High-performance Size-exclusion Chromatography Research Articles

A narrative review on conformational structure characterization of natural polysaccharides

AbstractPolysaccharides are structurally varied groups of biological macromolecules which broadly occurrence in nature. The structural features like detailed glycosidic linkages, monosaccharide composition, molecular weight (MW), and chain conformation could impact their functions. This paper attempts to review the current development on conformational characterization of polysaccharides and includes the influence of chain conformations on their biological activities. The chain conformations characterization methods mainly include static and dynamic light scattering, multiple angle laser light scattering (MALLS) detector, high‐performance size exclusion chromatography (HPSEC), viscosity analysis in the base of the theory of dilute polymer solution, circular dichroism (CD), Congo red test, differential scanning calorimetry (DSC), atomic force microscopy (AFM), single molecular AFM, fluorescence correlation spectroscopy (FCS), single‐molecule force spectroscopy (SMFS), nuclear magnetic resonance (NMR) spectroscopy, HPSEC‐MALLS analysis, as well as HPSEC‐MALLS‐refractive index (RI)‐viscosity detector (VS) system. This would be also helpful for development and application of polysaccharides from different natural sources.

Antibacterial and antioxidant properties of humic substances from composted agricultural biomasses

BackgroundBioactive components isolated from composted agricultural biomasses have been receiving progressive attention, because they may improve the antibiotic susceptibility of drug resistant bacterial strains. Here, three different humic substances (HS) were isolated from composted artichoke (HS-CYN) and pepper (HS-PEP) wastes, and from coffee grounds (HS-COF), and characterized by infrared spectrometry, NMR spectroscopy, thermochemolysis–GC/MS, and high-performance size-exclusion chromatography. The antibacterial activity of HS was evaluated against some pathogenic bacterial strains, while their bioactivity was determined by a germination assay on basil (Red–Violet variety) seeds.ResultsHS-CYN and HS-PEP exhibited the largest antioxidant activity and most significant antimicrobial capacity against some gram-positive bacterial strains, such as Staphylococcus aureus and Enterococcus faecalis. The same HS determined a significant increase of both root and epicotyls in seed germination experiments. The bioactivity of HS was related not only to their specific molecular composition but also to the conformational stability of their suprastructures. Specifically, the greatest bioactive and antimicrobial properties were related to the largest abundance of hydrophobic aromatic and phenolic components and to a more rigid conformational arrangement, that, in turn, appeared to be related to a small fragmentation degree of lignin structures.ConclusionsOur results showed that extraction of bioactive HS from green composts may be a sustainable and eco-compatible way to valorise agricultural byproducts. HS may be indeed exploited as substrates to produce novel materials not only to improve plant productivity but also for medical applications.Graphical

Quality differentiation method of similar phytomedicines with high sugar content based on the sugar-marker: Taking Schisandrae Chinensis Fructus and Schisandrae Sphenantherae Fructus as an example

• Sugar was used as quality marker to distinguish similar phytomedicines. • Taking SCF and SSF as an example, a set of quality control methods was established. • SCF and SSF from ten different areas were classified into three categories. Quality evaluation of phytomedicines is limited to small molecules as quality markers, even for herbs with high sugar contents. We established a high-resolution method for distinguishing similar medicinal materials using sugar as quality marker, taking Schisandrae Chinensis Fructus (SCF) and Schisandrae Sphenantherae Fructus (SSF) as an example. High performance liquid chromatography with an evaporative light-scattering detector (HPLC-ELSD), high performance size exclusion chromatography coupled with multi-angle laser light scattering detector and refractive index detector (HPSEC-MALLS-RID) and high performance liquid chromatography with photo-diode array (HPLC-PDA) after 1-phenyl-3-methyl-5-pyrazolone (PMP) pre-column derivatization were used respectively to determine monosaccharide contents, molecular weights and monosaccharide compositions of polysaccharides in this study. The differences of SCF and SSF from ten producing areas were compared by principal component analysis (PCA) and hierarchical cluster analysis (HCA). Results showed that contents of fructose and glucose were similar between SCF and SSF. Molecular weight ( M w) of SCF polysaccharides was ranging from 1.561 × 10 2 to 6.599 × 10 2 kDa, and that of SSF polysaccharides was ranging from 8.524 × 10 2 to 1.7416 × 10 3 kDa. Schisandra polysaccharides were mainly composed of mannose, galacturonic acid, glucose, galactose and arabinose. Based on PCA and HCA, SCF and SSF from ten different areas were classified into three categories. With great accuracy, sensitivity and stability, the methods established in this study had important reference value for quality evaluation, development and utilization of saccharide components in medicinal materials.

Purification of novel polypeptides from bee pupae and their immunomodulatory activityin vivo andin vitro

Edible insects have been proposed as an understudied food whose cultivation could be increased with global population growth. However, the bioactivators and bioactivities of bee pupae are poorly studied. In this paper, the active ingredients of bee pupa powder were analysed, and novel bee pupa polypeptides (BPP) were obtained through protein hydrolysis with alkaline protease. Two purified polypeptide components (BPP-21 and BPP-22) were isolated and purified on a diethylaminoethyl-sepharose fast flow column and a Sephadex G-25 column, and identified using size exclusion chromatography-high performance liquid chromatography and amino acid composition analyses. Due to its higher cell proliferation activity, BPP-22 was selected for further study of its immunomodulatory activity and mechanismin vivo andin vitro. The analysis of immunomodulatory activity showed that BPP-22 significantly increased the body weight growth rate, organ index, macrophage phagocytosis, delayed-type hypersensitivity reaction, cytokine level (interleukin (IL)-2 and interferon (IFN)-γ), immunoglobulin (Ig) levels (IgA, IgG, and IgM), and routine blood indexes in cyclophosphamide-treated immunosuppressed mice (P<0.01). Mechanistic research in RAW264.7 cells showed that BPP-22 might promote the secretion of cytokines (IL-2, tumour necrosis factor-α and IFN-γ) and the production of nitric oxide by increasing homologous mRNA expression and could exert immunomodulatory activity by increasing the phosphorylation of ERK and p38, and modulating the expression of intranuclear transcription factors (EIK-1, MEF-2 and CREB) in the MAPK signalling pathway. These findings are helpful for promoting the application of bee pupae as potential immunomodulatory agents and protein supplements.

Combination of chromatographic and spectroscopic characterization based on primitive ultraviolet absorbance detection to fulfill advanced monitoring of dissolved organic matter in municipal wastewater treatment plant

Effective and affordable monitoring tool for dissolved organic matter (DOM) in municipal wastewater treatment plant (WWTP) is in great need. In this study, high-performance size exclusion chromatography (HPSEC) with ultraviolet absorbance (UVA) detection and ultraviolet (UV) spectrometry were complementarily combined for advanced characterization of DOM in a municipal WWTP. DOM in different process units were chromatographically characterized mainly by UVA at 210 nm (UVA210), 254 nm (UVA254), UVA ratio index (URI, UVA210/UVA254). Differential and derivative UV spectrometry were also used for DOM characterization. HPSEC URI chromatographic analyses helped to acquire rich chemical information of DOM components with primitive UVA detection. Influent HPSEC fractions Ⅰ, Ⅳ, Ⅴ− 2, which were proved to consist of protein and polysaccharides, low molecular weight organic acids and hydrophobic organics respectively, were readily removable. HPSEC fractions Ⅱ and Ⅲ were proved to contain mostly recalcitrant humic substances (HS). Effluent HPSEC fraction Ⅴ− 1 contained nonbiodegradable saturated organics. UV spectrometry complemented HPSEC characterization by revealing that saturated organics generated during sand filtration and second derivative peak height at 295 nm (SDPH295) could be surrogate for biodegradable organics concentration in influent. Measures for DOM control optimization of this WWTP were proposed based on the DOM characteristics revealed. This study proved practicability of achieving advanced DOM monitoring with cheap and convenient but primitive chromatographic and spectroscopic characterization with UVA detection which may provide basis for developing applicable equipment for organic pollutants monitoring of municipal WWTP.

Chromatographic and spectroscopic comparison of dissolved organic matter variation in anaerobic-anoxic-oxic process with tertiary filtration and membrane bioreactor

Anaerobic-anoxic-oxic process with tertiary filtration (A2OWTF) and membrane bioreactor (MBR) was compared from the perspective of dissolved organic matter (DOM) variation in this study. A2OWTF and MBR wastewater treatment plants (WWTPs) samples were compared via conventional wastewater quality indexes, excitation-emission matrix (EEM) spectra, UV–vis spectra and high-performance size exclusion chromatography (HPSEC), which gradually revealed differences between the two processes from phenomena to mechanism. Lower removal of dissolved organic carbon (DOC) by MBR phenomenally revealed its DOM removal deficiency. EEM fluorescence regional integration (FRI), EEM parallel factor analysis (PARAFAC) and UV–vis Gaussian deconvolution qualitatively revealed more abundant humic-like substances (HS) and more complex effluent DOM composition for MBR. HPSEC provided more quantitative characterization. As for effluent after biotreatment, MBR exhibited lower removal rates of HPSEC fractions I (mainly containing protein and polysaccharides), IV (mainly containing low molecular weight organic acids) and fractions II, III (mainly containing HS) than A2OWTF (e.g., removal rates of MBR vs. A2OWTF calculated with UV absorbance at 254 nm (UVA254): 43.6% vs. 66.2%; 5.1% vs. 67.0%; −14.4% vs. 30.8%; −5.7% vs. 36.8% respectively for fractions I, IV, II, III). The massive HS generation in MBR also led to its higher trihalomethane formation potential (THMFP) for final effluent than A2OWTF. In conclusion, MBR should be prudently considered in terms of DOM removal for municipal WWTP upgrading.

Antiflammatory activity and potential dermatological applications of characterized humic acids from a lignite and a green compost

Long-term exposure to air pollution has been associated with the development of some inflammatory processes related to skin. The goal of modern medicine is the development of new products with antiflammatory action deriving from natural sources to improve environmental and economic sustainability. In this study, two different humic acids (HA) were isolated from from lignite (HA-LIG) and composted artichoke wastes (HA-CYN) and characterized by infrared spectrometry, NMR spectroscopy, thermochemolysis-GC/MS, and high-performance size-exclusion chromatography (HPSEC), while their antiflammatory activity was evaluated on HaCaT cells. Spectroscopic results showing the predominance of apolar aliphatic and aromatic components in HA-LIG, whereas HA-CYN revealed a presence of polysaccharides and polyphenolic lignin residues. The HA application on human keratinocyte pre-treated with Urban Dust revealed a general increase of viability suggesting a protective effect of humic matter due to the content of aromatic, phenolic and lignin components. Conversely, the gene expression of IL-6 and IL-1β cytokines indicated a significant decrease after application of HA-LIG, thus exhibiting a greater antiflammatory power than HA-CYN. The specific combination of HA protective hydrophobic components, viable conformational arrangements, and content of bioactive molecules, suggests an innovative applicability of humic matter in dermatology as skin protectors from environmental irritants and as antiflammatory agents.

Isolation of Circulating Extracellular Vesicles by High-Performance Size-Exclusion Chromatography.

Circulating extracellular vesicles (EVs) are gaining increased attention as carriers of proteins, nucleic acids, and lipids. Blood contains EVs from different cell sources that constitute an attractive target for biomarker studies. However, there is no consensus on the best approach to isolate EVs from blood. Non-EV proteins and lipoproteins in plasma/serum tend to contaminate isolated EVs and confound functional experiments. Here we describe a single-step, high-performance size-exclusion chromatography procedure for separation of EVs from most lipoproteins and non-EV proteins, and compare it to ultracentrifugation, still the most commonly used method for EV isolation.

Effects of High Hydrostatic Pressure Pretreatment on the Functional and Structural Properties of Rice Bran Protein Hydrolysates.

Rice bran protein (RBP) hydrolysis was conducted after high hydrostatic pressure (HHP) pretreatment. The structural and functional properties of HHP-pretreated rice bran protein hydrolysates (RBPH) were investigated. HHP pretreatments were conducted at 100, 200, and 300 MPa; then, enzymatic hydrolysis at atmospheric pressure was performed using trypsin. An RBPH sample that had not been pretreated by HHP was used as a control. Free sulfhydryl (SH) content, SDS-PAGE profiles, high-performance size exclusion chromatography (HPSEC), Fourier transform infrared (FTIR) spectrum, scanning electron microscopy (SEM), intrinsic fluorescence spectrum, solubility, and emulsifying and foaming properties were evaluated. Changes in particle size and ζ-potential were monitored. Compared with the control, the results of solubility, the emulsifying activity index (EAI) and the emulsifying stability index (ESI) increased significantly (p < 0.05) at 200 MPa. The content of free SH increased significantly (p < 0.05) at 100 MPa. FTIR spectrum and fluorescence analysis confirmed the changes in the secondary and tertiary structures. The experimental results indicated that the structural and functional properties of HHP-pretreated RBPH improved.

Synthesis of Human Bone Morphogenetic Protein-2 (hBMP-2) in E. coli Periplasmic Space: Its Characterization and Preclinical Testing.

Human BMP-2, a homodimeric protein that belongs to the TGF- β family, is a recognized osteoinductor due to its capacity of inducing bone regeneration and ectopic bone formation. The administration of its recombinant form is an alternative to autologous bone grafting. A variety of E. coli-derived hBMP-2 has been synthesized through refolding of cytoplasmic inclusion bodies. The present work reports the synthesis, purification, and characterization of periplasmic hBMP-2, obtained directly in its correctly folded and authentic form, i.e., without the initial methionine typical of the cytoplasmic product that can induce undesired immunoreactivity. A bacterial expression vector was constructed including the DsbA signal peptide and the cDNA of hBMP-2. The periplasmic fluid was extracted by osmotic shock and analyzed via SDS-PAGE, Western blotting, and reversed-phase high-performance liquid chromatography (RP-HPLC). The purification was carried out by heparin affinity chromatography, followed by high-performance size-exclusion chromatography (HPSEC). HPSEC was used for qualitative and quantitative analysis of the final product, which showed >95% purity. The classical in vitro bioassay based on the induction of alkaline phosphatase activity in myoblastic murine C2C12 cells and the in vivo bioassay consisting of treating calvarial critical-size defects in rats confirmed its bioactivity, which matched the analogous literature data for hBMP-2.

Extraction and Characterization of Pectin from Lemon Waste for Commercial Applications

The objective of this paper was preliminary to extract and characterization of purified pectin from lemon wastes. Dry lemon waste was extracted applying citric acid solvent or water at various concentrations under a similar condition (85 ºC for 4 h). It was found that the highest yield of pectin (20.8% dry basis) was achieved using hot water extraction with an esterification degree of 47.8%. It contained 63.2 ± 0.74% galacturonic acid, followed by 17.4 ± 0.76% total sugar. The monosaccharides found in pectin were arabinose (2.7 ± 0.20%), galactose (2.3 ± 0.01%), glucose (1.4 ± 0.09%), mannose (0.4 ± 0.01%), fructose (0.4 ± 0.05%), and xylose (0.1 ± 0.01%). The found pectin had a high atomic weight of 2060 kDa with a wide polydispersity index of 4.41, decided by high-Performance Size Exclusion Chromatography (HPSEC). The extricated lemon waste pectin was grouped into low methoxyl pectin, depends on the methoxyl content and degree of esterification affirmed by Fourier transform infrared spectroscopy (FT-IR) and rheological properties. In conclusion, the discoveries of the study show that lemon waste can be investigated as a promising elective for the commercial manufacturing of pectin.

Evaluation of polar compound distribution in edible oils under restaurant deep frying

The distribution of polar compounds (PCs) in palm oil (PO), rapeseed oil (RO), and high-oleic sunflower oil (HOSO) were monitored in French fries (FF), chicken nuggets (CN), and fish nuggets (FN) real restaurant deep-frying systems by high-performance size exclusion chromatography. The PO with long frying life (100–186 h) showed better oxidation stability in all frying systems compared with RO and HOSO. All the oils had a close increasing trend in triacylglycerol hydrolysis products (THP), while RO and HOSO had higher levels of oxidized triacylglycerol monomers (OTG) and oxidized triacylglycerol polymers (TGP) than PO during frying. During FF frying, the oils deteriorated slowest from the aspect of PCs rising to the discard point (27 %). The oils underwent more serious hydrolysis and polymerization while CN and FN were fried compared to FF frying. However, OTG contents in oils altered irregularly and there was no obvious disparity among different foods frying. Oil type, fried food, and even the interaction between them significantly (p < 0.001) affected polar compound distribution.

Fe(II)-activated peroxymonosulfate coupled with nanofiltration removes natural organic matter and sulfamethoxazole in natural surface water: Performance and mechanisms

Ferrous-activated peroxymonosulfate (PMS) is regarded as a promising technology to treat organic pollutants. However, the excessive sulfate anions generated in the oxidation process need to be considered with respect to their potential harm to the environment and human health. The removal of organic compounds and sulfate anions by Fe(II)/PMS oxidation coupled with nanofiltration (NF) was studied in this research. The mechanism of Fe(II)/PMS coupled with NF in natural organic matter (NOM) and sulfamethoxazole (SMX) removal were systematically investigated by comparison with single Fe(II)/PMS and NF treatments. The results demonstrated that the hybrid system showed better performance than the single treatments for both pollutants. High-performance size exclusion chromatography (HPSEC) analysis indicated that macromolecular organic matter in Songhua River water was broken down and converted into small fragments with a size of approximately hundreds of Da by Fe(II)/PMS oxidation. Zeta potential analysis showed that the zeta potential of the effluent decreased under the effect of Fe(III) and that some small organic molecules generated in the process of oxidation were negatively charged. The SMX removal experiment showed that Fe(II)/PMS oxidation played a leading role in SMX removal in the hybrid system. Moreover, a radical quenching experiment was conducted to explore the effects of SO4·− and HO· on SMX degradation. Fe(II)/PMS treatment effectively alleviated membrane fouling and improved the flux behaviour, with a stable sulfate anion rejection rate of approximately 90% achieved by NF in the long term. These results suggested that Fe(II)/PMS coupled with NF could control membrane fouling, intercept sulfate anions and improve effluent quality, which provides a new strategy for water treatment.

Quality Distinguish of Red Ginseng from Different Origins by HPLC–ELSD/PDA Combined with HPSEC–MALLS–RID, Focus on the Sugar-Markers

Red ginseng (RG) has been extensively utilized in Asian countries due to its pharmacological effects. For the quality evaluation of RG, small molecules, such as ginsenosides, have been widely considered as candidates of its quality markers (Q-markers), and various analytical techniques have been developed in order to identify these compounds. However, despite the efforts to analyze the hydrophobic constituents, it is worth pointing out that about 60% of the mass of RG is made of carbohydrates, including mono-, oligo- and polysaccharides. Consequently, the quality differentiation and identification of RG from the perspective of sugar-markers should be focused. High performance liquid chromatography and evaporative light scattering detector (HPLC–ELSD) method for the determination of disaccharides in RG was established. Furthermore, high performance size exclusion chromatography–multi-angle laser light scattering–refractive index detector (HPSEC–MALLS–RID) for the determination of molecular weight and high performance liquid chromatography photodiode array (HPLC–PDA) for the determination of compositional monosaccharides in RG polysaccharides were also established. HPLC–ELSD/PDA combined with HPSEC–MALLS–RID could be used to determine the contents of disaccharides, molecular weights, and compositional monosaccharides of RG polysaccharides, which could be used for quality control, and this is a new view on the sugar marker to quality differentiation of various origins of RG.

The mechanism exploration of the non-colonic toxicity and obesity inhibition of food-grade κ-carrageenan by transcriptome.

Previous study has suggested the colonic nontoxicity and obesity inhibition of food‐grade κ‐carrageenan in obese mice. Further study using transcriptome is important to provide further understanding on the gene expressions of inflammation and obesity. Here, the obese mice without any treatment (HFD) or with 5% food‐grade κ‐carrageenan diet intervention (H5%) were used to perform colonic transcriptome sequencing. The results showed that genes involved in the inflammatory pathways or tight junction protein encoding were not significantly dysregulated by 5% carrageenan. However, the expression of lipid metabolism genes meaningfully changed as evidenced by the decreased gene levels of adipocytokines, lipogenesis, lipid absorption and transport, and the increased adipolysis and oxidation. In addition, the carrageenan metabolism experiments by toluidine blue (TB) staining of colon and high‐performance size exclusion chromatography (HPSEC) of feces supernatant showed that the food‐grade κ‐carrageenan was not absorbed or significantly degraded in the digestive tract of obese mice. Hence, the fact that food‐grade κ‐carrageenan was not significantly metabolized by the organism and did not cause obvious dysregulation of colonic inflammatory genes provided evidences for its noncolonic toxicity in obese mice. An anti‐obesity potential of food‐grade κ‐carrageenan was probably mediated by the regulation of lipids metabolism‐related genes.

Removal of natural organic matter in full-scale conventional and advanced water treatment plants: Assimilable organic carbon and its precursors

This study aimed to investigate the performance of three full-scale long-time water treatment plants with influent from Taihu Lake for the removal of natural organic matter (NOM) and assimilable organic carbon (AOC), emphasizing on the processes of pre- and post-ozonation and biological activated carbon filtration (BACF). High-performance size exclusion chromatography (HPSEC) separation, hydrophilicity/hydrophobicity resin fractionation and excitation-emission matrix (EEM) fluorescence spectroscopy were applied to determine NOM fraction variation in purification processes and their relationships with AOC. The results indicated that NOM fractions with high hydrophilicity (NHPI) and lower molecular weight (1 kDa - 10 kDa) likely contributed to the majority of AOC. The advanced water treatment processes behaved negative removals of AOC since the BACF with long-time operation introduced large amounts of AOC precursors and could cause drastic rebound of AOC upon chlorination disinfection. