P. Semjonovs

University of Latvia, Rija, Riga, Latvia

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Publications (14)8.47 Total impact

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    ABSTRACT: Bacterial extracellular fructans, known as levans, have potential applications in food, pharmaceutical and cosmetic industries and high fructan producing strains could contribute into the cost reduction and more extensive commercial usage of them. An acetic acid bacteria (AAB) isolate P1464 was obtained from the Microbial Strain Collection of Institute of Microbiology and Biotechnology, University of Latvia and identified as Gluconobacter nephelii by DNA-DNA hybridization and the formation of extracellular fructans by this strain was confirmed. Isolated extracellular fructose polymers were characterized using FT-IR spectroscopy and the structural features of fructan appeared as similar to the reference sample of bacterial levan. Molecular mass estimates showed that the isolated G. nephelii P1464 fructose polymer has a relatively small molecular weight (Mw 1122.939 +/- 153.453 kDa) and a sizeable polydispersity (Mw/Mn = 21.57 +/- 1.60), as compared with other AAB, which could promote their physiological activity, including the prebiotic effects. Obtained at different cultivation conditions characteristics of fructan production, including the biotechnological indices such as the productivity (Qp) and yield (Yp/s) ranging from 0.774 to 1.244 g l(-1) *h and from 0.181 to 0.436 g g(-1) , respectively, confirmed, that G. nephelii P1464 could be used as promising strain for commercial production of levan. This article is protected by copyright. All rights reserved.
    No preview · Article · Nov 2015 · Letters in Applied Microbiology
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    Preview · Article · Sep 2015 · Current Nutrition & Food Science
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    ABSTRACT: Fish is a well-known source of proteins, minerals, fat-soluble vitamins, antioxidants and other bio-active ingredients. Fish and its processing by-products are relatively cheap raw materials however still rarely are used to create food products with increased nutritive value, functional foods or feed supplements. Application of certain strains of probiotic bifidobacteria for fermentation of non-dairy substrates is a great challenge for industry-targeted research and industry with further offering to the market of functional food products. Our study is the first report on application of bifidobacteria for fermentation of fish. It was shown that a new fish-based functional food product can be obtained after fermentation of Baltic herring mince, supplemented with carbohydrates and NaCl, with a single-strain probiotic culture Bifidobacterium animalis subsp. lactis Bb12. Evaluation of FT-IR spectroscopy data indicated changes of proteins and the composition of total carbohydrates in fermented Baltic herring samples compared to the control. Glucose and sucrose ensured quick acidification and the decrease of pH, to achieve the cell count of B. lactis Bb12 up to 108CFU g-1, thus meeting requirements of the viable cell-count of probiotic bacteria in functional food products. However the highest cell counts of probiotic bacteria and acidification were reached using fish mince supplemented with sucrose (2%) and NaCl (1%). The obtained fermented baltic herring paste or its concentrate-after freeze-drying, still with high content of viable probiotic cells (107-108CFU g-1), can be used as functional food product as well as food and feed ingredients.
    No preview · Article · May 2015 · American Journal of Food Technology
  • P. Semjonovs · L. Shakizova · I. Denina · E. Kozlinskis · D. Unite
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    ABSTRACT: Since, prophylactic properties and status of healthy food is generally attributed to cabbage and probiotic Bifidobacterium lactis Bb12, scientific research is needed for simultaneous application of vegetable and fruit juices and probiotic cultures for development of novel functional drinks especially taking into consideration growing demand for non-dairy fermented beverages. There are few reports on fermentation of vegetable and fruit juices with bifidobacteria cultures and to our knowledge, this is first report on cabbage juice fermentation by bifidobacteria. The aim of this research was to develop novel functional beverage based on cabbage juice fermented with probiotic B. lactis Bb12. The probiotic B, lactis Bb12 grew well in cabbage juice at 25°C as the sole culture or in mixed starters, which is quite notable for bifidobacteria. Strains of bifidobacteria were relatively NaCl-tolerant at 5 g L-1. The addition of fructan sources promoted B. lactis Bb12 survival in fermented cabbage juice during storage at 4°C for 2 weeks. The survival of B. lactis Bb12 was dependent upon the molecular weight of the fructan source and contributed to the extension of the shelf life of the fermented cabbage juice. In this study, it was shown that B. lactis Bb12 grows well in cabbage juice, achieving a concentration of 106 CFU mL-1, the minimum required concentration for probiotic efficacy. It was stated that combination of probiotic strain B. lactis Bb12 and fructan additives is a prospective approach for cabbage juice-based fermented functional synbiotic beverage development.
    No preview · Article · Mar 2014 · Research Journal of Microbiology
  • P. Semjonovs · I. Denina · R. Linde
