Separation of fructooligosaccharides using zeolite fixed bed columns

Monitoring of sugars adsorption breakthrough curves with online Raman spectroscopy

We introduce a new application for online Raman spectroscopy to monitor adsorption breakthrough curves of a glucose and xylose mixtures. Univariate and multivariate Partial Least Squares (PLS) calibration models are developed for each sugar when they are dissolved in water and in the case of the ethanol addition as a cosolvent. The models are validated by performing actual breakthrough experiments in a liquid phase using a column packed with a zeolite adsorbent. The first statistical moments of predicted curves are compared to the reference curves obtained with offline High-Performance Liquid Chromatography (HPLC). Glucose and xylose univariate predictions in the presence or absence of ethanol in the mixture are accurate and no improvements are found with the PLS models. Spectral subtraction coupled with the first derivative proved to be effective pretreatments to develop robust univariate models.

Chemical Fingerprint Analysis and Quantitative Analysis of Saccharides in Morindae Officinalis Radix by HPLC-ELSD

A method based on high performance liquid chromatography with evaporative light scattering detection (HPLC-ELSD) was developed for the quantitative analysis of three active compounds and chemical fingerprint analyses of saccharides in Morindae officinalis radix. Ten batches of Morindae officinalis radix were collected from different plantations in the Guangdong region of China and used to establish the fingerprint. The samples were separated with a COSMOIL Sugar-D column (4.6 mm × 250 mm, 5 μm) by using gradient elution with water (A) and acetonitrile (B). In addition, Trapped-Ion-Mobility (tims) Time-Of-Flight (tims TOF) was used to identify saccharides of Morindae officinalis radix. Fingerprint chromatogram presented 26 common characteristic peaks in the roots of Morinda officinalis How, and the similarities were more than 0.926. In quantitative analysis, the three compounds showed good regression (r = 0.9995-0.9998) within the test ranges, and the recoveries of the method were in the range of 96.7-101.7%. The contents of sucrose, kestose and nystose in all samples were determined as 1.21-7.92%, 1.02-3.37%, and 2.38-6.55%, respectively. The developed HPLC fingerprint method is reliable and was validated for the quality control and identification of Morindae officinalis radix and can be successfully used to assess the quality of Morindae officinalis radix.

Continuous enzymatic production and adsorption of laminaribiose in packed bed reactors

Bienzymatic production of laminaribiose from sucrose and glucose was combined with adsorption on zeolite BEA to introduce a first capture and purification step. Downstream processing including washing and desorption steps was characterized and optimized on a milliliter scale in batch mode. Results were then transferred to a packed bed system for enzymatic production and adsorption where the influence of adsorbent particle diameter on purity and productivity was evaluated. Finally, a continuous enzymatic production of laminaribiose was conducted over 10 days. The subsequent downstream processing of the loaded zeolites led to purities of over 0.5 g_{Laminaribiose} g_sugar ^-1 in the desorbate with a total productivity of 5.6 mg_{Laminaribiose} L_{enzyme bed} ^-1 h^-1 without the use of recycles.

Bile sequestration potential of an edible mineral (clinoptilolite) under simulated digestion of a high-fat meal: an in vitro investigation

Bile, important for cholesterol homeostasis, is a potential target of hypercholesterolemia management. Bile sequestration by orally administered resins, while mostly effective in reducing blood cholesterol, presents several side effects and disadvantages. Thus, widely available natural edible minerals such as clinoptilolite with adsorptive properties offer an alternative for bile sequestration. In an experimental setting mimicking the physiological conditions of digestion/absorption (pH, temperature, and retention times) with a series of assessment methods, scanning electron microscopy-energy dispersion X-ray analysis (SEM-EDX), X-ray diffraction (XRD), Fourier transform infrared analysis (FT-IR), thermogravimetric differential thermal analysis (TG-DTA), and molecular docking modeling, the ability of natural unmodified clinoptilolite to retain bile, while mixed with a simulated high-fat meal, was investigated. Our results demonstrate that clinoptilolite sequesters bile via adsorption of macromicelles at 75.4% efficiency, when the former is administered at a reasonable dose of 4% (w/w) of a meal's weight. This work provides the possibility of clinoptilolite utilization as a bile-sequestering/cholesterol-reducing agent.

