Lactic Acid Bacteria Cultures Research Articles

Development of a defined mixed starter culture for the improvement of Tej, Ethiopian honey wine.

Ethiopian honey wine, Tej, is the most popular traditionally fermented alcoholic beverage in Ethiopia. Owing to the spontaneous fermentation process, the final product is neither predictable nor consistent in quality. Attempts have not been made before to solve this problem. Thus, the aim of this study was to develop a potential mixed starter culture of yeast and lactic acid bacteria isolated from Tej samples for the production of Tej with consistent quality. One hundred seventy-seven lactic acid bacteria and 194 yeasts were isolated from 30 Tej samples collected from southwest Ethiopia. After sequentially testing the isolates towards physiological stress tolerance and desired metabolic products, 10 lactic acid bacteria and 10 yeast isolates were screened. Later, four lactic acid bacteria and four yeast isolates were found to be compatible in co-culture tests. Finally, the combination of lactic acid bacteria and yeast isolates was formulated using the design of expert version 7.0.0 software, and six formulates (F #1-6) were designed. Controlled Tej fermentation was performed under laboratory conditions using six lactic acid bacteria-yeast starter culture formulations. The sensory attributes, in terms of color, flavor, odor, turbidity, and overall acceptance analysis scored 4.8/5.0 (F #2) and 4.7/5.0 (F #6), with mean significant variations (p < 0.05) among the other formulates. These two formulates were considered the best-mixed starter cultures compared to the control and other formulates. Matrix-assisted laser desorption ionization-time of flight analysis revealed that the lactic acid bacteria starters (AAUL7 and AAUL10) belonged to Lactobacillus paracasei. While the yeast starters (AAUY2 and AAUY8) belonged to Saccharomyces cerevisiae. These mixed lactic acid bacteria-yeast starter cultures could be used as the best starter culture for the fermentation of Ethiopian honey wine, Tej, with consistent quality.

Effects of exogenous autoinducer-2 precursor on the ability of Lactiplantibacillus plantarum SH7 to degrade biogenic amines: In vitro and in a dry-sausage model

The effects of the exogenous autoinducer-2 (AI-2) precursor, 4,5-dihydroxy-2,3-pentanedione (DPD; 0, 300, 600, and 900 nmol/L), on the degradation capacity of Lactiplantibacillus plantarum SH7 toward biogenic amines (BA) were investigated both in vitro and in a dry-sausage model. L. plantarum SH7 exhibited a significant increase in BA-degradation capacity (putrescine, cadaverine, and histamine) under DPD treatments compared to the absence of DPD treatment in vitro. Additionally, a significant increase in the production of AI-2 signal molecule and diamine oxidase in L. plantarum SH7 was observed with the addition of exogenous DPD (p < 0.05). In the dry-sausage model, the contents of BAs (tryptamine, 2-phenethylamine, putrescine, cadaverine, and histamine) significantly decreased with the addition of DPD (p < 0.05). Meanwhile, the sausage with 600-nM DPD exhibited the lowest cadaverine content (11.13 mg/kg), while the sausage with 900-nM DPD exhibited the lowest tryptamine, putrescine, and histamine contents (12.44, 11.15, and 13.21 mg/kg, respectively). Results suggest that an optimal concentration of exogenous DPD can enhance the capacity of L. plantarum SH7 to degrade BAs and that the degradation of BAs by L. plantarum SH7 may be dependent on the LuxS/AI-2 quorum sensing (QS) system. This study provides the theoretical basis for the development of functional starter cultures of lactic acid bacteria with BA-degradation ability based on targeted LuxS/AI-2 QS system regulation and reducing the accumulation of BAs in fermented meat products.

Lactic Acid Bacteria Isolates and the Microbiome of Cincalok, Tempoyak, and Mandai: A Traditional Fermented Food from Kalimantan Island, Indonesia.