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    ABSTRACT: Kombucha is a traditional beverage consumed in various parts of the world. It is made by fermentation of sugared black tea by a consortium of yeasts and acetic acid bacteria. Recent studies have demonstrated that Kombucha possesses antioxidant, antimicrobial, hepatoprotective, nephroprotective and hypocholesterolaemic properties. Microbial composition of Kombucha association is highly variable therefore the chemical composition of obtained beverage can vary a lot and affect products quality. Thus, industrial production of Kombucha beverage is difficult and defined starter culture is strongly needed for obtaining the product with standard characteristics. In the present study individual starter cultures were used to obtain Kombucha like fermented beverage to evaluate its physiological effects in rat model for further development of functional beverage. Low density cholesterol, triglycerides and homocysteine levels elevated by fat diet decreased during intake of fermented beverage (2.5 mL kg-1 b.wt). To evaluate liver cell status alanine aminotransferase (ALAT) and aspartate Transaminase (ASAT) were assayed. It was shown that ASAT and ALAT decreased due to fermented beverage consumption in both-normal and high fat diet group. Zero rat mortality was observed during fermented beverage intake for 60 days (2.5-7.5 mL kg-1 b.wt.). This study on the consumption of fermented beverage obtained by use of defined starter suggests that it could be suitable for prevention of some metabolic disorders, like cardiovascular diseases or liver disorders, attributed to unhealthy lifestyle like high-fat diet. However, further research on physiological effects and possible mechanisms of action is needed and human studies would be welcomed.
    No preview · Article · Mar 2014 · Journal of Medical Sciences(Faisalabad)
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    ABSTRACT: Birch sap is traditionally used as a refreshing beverage in the springtime in northern Europe. The aim of this study was to determine the suitability of birch sap for the growth of potentially probiotic Lactobacillus reuteri strains in order to develop a non-dairy functional beverage. All L. reuteri strains used in the study grew well in birch sap. pH values fell from an initial pH 6 to pH 4.20-3.18 characteristic for fermented products. Total acidity up to 36 T° and sufficient cell count was reached (6.79 cfu/ml). Glucose and fructose supplementation as well as their combination at a concentration of 0.5-1% did not significantly improve the growth of L. reuteri. Supplementation with 0.5-2% sucrose and a 2% glucose-fructose combination had a notable effect, although the latter had less effect than the former. Given that the viable cell count is the most important parameter of probiotic products, supplementation with sucrose was chosen as the best way to improve the substrate. The addition of sucrose stimulated biomass formation and improved acidification power, with the best results for sucrose 0.5-2%. Several other food grade supplements were evaluated to improve the growth of L. reuteri strains in 1% sucrose-supplemented birch sap. The best results were achieved using peppermint and malt extract supplements, which clearly indicate that L. reuteri growth in birch sap is limited not only by the availability of carbon but also by the availability of other growth factors present in the supplements used.
    No preview · Article · Jan 2014
  • I Deniņa · P Semjonovs · A Fomina · R Treimane · R Linde
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    ABSTRACT: Unlabelled: Use of stevia-derived sweeteners was recently officially approved by the European Commission, and their application in the food industry has increased, especially in functional foods. However, there are scarce data about the influence of stevia on probiotic bacteria, which are important both as an inhabitant of the human gut and as a functional food additive. Taking into consideration the broad application of Lactobacillus reuteri in functional foods, the aim of the research was to evaluate the influence of stevia glycosides on its growth. Six Lact. reuteri strains were tested for their ability to grow in the presence of stevioside and rebaudioside A (0·2-2·6 g l(-1) ). The effect of stevia glycosides on biomass concentration, cell count, pH and lactic and acetic acid synthesis was analysed. Both glycosides impaired the growth of analysed strains. However, the inhibitory effect was strain specific, and the concentration-dependent effect was not observed for all parameters. The most pronounced concentration-dependent effect was on lactic and acetic acid production. Taking into account the observed strain-specific inhibitory effect of stevia glycosides, it could be suggested to evaluate the influence of them on each strain employed before their simultaneous application in functional foods. Significance and impact of the study: The study showed that the growth of Lactobacillus reuteri strains was inhibited in the presence of stevia sweeteners stevioside and rebaudioside A. Probiotics, for example Lact. reuteri strains, are often used as functional additives in health foods and are an important natural inhabitant of the human gastrointestinal tract. Stevia glycosides application in food is increasing; yet, there are no data about the influence of stevia glycosides on Lact. reuteri growth and very few data on growth of other lactobacilli, either in probiotic foods or in the gastrointestinal tract. This research shows that it is necessary to evaluate the influence of stevia glycosides on other groups of micro-organisms in further research.
