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Maija Tenkanen - One of the best experts on this subject based on the ideXlab platform.
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interactions between fava bean protein and Dextrans produced by leuconostoc pseudomesenteroides dsm 20193 and weissella cibaria sj 1b
Carbohydrate Polymers, 2018Co-Authors: Yan Xu, Leena Pitkänen, Rossana Coda, Ndegwa Henry Maina, Kati Katina, Maija TenkanenAbstract:Abstract The aim of this study was to study the interactions between dextran and fava bean protein. Two Dextrans produced by Leuconostoc pseudomesenteroides DSM 20193 and Weissella cibaria Sj 1b were purified and mixed with fava bean protein isolate (FPI) in water or in different buffers. The two isolated Dextrans presented a typical dextran structure, mainly α-(1 → 6) linkages (above 95%) and few α-(1 → 3) branches, but they differed in molar mass and conformation. Dry-heating incubation of FPI and dextran mixture facilitated the conjugation of dextran to FPI through the Maillard reaction. Both mixed and conjugated systems were further heat-treated, and different influences of the formed covalent bonds on rheological properties were observed. The W. cibaria Sj 1b dextran had a much higher gel-strengthening ability than the Ln. pseudomesenteroides DSM 20193 dextran. The intermolecular FPI-dextran interactions played an important role in stabilizing the mixed systems at different pH.
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challenges in analysis of high molar mass Dextrans comparison of hpsec asflfff and dosy nmr spectroscopy
Carbohydrate Polymers, 2014Co-Authors: Ndegwa Henry Maina, Leena Pitkänen, Liisa Virkki, Sami Heikkinen, Paivi Tuomainen, Maija TenkanenAbstract:Dilute solutions of various dextran standards, a high-molar mass (HMM) commercial dextran from Leuconostoc spp., and HMM Dextrans isolated from Weissella confusa and Leuconostoc citreum were analyzed with high-performance size-exclusion chromatography (HPSEC), asymmetric flow field-flow fractionation (AsFlFFF), and diffusion-ordered NMR spectroscopy (DOSY). HPSEC analyses were performed in aqueous and dimethyl sulfoxide (DMSO) solutions, while only aqueous solutions were utilized in AsFlFFF and DOSY. The study showed that all methods were applicable to dextran analysis, but differences between the aqueous and DMSO-based solutions were obtained for HMM samples. These differences were attributed to the presence of aggregates in aqueous solution that were less prevalent in DMSO. The study showed that DOSY provides an estimate of the size of HMM Dextrans, though calibration standards may be required for each experimental set-up. To our knowledge, this is the first study utilizing these three methods in analyzing HMM Dextrans.
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challenges in analysis of high molar mass Dextrans comparison of hpsec asflfff and dosy nmr spectroscopy
Carbohydrate Polymers, 2014Co-Authors: Ndegwa Henry Maina, Leena Pitkänen, Liisa Virkki, Sami Heikkinen, Paivi Tuomainen, Maija TenkanenAbstract:Dilute solutions of various dextran standards, a high-molar mass (HMM) commercial dextran from Leuconostoc spp., and HMM Dextrans isolated from Weissella confusa and Leuconostoc citreum were analyzed with high-performance size-exclusion chromatography (HPSEC), asymmetric flow field-flow fractionation (AsFlFFF), and diffusion-ordered NMR spectroscopy (DOSY). HPSEC analyses were performed in aqueous and dimethyl sulfoxide (DMSO) solutions, while only aqueous solutions were utilized in AsFlFFF and DOSY. The study showed that all methods were applicable to dextran analysis, but differences between the aqueous and DMSO-based solutions were obtained for HMM samples. These differences were attributed to the presence of aggregates in aqueous solution that were less prevalent in DMSO. The study showed that DOSY provides an estimate of the size of HMM Dextrans, though calibration standards may be required for each experimental set-up. To our knowledge, this is the first study utilizing these three methods in analyzing HMM Dextrans.
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nmr spectroscopic analysis of exopolysaccharides produced by leuconostoc citreum and weissella confusa
Carbohydrate Research, 2008Co-Authors: Ndegwa Henry Maina, Maija Tenkanen, Hannu Maaheimo, Riikka Juvonen, Liisa VirkkiAbstract:Abstract Dextrans are the main exopolysaccharides produced by Leuconostoc species. Other dextran-producing lactic acid bacteria include Streptococci , Lactobacilli , and Weissella species. Commercial production and structural analysis has focused mainly on Dextrans from Leuconostoc species, particularly on Leuconostoc mesenteroides strains. In this study, we used NMR spectroscopy techniques to analyze the structures of Dextrans produced by Leuconostoc citreum E497 and Weissella confusa E392. The Dextrans were compared to that of L. mesenteroides B512F produced under the same conditions. Generally, W. confusa E392 showed better growth and produced more EPS than did L. citreum E497 and L. mesenteroides B512F. Both L. citreum E497 and W. confusa E392 produced a class 1 dextran. Dextran from L. citreum E497 contained about 11% α-(1→2) and about 3.5% α-(1→3)-linked branches whereas dextran from W. confusa E392 was linear with only a few (2.7%) α-(1→3)-linked branches. Dextran from W. confusa E392 was found to be more linear than that of L. mesenteroides B512F, which, according to the present study, contained about 4.1% α-(1→3)-linked branches. Functionality, whether physiological or technological, depends on the structure of the polysaccharide. Dextran from L. citreum E497 may be useful as a source of prebiotic gluco-oligosaccharides with α-(1→2)-linked branches, whereas W. confusa E392 could be a suitable alternative to widely used L. mesenteroides B512F in the production of linear dextran.
Magali Remaud Simeon - One of the best experts on this subject based on the ideXlab platform.
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In Vitro Fermentation of Linear and alpha-1,2-Branched Dextrans by the Human Fecal Microbiota
Applied and Environmental Microbiology, 2011Co-Authors: Shahrul R. Sarbini, Sofia Kolida, Thierry Naeye, Alexandra Einerhand, Yoann Brison, Magali Remaud Simeon, Pierre Monsan, Glenn R. Gibson, Robert A. RastallAbstract:The role of structure and molecular weight in fermentation selectivity in linear alpha-1,6 Dextrans and Dextrans with alpha-1,2 branching was investigated. Fermentation by gut bacteria was determined in anaerobic, pH-controlled fecal batch cultures after 36 h. Inulin (1%, wt/vol), which is a known prebiotic, was used as a control. Samples were obtained at 0, 10, 24, and 36 h of fermentation for bacterial enumeration by fluorescent in situ hybridization and short-chain fatty acid analyses. The gas production of the substrate fermentation was investigated in non-pH-controlled, fecal batch culture tubes after 36 h. Linear and branched 1-kDa Dextrans produced significant increases in Bifidobacterium populations. The degree of alpha-1,2 branching did not influence the Bifidobacterium populations; however, alpha-1,2 branching increased the dietary fiber content, implying a decrease in digestibility. Other measured bacteria were unaffected by the test substrates except for the Bacteroides-Prevotella group, the growth levels of which were increased on inulin and 6- and 70-kDa Dextrans, and the Faecalibacterium prausnitzii group, the growth levels of which were decreased on inulin and 1-kDa Dextrans. A considerable increase in short-chain fatty acid concentration was measured following the fermentation of all Dextrans and inulin. Gas production rates were similar among all Dextrans tested but were significantly slower than that for inulin. The linear 1-kDa dextran produced lower total gas and shorter time to attain maximal gas production compared to those of the 70-kDa dextran (branched) and inulin. These findings indicate that Dextrans induce a selective effect on the gut flora, short-chain fatty acids, and gas production depending on their length.
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Synthesis of Dextrans with controlled amounts of α-1,2 linkages using the transglucosidase GBD–CD2
Applied Microbiology and Biotechnology, 2010Co-Authors: Yoann Brison, Pierre Monsan, Emeline Fabre, Claire Moulis, Jean-charles Portais, Magali Remaud SimeonAbstract:GBD–CD2 is an α-1,2 transglucosidase engineered from DSR-E, a glucansucrase naturally produced by Leuconostoc mesenteroides NRRL B-1299. This enzyme catalyses from sucrose, the α-1,2 transglucosylation of glucosyl moieties onto α-1,6 dextran chains. Steady-state kinetic studies showed that hydrolysis and transglucosylation reactions occurred at the early stage of the reaction in the presence of 70 kDa dextran as acceptor and sucrose. The transglucosylation reaction catalysed by GBD–CD2 follows a Ping Pong Bi Bi mechanism with a high k _cat value of 970 s^−1. The amount of the synthesised α-1,2 side chains was found to be directly dependent on the initial molar ratio [Sucrose]/[Dextran]. Dextrans with controlled α-1,2 linkage contents ranging from 13% to 40% were synthesised. The procedure resulted in the production of Dextrans with the highest content of α-1,2 linkages ever reported.
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Synthesis of Dextrans with controlled amounts of α-1,2 linkages using the transglucosidase GBD-CD2
Applied Microbiology and Biotechnology, 2010Co-Authors: Y. Brison, P. Monsan, Emeline Fabre, Claire Moulis, Jean-charles Portais, Magali Remaud SimeonAbstract:GBD-CD2 is an α-1,2 transglucosidase engineered from DSR-E, a glucansucrase naturally produced by Leuconostoc mesenteroides NRRL B-1299. This enzyme catalyses from sucrose, the α-1,2 transglucosylation of glucosyl moieties onto α-1,6 dextran chains. Steady-state kinetic studies showed that hydrolysis and transglucosylation reactions occurred at the early stage of the reaction in the presence of 70 kDa dextran as acceptor and sucrose. The transglucosylation reaction catalysed by GBD-CD2 follows a Ping Pong Bi Bi mechanism with a high kcat value of 970 s-1. The amount of the synthesised α-1,2 side chains was found to be directly dependent on the initial molar ratio [Sucrose]/[Dextran]. Dextrans with controlled α-1,2 linkage contents ranging from 13% to 40% were synthesised. The procedure resulted in the production of Dextrans with the highest content of α-1,2 linkages ever reported.
Ndegwa Henry Maina - One of the best experts on this subject based on the ideXlab platform.
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interactions between fava bean protein and Dextrans produced by leuconostoc pseudomesenteroides dsm 20193 and weissella cibaria sj 1b
Carbohydrate Polymers, 2018Co-Authors: Yan Xu, Leena Pitkänen, Rossana Coda, Ndegwa Henry Maina, Kati Katina, Maija TenkanenAbstract:Abstract The aim of this study was to study the interactions between dextran and fava bean protein. Two Dextrans produced by Leuconostoc pseudomesenteroides DSM 20193 and Weissella cibaria Sj 1b were purified and mixed with fava bean protein isolate (FPI) in water or in different buffers. The two isolated Dextrans presented a typical dextran structure, mainly α-(1 → 6) linkages (above 95%) and few α-(1 → 3) branches, but they differed in molar mass and conformation. Dry-heating incubation of FPI and dextran mixture facilitated the conjugation of dextran to FPI through the Maillard reaction. Both mixed and conjugated systems were further heat-treated, and different influences of the formed covalent bonds on rheological properties were observed. The W. cibaria Sj 1b dextran had a much higher gel-strengthening ability than the Ln. pseudomesenteroides DSM 20193 dextran. The intermolecular FPI-dextran interactions played an important role in stabilizing the mixed systems at different pH.
