Starter Culture Strains Research Articles

Modeling of the conditions of the process of biotransformation of fish raw materials by bacterial starter cultures

Abstract In food biotechnology, special attention is given to the biotransformation by promising strains of bacterial starter cultures to obtain food products with improved quality characteristics and functional properties. Biotransformation using bacterial starter cultures may be a means to increase the shelf life of fish products, enhance their organoleptic properties, and increase their nutritional value through the formation of metabolites of their activity, which are the main factors of bioconservation and synthesis of vitamins and other biologically active substances. The probiotic properties of bacterial starter cultures will significantly influence the optimization of the indigenous microflora of the gastrointestinal tract, thereby strengthening the human body and its immune system overall to maintain a healthy lifestyle. The development of this trend is associated with the interest of the Russian population in products with a probiotic focus. In this regard, an analysis of data on the justification of the use of bacterial starter cultures for the biotransformation of fish raw materials has been conducted, and the necessary bacterial starter cultures have been selected. Based on theoretical and practical foundations, mathematical models of the biotransformation process by bacterial starter cultures have been constructed depending on the properties of fish raw materials and the biotechnological characteristics of the introduced microorganisms. The conducted research has been used to develop subsequent technological regimes for the biotransformation of fish raw materials by bacterial starter cultures as the basis for the formulations of “fast food” products containing functional components, which is justified by the accelerated pace of life and the desire of modern society to monitor their diet by consuming products that support a healthy lifestyle.

Probiotic Bifidobacterium animalis ssp. lactis Probio-M8 improves the fermentation and probiotic properties of fermented milk

Probiotics are increasingly used as starter cultures to produce fermented dairy products; however, few studies have investigated the role of probiotics in milk fermentation metabolism. The current study aimed to investigate whether adding Bifidobacterium animalis ssp. lactis Probio-M8 (Probio-M8) as a starter culture strain could improve milk fermentation by comparing the physicochemical characteristics and metabolomes of fermented milks produced by a commercial starter culture with and without Probio-M8. Our results showed that adding Probio-M8 shortened the milk fermentation time and improved the fermented milk texture and stability. Metabolomics analyses revealed that adding Probio-M8 affected mostly organic acid, AA, and fatty acid metabolism in milk fermentation. Targeted quantitative analyses revealed significant increases in various metabolites related to the sensory quality, nutritive value, and health benefits of the probiotic fermented milk, including 5 organic acids (acetic acid, lactic acid, citric acid, succinic acid, and tartaric acid), 5 EAA (valine, arginine, leucine, isoleucine, and lysine), glutamic acid, and 2 essential fatty acids (α-linolenic acid and docosahexaenoic acid). Thus, applying probiotics in milk fermentation is desirable. This study has generated useful information for developing novel functional dairy products.

Detection and classification of the integrative conjugative elements of Lactococcus lactis

Lactococcus lactis is widely applied by the dairy industry for the fermentation of milk into products such as cheese. Adaptation of L. lactis to the dairy environment often depends on functions encoded by mobile genetic elements (MGEs) such as plasmids. Other L. lactis MGEs that contribute to industrially relevant traits like antimicrobial production and carbohydrate utilization capacities belong to the integrative conjugative elements (ICE). Here we investigate the prevalence of ICEs in L. lactis using an automated search engine that detects colocalized, ICE-associated core-functions (involved in conjugation or mobilization) in lactococcal genomes. This approach enabled the detection of 36 candidate-ICEs in 69 L. lactis genomes. By phylogenetic analysis of conserved protein functions encoded in all lactococcal ICEs, these 36 ICEs could be classified in three main ICE-families that encompass 7 distinguishable ICE-integrases and are characterized by apparent modular-exchangeability and plasticity. Finally, we demonstrate that phylogenetic analysis of the conjugation-associated VirB4 ATPase function differentiates ICE- and plasmid-derived conjugation systems, indicating that conjugal transfer of lactococcal ICEs and plasmids involves genetically distinct machineries. Our genomic analysis and sequence-based classification of lactococcal ICEs creates a comprehensive overview of the conserved functional repertoires encoded by this family of MGEs in L. lactis, which can facilitate the future exploitation of the functional traits they encode by ICE mobilization to appropriate starter culture strains.