Indonesia has abundant traditional fermented food with various lactic acid bacteria (LAB), which can be developed into probiotics for pharmaceutical and functional food and feed products. This research is aimed at (1) obtaining and identifying LAB isolates and (2) studying the microbiome (bacterial diversity and abundance) of spontaneously-fermented traditional foods of Kalimantan Island, Cincalok, Tempoyak, and Mandai. To obtain LAB isolates, food samples were serially diluted and inoculated on MRS agar that contained 1% CaCO3 (MRSA). Isolates forming clear zones were purified and identified by DNA barcoding. The microbiome was studied using genomic-sequencing techniques and analysed for taxonomic composition. Seven pure isolates were obtained from Cincalok, two Tempoyak, and one Mandai. DNA barcoding revealed that the Cincalok seven isolates were Staphylococcus carnosus (strain HSP-S16), Tetragenococcus halophilus (FSB201), Corynebacterium phoceense, Vagococcus vulneris (SS1995), Enterococcus faecalis (S11-6), Pisciglobus halotolerans (C01), and Priestia filamentosa (P3.1); two from Tempoyak, Levilactobacillus brevis (E1D3BL1) and Lactiplantibacillus plantarum (UMCC-2996); and one from Mandai, Staphylococcus cohnii (XAAS.x13; non-LAB). The T. halophilus, E. faecalis, P. halotolerans, L. brevis, and L. plantarum belong to LAB. The P. halotolerans from Cincalok and non-LAB in these three fermented foods were the first documented report. The microbiome revealed the dominance of Firmicutes phyla in the fermented foods, with 93% in Cincalok, 89.94% in Tempoyak, and 60.32% in Mandai. On the genus level, Cincalok was dominated by Tetragenococcus 40.33%, Anaerococcus 23.29%, Vagococcus 9.27%, and Lactobacillus 6.84%. Meanwhile, Tempoyak was dominated only by Lactobacillus 89.94%. Mandai were dominated by Lactobacillus 31.97%, Proteus 17.14%, Aerococcus 16.85%, Mangrovibacter 15.15%, and Vagococcus 6.2%. However, Mandai's microbiome LAB was not culturable/isolated on MRSA. The plausibility is that those unculturable LAB require coculturing with other bacteria and additional media components to grow on MRSA. This study is the first report regarding the microbiome of Cincalok, Tempoyak, and Mandai, along with their culturable LAB isolates.

Inactivation efficacy of four commercial post-process treatments against Listeria monocytogenes and impact on the commercial quality of leafy greens

The problem of product contamination with human pathogenic microorganisms is still unsolved. Although prevention through the implementation of good agricultural practices and good manufacturing practices is the gold standard, product decontamination strategies can be used to complement preventive measures. Different bioprotective treatments have been suggested to reduce the risk of listeriosis in fresh produce, but more information is needed before industrial implementation. This study focused on the efficacy of four commercial treatments against Listeria monocytogenes growth and their effect on the organoleptic quality of baby spinach, cut romaine, cut iceberg, and shredded cabbage. The treatments included SafePro® (CHR Hansen, DK) and Holdbac® (DowDuPont, US), based on the use of lactic acid bacteria (LAB) cultures as well as two different bacteriophage solutions, ListShield (Intralytix, US) and PhageGuard Listex™ (PhageGuard, US). The selected treatments were tested under simulated commercial conditions. The application was performed after processing and before packaging using a fine mist spray. In all the trials, Listex™ showed the best results in reducing L. monocytogenes growth during shelf life in the four leafy greens chosen. Microbial reductions were close to 2 log units. L. monocytogenes reductions were observed 1 day after Listex™ application and the efficacy was maintained during storage (15 days at 7°C). Organoleptic quality, including flavor, texture, browning/yellowing, decay, and visual appearance of the four leafy greens was not significantly affected by the application of Listex™ when compared to the untreated products. Post-process treatment with Listex™ based on bacteriophages effectively reduced L. monocytogenes and can be recommended as a control tool to reduce the risks for the presence of L. monocytogenes in leafy greens.

