Sakei Research Articles

Effect of Inulin Addition on Physicochemical, Microbiological, Textural, and Sensorial Characteristics of Fermented Butifarra with Lactobacillus sakei

Butifarra, with the addition of inulin, was produced for the first time. The objective of this study was to investigate the effect of inulin in butifarra fermented with Lactobacillus sakei ATCC® 15521™ on physicochemical properties, instrumental texture, microbiology, and sensory evaluation. Initially, fermented butifarra was prepared with the addition of 5% and 7.5% inulin and a control butifarra was prepared without inulin addition. The butifarra was analyzed by physicochemical, microbiological, instrumental texture, and sensory evaluation. The results indicated that the analysis of physicochemical properties, fat, protein, and ash content showed no significant differences between the experimental and control butifarra (p > 0.05); in other words, this type of fiber did not cause alterations in the butifarra. The mesophilic microorganism count, total and fecal coliforms, and positive staphylococcus were assessed according to Colombian Technical Standard 1325 of 2008. The hardness of the butifarra with higher inulin content on day 9 was, on average, ~55% greater than the control. The adhesiveness increased in each formulation as the days of fermentation increased, showing significant differences relative to the control. In general, the best sensory properties evaluated were related to the butifarra samples with higher inulin content in the formulation, so it is established that inulin did not alter the sensory properties of the butifarra, but rather potentiated the sensory attributes, making it suitable for use in fermented meat formulations. It can be stated that the addition of inulin to fermented butifarra is possible.

The Effect of Lactobacillus sakei on Growth Performance and Intestinal Health in Dogs: Gut Microbiota and Metabolism Study.

The gut microbiota is the largest and most complex ecosystem consisting of trillions of microorganisms, which influenced by various external factors. As an important probiotic species, Lactobacillus helps to improve gut microbial diversity and composition, underlying potential efficacy in growth performance and disease prevention. However, limited studies have been investigated the relationship between Lactobacillus sakei and intestinal health in dogs. In this study, dogs in the two groups were fed a standard diet (group C, n = 8) and Lactobacillus sakei diet (group P, n = 8), respectively. The growth performance, serum biochemical indices, antioxidant capacity, gut microbiota, and metabolism of dogs in both groups were studied. Results from growth trials showed that L. sakei can significantly improve the growth performance of dogs, including increased weight gain (p < 0.05), serum biochemical indices, i.e., ALP, TP, and ALB (p < 0.05), and better antioxidant capacity, i.e., SOD and GSH-Px (p < 0.05). Significant changes in the gut microbial composition were detected in dogs fed Lactobacillus sakei, as evidenced by an increase in the level of Firmicutes, Spirochaetota, and Patescibacteria, all of them play an important role in maintaining intestinal health. Moreover, a decrease in the level of microorganisms that threaten health, such as Mucispirillum and Clostridium_sensu_stricto_13. The metabolic analysis showed that the Lactobacillus sakei enhanced metabolic pathways such as vitamin B6 metabolism, glutathione metabolism, retinol metabolism, and fatty acid degradation. Our findings suggested that Lactobacillus sakei supplementation had beneficial effects on the growth performance and health status of dogs by improving gut microbiota balance and promoting metabolism. There are an estimated 200 million dogs in China, and the population is continuing to grow at a rapid pace. It is essential to explore an effective way to promote health in dogs. Intestinal diseases, particularly colitis and diarrhea, are common clinical conditions in dogs and are associated with gut microbiota. Lactobacillus sakei, as an important species of probiotics, the relationship between L. sakei and intestinal health in dogs remains unclear. Our study suggests that L. sakei significantly promotes growth performance and health states involving weight gain, regulation of gut microbiota, and metabolism. Overall, our findings shed light on the potential role of L. sakei as an alternative in promoting health in dogs.