The microbial and metabolite composition of Gouda cheese made from pasteurized milk is determined by the processing chain

Gouda cheeses of different production batches and ripening times often differ in metabolite composition, which may be due to the starter culture mixture applied or the growth of non-starter lactic acid bacteria (NSLAB) upon maturation. Therefore, a single Gouda cheese production batch was systematically investigated from the thermized milk to the mature cheeses, ripened for up to 100 weeks, to identify the main bacterial species and metabolites and their dynamics during the whole production and ripening. As this seemed to be starter culture strain- and NSLAB-dependent, it requested a detailed, longitudinal, and quantitative investigation. Hereto, microbial colony enumeration, high-throughput full-length 16S rRNA gene sequencing, and a metabolomic approach were combined. Culture-dependently, Lactococcus lactis was the most abundant species from its addition as part of the starter culture up to the first two months of cheese ripening. Afterward, the NSLAB Lacticaseibacillus paracasei became the main species during ripening. The milk was a possible inoculation source for the latter species, despite pasteurization. Culture-independently, the starter LAB Lactococcus cremoris and Lc. lactis were the most abundant species in the cheese core throughout the whole fermentation and ripening phases up to 100 weeks. The cheese rind from 40 until 100 weeks of ripening was characterized by a high relative abundance of the NSLAB Tetragenococcus halophilus and Loigolactobacillus rennini, which both came from the brine. These species were linked with the production of the biogenic amines cadaverine and putrescine. The most abundant volatile organic compound was acetoin, an indicator of citrate and lactose fermentation during the production day, whereas the concentrations of free amino acids were an indicator of the ripening time.

Various cold storage-backslopping cycles show the robustness of Limosilactobacillus fermentum IMDO 130101 as starter culture for Type 3 sourdough production

Type 3 sourdoughs, which are starter culture-initiated and subsequently backslopped, are less studied than other sourdough types. Yet, they can serve as a model to assess how competitive starter culture strains for sourdough production are and how the microbial composition of such sourdoughs may evolve over time. In the present study, Limosilactobacillus fermentum IMDO 130101 was used to produce Type 3 sourdoughs, prepared from wheat and wholemeal wheat flours. Therefore, an initial fermentation of the flour-water mixture was performed at 30 °C for 48 h. This was followed by cold storage-backslopping cycles, consisting of refreshments (50 %, v/v), fermentation steps of 16 h, and storage at 4 °C each week, every three weeks, and every six weeks. The microbial dynamics (culture-dependent and -independent approaches) and metabolite dynamics were measured. In all sourdoughs produced, starter culture strain monitoring, following an amplicon sequence variant approach, showed that Liml. fermentum IMDO 130101 prevailed during one month when the sourdoughs were refreshed each week, during 24 weeks when the sourdoughs were refreshed every three weeks, and during 12 weeks when the sourdoughs were refreshed every six weeks. This suggested the competitiveness and robustness of Liml. fermentum IMDO 130101 for a considerable duration but also showed that the strain is prone to microbial interference. For instance, Levilactobacillus brevis and Pediococcus spp. prevailed upon further cold storage and backslopping. Also, although no yeasts were inoculated into the flour-water mixtures, Kazachstania unispora, Torulaspora delbrueckii, and Wickerhamomyces anomalus were the main yeast species found. They appeared after several weeks of storage and backslopping, which however indicated the importance of an interplay between LAB and yeast species in sourdoughs. The main differences among the mature sourdoughs obtained could be explained by the different flours used, the refreshment conditions applied, and the sampling time (before and after backslopping). Finally, the metabolite quantifications revealed continued metabolite production during the cold storage periods, which may impact the sourdough properties and those of the breads made thereof.

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.

Fermented camel milk influenced by soy extract: Apparent viscosity, viscoelastic properties, thixotropic behavior, and biological activities

During fermentation, camel milk forms a fragile, acid-induced gel, which is less stable compared with the gel formed by bovine milk. In this study, camel milk was supplemented with different levels of soy extract, and the obtained blends were fermented with 2 different starter culture strains (a high acidic culture and a low acidic culture). The camel milk-soy extract yogurt treatments were evaluated for pH value, acidity, total phenolic compounds, antioxidant capacities, degree of hydrolysis, α-amylase and α-glucosidase inhibition, angiotensin-converting enzyme inhibition, antiproliferative activities, and rheological properties after 1 and 21 d of storage at 4°C. The results revealed that some of the investigated parameters were significantly affected by the starter culture strain and storage period. For instance, the effect of starter cultures was evident for the degree of hydrolysis, antioxidant capacities, proliferation inhibition, and rheological properties because these treatments led to different responses. Furthermore, the characteristics of camel milk-soy extract yogurt were also influenced by the supplementation level of soy extract, particularly after 21 d of storage. This study could provide valuable knowledge to the dairy industry because it highlighted the characteristics of camel milk-soy yogurt prepared with 2 different starter culture strains.