Correlation between the bacterial flora and sensory quality of Bayannur sour porridge

In this study, the bacterial flora structure, sensory quality and culturable lactic acid bacteria resources of sour porridge in Bayannur area were analyzed. Furthermore, these bacterial sequencing data were combined with the high-throughput sequencing data of Ordos sour porridge to analyze the microbiota differences. MiSeq results showed that Lactiplantibacillus, Acetobacter, Lacticaseibacillus, Lactobacillus, and Limosilactobacillus were the main bacterial genera in sour porridge. Further comparative analysis showed that the average relative abundance of 7 dominant bacteria genera was significantly higher in sour porridge from Bayannur area (P < 0.05). Electronic nose and electronic tongue demonstrated that the primary volatile flavor substances in sour porridge were terpene compounds, and the change in taste characteristics was mainly reflected in the sour taste index. Correlation showed that most of LAB genera and Acetobacter were positively correlated with the formation of aromatic compounds. Pure culture showed that Lacticaseibacillus paracasei and Lactiplantibacillus plantarum were the dominant LAB in sour porridge. Overall, certain differences in the bacterial flora of sour porridge from different regions were identified, with Lactiplantibacillus, Acetobacter, Lacticaseibacillus, Lactobacillus, and Limosilactobacillus being characteristic of sour porridge in Bayannur area. Moreover, some LAB genera and Acetobacter were found to have a positive effect on flavor formation in sour porridge.

The Application of Protective Cultures in Cheese: A Review

A number of non-thermal preservation strategies have been adopted from the dairy industry to improve cheese quality and safety. The application of lactic acid bacteria cultures that produce bacteriocins has been extensively studied as a means of bio-preservation. However, the application of purified bacteriocins as a bio-protective agent is limited in cheese. The application of protective cultures is another strategy, and the aim of the current review is to provide an overview of the application of commercial and autochthonous adjunct cultures on the bio-protection of cheese; both public health and spoilage aspects are considered.

Phenotypic, Technological, Safety, and Genomic Profiles of Gamma-Aminobutyric Acid-Producing Lactococcus lactis and Streptococcus thermophilus Strains Isolated from Cow's Milk.

Gamma-aminobutyric acid (GABA)-producing lactic acid bacteria (LAB) can be used as starters in the development of GABA-enriched functional fermented foods. In this work, four GABA-producing strains each of Lactococcus lactis and Streptococcus thermophilus species were isolated from cow's milk, and their phenotypic, technological, and safety profiles determined. Genome analysis provided genetic support for the majority of the analyzed traits, namely, GABA production, growth in milk, and the absence of genes of concern. The operon harboring the glutamate decarboxylase gene (gadB) was chromosomally encoded in all strains and showed the same gene content and gene order as those reported, respectively, for L. lactis and S. thermophilus. In the latter species, the operon was flanked (as in most strains of this species) by complete or truncated copies of insertion sequences (IS), suggesting recent acquisition through horizontal gene transfer. The genomes of three L. lactis and two S. thermophilus strains showed a gene encoding a caseinolytic proteinase (PrtP in L. lactis and PrtS in S. thermophilus). Of these, all but one grew in milk, forming a coagulum of good appearance and an appealing acidic flavor and taste. They also produced GABA in milk supplemented with monosodium glutamate. Two L. lactis strains were identified as belonging to the biovar. diacetylactis, utilized citrate from milk, and produced significant amounts of acetoin. None of the strains showed any noticeable antibiotic resistance, nor did their genomes harbor transferable antibiotic resistance genes or genes involved in toxicity, virulence, or pathogenicity. Altogether these results suggest that all eight strains may be considered candidates for use as starters or components of mixed LAB cultures for the manufacture of GABA-enriched fermented dairy products.