The microscopic structure of pork neck after cooling with showering stiving and processing by culture Lactobacillus sakei

Microstructural changes in meat that occur during refrigerated storage depend on the hygiene of slaughtering and primary processing of animal carcasses, their cooling conditions, storage period, and microbial contamination and reflect the processes of meat maturation and spoilage. To extend the shelf life of pork in half-carcasses in a chilled state, 20 heads of 6-month-old large white pigs were used, which were delivered to the meat processing enterprise for slaughter. All half carcasses were cooled in a refrigerating chamber using showering, 1 hour later they were divided into 2 groups: control (without treatment) and experimental with the final treatment with a suspension of lactic acid bacteria of the SafePro® B-2 strain (Lactobacillus sakei). It has been found that cooling of pork half-carcasses in a refrigerating chamber with stiving and final processing by a culture suspension of lactic-acid microorganisms of strain SafePro® B-2 (Lactobacillus sakei) on the 4th day of storage had a positive effect on the microscopic structure of the pork neck and was characterized by a uniform color distribution when histologic specimens of muscular tissue are colored with hematoxylin and eosin, and minor cracks in the sarcoplasm, preservation of transverse and longitudinal striation of muscular fibers in comparison with that of the unprocessed pork half-carcasses with cultures of lactic-acid microorganisms. The microscopic structure of the muscular tissue of the pork half-carcass neck after cooling with stiving and final processing by a culture of lactic-acid microorganisms of strain SafePro® B-2 for 7 days of storage had a more distinct histoarchitecture in comparison with that of the unprocessed pork half-carcasses, as well as was characterized by insignificant areas of muscular fibers with transverse cracks, suspended development period of autolysis processes, partial preservation of transverse and longitudinal striation of muscle fibers. This points to a positive effect of lactic acid bacteria of strain SafePro® B-2 (Lactobacillus sakei) on the quality of the pork meat and contributes to the extension of its shelf life under chilled vintage.

Application of beekeeping products in the technology of raw smoked sausages

The safety of fermented sausage products is due to the elimination of a number of risks of biological origin, mainly of a microbiological nature. One of the most promising directions for the development of barrier technologies is the use of starter cultures and the biologically active substances produced by them in the production of fermented meat products. The research aims to study the influence of starter cultures and honey on a complex of physico-chemical, structuralmechanical, organoleptic indicators and nutritional value of raw smoked sausages. The article presents changes in the physical and chemical parameters of raw smoked sausages when using starter cultures in combination with different types of honey. When performing the work, 4 types of honey were used: from sunflower, phacelia, honeydew honey and from medicinal herbs. At the first stage of research, the proportion of honey application and the type of starter crops were selected. The next stage of the study was to determine the impact of the starter cultures included in the product BIOSTART PLUS 50 (lactic acid bacteria Lactobacillus Sake and yeasts Debaryomyces Hansenii) and honey on moisture loss during fermentation of raw smoked sausages, physicochemical parameters of finished products. Determination of moisture content in samples was carried out by drying in a drying cabinet at a temperature of 103±2°C. Conducted studies prove that the use of the product BIOSTART PLUS 50 (lactic acid bacteria Lactobacillus Sakei and yeasts Debaryomyces Hansenii) and honey allows shortening the ripening and drying technological process. A comparative analysis of manufactured raw-smoked sausages in terms of nutritional value makes it possible to state that manufactured raw-smoked sausages with the addition of honey meet the requirements of the standard. The results of the set of studies carried out in this work showed that the use of a composition of lactic acid bacteria and yeast with the use of honey as a source of carbohydrates will allow intensifying the technological process and improve the quality of finished products

Purification, characterization, and mode of action of Sakacin ZFM225, a novel bacteriocin from Lactobacillus sakei ZFM225

Bacteriocins from lactic acid bacteria (LAB) have attracted widespread attention as a new type of biological preservative due to their safety, high efficiency, and non-toxic characteristics. In this study, we focused on Sakacin ZFM225, a novel bacteriocin produced by Lactobacillus sakei ZFM225, which was isolated from raw milk. It was purified by a strategy including precipitation with 70% ammonium sulfate, cation exchange chromatography and reverse-phase high performance liquid chromatography (RP-HPLC). The predicted molecular weight of Sakacin ZFM225 was 14950.92 Da. Sakacin ZFM225 exhibited resistance to high temperatures, strong activity under acidic conditions, and sensitivity to trypsin and pepsin. Bacteriocins from Lactobacillus sakei mainly inhibited the growth of Listeria monocytogenes. The bacteriocin possessed a broad-spectrum inhibition which could kill many foodborne pathogens such as Pseudomonas aeruginosa, Micrococcus luteus, and Staphylococcus aureus. We further demonstrated that the mode of action of Sakacin ZFM225 was related to the formation of cell membrane porosity, and excluded Lipid Ⅱ as its target. These results suggest that this new bacteriocin has great potential in food industry as a biological preservative and even medical field.