Yeast strains do have an impact on the production of cured cocoa beans, as assessed with Costa Rican Trinitario cocoa fermentation processes and chocolates thereof.

The microbiological and metabolic outcomes of good cocoa fermentation practices can be standardized and influenced through the addition of starter culture mixtures composed of yeast and bacterial strains. The present study performed two spontaneous and 10 starter culture-initiated (SCI) cocoa fermentation processes (CFPs) in Costa Rica with local Trinitario cocoa. The yeast strains Saccharomyces cerevisiae IMDO 050523, Hanseniaspora opuntiae IMDO 020003, and Pichia kudriavzevii IMDO 060005 were used to compose starter culture mixtures in combination with the lactic acid bacterium strain Limosilactobacillus fermentum IMDO 0611222 and the acetic acid bacterium strain Acetobacter pasteurianus IMDO 0506386. The microbial community and metabolite dynamics of the cocoa pulp-bean mass fermentation, the metabolite dynamics of the drying cocoa beans, and the volatile organic compound (VOC) profiles of the chocolate production were assessed. An amplicon sequence variant approach based on full-length 16S rRNA gene sequencing instead of targeting the V4 region led to a highly accurate monitoring of the starter culture strains added, in particular the Liml. fermentum IMDO 0611222 strain. The latter strain always prevailed over the background lactic acid bacteria. A similar approach, based on the internal transcribed spacer (ITS1) region of the fungal rRNA transcribed unit, was used for yeast strain monitoring. The SCI CFPs evolved faster when compared to the spontaneous ones. Moreover, the yeast strains applied did have an impact. The presence of S. cerevisiae IMDO 050523 was necessary for successful fermentation of the cocoa pulp-bean mass, which was characterized by the production of higher alcohols and esters. In contrast, the inoculation of H. opuntiae IMDO 020003 as the sole yeast strain led to underfermentation and a poor VOC profile, mainly due to its low competitiveness. The P. kudriavzevii IMDO 060005 strain tested in the present study did not contribute to a richer VOC profile. Although differences in VOCs could be revealed in the cocoa liquors, no significant effect on the final chocolates could be obtained, mainly due to a great impact of cocoa liquor processing during chocolate-making. Hence, optimization of the starter culture mixture and cocoa liquor processing seem to be of pivotal importance.

Fermented milk and vegetable "Products for live"

In the dairy market of Kazakhstan, the demand for mass-produced dairy products is decreasing and expanding to innovative fermented milk products for functional nutrition. The main feature of the new technology is multicomponent formulations, which include the main raw materials and biocorrectors, ensuring their high biological and nutritional value. New dessert products are prepared on a dairy or protein basis using vegetable ingredients, fermented with strains of dry starter cultures of direct application or immobilized starter culture Bifimm probio. The purpose is to apply immobilized living cells of pure cultures of lacto- and bifidobacteria as a biocatalyst for the fermentation of dairy-vegetable media. During the study, the method of immobilization of microbial cells in biopolymer gels was used. The most effective method is the inclusion of cells in an aqueous solution of biopolymers with a concentration of 25 %. For immobilization, pure cultures of lactic acid and bifidobacteria were selected in the gel as part of the concentrates "BK-Altai-LS Bifi", "Poleznaya Partiya", "Genesis", "Narine", "Bio-yogurt Vivo", and the main prescription ingredients were selected: milk with a mass fraction of fat of 1 %, 2.5 %, 3.2 %, natural grain additives, jams, juices, nuts. Formulations, technological schemes and production methods, prototypes were developed, quality and safety indicators were determined. Studies have shown the effectiveness of immobilized starter cultures in the formation of fermented dessert products. Out of 20 prototypes with the best indicators, 5 samples were selected, in which the optimal ratio of milk, probio Bifimm starter cultures and biocorrectors averaged 70:20:10. The quality and safety analysis showed that new fermented milk products using immobilized starter cultures have a positive effect of more than -70 % compared to direct-use starter cultures, have functional properties and can be used for healthy nutrition in Kazakhstan.