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challenges in analysis of high molar mass Dextrans comparison of hpsec asflfff and dosy nmr spectroscopy
Carbohydrate Polymers, 2014Co-Authors: Ndegwa Henry Maina, Leena Pitkänen, Liisa Virkki, Sami Heikkinen, Paivi Tuomainen, Maija TenkanenAbstract:Dilute solutions of various dextran standards, a high-molar mass (HMM) commercial dextran from Leuconostoc spp., and HMM Dextrans isolated from Weissella confusa and Leuconostoc citreum were analyzed with high-performance size-exclusion chromatography (HPSEC), asymmetric flow field-flow fractionation (AsFlFFF), and diffusion-ordered NMR spectroscopy (DOSY). HPSEC analyses were performed in aqueous and dimethyl sulfoxide (DMSO) solutions, while only aqueous solutions were utilized in AsFlFFF and DOSY. The study showed that all methods were applicable to dextran analysis, but differences between the aqueous and DMSO-based solutions were obtained for HMM samples. These differences were attributed to the presence of aggregates in aqueous solution that were less prevalent in DMSO. The study showed that DOSY provides an estimate of the size of HMM Dextrans, though calibration standards may be required for each experimental set-up. To our knowledge, this is the first study utilizing these three methods in analyzing HMM Dextrans.
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challenges in analysis of high molar mass Dextrans comparison of hpsec asflfff and dosy nmr spectroscopy
Carbohydrate Polymers, 2014Co-Authors: Ndegwa Henry Maina, Leena Pitkänen, Liisa Virkki, Sami Heikkinen, Paivi Tuomainen, Maija TenkanenAbstract:Dilute solutions of various dextran standards, a high-molar mass (HMM) commercial dextran from Leuconostoc spp., and HMM Dextrans isolated from Weissella confusa and Leuconostoc citreum were analyzed with high-performance size-exclusion chromatography (HPSEC), asymmetric flow field-flow fractionation (AsFlFFF), and diffusion-ordered NMR spectroscopy (DOSY). HPSEC analyses were performed in aqueous and dimethyl sulfoxide (DMSO) solutions, while only aqueous solutions were utilized in AsFlFFF and DOSY. The study showed that all methods were applicable to dextran analysis, but differences between the aqueous and DMSO-based solutions were obtained for HMM samples. These differences were attributed to the presence of aggregates in aqueous solution that were less prevalent in DMSO. The study showed that DOSY provides an estimate of the size of HMM Dextrans, though calibration standards may be required for each experimental set-up. To our knowledge, this is the first study utilizing these three methods in analyzing HMM Dextrans.
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nmr spectroscopic analysis of exopolysaccharides produced by leuconostoc citreum and weissella confusa
Carbohydrate Research, 2008Co-Authors: Ndegwa Henry Maina, Maija Tenkanen, Hannu Maaheimo, Riikka Juvonen, Liisa VirkkiAbstract:Abstract Dextrans are the main exopolysaccharides produced by Leuconostoc species. Other dextran-producing lactic acid bacteria include Streptococci , Lactobacilli , and Weissella species. Commercial production and structural analysis has focused mainly on Dextrans from Leuconostoc species, particularly on Leuconostoc mesenteroides strains. In this study, we used NMR spectroscopy techniques to analyze the structures of Dextrans produced by Leuconostoc citreum E497 and Weissella confusa E392. The Dextrans were compared to that of L. mesenteroides B512F produced under the same conditions. Generally, W. confusa E392 showed better growth and produced more EPS than did L. citreum E497 and L. mesenteroides B512F. Both L. citreum E497 and W. confusa E392 produced a class 1 dextran. Dextran from L. citreum E497 contained about 11% α-(1→2) and about 3.5% α-(1→3)-linked branches whereas dextran from W. confusa E392 was linear with only a few (2.7%) α-(1→3)-linked branches. Dextran from W. confusa E392 was found to be more linear than that of L. mesenteroides B512F, which, according to the present study, contained about 4.1% α-(1→3)-linked branches. Functionality, whether physiological or technological, depends on the structure of the polysaccharide. Dextran from L. citreum E497 may be useful as a source of prebiotic gluco-oligosaccharides with α-(1→2)-linked branches, whereas W. confusa E392 could be a suitable alternative to widely used L. mesenteroides B512F in the production of linear dextran.
Liisa Virkki - One of the best experts on this subject based on the ideXlab platform.