    No preview · Article · Oct 2013 · Letters in Applied Microbiology
  • P. Semjonovs · I. Denina · A. Fomina · L. Sakirova · L. Auzina · A. Patetko · D. Upite
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    ABSTRACT: Recently demand for non-dairy-based probiotic products has increased and is a global trend. Recently great interest is arising for vegetable and especially vegetable juices fermentation for development of non-dairy functional products. Health promoting properties of pumpkin (Cucurbita pepo) is well known but there are only few data on pumpkin juice fermentation. Starter cultures have great influence on product organoleptic properties and therefore careful selection of cultures suitable for fermentation of certain raw materials is required. Recent studies marked out probiotic strains of Lactobacillus reuteri between other probiotics but there are no data on application of L. reuteri strains for juice e.g., pumpkin fermentation. The objective of this study was to determine the suitability of L. reuteri strains for fermentation of pumpkin juice and development of fermented potentially probiotic pumpkin juice-based beverage. L. reuteri strains used in the study grew well in pumpkin juice however strain specific growth trends were observed. Salt tolerance combined with very good sensory properties was chosen as characteristic parameters to select most prospective L. reuteri strains. It was shown that pumpkin juice supplementation with additional sugars (glucose, fructose or sucrose 1-4%) did not promote fermentation process and was disadvantage. L. reuteri strains exhibited excellent survival during 4 weeks cold storage of fermented pumpkin juice at the level of 109 CFU mL-1 that is sufficient for probiotics effective supply with food. It was concluded that application of certain L. reuteri strains for pumpkin juice fermentation is a promising way for development of novel non-dairy based probiotic fermented beverage.
    No preview · Article · May 2013 · Biotechnology(Faisalabad)
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    Pavels Semjonovs · Peteris Zikmanis
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    ABSTRACT: A novel strain of lactic acid bacteria Pediococcus pentosaceus P 773 was isolated from spoiled beer and identified by means of 16S rDNA sequence analysis. The ability to assimilate lactose as a sole carbon source as a specific feature for this strain was detected and confirmed on dairy substrates. In the presence of sucrose containing substrates (sucrose, raffinose) this P. pentosaceus P 773 lactose-positive strain produced a complex of extracellular polysaccharides (Qp=0.08g/l/h) with a molecular mass about 2,000kDa composed by glucose and fructose residues at a ratio 3:1, respectively. These exopolysaccharides were capable to stimulate the growth rate and biomass productivity of common constituent cultures of probiotic dairy starters (Bifidobacterium lactis, Lactobacillus acidophilus, Streptococcus thermophilus) as well as were assimilated as a sole carbon source by these strains. The present study confirmed the presence of lactose-positive and exopolysaccharide-producing strain of P. pentosaceus in natural environment which could be used as a starter culture to impart more functional attributes to fermented food.
    Full-text · Article · Jul 2008 · European Food Research and Technology
  • P. Semjonovs · P. Zikmanis · M. Bekers
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    ABSTRACT: Supplementation of milk and oat hydrolysate containing medium with Jerusalem artichoke concentrate (JAC) and subsequent fermentation with probiotic dairy starters resulted in substantial stimulation of probiotics Bifidobacterium lactis and Lactobacillus acidophilus as well as yogurt starter culture Lactobacillus bulgaricus development and acidification rate. The strain-specific responses of the general yogurt cultures, as well as probiotics to the addition of JAC, should be considered to achieve optimal composition of probiotic strains and conformable fermentation conditions. JAC is suggested to be perspective prebiotic additive for fermented synbiotic milks or oat-hydrolysate-based products.
    No preview · Article · Dec 2007 · Food Biotechnology
  • J Raipulis · M.M. Toma · P Semjonovs
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    ABSTRACT: Antigenotoxic activity of probiotic bacteria against furazolidone was studied using the short-term bacterial assay SOS chromotest, with Escherichia coli PQ37 as the test organism. The supernatants from probiotic and furazolidone co-incubation exhibited rather strong suppression on SOS induction produced by furazolidone on E. coli PQ 37 (sfiA: lacZ). Genotoxicity inhibition was found for all strains of the examined bacteria belonging to three genera. The highest genotoxicity inhibition was detected for Bifidobacterium lactis Bb-12 (92.0%) and for Lactobacillus acidophilus T20 (81.9%).
    No preview · Article · Aug 2005 · International Journal of Food Microbiology
  • RaipulisJ · Toma M. · Semjonovs P.

    No preview · Conference Paper · Sep 2004
  • I. Vina · R. Linde · A. Patetko · P. Semjonovs

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  • P. Semjonovs · J. Jasko · L. Auzina · P. Zikmanis

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