The Effect of Commonly Used Organic Acids on the Microbiota of Cured Deli-Style Turkey Breast

The purpose of this study was to investigate changes in the microbial community structure consisting of spoilage lactic acid bacteria (LAB) when sodium lactate (SL) and SL + sodium diacetate (SD) are included in RTE meat product formulations at concentrations commonly used for controlling Listeria monocytogenes. Sliced cooked, vacuum-packaged turkey breast samples containing no SD or SL (control [C]), 0.125% SD, and the combination of 2.5% SL + 0.125%SD (SLSD) were inoculated with a target of 3 log colony-forming units (CFU)/g of 5 different LAB species (Lactobacillus sakei, Leuconostoc mesenteroides [bacon and deli-shaved ham isolates], Lactococcus lactis, and Enterococcus faecium) and stored at 4°C for 35 d. Microbial community changes were analyzed utilizing 16S ribosomal RNA (rRNA) gene sequencing for the V4 region from the samples collected at days 0, 7, 14, 21, and 35. No significant difference (P&amp;gt;0.05) was observed between the richness of microbial community for all treatments. According to Bray-Curtis dissimilarity matrix and permutational analysis of variance, a significant difference in β-diversity was observed only between C and SLSD (P&amp;lt;0.05) because of the antimicrobial effect of the addition of SL that slowed down changes in microbial community composition until day 14. L. sakei remained a dominant strain throughout 35 d of storage regardless of treatment, whereas L. mesenteroides existed with a very low abundance. Two of the five strains were not seen after day 7. No significant effect (P&amp;gt;0.05) was observed for the SD treatment compared with C in the microbiota. According to the results from this study, only SLSD affected the microbial community structure at the beginning of the storage. This study demonstrated that the incorporation of SL in the formulation slowed down the microbial spoilage and the changes in the microbiota of RTE meat products.

Lactiplantibacillus plantarum: a new example of inclusion body producing bacteria

BackgroundLactic Acid Bacteria such as Lactococcus lactis, Latilactobacillus sakei (basonym: Lactobacillus sakei) and Lactiplantibacillus plantarum (basonym: Lactobacillus plantarum) have gained importance as recombinant cell factories. Although it was believed that proteins produced in these lipopolysaccharides (LPS)-free microorganisms do not aggregate, it has been shown that L. lactis produce inclusion bodies (IBs) during the recombinant production process. These protein aggregates contain biologically active protein, which is slowly released, being a biomaterial with a broad range of applications including the obtainment of soluble protein. However, the aggregation phenomenon has not been characterized so far in L. plantarum. Thus, the current study aims to determine the formation of protein aggregates in L. plantarum and evaluate their possible applications.ResultsTo evaluate the formation of IBs in L. plantarum, the catalytic domain of bovine metalloproteinase 9 (MMP-9cat) protein has been used as model protein, being a prone-to-aggregate (PTA) protein. The electron microscopy micrographs showed the presence of electron-dense structures in L. plantarum cytoplasm, which were further purified and analyzed. The ultrastructure of the isolated protein aggregates, which were smooth, round and with an average size of 250–300 nm, proved that L. plantarum also forms IBs under recombinant production processes of PTA proteins. Besides, the protein embedded in these aggregates was fully active and had the potential to be used as a source of soluble protein or as active nanoparticles. The activity determination of the soluble protein solubilized from these IBs using non-denaturing protocols proved that fully active protein could be obtained from these protein aggregates.ConclusionsThese results proved that L. plantarum forms aggregates under recombinant production conditions. These aggregates showed the same properties as IBs formed in other expression systems such as Escherichia coli or L. lactis. Thus, this places this LPS-free microorganism as an interesting alternative to produce proteins of interest for the biopharmaceutical industry, which are obtained from the IBs in an important number of cases.

