Characteristic physicochemical features of the biopolymer inulin in solvent added and depleted states

Effects of calcium supplementation on the composition and activity of in vitro simulated gut microbiome during inulin fermentation

The gut microbiome influences the availability of micronutrients in the gastrointestinal tract. However, our insights into how colonic fermentation of prebiotic fibers and lactose is modulated by the presence of micronutrients and local pH environment are limited. Here, we investigated the influence of different calcium salts (calcium phosphate (CaPi), calcium citrate (CaCi), and calcium carbonate (CaCa)) on gut microbiome composition and metabolism using inulin and lactose as carbohydrate sources under low, medium, and high in vitro colonic pH gradients. Our results showed that in vitro colonic pH gradient had a significant effect on gut microbiome diversity (observed ASVs and Shannon diversity index, p < 0.05). After 24 hours of fermentation, the calcium sources had a significant effect on beta diversity at all colonic pH gradients (adjusted p < 0.05). Although changes in GM composition were more pronounced after 24 hours, after 6 hours of fermentation, the CaPi group exhibited a higher abundance of Leuconostoc than other groups. After 24 hours of fermentation, the CaPi group exhibited a higher Blautia abundance at high colonic pH gradient and lower Bacteroides abundance at all colonic pH gradient levels. The CaCi and CaCa groups exhibited a pH-dependent decrease in the abundance of Bacteroides. In addition, Bifidobacterium abundance remained over 1% regardless of colonic pH gradient, calcium source, or fermentation time. In addition, short-chain fatty acid (SCFA) production was dependent on the calcium source. For instance, compared to the control group, the CaCi group exhibited higher acetate production at low and high colonic pH gradients, while the CaPi and CaCa groups showed enhanced lactate production at medium and low pH gradients. These findings can increase our understanding of the impacts of calcium-rich diets on the human gut microbiome and its metabolic activity.

Characterization and identification of inulin from Pachyrhizus erosus and evaluation of its antioxidant and in-vitro prebiotic efficacy

Inulin is the polysaccharide obtained from different plant sources i.e. Wheat, Chicory, Jerusalem artichoke and Dahlia. In this study, Jicama (Pachyrhizus erosus) is used to isolate inulin using the microwave heating. The 1H NMR study reveals the presence of fructose and glucose unit which is the backbone of inulin. Further FT-IR and Raman confirmed the functional groups present in inulin. The UV-Vis spectroscopy analysis depicts the purity of the isolated inulin. The shape and size of the extracted inulin was determined from scanning electron microscopy and dynamic light scattering appeared as flat-flakes and 135 nm respectively. X-ray diffractogram showed semi-crystalline nature suggesting the stability of the extracted inulin. The isolated inulin has phenolic and flavonoid content of 8.1804 ± 6.26 mg gallic acid equivalent/g and 14.387 ± 4.192 mg rutin equivalent/g of dried polysaccharide respectively. The inhibition percentage of DPPH and FRAP of isolated inulin were found to be 75.74 ± 4.5% and 0.11 ± 0.007 respectively. The isolated inulin promotes the growth of probiotics like Enterococcus faecium (MZ540315) and Lactiplantibacillus plantarum (MZ540317). All the analysis suggest the isolated inulin has good prebiotic potential as the commercially available one. The current study proposes that isolated inulin can be used as a prebiotic in the future.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05619-6.

Multifunctional tunable p(inulin) microgels

Inulin, inulin-silica and modified inulin microgels were prepared in a single step via crosslinking within microemulsion, and used as drug delivery devices. Inulin-silica composite micro particles were also synthesized in the presence of tetraethyl orthosilicate (TEOS) via a water-in-oil microemulsion polymerization/crosslinking technique. To generate porous inulin particles, inulin-silica particles were treated with 0.5M NaOH solution to dissolve silica particles. Furthermore, virgin inulin (p(inulin)) and porous inulin microgels (por-p(inulin)) were quaternized successfully by treatment with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTMAC) in aqueous solution, generating positive charges on the biopolymer as q-p(inulin). Rosmarinic acid (RA) was used as model drug for loading and release studies by synthesized inulin-based microgels in phosphate buffer solution (PBS) at pH7.4. It was shown that the absorption and release rate are influenced by zeta potential and porosity of the microgels.

Solution behavior of normal and reverse triblock copolymers (pluronic L44 and 10R5) individually and in binary mixture

Solution properties of pluronics L44 or L [(PEO)(10)(PPO)(23)(PEO)(10)] and 10R5 or R [(PPO)(8)(PEO)(22)(PPO)(8)] were studied individually as well in their binary mixtures in aqueous medium. The critical micelle concentration (CMC), critical micelle temperature, and cloud point (CP) were determined. Ideal and nonideal behaviors of their mixtures in the formation of CMC and CP were observed; the energetics of the studied processes were determined. Spectrophotometry, isothermal titration calorimetry and dynamic light scattering (DLS) methods were used for evaluations. Morphologies of the dispersed L, R, and their mixtures along with their polydispersities were determined from DLS measurements. Atomic force microscopy was also employed. The interfacial properties of L and R were investigated forming Langmuir monolayers in a surface balance. The surface pressures (π) generated by the compounds were moderate, the area per molecule was higher for R than L. R has shown antibacterial activity against both gram positive and gram negative bacteria whereas L was inactive in this respect.

Behavior of the amphiphile CHAPS alone and in combination with the biopolymer inulin in water and isopropanol-water media

Self-aggregation of the zwitterionic surfactant 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS) in water and isopropanol-water media, and interaction of the amphiphile with the biopolymer inulin in these media were investigated. The micellar properties of the zwitterionic surfactant and its associated interfacial and bulk properties along with the related energetic, and aggregation number were determined. The different stages of interaction of the CHAPS-inulin combines were identified and assessed. The complexes were formed and aggregated in solution at different stages of their molecular compositions. The aggregated sizes were determined by dynamic light scattering study and the morphology in the solvent removed states were examined using scanning electron microscope and transmission electron microscope techniques. The results witnessed formation of ensembles of varied and striking patterns.

Interaction of gums (guar, carboxymethylhydroxypropyl guar, diutan, and xanthan) with surfactants (DTAB, CTAB, and TX-100) in aqueous medium

The interaction of surfactants dodecyltrimethylammonium bromide (DTAB), cetyltrimethylammonium bromide (CTAB), and p-tert-octylphenoxypolyoxyethylene (9.5) ether (TX-100) with guar (Gr), carboxymethylhydroxypropyl guar (CMHPG), diutan (Dn), and xanthan (Xn) gums has been studied employing conductometry, tensiometry, microcalorimetry, viscometry, and atomic force microscopy (AFM) techniques. Both weak and strong interactions were observed. CTAB interacted stronger than DTAB with the gums. The surfactant-gum interaction process was enhanced by the presence of borate ions in the solution; the borate ion itself also manifested interaction with the surfactants comparable with that of water-soluble polymers polyvinyl alcohol, polyoxyethylene, and so forth. Viscometric results supported configurational changes of the gum molecules by interaction with surfactants. The geometry of the pure gums and their CTAB interacted products in the dried states was ascertained from AFM measurements; spherical and prolate shapes were observed for pure gums, and distorted states were observed for their surfactant complexed species. Detailed topological features of these entities were ascertained.