Impact of single and mixed cultures of yeasts and lactic acid bacteria in coffee fermentation and cup quality

AbstractSaccharomyces cerevisiae LBTF 21.3, Pichia manshurica LBTF 21.1, and Leuconostoc lactis LBTF 21.1 were used as single and mixed cultures in coffee fermentations. Fermentations carried out in glass jars with P. manshurica LBTF 21.1/Leuc. lactis LBTF 21.1 showed higher fermentation rates than S. cerevisiae LBTF 21.3/P. manshurica LBTF 21.1 or S. cerevisiae LBTF 21.3/Leuc. lactis LBTF 21.1. The highest cup quality was reached with P. manshurica LBTF 21.1/Leuc. lactis LBTF 21.1 (83.0 points). Full factorial design (22) carried out with P. manshurica LBTF 21.1 revealed that the higher proportion of water added before the fermentation resulted in higher production of acetic acid. A contrary effect of this variable was observed on the production of lactic acid with Leuc. lactis LBTF 21.1. Fermentations conducted in bioreactor evidenced the production of acetaldehyde by P. manshurica LBTF 21.1/Leuc. lactis LBTF 21.1, P. manshurica LBTF 21.1, and Leuc. lactis LBTF 21.1. Additionally, the highest cup quality was reached in fermentations with P. manshurica LBTF 21.1 (82.5 points) followed by Leuc. lactis LBTF 21.1 (81.5 points) and P. manshurica LBTF 21.1/Leuc. lactis LBTF 21.1 (81.0 points). Fermentations of coffee with single and mixed cultures are interesting strategies for the improvement of the sensory quality.

Fermentation of Kalamata Natural Black Olives Using Selected Lactic Acid Bacteria as Starters

Fermented foods such as table olives are produced through a spontaneous process that has been improved over the years, ensuring the safety and quality of the final product. The aim of the present work was to study the action of starter cultures of lactic acid bacteria (Lacticaseibacillus rhamnosus GG ATCC53103, Levilactobacillus brevis ATCC8287, and Lactiplantibacillus plantarum ATCC14917) which were previously shown to have probiotic and antioxidant potential during the fermentation of natural Greek-style black olives (Kalamata) in brine containing 6% (w/v) NaCl at a temperature of 20 °C for a period of 150 days. At a molecular level, the main metabolites in every fermentation process were identified using an HPLC method. The results showed that the concentration of the metabolites increased gradually, developing a stable pattern after the 90th day of fermentation. In addition, the DL-p-hydroxyphenyllactic acid (OH-PLA) was identified as the phenolic acid with the highest concentration, independently of the selected starter culture. Microbial genomic DNA was also extracted from the olives’ surface at the final stages of fermentation (150 days) and was subjected to 16S rRNA sequencing using the Nanopore MinION™ NGS tool, enabling a comprehensive analysis of the microbial community. According to the findings, the most abundant genera were Lactobacillus and Leuconostoc. To the best of our knowledge, this is the first study exploring these particular starters for olive fermentation.

Vitamin B12 production in solubilized protein extract of bioprocessed wheat bran with Propionibacterium freudenreichii

Wheat bran, a nutrient-rich byproduct of wheat milling, has the potential to be used for the production of vitamin B12 (B12) in order to fortify plant-based foods that are lacking in this vitamin. This study aimed to investigate B12 production in the soluble extract of bioprocessed wheat bran using Propionibacterium freudenreichii. The optimal conditions for B12 production were found to be a bioprocessing time of 24 h, along with the use of a commercial starter culture of lactic acid bacteria and yeast, with pH adjusted from 4.0 to 6.4. The highest B12 production (55 ng/mL) was achieved within three days of fermentation. Cobalt supplementation (as CoCl2 or food-grade yeast extract) resulted in up to four-fold increase in B12 production. Similar results (50–70 ng/mL) were obtained when the processes were scaled up, with bioprocessing involving up to 15 kg and B12 fermentation involving up to 5 L, demonstrating the robustness of the procedure. Microbiological safety was ensured with the absence of Enterobacteriaceae in the extracts after bioprocessing and B12 fermentation. Overall, this study highlights the potential of under-utilized wheat bran as a raw material for producing B12-enriched bran extract, which can be used to fortify plant-based products in various food applications.

THE INFLUENCE OF NUTRIENTS AND LACTULOSE PREBIOTIC ON THE FERMENTATION PROCESSES IN THE TECHNOLOGY OF RECEIVING A FUNCTIONAL FOOD PRODUCT WITH AN INCREASED TITER OF VIABLE LACTIC ACID BACTERIA

A study of the influence of biologically active substances (fat-soluble vitamins, omega-3 fatty acids and vitamin D, as well as water-soluble vitamin C), prebiotic lactulose on the titer of viable cells of lactic acid bacteria was carried out for the further use of the obtained research results in the biotechnology of functional food products, obtained thanks to the successful course fermentation processes. Experiments have proven the expediency of using biologically active substances as stimulators of the growth of lactic acid bacteria, which contribute to the increase of biomass and support of their vital activity for 192 hours. Research has established that at the end of the experiment (192 hours), the highest titer of lactic acid bacteria was recorded in samples 1, 2, 3, 4, to which the prebiotic lactulose was added in the amount of 1, 3, 5 and 7 %, respectively. This is due to the fact that the prebiotic acts as a specific substrate that is used by the symbiosis of pure cultures of lactic acid bacteria for a long time, unlike milk sugar. Analyzing the obtained data, it is indicated that thanks to the addition of fat-soluble nutrients omega-3 fatty acids and vitamin D, as well as water-soluble vitamin C, there is a significant increase in the titer of viable cells of probiotic cultures at 6 and 24 hours of the experiment, although at the end of the experiment (by 192 hour) in these samples, an insignificant decrease of this indicator was recorded — from 10 to 8.9 log cells/ml. In the control sample (without the addition of biologically active substances and lactulose prebiotic), a significant decrease in the titer of viable cells of lactic acid bacteria was noted, compared to the test samples to which nutrients were added. The titer of lactic acid bacteria cells in the control sample was reduced by 192 hours from 8.5 to 5.5 log cells/ml. It is recommended to use the studied nutrients in the indicated concentrations to stimulate the growth and maintain the viability of lactic acid bacteria cultures in the technology of production of functional food products.

Effects of Different Lactic Acid Bacteria in Single or Mixed Form on the Fermentative Parameters and Nutrient Contents of Early Heading Triticale Silage for Livestock.

Lactic acid bacteria (LAB) are excellent anaerobic fermenters that produce highly valuable grass-based animal feed containing essential nutrients. In the present study, an ensiling process was used to improve anaerobic fermentation in triticale silage under different moisture conditions with LAB. The triticale was treated with either a single bacterium or combined LAB and then vacuum-sealed. After 180 and 360 days of storage, the silage's fermentation characteristics, microbial changes and nutrient contents were analyzed. The pH of the silage was significantly lower than the control silage. There was a significant difference in the pH values between the silages treated with single or mixed LAB. The LAB treatment led to a substantial increase in lactic acid (LA), a decrease in butyric acid (BA), and marginal levels of acetic acid (AA). The LA content after the mixed LAB treatment was significantly higher than that after the single culture LAB treatment. After single or combined inoculant treatments, the LAB population in the silage increased, while the yeast and mold levels decreased. These findings suggest that the addition of LAB to silage during ensiling could enhance the nutritional quality and reduce unwanted microbial growth. The mixed LAB treatments produced silage with a significantly higher nutritional value than the single LAB treatments.

Development of a low pollution medium for the cultivation of lactic acid bacteria

Protein rich culture media are employed in the production of lactic acid bacteria (LAB); however, production costs are high. In this work media formulation and evaluation for LAB production were conducted considering physiological properties of lactic acid bacteria. Consumption efficiency (E), yield production (Y) and specific substrate consumption rate (qS) values as response variables were used. Four culture media were used: (1) Man Rogosa Sharp (MRS); (2) cabbage liquor (MC); (3) a new balanced culture medium (MX); and (4) MX supplemented with cabbage liquor (MXC). The culture media were evaluated using two strains: Lactobacillus acidophilus ATCC 4356 and Lactiplantibacillus plantarum ATCC 10241. The EGLU for L. plantarum was 100 % in the three media and YX/S value was 0.02 ± 0.003 in MRS and MX, while YLAC/S was 0.57 ± 0.03 in MRS and 0.51 ± 0.02 in MX. In MXC, the value obtained for YX/S was 0.07 ± 0.002 while YLAC/S was 0.47 ± 0.04. Specific glucose consumption and lactate formation rates for L. plantarum in MRS and MX media did not show significant differences. These results suggest that MX and MXC can be used for efficient production of the LAB at low cost.

Bioprotection Potential of Lacticaseibacillus rhamnosus LRH01 and Lactiplantibacillus plantarum LP01 against Spoilage-Associated Penicillium Strains in Yoghurt

Penicillium spp. are considered a major spoilage fungus in dairy products. Due to the growing concerns over food safety issues and the demand for “clean label” food products from consumers, the use of lactic acid bacteria (LAB) as a bioprotective tool to control fungal spoilage of dairy products appears to be a promising alternative. Here, the antifungal activities of ten LAB cultures against five dairy-spoilage-associated Penicillium strains were studied in a model system, and the most potent bioprotective cultures were further tested in yoghurt. Lacticaseibacillus rhamnosus (L. rhamnosus) LRH01 and Lactiplantibacillus plantarum (L. plantarum) LP01 exhibited potent antifungal efficacy at low concentrations. The inhibitory effects of cell-containing fermentates (C-fermentates), cell-free fermentates (CF-fermentates), and volatiles produced by the two cultures were tested in a yoghurt serum medium. The C-fermentates showed antifungal effects, while the removal of cells from C-fermentates led to decreased antifungal activities. Volatiles alone displayed some antifungal efficiency, but less than the fermentates. In a yoghurt matrix, the specific effect of manganese depletion by the bioprotective cultures on mold growth was investigated. Here, the LAB cultures could completely suppress the growth of molds, while addition of manganese partially or fully restored the mold growth, demonstrating that manganese depletion played a key role in the antifungal activity of the tested LAB cultures in the yoghurt matrix. Both L. plantarum LP01 and L. rhamnosus LRH01 showed efficient antifungal activities in the yoghurt serum, while L. rhamnosus LRH01 exhibited the most potent inhibitory effects on Penicillium strains when added during the processing of the yoghurt with subsequent storage at 7 °C for 22 days. Our findings suggested that L. rhamnosus LRH01 could be a promising bioprotective culture for yoghurt biopreservation.

Characterization of potential probiotic starter cultures of lactic acid bacteria isolated from Ethiopian fermented cereal beverages, Naaqe and Cheka.