Characteristics of alanine racemase in Lactobacillus sakeiZH-2 strain.

Some d-amino acid functions for food production are widely known: d-alanine improves sensory evaluations of sake, beer, and fermented foods. Therefore, for the application of d-amino acids, alanine racemase (ALRase) in Lactobacillus sakei ZH-2, which has strong racemization, was analyzed using molecular biological methods. It had been hypothesized that ALRase coding DNA, alr, in ZH-2 strain differs from those of other Lactobacillus sakei strains. However, complete genome sequencing by the National Center for Biotechnology (NCBI) revealed the amino acid sequence of alr in ZH-2 strain to have homology of 99.4% similarity with the alr in Lactobacillus sakei 23K strain. However, it is considered that the sequence of alr was a unique amino acid sequence in the lactic acid bacteria group. DNA "alr" of ZH-2 strain has a 1140 bp DNA base with 41 kDa molecular mass. Its molecular mass was inferred as approximately 38.0 kDa using SDS-PAGE. Its optimum conditions are pH 9.0 at 30-40°C, showing stability at pH 9.0-10.0 and 4-40°C. Its cofactor is pyridoxal phosphate. Its activity is activated more by copper and zinc ions than by the lack of a metal ion. Additionally, its K m is 1.32 × 10-3 (mol), with V max of 4.27 × 10-5 (μmol-1 min-1). ALRase reacted against alanine most strongly in other substrates such as amino acids. The enzyme against serine was found to have 40% activity against alanine. The enzyme converted up to 54.5% of d-alanine from l-alanine ZH-2 strain.

Protective effects of Heat-killed Lactobacillus sakeiCVL-001 on DSS-induced ulcerative colitis in mice

Abstract Recently, the incidence of Inflammatory Bowel Disease (IBD) is increasing due to westernized lifestyle and eating habits. IBD is a representative gastrointestinal immune disease, and casued by an excessive immune response in the gastrointestinal tract. In recent studies, lactic acid bacteria which known as beneficial intestinal microbiota have protective effects on IBD by various mechanisms. Here, we evaluated the protective effect of Lactobacillus sakei CVL-001 isolated from korean tradtional food kimchi against dextran sulfate sodium-induced colitis in mice. First, administration of Heat-killed (HK) CVL-001 showed protective effects against DSS-induced colitis. Also, colonic mRNA expression levels showed that pro-inflammatory cytokine was downlregulated and anti-inflammatory cytokine was upregulated. Nucleotide-oligomerization domain 2 (NOD2) is well known as innate immune receptor and deeply related to IBD. We found that HK CVL-001 induced a NOD2-dependent regulatory phenotype in mouse bone marrow derived dendritic cell (BMDCs). Especially, we demonstrated that the expression of CD103, which is known as a marker of tolerogenic DC, was expressed mediated by NOD2. In vivo studies, colon administered with HK CVL-001 favoured the expansion of mucosal CD103 DCs and regulatory T cells. However, protective effect was abolished in NOD2 knockout mice. This results indicated that Heat killed L. sakei CVL-001 might be used therapeutic agent and strategy in IBD. This research was supported by the Mid-Career Researcher Programs (Grant No. 2022R1A2C2012287) of the National Research Foundation of Korea funded by the Ministry of Science and ICT (Information and Communication Technologies).

