Concentration of xylooligosaccharides with a low degree of polymerization using membranes and their effect on bacterial fermentation

ABSTRACTCapillary gas chromatography has been used to monitor the stoichi-ometries, structures, and abundances of low molecular weight polysilicate esters formed by partial hydrolysis of methanolic tetramethylorthosili-cate and redistribution of methanolie hexamethyoxydisiloxane under acidic (HC1) and basic (KOH) conditions. The polysilicate molecular size distributions, expressed in terms of mole percent of total silicon present as a function of degree of polymerization, show maxima near the number average degree of polymerization under acidic conditions. Under basic conditions, the distribution has its maximum at the monomer percent and extends to very high molecular weights, yielding a distribution far broader than the one observed under acidic conditions. These features are in agreement with covalent network theories of silica gelation, as opposed to particle aggregation theories. Weight fraction distributions of the type observed under acidic conditions are characteristic of linear polymers with a low degree of crosslinking and weight fraction distributions of the type observed under basic conditions are characteristic of branched polymers with high degree of crosslinking. The low degree of crosslinking obtained under acidic conditions is observed to arise from steric crowding that discourages branching in polysilicate structures.

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Enzyme-Catalyzed Production of Potato Galactan-Oligosaccharides and Its Optimization by Response Surface Methodology

Materials ◽

10.3390/ma12091465 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1465 ◽

Cited By ~ 1

Author(s):

Mirian Angelene González-Ayón ◽

Ángel Licea-Claveríe ◽

José Benigno Valdez-Torres ◽

Lorenzo A. Picos-Corrales ◽

Rosabel Vélez-de la Rocha ◽

...

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Degree Of Polymerization ◽

Enzyme Substrate ◽

Low Degree ◽

Ft Ir ◽

Cellvibrio Japonicus ◽

Substrate Ratio ◽

Optimized Conditions ◽

Hydrolysis Of

This work shows an optimized enzymatic hydrolysis of high molecular weight potato galactan yielding pectic galactan-oligosaccharides (PGOs), where endo-β-1,4-galactanase (galactanase) from Cellvibrio japonicus and Clostridium thermocellum was used. For this, response surface methodology (RSM) by central composite design (CCD) was applied. The parameters varied were temperature (°C), pH, incubation time (min), and enzyme/substrate ratio (U/mg). The optimized conditions for the production of low degree of polymerization (DP) PGOs were obtained for each enzyme by spectrophotometric assay and confirmed by chromatography. The optimal conditions predicted for the use of C. japonicus galactanase to obtain PGOs of DP = 2 were T = 51.8 °C, pH 5, E/S = 0.508 U/mg, and t = 77.5 min. For DP = 3, they were T = 21 °C, pH 9, E/S = 0.484 U/mg, and t = 12.5 min; and for DP = 4, they were T = 21 °C, pH 5, E/S = 0.462 U/mg, and t = 12.5 min. The efficiency results were 51.3% for substrate hydrolysis. C. thermocellum galactanase had a lower yield (35.7%) and optimized conditions predicted for PGOs of DP = 2 were T = 60 °C, pH 5, E/S = 0.525 U/mg, and time = 148 min; DP = 3 were T = 59.7 °C, pH 5, E/S = 0.506 U/mg, and time = 12.5 min; and DP = 4, were T = 34.5 °C, pH 11, E/S = 0.525 U/mg, and time = 222.5 min. Fourier transformed infrared (FT-IR) and nuclear magnetic resonance (NMR) characterizations of PGOs are presented.

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Fructans with Varying Degree of Polymerization Enhance the Selective Growth of Bifidobacterium animalis subsp. lactis BB-12 in the Human Gut Microbiome In Vitro

Applied Sciences ◽

10.3390/app11020598 ◽

2021 ◽

Vol 11 (2) ◽

pp. 598

Author(s):

Pieter Van den Abbeele ◽

Cindy Duysburgh ◽

Jonas Ghyselinck ◽

Shellen Goltz ◽

Yulia Berezhnaya ◽

...

Keyword(s):

Gut Microbiome ◽

Lactate Production ◽

Degree Of Polymerization ◽

Human Gut ◽

Short Term ◽

Gastrointestinal Health ◽

Bifidobacterium Animalis ◽

Low Degree ◽

Butyrate Production

Synbiotics aim to improve gastrointestinal health by combining pre- and probiotics. This study evaluated combinations of Bifidobacterium animalis subsp. lactis BB-12 with seven fructans: oligofructoses (OF1-OF2; low degree of polymerization (DP)), inulins (IN1-IN2-IN3; high DP) and OF/IN mixtures (OF/IN1-OF/IN2). During monoculture incubations, all fructans were fermented by BB-12 as followed from increased BB-12 numbers and increased acetate and lactate concentrations, with most pronounced fermentation for low DP fructans (OF1-OF2). Further, short-term colonic incubations for three human donors revealed that also in presence of a complex microbiota, all fructans (particularly OF1) consistently selectively enhanced the growth of BB-12. While each fructan as such already increased Bifidobacteriaceae numbers with 0.94–1.26 log(cells/mL), BB-12 co-supplementation additionally increased Bifidobacteriaceae with 0.17–0.46 log(cells/mL). Further, when co-supplemented with fructans, BB-12 decreased Enterobacteriaceae numbers (significant except for IN1-IN3). At metabolic level, all fructans decreased pH due to increased acetate and lactate production, while OF/IN2-IN1-IN2-IN3 also stimulated propionate and butyrate production. BB-12 co-supplementation further increased propionate and butyrate for OF/IN2-IN3 and IN1-IN2, respectively. Overall, combinations of BB-12 with fructans are promising synbiotic concepts, likely due to intracellular consumption of low DP-fructans by BB-12 (either present in starting product or released upon fermentation by indigenous microbes), thereby enhancing effects of the co-administered fructan.

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Production of oligomeric procyanidins by mild steam explosion treatment of grape seeds

Bioresources and Bioprocessing ◽

10.1186/s40643-021-00376-4 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Jie Zhang ◽

Dan Liu ◽

Aoke Wang ◽

Li Cheng ◽

Wenya Wang ◽

...

Keyword(s):

Antioxidant Activity ◽

Steam Explosion ◽

Phenolic Content ◽

Degree Of Polymerization ◽

High Yield ◽

Total Phenolic ◽

Grape Seeds ◽

Low Degree ◽

High Antioxidant Activity ◽

The Mean

Abstract Background Sixty five percent of procyanidins in grape seeds is polymeric procyanidins (PPC), and they could not be assimilated directly by human. To enhance procyanidin assimilation, steam explosion treatment (SE) was used to facilitate the preparation of oligomeric procyanidins (OPC) from grape seeds. Results The results indicate that SE treatment made grape seeds loose and porous, and decreased the mean degree of polymerization (mDP) of procyanidins. The procyanidins content and total phenolic content (TPC) were decreased with the increase of SE severity, while the amount of catechin (CA), epicatechin (EC) and epicatechin-3-O-gallate (ECG) were increased, resulting in significant increase of antioxidant activity. Conclusions Although SE treatment could depolymerize PPC and produce CA/EC/ECG with high yield, it caused the yield loss of total procyanidins. SE treatment is a potential effective method to prepare procyanidins with low degree of polymerization and high antioxidant activity. However, it still needs to study further how to balance the yield of total procyanidins and catechin monomers (CA/EC/ECG).

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