To test the in vitro probiotic potential and starter culture capacity of lactic acid bacteria (LAB) isolated from Naaqe and Cheka, cereal-based Ethiopian traditional fermented beverages. 44 strains were isolated from spontaneously fermented Ethiopian cereal-based beverages, Naaqe and Cheka, with 24 putatively identified as LAB and 14 identified up to the species level. The species Limosilactobacillus fermentum (6/12; 50%) and Weissella confusa (5/12, 41.67%) were the predominant species identified from Naaqe, while the two Cheka isolates were Limosilactobacillus fermentum and Pediococcus pentosaceus. Six LAB strains inhibited eight of the nine gastrointestinal indicator key pathogens in Ethiopia, including Escherichia coli, Salmonella enterica subsp. enterica var. Typhimurium, Staphylococcus aureus, Shigella flexneri, and Listeria monocytogenes. Three of the LAB isolates exhibited strain-specific immunostimulation in human monocytes. Based on these probiotic properties and growth, six strains were selected for in situ evaluation in a mock fermentation of Naaqe and Cheka. During primary fermentations, L. fermentum 73B, P. pentosaceus 74D, L. fermentum 44B, Weissella confusa 44D, L. fermentum 82C and Weissella cibaria 83E and their combinations demonstrated higher pH-lowering properties and colony-forming unit counts compared to the control spontaneous fermentation. The same pattern was also observed in the secondary mock fermentation by the Naaqe LAB isolates. In this study, we selected six LAB strains with antipathogenic, immunostimulatory and starter culture potentials that can be used as autochthonous probiotic starters for Naaqe and Cheka fermentations, once their health benefit is ascertained in a clinical trial as a next step.

Inoculation with Lentilactobacillus buchneri alone or in combination with Lentilactobacillus hilgardii modifies gene expression, fermentation profile, and starch digestibility in high-moisture corn.

Inoculants combining Lentilactobacillus buchneri and Lentilactobacillus hilgardii have been shown to improve the aerobic stability of high-moisture corn (HMC) and whole-plant corn silage, but the mode of action of this co-inoculation remains to be elucidated. This study used metatranscriptomics to evaluate the effects of inoculation with L. buchneri alone or combined with L. hilgardii on the bacterial community, gene expression, fermentation profile, and starch digestibility in HMC. High-moisture corn not inoculated (Control) or inoculated with L. buchneri NCIMB 40788 (LB) or L. buchneri NCIMB 40788 combined with L. hilgardii CNCM-I-4785 (Combo) was ensiled in mini silo bags for 30, 60, 120, and 180 days. The fermentation profile was evaluated at all time points. Metatranscriptomics was performed on samples collected on day 120. Combo had a greater alpha diversity richness index of contigs than LB and Control, and inoculation with Combo and LB modified the beta-diversity of contigs compared to Control. Out of 69 genes of interest, 20 were differentially expressed in LB compared to Control and 25 in Combo compared to Control. Of those differently expressed genes, 16 (10 of which were associated with carbohydrate metabolism and six with amino acid metabolism) were differently expressed in both LB and Combo compared to Control, and all those genes were upregulated in the inoculated silages. When we compared Combo and LB, we found seven genes expressed differently, four associated with carbohydrate metabolism and downregulated in Combo, and three associated with amino acid metabolism and upregulated in Combo. At day 120, the inoculated silages had more culturable lactic acid bacteria, higher Lactobacillus relative abundance, and lower Leuconostoc relative abundance than Control. The concentration of acetic acid remained low throughout ensiling in Control, but in LB and Combo, it increased up to day 60 and remained stable from day 60 to 180. The 1,2-propanediol was only detected in LB and Combo. Inoculation did not affect the concentration of starch, but starch digestibility was greater in Combo than in Control. Inoculation of HMC with Combo modified the gene expression and fermentation profile compared to Control and LB, improving starch digestibility compared to uninoculated HMC.

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The article considers the issues of providing the dairy industry with Russian-made bacterial sourdough, ways to solve the problem of import substitution, providing biofactories with collection cultures of lactic acid bacteria, the assortment and classification of bacterial starter cultures, features of the use of additional and protective cultures, compliance of the species composition of starter cultures with the requirements of the legislation of the Customs Union.