Интеграция бактериальных заквасочных культур с рыбным сырьем: подбор и обоснование

An important aspect of the technology of processing fish raw materials is the development of food products of various directions using modern methods of biotechnological processing. In this regard, in food biotechnology, special attention is paid to biotransformation by promising strains of bacterial starter cultures to produce food products with improved quality characteristics, and in particular with a functional orientation. The use of bacterial starter cultures in the production of fish food products can be a way to extend the shelf life due to the formation of metabolites of their vital activity (acids and bacteriocins), which are the main factor of bioconservation. At the same time, the biochemical activity of bacterial starter cultures will contribute to improving the organoleptic and structural-mechanical properties of raw materials, as well as increasing the nutritional value and synthesis of vitamins and other nutrients, and giving the final product probiotic properties. This trend is a response to the interest of the population of the Russian Federation in probiotic products, which allows to normalize the indigenous microflora of the gastrointestinal tract, thereby strengthening the human body and its immune system as a whole. In this regard, the analysis of data on the justification of the use of bacterial starter cultures for the biotransformation of fish raw materials was carried out, and the necessary strains of microorganisms were selected. The analysis of scientific and technical databases has shown the prospects of scientific developments on the use of bacterial starter cultures as protective microorganisms and the study of the influence of the conditions of cultivation and preservation of bioactivity of a living cell under the influence of physical and chemical factors during the technological process of production and subsequent storage of products, which is of particular importance for the creation of probiotic food products. The conducted research will be used in the construction of mathematical models of the process of biotransformation of fish raw materials as a basis for the development of technological processing parameters for its subsequent use in the formulations of "fast food" products containing functional components, which is justified by the accelerated rhythm of life and the desire of modern society to monitor their nutrition by eating products that support a healthy lifestyle.
 In food biotechnology, special attention is given to biotransformation of promising strains of bacterial starter cultures for the production of food products with improved quality characteristics and functional orientation. In this regard, the analysis of data on the justification of the use of commercial, potentially commercial fish types for biotransformation by bacterial starter cultures and the selection of the necessary strains of microorganisms, which will be used in the construction of mathematical models of the process of biotransformation of fish raw materials as a basis for the development of technological parameters of processing.

Application of comparative genomics of Acetobacter species facilitates genome-scale metabolic reconstruction of the Acetobacter ghanensis LMG 23848T and Acetobacter senegalensis 108B cocoa strains.

Acetobacter species play an import role during cocoa fermentation. However, Acetobacter ghanensis and Acetobacter senegalensis are outcompeted during fermentation of the cocoa pulp-bean mass, whereas Acetobacter pasteurianus prevails. In this paper, an in silico approach aimed at delivering some insights into the possible metabolic adaptations of A. ghanensis LMG 23848T and A. senegalensis 108B, two candidate starter culture strains for cocoa fermentation processes, by reconstructing genome-scale metabolic models (GEMs). Therefore, genome sequence data of a selection of strains of Acetobacter species were used to perform a comparative genomic analysis. Combining the predicted orthologous groups of protein-encoding genes from the Acetobacter genomes with gene-reaction rules of GEMs from two reference bacteria, namely a previously manually curated model of A. pasteurianus 386B (iAp386B454) and two manually curated models of Escherichia coli (EcoCyc and iJO1366), allowed to predict the set of reactions present in A. ghanensis LMG 23848T and A. senegalensis 108B. The predicted metabolic network was manually curated using genome re-annotation data, followed by the reconstruction of species-specific GEMs. This approach additionally revealed possible differences concerning the carbon core metabolism and redox metabolism among Acetobacter species, pointing to a hitherto unexplored metabolic diversity. More specifically, the presence or absence of reactions related to citrate catabolism and the glyoxylate cycle for assimilation of C2 compounds provided not only new insights into cocoa fermentation but also interesting guidelines for future research. In general, the A. ghanensis LMG 23848T and A. senegalensis 108B GEMs, reconstructed in a semi-automated way, provided a proof-of-concept toward accelerated formation of GEMs of candidate functional starter cultures for food fermentation processes.

Functional yeast starter cultures for cocoa fermentation.

SummaryThe quest to develop a performant starter culture mixture to be applied in cocoa fermentation processes started in the 20th century, aiming at achieving high‐quality, reproducible chocolates with improved organoleptic properties. Since then, different yeasts have been proposed as candidate starter cultures, as this microbial group plays a key role during fermentation of the cocoa pulp‐bean mass. Yeast starter culture‐initiated fermentation trials have been performed worldwide through the equatorial zone and the effects of yeast inoculation have been analysed as a function of the cocoa variety (Forastero, Trinitario and hybrids) and fermentation method (farm‐, small‐ and micro‐scale) through the application of physicochemical, microbiological and chemical techniques. A thorough screening of candidate yeast starter culture strains is sometimes done to obtain the best performing strains to steer the cocoa fermentation process and/or to enhance specific features, such as pectinolysis, ethanol production, citrate assimilation and flavour production. Besides their effects during cocoa fermentation, a significant influence of the starter culture mixture applied is often found on the cocoa liquors and/or chocolates produced thereof. Thus, starter culture‐initiated cocoa fermentation processes constitute a suitable strategy to elaborate improved flavourful chocolate products.

Exopolysaccharide production in fermented milk using Lactobacillus casei strains AP and AG.

This study evaluated the ability of two strains of bacterial starter cultures, Lactobacillus casei AP (AP) and Lactobacillus casei AG (AG), to produce exopolysaccharides (EPSs). First, the physicochemical properties of the fermented milk produced by AP and AG were assessed, including physical qualities like viscosity and syneresis and chemical qualities, such as pH, acidity, protein, lactose, fat content, and total solid. Then, AP and AG's ability to produce EPS was measured. Additionally, the EPS' microstructure was observed using a scanning electron microscope, and its chemical structure was assessed using Fourier transform-infrared (FT-IR) spectroscopy. Also, AP and AG's ability to produce EPS was tracked at the molecular level by studying the glycosyltransferase (gtf) gene. Statistical analysis showed that the milk fermented using AP and AG had similar physicochemical qualities (P > 0.05) but significantly different physical qualities (P < 0.05). Additionally, the milk fermented with AP had lower viscosity (1137.33 ± 34.31 centiPoise) than AG (1221.50 ± 20.66 centiPoise). In addition, the milk fermented using AP had higher syneresis (19.42%) than AG (17.83%). The higher viscosity and lower syneresis in the milk fermented using AG were associated with AG's ability to produce more EPS (1409 mg/L) than AP (1204 mg/L). In addition, according to the FT-IR analysis, the AP- and AG-synthesized EPS contained absorption bands at 3323, 2980, 2901, 1642, 1084, 1043, and 873 cm−1. The absorption band at 1642 and 2980 cm−1 corresponds to carbonyl and methylene groups, respectively. Absorption band 873 cm−1 is characteristic of the α-glycosidic bond of α-glucan in EPS. Moreover, the absorption bands on the wavelength region corresponding to the functional groups in the AP- and AG-produced EPS were similar to those in commercially available EPS. Lastly, gtf, contributing to EPS synthesis, was found in the genomes of AP and AG, suggesting the role of glycosyltransferase in the EPS synthesis by both strains.

Antioxidant Properties of Fermented Camel Milk Prepared Using Different Microbial Cultures

This study investigated the effect of using different combinations of commercial starter culture and lactobacilli strains on the antioxidant properties of fermented camel milk for 14 days. The bacterial strains included Lb. casei subsp. casei B-1922, Lb. paracasei subsp. paracasei B-4560, Lb. rhamnosus B-442 and Lb. rhamnosus B-1445. The antioxidant activity of fermented milk was estimated using DPPH radical scavenging activity, ferrous ion chelating activity (FCA) and ferric reducing power assays. The total phenolic content (TPC), titratable acidity, proteolysis degree and sensory acceptability of samples were also evaluated. The results showed that all the studied parameters were affected by both the type of starter culture and storage. Samples containing the commercial starter and Lb. rhamnosus B-1445 had the highest DPPH radical scavenging activity and TPC throughout storage. Fermented milks prepared using the commercial starter and Lb. rhamnosus B-442 or Lb. paracasei retained their high FCA and reducing power throughout storage compared to the other samples. Fermented milk containing the commercial starter and Lb. casei showed the lowest antioxidant activity. The DPPH scavenging activity for all fermented milks decreased sharply during storage, while the change in FCA, reducing power and TPC differed among the samples during storage. The highest acidity was observed in the samples containing the commercial starter and Lb. paracasei, while fermented milk prepared using commercial starter and Lb. rhamnosus B-1445 had the lowest acidity. Samples containing the commercial starter and Lb. casei had the greatest proteolysis during the first week of storage, while samples containing the commercial starter and Lb. rhamnosus B-1445 had the highest proteolysis on day 14. Fermented milks with commercial starter and Lb. rhamnosus B-1445 or Lb. paracasei were the most acceptable products, while samples containing the commercial starter and Lb. casei were less acceptable.