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challenges in analysis of high molar mass Dextrans comparison of hpsec asflfff and dosy nmr spectroscopy
Carbohydrate Polymers, 2014Co-Authors: Ndegwa Henry Maina, Leena Pitkänen, Liisa Virkki, Sami Heikkinen, Paivi Tuomainen, Maija TenkanenAbstract:Dilute solutions of various dextran standards, a high-molar mass (HMM) commercial dextran from Leuconostoc spp., and HMM Dextrans isolated from Weissella confusa and Leuconostoc citreum were analyzed with high-performance size-exclusion chromatography (HPSEC), asymmetric flow field-flow fractionation (AsFlFFF), and diffusion-ordered NMR spectroscopy (DOSY). HPSEC analyses were performed in aqueous and dimethyl sulfoxide (DMSO) solutions, while only aqueous solutions were utilized in AsFlFFF and DOSY. The study showed that all methods were applicable to dextran analysis, but differences between the aqueous and DMSO-based solutions were obtained for HMM samples. These differences were attributed to the presence of aggregates in aqueous solution that were less prevalent in DMSO. The study showed that DOSY provides an estimate of the size of HMM Dextrans, though calibration standards may be required for each experimental set-up. To our knowledge, this is the first study utilizing these three methods in analyzing HMM Dextrans.
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challenges in analysis of high molar mass Dextrans comparison of hpsec asflfff and dosy nmr spectroscopy
Carbohydrate Polymers, 2014Co-Authors: Ndegwa Henry Maina, Leena Pitkänen, Liisa Virkki, Sami Heikkinen, Paivi Tuomainen, Maija TenkanenAbstract:Dilute solutions of various dextran standards, a high-molar mass (HMM) commercial dextran from Leuconostoc spp., and HMM Dextrans isolated from Weissella confusa and Leuconostoc citreum were analyzed with high-performance size-exclusion chromatography (HPSEC), asymmetric flow field-flow fractionation (AsFlFFF), and diffusion-ordered NMR spectroscopy (DOSY). HPSEC analyses were performed in aqueous and dimethyl sulfoxide (DMSO) solutions, while only aqueous solutions were utilized in AsFlFFF and DOSY. The study showed that all methods were applicable to dextran analysis, but differences between the aqueous and DMSO-based solutions were obtained for HMM samples. These differences were attributed to the presence of aggregates in aqueous solution that were less prevalent in DMSO. The study showed that DOSY provides an estimate of the size of HMM Dextrans, though calibration standards may be required for each experimental set-up. To our knowledge, this is the first study utilizing these three methods in analyzing HMM Dextrans.
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nmr spectroscopic analysis of exopolysaccharides produced by leuconostoc citreum and weissella confusa
Carbohydrate Research, 2008Co-Authors: Ndegwa Henry Maina, Maija Tenkanen, Hannu Maaheimo, Riikka Juvonen, Liisa VirkkiAbstract:Abstract Dextrans are the main exopolysaccharides produced by Leuconostoc species. Other dextran-producing lactic acid bacteria include Streptococci , Lactobacilli , and Weissella species. Commercial production and structural analysis has focused mainly on Dextrans from Leuconostoc species, particularly on Leuconostoc mesenteroides strains. In this study, we used NMR spectroscopy techniques to analyze the structures of Dextrans produced by Leuconostoc citreum E497 and Weissella confusa E392. The Dextrans were compared to that of L. mesenteroides B512F produced under the same conditions. Generally, W. confusa E392 showed better growth and produced more EPS than did L. citreum E497 and L. mesenteroides B512F. Both L. citreum E497 and W. confusa E392 produced a class 1 dextran. Dextran from L. citreum E497 contained about 11% α-(1→2) and about 3.5% α-(1→3)-linked branches whereas dextran from W. confusa E392 was linear with only a few (2.7%) α-(1→3)-linked branches. Dextran from W. confusa E392 was found to be more linear than that of L. mesenteroides B512F, which, according to the present study, contained about 4.1% α-(1→3)-linked branches. Functionality, whether physiological or technological, depends on the structure of the polysaccharide. Dextran from L. citreum E497 may be useful as a source of prebiotic gluco-oligosaccharides with α-(1→2)-linked branches, whereas W. confusa E392 could be a suitable alternative to widely used L. mesenteroides B512F in the production of linear dextran.