Monitoring and traceability of spoilage bacteria from three representative braised chickens based on culture-dependent and high-throughput sequencing

Culture-dependent methods and high-throughput sequencing technology were used to monitor the spoilage bacteria of braised chickens from three regions. The microorganisms in the braised chickens, which were vacuum-packed and stored at 4 °C, were isolated, identified, and traced, and the changes in meat quality were also measured. The high-throughput sequencing of braised chickens from different regions showed that the bacterial diversity decreased and the relative abundance increased during storage. At the end of storage, Lactobacillus, Brochothrix, Leuconostoc, Carnobacterium, and Enterobacteriaceae; Lactobacillus, Weissella, Aerococcus, Enterobacter, and Lactococcus; Enterobacteriaceae, Enterococcus, Serratia, Vagococcus, Lactobacillus, and Hafnia-obesumbacterium were the dominant microorganisms of braised chickens from the three regions. Twelve strains, namely Lactobacillus curvatus, Weissella viridescens, Leuconostoc citreum, Lactobacillus sakei, Brochothrix thermophacta, Serratia liquefaciens, Weissella hellenica, Lelliottia amnigena, Pantoea agglomerans, Rahnella sp., Enterococcus devriesei, and Enterobacteriaceae bacterium, were isolated and identified. The random forest method was used to predict the source of the samples according to the species of bacteria, and prediction accuracies of 91.7%, 83.3%, and 75% at the order, family, and genus levels, respectively, were achieved. The source of food spoilage bacteria could be traced with high accuracy through the sample microorganism, which provides a new direction for the study of food spoilage bacteria.

Effects of three different probiotics of Tibetan sheep origin and their complex probiotics on intestinal damage, immunity, and immune signaling pathways of mice infected with Clostridium perfringens type C.

Tibetan sheep have unique intestinal microorganisms in their intestines that are adapted to the highland alpine and anoxic environment. To further clarify the probiotic properties of Tibetan sheep-derived probiotics, we selected three Tibetan sheep-derived probiotic isolates (Enterococcus faecalis EF1-mh, Bacillus subtilis BS1-ql, and Lactobacillus sakei LS-ql) to investigate the protective mechanisms of monocultures and their complex strains against Clostridium perfringens type C infection in mice. We established a model of C. perfringens type C infection and used histology and molecular biology to analyze the effects and mechanisms of different probiotic treatments on mice after C. perfringens type C infection. After supplementation with either probiotics or complex probiotics, mice were improved in terms of weight reduction and reduced the levels of cytokines in serum and increased the levels of intestinal sIgA, and supplementation with complex probiotics was effective. In addition, both probiotic and complex probiotic supplementation effectively improved the damage of intestinal mucosa and spleen tissue. The relative expressions of Muc 2, Claudin-1, and Occludin genes were increased in the ileum. The three probiotics and the compound probiotics treatment significantly reduced the relative mRNA expression of toll-like/MyD88/NF-κB/MAPK. The effect of probiotic treatment was similar to the results of engramycin treatment, but the effect of engramycin treatment on intestinal sIgA was not significant. Our results clarify the immunomodulatory effects of the three probiotic isolates and the complex probiotics on C. perfringens infection, and the repair of the intestinal mucosal barrier.

The Probiotic Lactobacillus sakei Subsp. Sakei and Hawthorn Extract Supplements Improved Growth Performance, Digestive Enzymes, Immunity, and Resistance to the Pesticide Acetamiprid in Common Carp (Cyprinus carpio).

This study evaluated the impacts of the probiotic, Lactobacillus sakei (L. sakei), and the extract of hawthorn, Crataegus elbursensis, on growth and immunity of the common carp exposed to acetamiprid. Fish (mean ± SE: 11.48 ± 0.1 g) feeding was done with formulated diets (T 1 (control): no supplementation, T 2: 1 × 106 CFU/g LS (Lactobacillus sakei), T3: 1 × 108 CFU/g LS, T 4: 0.5% hawthorn extract (HWE), and T 5: 1% HWE) for 60 days and then exposed to acetamiprid for 14 days. The growth performance improved in the fish fed LS at dietary level of 1 × 108 CFU/g, even after exposure to acetamiprid (P < 0.05). Intestinal Lactobacillus sakei (CFU/g) load increased (P < 0.05), following supplementation with the probiotic-enriched diet. The LS-treated fish had increases in the activity of digestive enzymes (P < 0.05). Both LS and HWE stimulated antioxidant enzymes and immune system components in serum and mucus (alkaline phosphatase (ALP), protease, total Ig, and lysozyme) (P < 0.05). However, the changes were different depending on the kind of the supplement. The malondialdehyde (MDA) levels decreased in HWE-treated fish after acetamiprid exposure (P < 0.05). Both LS and HWE reduced the liver metabolic enzymes (LDH, ALP, AST, ALT, and LDH) in serum both before and after exposure to the pesticide (P < 0.05). However, each enzyme exhibited a different change trend depending on the type of the supplement. HWE showed a stress-ameliorating effect, as glucose and cortisol levels declined in the HWE-treated fish (P < 0.05). This study indicated the immunomodulatory impacts of LS (1 × 108 CFU/g) and HWE (at dietary levels of 0.5-1%). The probiotic showed more performance compared to HWE. However, the HWE mitigated oxidative stress more efficiently than the probiotic.

