microbiome plays a vital role in maintaining intestinal homeostasis, and its modulation through dietary interventions has garnered considerable interest in improving human health. In this study, we investigated the effect of traditional Kazakh fermented milk products derived from camel milk on the gut microbiome of rats. Objective:The animals were divided into three groups: the Bactrian milk group (BCM), the camel yogurt group (CMY), and the camel cheese group (CMC). Results:After 4 weeks of intervention, the relative abundance of bacterial taxa varied significantly in the BCM and Bactrian milk derivative groups. The CMY group demonstrated a 2-fold increase in the relative abundance of the genus Ligilactobacillus (p=0.032), whereas the CMC group showed a 3-fold decrease (p=0.009). Prevotella_9 exhibited an inverse abundance vector in the CMY (p=0.0005) and CMC (p=0.0001) groups compared to the BCM group. Additionally, 53 metabolic pathways were predicted, each showing varying relative abundances in response to dietary interventions. Notably, the metabolic pathways associated with amines, polyamines, cell structure, fatty acids, and nucleoside and nucleotide biosynthesis underwent the greatest changes. Conclusion:Consumption of camel milk yogurt led to an increase in biodiversity and abundance in the gut microbiota (p&lt;0.01), as evidenced by Shannon and Simpson's indices. In summary, our study demonstrates that fermented camel milk products significantly influence the gut microbiome and metabolic pathways.Keywords: Bactrian camel milk, gut microbiota, rats, yogurt, soft cheese

Variations of volatile flavors and microbial communities in Chinese Chaozhou pickle during natural fermentation revealed by GC-IMS and high-throughput sequencing

Chaozhou pickle, a traditional Chinese fermented vegetable product, is highly regarded among consumers due to its unique flavor. This work monitored the flavor substances and microbial communities of Chaozhou pickles during fermentation by gas chromatography-ion mobility spectrometry (GC-IMS) and high-throughput sequencing. A total of 70 volatile compounds were identified from Chaozhou pickles. In addition to fruit aroma esters, the pickles also contain aldehydes, ketones, alcohols, acids, and heterocyclic compounds. The four pickles exhibited a prevalence of Cyanobacteria, Proteobacteria, and Firmicutes as the leading bacterial phyla, while Weissella, Leuconostoc, and Lactobacillus were identified as the predominant bacterial genera. Physiochemical quality and acid properties of Chaozhou pickle were also investigated. Results revealed a significant reduction in hardness, chewiness and pH during fermentation, as well as a notable increase in free amino acids, and organic acid levels. These results could contribute to a greater comprehension of the role of microorganisms in flavor formation during fermentation and provide a scientific foundation for the industrialization of Chaozhou pickle.

Draft genome sequence of Lactococcus lactis subsp. lactis RTIII518: a potent dairy starter isolated from traditional lait caillé in Burkina Faso.

Lactococcus lactis subsp. lactis RTIII518 was isolated from lait caillé, a traditional fermented milk product from Burkina Faso. The draft genome size is 25,554,260 base pairs with 76 contigs, 34.26% average content of GC, 50 tRNAs, 4 rRNA, and 2,498 coding genes.

Chromatin regulator Eaf3p regulates nitrogen metabolism in Saccharomyces cerevisiae as a trans-acting factor.

In this study, the mechanism of chromatin regulator Eaf3p regulating nitrogen metabolism in S. cerevisiae was investigated. It provides theoretical support for epigenetic modifications of cells to alter the level of histone modifications, coordinate the expression of multiple genes, and make it more conducive to the co-metabolism of multiple nitrogen sources. Moreover, it provides new ideas for industrial brewing yeast strains to achieve nitrogen source metabolism balance, reduce the accumulation of harmful nitrogen metabolites, and improve fermentation efficiency. This study provides a reference for changing the performance of microbial strains and improving the quality of traditional fermentation products and provides a theoretical basis for studying epigenetic modification and nitrogen metabolism regulation. It has an important theoretical explanation and practical application value. In addition, this study also provides useful clues for the study.