Leena Pitkänen - One of the best experts on this subject based on the ideXlab platform.
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interactions between fava bean protein and Dextrans produced by leuconostoc pseudomesenteroides dsm 20193 and weissella cibaria sj 1b
Carbohydrate Polymers, 2018Co-Authors: Yan Xu, Leena Pitkänen, Rossana Coda, Ndegwa Henry Maina, Kati Katina, Maija TenkanenAbstract:Abstract The aim of this study was to study the interactions between dextran and fava bean protein. Two Dextrans produced by Leuconostoc pseudomesenteroides DSM 20193 and Weissella cibaria Sj 1b were purified and mixed with fava bean protein isolate (FPI) in water or in different buffers. The two isolated Dextrans presented a typical dextran structure, mainly α-(1 → 6) linkages (above 95%) and few α-(1 → 3) branches, but they differed in molar mass and conformation. Dry-heating incubation of FPI and dextran mixture facilitated the conjugation of dextran to FPI through the Maillard reaction. Both mixed and conjugated systems were further heat-treated, and different influences of the formed covalent bonds on rheological properties were observed. The W. cibaria Sj 1b dextran had a much higher gel-strengthening ability than the Ln. pseudomesenteroides DSM 20193 dextran. The intermolecular FPI-dextran interactions played an important role in stabilizing the mixed systems at different pH.
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challenges in analysis of high molar mass Dextrans comparison of hpsec asflfff and dosy nmr spectroscopy
Carbohydrate Polymers, 2014Co-Authors: Ndegwa Henry Maina, Leena Pitkänen, Liisa Virkki, Sami Heikkinen, Paivi Tuomainen, Maija TenkanenAbstract:Dilute solutions of various dextran standards, a high-molar mass (HMM) commercial dextran from Leuconostoc spp., and HMM Dextrans isolated from Weissella confusa and Leuconostoc citreum were analyzed with high-performance size-exclusion chromatography (HPSEC), asymmetric flow field-flow fractionation (AsFlFFF), and diffusion-ordered NMR spectroscopy (DOSY). HPSEC analyses were performed in aqueous and dimethyl sulfoxide (DMSO) solutions, while only aqueous solutions were utilized in AsFlFFF and DOSY. The study showed that all methods were applicable to dextran analysis, but differences between the aqueous and DMSO-based solutions were obtained for HMM samples. These differences were attributed to the presence of aggregates in aqueous solution that were less prevalent in DMSO. The study showed that DOSY provides an estimate of the size of HMM Dextrans, though calibration standards may be required for each experimental set-up. To our knowledge, this is the first study utilizing these three methods in analyzing HMM Dextrans.
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challenges in analysis of high molar mass Dextrans comparison of hpsec asflfff and dosy nmr spectroscopy
Carbohydrate Polymers, 2014Co-Authors: Ndegwa Henry Maina, Leena Pitkänen, Liisa Virkki, Sami Heikkinen, Paivi Tuomainen, Maija TenkanenAbstract:Dilute solutions of various dextran standards, a high-molar mass (HMM) commercial dextran from Leuconostoc spp., and HMM Dextrans isolated from Weissella confusa and Leuconostoc citreum were analyzed with high-performance size-exclusion chromatography (HPSEC), asymmetric flow field-flow fractionation (AsFlFFF), and diffusion-ordered NMR spectroscopy (DOSY). HPSEC analyses were performed in aqueous and dimethyl sulfoxide (DMSO) solutions, while only aqueous solutions were utilized in AsFlFFF and DOSY. The study showed that all methods were applicable to dextran analysis, but differences between the aqueous and DMSO-based solutions were obtained for HMM samples. These differences were attributed to the presence of aggregates in aqueous solution that were less prevalent in DMSO. The study showed that DOSY provides an estimate of the size of HMM Dextrans, though calibration standards may be required for each experimental set-up. To our knowledge, this is the first study utilizing these three methods in analyzing HMM Dextrans.