Optimization of a natural antimicrobial formulation against potential meat spoilage bacteria and food-borne pathogens: Mixture design methodology and predictive modeling.

This study is about the combined antimicrobial effect of essential oils (EOs), namely Mediterranean (MN) EO, German thyme (GT) EO, Cinnamon (CN) EO, Indian (IN) EO, Asian (AN) EO, and citrus extract (CE) against spoilage bacteria (Lactobacillus sakei, Lactobacillus curvatus, Leuconostoc mesenteroides, Carnobacterium divergens, Brochothrix thermosphacta, and Pseudomonas aeruginosa) and selected pathogenic bacteria (E. coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes). Firstly, each EO and CE were screened for antibacterial activity by microdilution assay, and the most efficient antimicrobial extracts were selected based on the lowest MIC values to perform the combination assays. Afterward, a simplex-centroid mixture design was used to develop optimal antimicrobial mixtures capable of protecting meat from spoilage and pathogenic bacteria. The optimization tool allowed us to postulate models and validate them statistically as well as to create a prediction profile of the experiment. Thus, the optimal mixtures named active formulation 1 (AF1) containing MN EO/GT EO/VC EO/CE with a ratio of 1:2:2:1 and active formulation 2 (AF2) containing IN EO/AN EO/CE/VC EO with a ratio of 2:2:1:2, were developed based on the demonstration of their synergistic effect against tested bacteria. The obtained formulations at organoleptically acceptable concentrations could be applied in the preservation of meat and meat products.

Bacteriobiota and Chemical Changes during the Ripening of Traditional Fermented "Pirot 'Ironed' Sausage".

"Pirot 'ironed' sausage" (Pis) is a traditional, fermented sausage, made from different types of meat (beef and chevon), without additives or starter cultures. The physical-chemical properties (pH, water activity, fats, moisture, and protein contents) were examined in the initial meat batter stuffing and during ripening. Total bacterial diversity was examined at different time points using both culturable (traditional) and non-culturable (NGS sequencing) approaches. During the ripening, a decrease in pH value, aw, and moisture content was observed, as well as an increase in protein and fat content. At least a two-fold significant decrease was noted for colorimetric values during the ripening period. The dominance of Proteobacteria and Firmicutes was observed in the non-culturable approach in all studied samples. During the ripening process, an increase in Firmicutes (from 33.5% to 63.5%) with a decrease in Proteobacteria (from 65.4% to 22.3%) was observed. The bacterial genera that were dominant throughout the ripening process were Lactobacillus, Photobacterium, Leuconostoc, Weissella, and Lactococcus, while Carnobacterium, Brochothrix, and Acinetobacter were found also, but in negligible abundance. Among the culturable bacteria, Latilactobacillus sakei (Lactobacillus sakei) and Leuconostoc mesenteoides were present in all stages of ripening.

Characterization, enzymatic and biological properties of a dominant lactic acid bacteria strain of Lactobacillus sakei subsp. sakei isolated from stinky mandarin fish

Presently in order to excavate suitability of resources of lactic acid bacteria for fermentation of mandarin fish, a strain of lactic acid bacteria (LAB), which was cultivated from stinky mandarin fish via using traditional MRS medium (CMC 1-8), was firstly isolated and purified. Subsequently, it was discovered that the as-harvested LAB was recognized as Lactobacillus sakei subsp. sakei with assistance of technology of phenotypic identifying and 16S rRNA sequencing. Concurrently, relevant characteristics in aspects of growth curve, acid production capacity, temperature and salt tolerance of Lactobacillus sakei subsp. sakei were plainly investigated. Furthermore, the preliminary research on protease properties and biological properties was revealed. The results unfolded that the strain could grow and produce acid normally at 37 °C, and deliver a strong tolerance even under 3% NaCl at 12 °C, which could be significant sufficiently to satisfy the low-temperature and salty fermentation of mandarin fish. The best compatible temperature and pH value for protease production were at 70 °C and 9.0, respectively. Resultantly, the main metabolites, containing polyphenols, flavonoids and soluble polypeptides, performed a remarkable effect on scavenging abilities of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazine (DPPH) free radical and ferricyanide reducing ability, of which the IC50 were 1.05, 6.87, and 4.62 mg/mL, respectively. And, the metabolites displayed partial inhibitory effects on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis. Therefore, CMC 1-8 can potentially serve as a functional microorganism to directionally ferment mandarin fish.

Incorporation of cinnamon essential oil-loaded Pickering emulsion for improving antimicrobial properties and control release of chitosan/gelatin films

In this research, cinnamon essential oil (CEO) loaded Pickering emulsion was incorporated into chitosan (CS)/gelatin (GEL) complex films. These antimicrobial functionalizations of biobased packaging films containing different contents (5, 7.5, and 10 mL) of CEO-loaded Pickering emulsion were evaluated on the microstructure, physicochemical, mechanical, barrier and antimicrobial properties. CEO-loaded Pickering emulsion was herein prepared with zein nanoparticles as a stabilizer showed an average size of 113.37 nm and exhibited excellent physical stability. Fourier transform infrared spectroscopy (FTIR) and wide-angle X-ray scattering (WAXS) analyses revealed that the CEO-loaded Pickering emulsion showed compatibility with CS/GEL matrix. Not only mechanical properties but also barrier properties of the prepared films were significantly improved (P < 0.05) by incorporating CEO-loaded Pickering emulsion. Furthermore, incorporating CEO-loaded Pickering emulsion with CS/GEL led to the formation of high antimicrobial against Pseudomonad paralactis MN10 and Lactobacillus sakei VMR17 with slow-release behavior of CEO. These results suggested that Pickering emulsion is a promising antimicrobial agent delivery system for biopolymer based active packaging, notably for the conception of novel active packaging biobased polymers.

Physicochemical characteristics and gel-forming properties of mandarin fish (Siniperca chuatsi) protein during the fish fermentation with Lactobacillus sake SMF-L5: The formation of garlic-cloves shaped protein gel

Mandarin fish (Siniperca chuatsi) during fermentation presents a unique elastic texture. In this investigation, the physicochemical and gel-forming properties of fish proteins were evaluated to explain the formation of elastic characteristics. During fermentation, the combined effects of acidification by Lactobacillus sake SMF-L5, increased sodium chloride, and decreased moisture content in the fish protein generated a suitable microenvironment for gelation. The mass transfer of sodium chloride was accompanied by NMR relaxation of the immobilized water. The ripening fermented fish had a functionally available MHC, a higher fractal dimension, and a stable α-helical structure. Also, it exhibited excellent gel-forming performances, mainly including garlic-cloves shaped protein gel, stronger springiness, and enhanced L* and whiteness. Correlation analysis showed that the gel’s physical properties were differently related to the protein’s physicochemical characteristics except for total free amino acids. These results could lay a theoretical foundation for the gel formation mechanism of fermented mandarin fish.

Influence of growth parameters on bacteriocin-like inhibitory substances (BLIS) production by lactic acid bacteria.