Screening of protease-producing lactic acid bacteria from Indonesian fermented fish products and its application in chitin extraction from vannamei shrimp (Litopenaeus vannamei) shell

This study aimed to screen lactic acid bacteria (LAB) from traditional Indonesian fermented fish products, namely wadi and jambal, with high protease activity for chitin production from Litopenaeus vannamei shrimp shells. Twenty-eight colonies were successfully isolated and identified through biochemical tests such as catalase and Gram staining. Seven out of the twenty-eight colonies were identified as lactic acid bacteria based on their Gram-positive and catalase-negative results. These strains from wadi samples were named GWB 1.3, GWB 1.7, and GWB 2.5, while those from jambal samples were named GMJB 1.3, GMJB 1.6, GMJB 2.6, and GMJB 2.7. The protease activity of these strains was tested using the well-diffusion method on skim milk agar to assess their deproteinized activity. The diameter of the clear zone formed after 24, 48, and 72 hours of incubation was measured. GWB 1.7 and GMJB 2.6 showed the largest clear zone diameter with 21.3 mm and 22.5 mm, respectively, and were selected for the single step-fermentation of shrimp shells. The fermentation process was conducted in 6 days with different inoculum ranging from 0%, 5%, 10%, 15%, and 20% (v/v) as treatments. All treatments, including moisture, ash, and protein, were evaluated for proximate content in the final days. The results indicate that the 20% inoculum showed the highest deproteinization and demineralization for both bacterial strains. GWB 1.7 exhibited a demineralization of 43.7% and deproteinization of 25.2%, while GMJB 2.6 showed a demineralization of 39% and deproteinization of 16.1%. This study demonstrated that lactic acid bacteria from wadi and jambal samples could produce chitin from shrimp shells, a valuable biopolymer with various applications.

Modelling the Survival of Acid-Adapted and Nonadapted Escherichia coli O157:H7 in Burkina: A Western African Traditional Fermented Milk Product.

Burkina, a traditional fermented dairy product, is consumed in most parts of West Africa, including Ghana. Studies on the microflora of Burkina have indicated the presence of Escherichia coli and other pathogenic organisms. Thus, predicting the survival of E. coli in the product will inform the best manufacturing and handling practices. This study investigated the combined effect of storage temperature and time on the survival of acid-adapted and acid-non-adapted E. coli O157:H7 in Burkina. Samples were pasteurised and inoculated with acid-adapted or acid-non-adapted E. coli O157:H7. They were stored at 5, 15, and 30°C for 0, 2, 4, 6, 8, 10, 12, 14, 18, and 48 h, and the bacteria colonies were enumerated. Growth rate (survival versus time) models were developed using MATLAB software. Observed data were fitted to the Baranyi model using the DMFit curve fitting software. The E. coli O157:H7 strain appeared inherently tolerant to acid, with storage time having the most significant effect on the response parameter, survival (log CFU/mL). A negative correlation was observed for the primary models (survival versus time), which accounted for 79-97% of the relationship (p < 0.05). Although E. coli survived, its growth was inhibited over time regardless of acid adaptation.

Ethnopharmacology of Assamese Fermented Foods: Traditional Wisdom, Therapeutic Potential, and Evolutionary Insights

The migration patterns of humans from various regions over extended periods form the ancestors of the present-day ethnic communities in Assam, a region located in Northeast India. Throughout the process of assimilation, the people of this area developed the skill of fermenting different types of perishable and inedible raw agricultural products into tasty, preserved, and superior foods and drinks pleasing to the senses. Fermented foods have played a crucial role in the cultural and dietary practices of diverse ethnic communities worldwide since ancient times. Particularly in developing countries, their inclusion holds significant importance as it provides a cost-effective method of preserving food while enhancing its nutritional and sensory attributes. The native population of Northeast India, particularly in Assam, has a long-standing tradition of preparing and consuming various smoked, sun-dried, fermented, and salted fish products. This practice, which originated from the astute observations of our ancestors, has resulted in a wide range of fermented food items and beverages that are unique to this region. Among these, Judima, Rice beer, Apong, Jou, Sujen, Khorisa, Kahudi, Napham, Kharoli, Xaj-pani, Chokot, Shidol, and traditional fermented fish products like karati, bordia, and lashim hold significant prominence. These ethnic fermented foods not only influence the local healthcare system but also possess potential therapeutic benefits for disease prevention and managing physiological disorders. The phytochemical constituents present in these fermented foods, individually or in combination, exhibit noteworthy therapeutic potential. The objective of this review is to provide an in-depth understanding of the diverse range of ethnic fermented foods in Northeast India, specifically Assam, their impact on health, and the evolutionary development of their preparation techniques.