Water-in-water Pickering emulsion: A fascinating microculture apparatus for embedding and cultivation of Lactobacillus helveticus

Currently, the cultivation of lactic acid bacteria is mainly carried out by improving the fermentation process and culture conditions, which was difficult to ensure the survival quantity and culture efficiency. The primary purpose of this work was to construct water-in-water (W/W) Pickering emulsion as a microculture for probiotics. The W/W Pickering emulsion consisting of maltodextrin (MD) and hydroxypropylmethylcellulose (HPMC) was constructed by using microcrystal celluloses (MCC) as the Pickering stabilizers. The effects of MCC concentration, NaCl concentration, MRS broth concentration, and pH value on the formation and stability of W/W Pickering emulsion have been investigated. The stability of W/W Pickering emulsions was driven by the electrostatic repulsion provided by the MCC. The stability of the emulsion was reduced by increasing NaCl and MRS broth concentrations, primarily because their charge shielding effect weakened the electrostatic repulsion between the MCC particles. The W/W Pickering emulsion had higher stability in a weakly acidic environment. The results from another trial revealed that Lactobacillus helveticus CICC 22,536 had little influence on the stability of the W/W Pickering emulsion when it was encapsulated in the emulsion. Moreover, Lactobacillus helveticus was able to be cultured in the emulsion, and the numbers of Lactobacillus helveticus after being cultured for 16 h were increased to 1.1 × 109 CFU/mL. These findings indicated that the W/W Pickering emulsion provided a new approach and an attractive platform for the cultivation of probiotic bacteria.

Detection of Lactic Acid Bacteria (LAB) In Soaking Water of Arabica Coffee Cherries on Mount Sindoro

Coffee is one of the major commodities in Indonesia's agricultural sector, where Indonesia is the fourth largest coffee producer in the world. Arabica coffee is the only type of coffee produced on Mount Sindoro. The used water is wasted in the sewers when washing and sorting coffee. Even though the skin covering the cherry flesh is likely to contain natural microorganism life since the coffee cherries grow during ripening on the tree. Therefore, this study aims to determine whether there is the presence or absence of Lactic Acid Bacteria (LAB) groups in the water used to soak the Arabica coffee cherries. The research method was carried out with 200 ml of water samples soaked in Arabica coffee cherries for 4 hours, isolating microorganisms from the 10-1 to 10-3 dilution series of soaking water using the spread plate method and reinoculation to obtain pure LAB cultures, then detected macroscopically through observation of colony morphology and microscopically detected, including physiological and biochemical reaction tests. Data analysis was conducted in a fully descriptive-qualitative manner concerning Bergey's Manual of Determinative Bacteriology and other books supporting the detection of the BAL groups obtained. The study results obtained three isolates, but only one isolate was detected as LAB. The isolate belongs to the Streptococcaceae family's LAB group- the Lactococcus genus.

Optimization of lactic acid bacterial starter culture to improve the quality and flavor characteristics of traditional Hurood

Hurood is a traditional fermented milk product prepared by traditional Mongolian techniques of fermenting raw milk, partial degreasing, heating, whey drainage, emulsification of curd, and molding. Currently, Hurood available in the market is generally prepared by small-scale enterprises at home or in open air. Therefore, lack of standardization of bacterial starter culture leads to variation in the flavor and sensory properties of Hurood from batch to batch. In this study, we aimed to assess the best starter culture combination obtained from 37 lactic acid bacterial strains isolated from traditional Hurood. The solidification state and sensory quality were used as indexes for determining the fermentation efficiency of the bacterial starter culture combinations. The yield and texture characteristics were used to determine the optimal ratio of bacterial strains in a combination and the processing conditions for traditional Hurood production. The most optimal bacterial culture combination was observed to be NF 9-3:NF 10-4:CH 3-1 in 5:4:1 ratio and in 3% amount. The most optimal whey temperature and heating-stirring temperature were observed to be 55°C to 60°C and 85°C to 90°C, respectively. Hurood prepared with the optimal combination of bacterial strains exhibited significantly enhanced sensory quality, flavor, and contents of AA and fatty acids. Therefore, the use of optimal starter culture of lactic acid bacteria could produce Hurood with significantly superior sensory qualities, making the product more acceptable to consumers.