This study aimed to investigate the possible production of bacteriocin-like inhibitory substances (BLIS) and optimize it by Lactobacillus sakei and combined Lactobacillus curvatus/Pediococcus acidilactici, lactic acid bacteria used for the meat fermentation. The effect of growth parameters on BLIS production was evaluated by measuring the antibacterial activity of the cell-free supernatant of these bacteria. The stability of the cell-free supernatant of combined L.curvatus/P.acidilactici bacteria was also examined after heat treatment and pH variations. Results showed highest BLIS production by L.curvatus/P.acidilactici was at growth temperatures of 28°C and pH 5, while the optimum condition for production of BLIS by L.sakei was 24°C and pH 6.5. The BLIS production by L. curvatus/P. acidilactici bacteria was greatly influenced by carbon and nitrogen sources. The antimicrobial activity of BLIS in supplemented De Man, Rosa, and Sharpe broth (MRS) was 2044.44 AU/mL, 4.84-fold greater than unsupplemented MRS. None of the carbon sources used in this study affected the BLIS production by the L.sakei, while pea peptone enhanced the antimicrobial activity and showed a value of 188.89 AU/mL, 1.47-fold greater than unsupplemented MRS. The characterization of the cell-free supernatant of L. curvatus/P. acidilactici bacteria showed the heat stability and activity of BLIS at pH 2-10.

Effects of NaCl curing and subsequent fermentation with Lactobacillus sakei or Lactobacillus plantarum on protein hydrolysis and oxidation in yak jerky

The impacts of added NaCl and subsequent fermentation with Lactobacillus sakei or Lactobacillus plantarum on proteolysis and protein oxidation in yak jerky were investigated. The proteolytic activity, peptide content and free amino acid concentration displayed decline patterns as NaCl content increased from 0 to 4% (P < 0.05), while the salted jerky fermented with lactobacillus demonstrated higher proteolysis profiles than the control without starter cultures (P < 0.05), and jerky fermented with Lactobacillus sakei showed the highest proteolysis. Adding NaCl promoted protein carbonylation, sulfhydryl loss and tryptophan fluorescence quenching. Fermentation with lactobacillus, especially with Lactobacillus sakei, effectively reduced the oxidation of sarcoplasmic and myofibrillar proteins in salted jerky (P < 0.05). Electrophoretogram showed that the changes in number and intensity of protein bands were from combined action of NaCl curing and microbial fermentation. The results suggest that both of NaCl addition and subsequent fermentation influence the protein chemical properties and hence modify the relevant quality traits of yak jerky.

The Inhibition of SARS-CoV-2 and the Modulation of Inflammatory Responses by the Extract of Lactobacillus sakei Probio65.

In the three years since the first outbreak of COVID-19 in 2019, the SARS-CoV-2 virus has continued to be prevalent in our community. It is believed that the virus will remain present, and be transmitted at a predictable rate, turning endemic. A major challenge that leads to this is the constant yet rapid mutation of the virus, which has rendered vaccination and current treatments less effective. In this study, the Lactobacillus sakei Probio65 extract (P65-CFS) was tested for its safety and efficacy in inhibiting SARS-CoV-2 replication. Viral load quantification by RT-PCR showed that the P65-CFS inhibited SARS-CoV-2 replication in human embryonic kidney (HEK) 293 cells in a dose-dependent manner, with 150 mg/mL being the most effective concentration (60.16% replication inhibition) (p &lt; 0.05). No cytotoxicity was inflicted on the HEK 293 cells, human corneal epithelial (HCE) cells, or human cervical (HeLa) cells, as confirmed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The P65-CFS (150 mg/mL) also reduced 83.40% of reactive oxidizing species (ROS) and extracellular signal-regulated kinases (ERK) phosphorylation in virus-infected cells, both of which function as important biomarkers for the pathogenesis of SARS-CoV-2. Furthermore, inflammatory markers, including interferon-α (IFN-α), IFN-ß, and interleukin-6 (IL-6), were all downregulated by P65-CFS in virus-infected cells as compared to the untreated control (p &lt; 0.05). It was conclusively found that L. sakei Probio65 showed notable therapeutic efficacy in vitro by controlling not only viral multiplication but also pathogenicity; this finding suggests its potential to prevent severe COVID-19 and shorten the duration of infectiousness, thus proving useful as an adjuvant along with the currently available treatments.