Влияние микрокапсулированных стартовых культур на образование биологически активных пептидов в готовых мясных продуктах

Of particular importance in the production of fermented meat products are starter cultures with a proteolytic system that promotes the proteolysis of the protein components of meat raw materials. Numerous compounds, which may have biological activity, were formed as a result of the proteolysis, for example, biologically active peptides or bacteriocins. Nevertheless, there are some technological difficulties in the use of bacteria that contribute to the formation of biologically active peptides in raw meat. The solution to this problem can be microencapsulation. In this study, industrially valuable strains of starter cultures were selected, and proteolytic activity genes were identified. Thus, the proteolytic genes of the PRTB10/PRTB20 and P15C/P06C families were found in the P. acidilactici 38 and P. pentosaceus 28 strains, while the genes of the Jp23/Jp25 and prti2/IP6Xba families were found in the L. acidophilus AT-45 strain. The prti2/IP6Xba genes were also found in the S. carnosus 111-2 strain. A technology is proposed for incorporating microorganisms into alginate capsules with an alginate gel concentration of 5%, which makes it possible to form strong capsules capable of maintaining the viability of starter cultures in the production of boiled sausage: when incubating heat-treated capsules to 72 °С on chalk agar, the survival rate of microorganisms from 30 to 90% was recorded. The protein profile of the samples of boiled sausages produced using microencapsulated starter cultures was studied. A significant interaction of some strains with proteins of the actomyosin complex was shown, and the enzymes of energy metabolism from muscle tissue were subjected to destructive changes - muscle creatine phosphate kinase, enolase, and adenylate kinase 1. The paper contains 4 Figures, 4 Tables, and 27 References. The Authors declare no conflict of interest.

Studies on the Effectiveness of Wild and Commercialstrains of Lactic Acid Bacteria Starter Culture during Backsloping for Yoghurt Production

Yogurt is one of the traditionally fermented dairy products which are usually prepared with lactic acid bacteria cultures containing Streptococcus thermophilus and Lactobacillus bulgaricus. This starter culture could be prepared in addition to other bacteria as probiotics. Yoghurt has gained widespread consumer acceptance as a healthy diet. Yoghurts products are produced in Nigeria by using the imported starter culture bacteria and has played significant roles in helping dairy farmers convert their short-life, highly perishable fresh milk to fairly more stable products like cheese and yoghurt which are highly nutritious too for both low-and high-income earners. However, there are concerns over the growing food and food-related import dependency in the sub-African countries and Nigeria in particular which have increased during the last few years. The selection of indigenous starter culture strains withthecapacity for backsloping in yoghurt production might reduce importation and improve economy in a way. A foundamental benefit of backsloping is that it reduces the fermentation time while successfully maintaining sensory attributes of the product. The goal of this study was to determine the effects of backsloping fermentation of milk using indigenous and commercial (Exotic) strains of Lactic Acid Bacteria. Yoghurt fermentation was carried out by backsloping method using three commercial (Exotic) formulated cultures of Lactobacillus bulgaricus and Streptococcus thermophillus; ES07, ES32 and ES14 respectively as well aswild (isolated) formulated culture strains; WS11, WS65 and WS13 respectively and were used to produce yoghurt using backsloping method.. The overall sensory attributes of yoghurts produced using exotic compared with indigenous strains showed no significant (p &gt; 0.05) difference in term of acidification and coagulation ability. The pH of fermented products using commercial cultures ranged from 4.53-5.32, While pH of yoghurts produced using isolated cultures ranged from 4.35 – 4.72, total plate count 2.7 x 107- 2.3 x 108cfu/ml during the 10 hour fermentation times.The overall acceptability were in the decreasing order; WS65&gt;WS11&gt;ES07&gt;WS13&gt;ES14&gt;ES32.. From this order, backloping has equal advantages when both local and commercial starter cultures are used. Therefore, Starter culture formulation using indigenous strains could be further developed genetically for commercial applications because they compete favourably with their exotic counterparts. Hence, the current challenges of importation due to Covid-19 economic reality and foreign exchange will reduce to a minimal if the indigenous strains are utilised.