Characterization and identification of Lactobacillus rhamnosus and Enterococcus durans as probiotic potential isolated from selected dairy products in Egypt

AbstractProbiotics are living microbes that promote consumer health when taken in significant quantities with food. The aim of this research was identifying the probiotic properties (in vitro) of lactic acid bacteria (LAB) isolated from traditional fermented dairy products from Egypt (Kareish cheese, Rayeb milk, local yoghurt and buttermilk). Only 13 isolates were characterizes as Gram-positive, endospore-negative, non-motile and catalase-negative with small round colonies. All 13 isolates were examined for its probiotic properties (antibacterial activity, antibiotic susceptibility, acidity and bile salt tolerance). All isolates showed antimicrobial effect against bacterial pathogens tested. LAB-6 had a significantly larger inhibition zone followed by LAB-2 and LAB-3. Moreover, LAB-6 was the most resistant to all antibiotics tested. Seven of thirteen isolates were Penicillin-resistant. Only LAB-3 exhibited strong chlorophenicol resistance. The isolates that affect pathogens and resistant to antibiotics were found acid-and-bile salt-tolerant in varying degrees. All bile and acid tolerant isolates revealed variable antibiotic sensitivity. Regarding to previous results, only three selected isolates (LAB-2, LAB-3, and LAB-6) had their 16SrRNA gene sequences compared to Gene-Bank. Isolate LAB-2 was found in the genus Lactobacillus, with 98.7% similarity to L. rhamnosus OP268116 strain GCM20300. LAB-3 was Lactobacillus, with 98.9% similarity to L. rhamnosus OP268117 strain 6481. Comparative genomic research demonstrated very minimal changes between isolate LAB-6 and Enterococcus durans OP268118 strain CAU5334. Thus, these isolates could be used as food biopreservatives, starter cultures in the fermented dairy products and cheese industry, or novel strategies to combat the rising number of antibiotic-resistant pathogens in human infections.

Microbial community succession and its correlation with the dynamics of flavor compound profiles in naturally fermented stinky sufu.

Wuhan stinky sufu is a traditional fermented soybean product with a short ripening period and unique flavor. The aim of this study was to explore the characteristic flavor compounds and core functional microbiota of naturally fermented Wuhan stinky sufu. The results indicated that 11 volatile compounds including guaiacol, 2-pentylfuran, dimethyl trisulfide, dimethyl disulfide, acetoin, 1-octen-3-ol, (2E)-2-nonenal, indole, propyl 2-methylbutyrate, ethyl 4-methylvalerate, nonanal were characteristic aroma compounds, and 6 free amino acids (Ser, Lys, Arg, Glu, Met and Pro) were identified as taste-contributing compounds. 4 fungal genera (Kodamaea, unclassified_Dipodascaceae, Geotrichum, Trichosporon), and 9 bacterial genera (Lysinibacillus, Enterococcus, Acidipropionibacterium, Bifidobacterium, Corynebacterium, Lactococcus, Pseudomonas, Enterobacter, and Acinetobacter) were identified as the core functional microbiota with positive effects on the production of flavor compounds. These findings would enhance the understanding of core flavor-producing microorganisms in naturally fermented soybean products and potentially provide guidance for enhancing the quality of sufu.

Multi-omics analysis of microbial communities and metabolites during the fermentation of traditional Midu Juanti

The current study employed a combination of high-throughput sequencing and non-targeted metabolomics techniques to elucidate the changes in the quality, microbial communities, and metabolites throughout the fermentation process of traditional Midu Juanti, a traditional fermented meat product that originates from ethnic minority regions in southwestern China. The findings show that 22 dominant genera (7 bacterial and 15 fungal genera), with a relative abundance >1%, were successfully identified during the fermentation of Midu Juanti. Additionally, 979 metabolites were identified using the Human Metabolome Database (HMDB) annotation. Among these, lipids and lipid-like molecules constituted the largest proportion, followed by organic acids and their derivatives. Moreover, based on the variable importance in the projection (VIP) > 2 and P < 0.05, 60 differentially changed metabolites (DCMs) were identified. Meanwhile, the presence of Lactobacillus was positively correlated with 54 DCMs (P < 0.05, |r| > 0.5), including tryptophyl-threonine and (5R)-5-hydroxyhexanoic acid. Conversely, a negative correlation was observed between the presence of Monascus and these 54 DCMs (P < 0.05, |r| > 0.5). This study has the potential to enhance the processing theory of fermented meat products and establish a solid theoretical foundation for the control and enhancement of the quality of Midu Juanti.

Nutritional ingredients and prevention of chronic diseases by fermented koumiss: a comprehensive review.

Koumiss, a traditional fermented dairy product made from fresh mare milk, is a sour beverage that contains an abundance of microbial communities, including lactic acid bacteria, yeast and others. Firstly, probiotics such as Lacticaseibacillus in koumiss can induce the secretion of immunoglobulin G in serum and interleukin-2 in the spleen while beneficial Saccharomyces can secrete antibacterial compounds such as citric acid and ascorbic acid for specific immunopotentiation. Additionally, more isoflavone in koumiss can regulate estrogen levels by binding to its receptors to prevent breast cancer directly. Bile salts can be converted into bile acids such as taurine or glycine by lactic acid bacteria to lower cholesterol levels in vivo. Butyric acid secretion would be increased to improve chronic gastrotis by regulating intestinal flora with lactic acid bacteria. Finally, SCFA and lCFA produced by Lacticaseibacillus inhibit the reproduction of pathogenic microorganisms for diarrhea prevention. Therefore, exploring the mechanisms underlying multiple physiological functions through utilizing microbial resources in koumiss represents promising avenues for ameliorating chronic diseases.

Relationship between microorganisms and volatile components in each fermentation process in the kusaya gravy that plays an important role in the manufacturing of kusaya, a traditional Japanese fermented fish product.

The relationship between the microbiota and volatile components of kusaya gravy involved in the manufacturing of kusaya, a traditional Japanese fermented fish product, in the Izu Islands (Niijima and Hachijojima) and the fermentation processes are not clear. In this study, we aimed to investigate the relationship between the microbiota and volatile compounds involved in the manufacturing and management of kusaya gravy. 16S ribosomal RNA (rRNA) gene-based amplicon sequencing revealed that the microbiota in kusaya gravy was significantly different between the two islands, and the microbiota hardly changed during each fermentation process. Gas chromatography-mass spectrometry analysis also revealed that the volatile components were strongly related to the microbiota in kusaya gravy, with Hachijojima samples containing sulfur-containing compounds and Niijima samples containing short-chain fatty acids. Therefore, our findings suggest that kusaya gravy is a characteristic fermented gravy with a stable microbiota, and the fermented pickling gravy is fermented by microorganisms.

Sensory characteristics and consumer acceptability of four variants of mabisi, a traditionally fermented Zambian dairy product

Consumer acceptability of four variants of mabisi, a traditional fermented Zambian dairy product, was determined as a first step towards identifying directions for improving and stabilizing consumer-oriented product quality. The four mabisi variants differed in their production methods and associated sensory properties. The variants were tonga, backslopping, barotse and illa mabisi, characterized by undisturbed fermentation, using part of a previous batch, removing whey followed by the addition of fresh milk and vigorous shaking, respectively. Sixteen panelists generated and evaluated the intensity of ten descriptive sensory terms while 268 consumers rated their preferences for overall liking and five other hedonic attributes. Significant differences (p < 0.05) were observed between the four variants for all sensory attributes except fermented odor. The products were distinguished by the textural attributes of thickness, smoothness, and creaminess. A multifactor analysis further demonstrated that textural attributes were the drivers of mabisi liking. When clustered according to overall liking, consumers were segmented into 3 clusters namely with a barotse-tonga preference (n = 94), absolute barotse preference (n = 84), and backslopping-illa-tonga preference (n = 90). Overall, our findings show that barotse and tonga mabisi were more appealing to larger consumer segments, warranting further research into the optimization of product quality.

Kajian Produksi Dan Analisis Mutu Pangan Tradisional Sere Kedele Di Kabupaten Klungkung, Bali

&#x0D; &#x0D; &#x0D; Sere kedele is a traditional fermented soybean product. This type of food is processed by home industries, especially in Klungkung Regency and several areas in Gianyar. This research was conducted to obtain information related to the traditional production process and analysis of the quality of sere kedele, especially in the Klungkung Regency, Bali. This research carried out in two stages, namely a survei to determine the production process, raw/additional materials used, presentation method, production area, and distribution of sere kedele in Klungkung Regency. The second stage is to analyze the chemical properties of traditional sere kedele food in Klungkung Regency. The survei results show that there are five producers of sere kedele in the villages of Tusan, Tihingan, Galiran, Tojan, Akah and Besang. The processing of sere kedele is different for each producer, such as the length of boiling, the length of fermentation, and the stage of adding seasonings. The samples used in this study is raw sere kedele and fried sere kedele. Sere kedele mentah in Klungkung Regency contains water content 56.85%-60.85%, ash content 1.21%-1.34%, protein content 14.68%-22.04%, fat content 5.69%-9.62%, and carbohydrate content of 13.64%-15.16%. Meanwhile, fried soybean sere has a water content of 1.42%-4.46%, an ash content of 1.45%-1.83%, a protein content of 13.45%-30.65%, fat content of 36.14%-42,1%, and carbohydrate content is 26.78% -41.49%.&#x0D; Keywords: sere kedele, Klungkung, fermentation, traditional food&#x0D; &#x0D; &#x0D;

Selection of yeast strains in naturally fermented cured meat as promising starter cultures for fermented cured beef, a traditional fermented meat product of northern China.

Fermented meat products are meat products with a unique flavor, color, and texture as well as an extended shelf life under natural or artificially controlled conditions. Microorganisms or enzymes are used to ferment the raw meat so that it undergoes a series of biochemical and physical changes. Common fermentation strains are lactic acid bacteria, yeasts, staphylococci, molds, and so forth. Studies on the inhibitory effect of yeast fermentation strain on N-nitrosamines in fermented meat products have not been reported. Two excellent yeast starters were identified to solve the problem of nitrosamines in fermented meat products. Meyerozyma guilliermondii and Debaryomyces hansenii led to weak acid production, strong resistance to NaCl and NaNO2 , and high tolerance to low acidic conditions. The inoculated fermented beef exhibited decreased lightness, moisture content, water activity, pH, protein content, nitrite content, and N-nitrosamine content in comparison with the control group fermented bacon. M. guilliermondii had a better effect, reducing pH from 5.69 to 5.41, protein content from 254.24 to 221.92 g·kg-1 , nitrite content from 28.61 to 25.33 mg·kg-1 and N-nitrosamine by 18.97%, and giving the fermented beef the desired meat color, mouthfeel, odor, taste, and tissue quality. In this study, two strains of yeast fermenters that can degrade N-nitrosamine precursors were identified, which to some extent solves the problem of the high risk of generating nitrosamines such as N-nitrosodiethylamine (NDEA) by processing fermented meat products with nitrites as precursors. These two strains are likely to be used as starter cultures for fermented meat products. © 2023 Society of Chemical Industry.

Improvement of the quality of cured rabbit meat product (Chan Si Tu) using Staphylococcus xylosus as starter culture

Starter cultures can help improve the quality and safety of traditional fermented meat products. This work was conducted to evaluate the effects of the inoculum of Staphylococcus xylosus on the quality characteristics of a Sichuan cured rabbit product (Chan Si Tu). Physicochemical analyses showed that meats inoculated with S. xylosus had a significant increase in lightness, redness, cohesiveness and chewiness (P&lt;0.05). In addition, a lower content of nitrite, diethylnitrosamine and histamine, was observed in the inoculated samples (P&lt;0.05). The thiobarbituric acid reactive substances (TBARS) value in the S. xylosus incubation group was 0.108±0.004 mg/kg, which was significantly lower than that in the control group (P&lt;0.01). Interestingly, a lower TBARS value was observed in the incubation samples through storage. Furthermore, solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC-MS) analysis identified a total of 73 volatiles, and the species and abundance of theses volatile compounds were higher in the samples with added S. xylosus, and 12 with odour activity value&gt;1 were proposed as the most odouractive compounds that enhanced the complexity of the product. Thus, inoculation with S. xylosus in the cured rabbit meat product (Chan Si Tu) can effectively enhance the product quality.