Dietary Sugars Analysis: Quantification of Fructooligossacharides during Fermentation by HPLC-RI Method

In this work, a simple chromatographic method is proposed and in-house validated for the quantification of total and individual fructooligossacharides (e.g., 1-kestose, nystose, and 1(F)-fructofuranosylnystose). It was shown that a high-performance liquid chromatography with refractive index detector could be used to monitor the dynamic of fructooligossacharides production via sucrose fermentation using Aspergillus aculeatus. This analytical technique may be easily implemented at laboratorial or industrial scale for fructooligossacharides mass-production monitoring allowing also controlling the main substrate (sucrose) and the secondary by-products (glucose and fructose). The proposed chromatographic method had a satisfactory intra- and inter-day variability (in general, with a relative standard deviation lower than 5%), high sensitivity for each sugar (usually, with a relative error lower than 5%), and low detection (lower than 0.06 ± 0.04 g/L) and quantification (lower than 0.2 ± 0.1 g/L) limits. The correct quantification of fructooligossacharides in fermentative media may allow a more precise nutritional formulation of new functional foods, since it is reported that different fructooligossacharides exhibit different biological activities and effects.

Plant cell wall polysaccharides as potential resources for the development of novel prebiotics

Prebiotic oligosaccharides, with a degree of polymerization (DP) of mostly less than 10, exhibit diverse biological activities that contribute to human health. Currently available prebiotics are mostly derived from disaccharides and simple polysaccharides found in plants. Subtle differences in the structures of oligosaccharides can cause significant differences in their prebiotic proper-ties. Therefore, alternative substances supplying polysaccharides that have more diverse and complex structures are necessary for the development of novel oligosaccharides that have actions not present in existing prebiotics. In this review, we show that structural polysaccharides found in plant cell walls, such as xylans and pectins, are particularly potential resources supplying broadly diverse polysaccharides to produce new prebiotics.

Evaluation of Clavulanic Acid Adsorption in MgAl-Layered Double Hydroxides: Kinetic, Equilibrium and Thermodynamic Studies

Kinetics, equilibrium and thermodynamic studies of clavulanic acid adsorption onto hydrotalcites have been conducted with the aim of selecting the best conditions for biomolecular separation. For this purpose, hydrotalcites of different compositions (containing 30, 63 and 70% MgO in their compositions) were tested, with and without pre-treatment (uncalcined and calcined). A model was obtained to predict the degradation constant. This model may be useful in predicting the extent of clavulanic acid hydrolysis in the adsorption process. Adsorption studies were performed in stirred batch glass reactors. Assays were performed using solutions under different conditions, as well as variable solid/liquid ratios.

It was shown that distilled water and a solid/liquid ratio of 15.0 mg/ℓ generated the most favourable conditions for adsorption. A calcined hydrotalcite containing 70% MgO was selected for further study since it presented the best adsorption performance. The adsorbents were characterized by X-ray diffraction methods, Fourier-transform infrared spectroscopy and scanning electron microscopy. Adsorption equilibrium was evaluated from adsorption isotherms determined at different temperatures. The experimental isotherm data were well fitted by a linear equilibrium model with the corresponding adsorption constants being K = 0.404, 0.602, 0.849 and 1.083 ℓ/g at 16.5, 19.0, 21.5 and 24.0 °C, respectively, showing an increased adsorption capacity at higher temperatures.

Thermodynamic evaluation of the process allowed the Gibbs' free energy (ΔG0), the standard enthalpy change (ΔH0) and the standard entropy change (ΔS0) to be estimated as follows: ΔG0 = 2.100, 1.301, 0.503 and −0.295 kJ/mol at 16.5, 19.0, 21.5 and 24.0 °C, respectively; ΔH0 = 94.602 kJ/mol; and ΔS0 = 0.319 kJ/(mol K), respectively. The positive value of ΔH0 confirmed the endothermic nature of clavulanic acid adsorption onto HT70c hydrotalcites, which was considered to be mass transport reaction-controlled process.