DEVELOPMENT OF A BACTERIAL STEERING STERE FOR A FODDER BALANCING CONCENTRATE «ECOBALANCE» FOR REGULATING MICROBIOLOGICAL PROCESSES IN COW'S PEREASTERS AND INCREASING DAIRY PRODUCTIVITY

Researches of physiological and biochemical characteristics of microorganisms from the Republican collection of industrial strains of starter cultures and their bacteriophages were carried out. Strains of Lactobacillus plantarum, Lactobacillus casei, Lactobacillus fermentum was selected. Consortia of microorganisms for use in the starter culture to regulate microbiological processes in the proventriculus of cows was developed. The effect of various components of the filler on the ability of lactic acid microorganisms to develop in their presence was investigated. The procedure for introducing and mixing technology of the starter culture and dry components of the feed concentrate has been worked out.

Assessment of the Effects of Back Sloping on Some Starter Culture Strains and the Organoleptic Qualities of their Yoghurt Products

Fermented milk is an essential commodity in Africa and beyond. Many techniques have been developed over time for the manufacture of different forms of yoghurt products. One of these Traditional methods includes back slopping). The advantages of this method include faster fermentation rates due to reduction in lag time, and subsequent production of relevant metabolites as well as allowing for a more reliable product formation on a consistent basis. The aim of this study was to better understand, the effects of back sloping on the microbial community as well as on the organoleptic characteristics of the yoghurts produced using the method. The model from this work could be used to study the dynamics of the microbial community associated with back-slopping practices and the understanding of possible associated defects in order to allow better control over the application of the method on commercial levels. We characterized the yoghurt produced from both microbial compositional study using culture-dependent morphological examinations on MRS, M17, Nutrient Agar and Potato dextrose Agar, as well as from organoleptic point of view. The results show that back sloping up to three-fold (batch) gave increasing acceptance but decreased afterwards. Acidification activity which determines proteolysis of casein for coagulation to take place also increased up to three folds. Residual lactose, syneresis and moisture content also decreased favourably by three fold order. Therefore, back sloping could be recommended on commercial level especially in the developing countries where facilities for consistent supply of pouched starter culture are limited because, aside the above mentioned advantages, this process also favours the growth of bacteria which release antimicrobial substances thereby ensuring the growth of the same species while reducing the growth of other organisms thereby preserving the products’ quality.

Metabolomic evaluation of different starter culture effects on water-soluble and volatile compound profiles in nozawana pickle fermentation

Metabolomic characterization of a lactic-fermented pickle of nozawana (Brassica rapa L. var. hakabura) was conducted to evaluate the effects of different starter culture strains on the chemical profiles. We compared the profiles of water-soluble and volatile compounds obtained by non-targeted nuclear magnetic resonance and solid-phase microextraction gas chromatography/mass spectrometry analyses. Principal component analyses indicated that the fermented samples differed significantly in terms of the levels of various compounds, including taste- and aroma-active components, such as water-soluble residual sugars, organic acids, mannitol, ethanol, dihydroxyacetone, ornithine, γ-aminobutyric acid, choline, volatile isothiocyanates, 3,4-epithiobutyl cyanide, 2,3-butanedione, acetoin, ethyl acetate, dimethyl trisulfide, and S-methyl thioacetate. Fermentation with a Latilactobacillus curvatus culture was associated with a unique metabolite profile characterized by higher levels of isothiocyanates and hexanoic acid and lower levels of lactic acid, acetic acid, acetoin, and 2,3-butanedione. These variations in the chemical profile might be associated with different qualities in fermented nozawana pickle products.

Genome Sequencing of Kocuria varians Strain 80, Isolated from Starter Culture for Dry Sausage.

The genome of the meat starter culture strain Kocuria varians 80 was sequenced and assembled into a single 2.82-Mb chromosome. Genome sequence comparison of K. varians strain 80 and previously sequenced strains revealed predicted proteomic differences that can impact its technological properties.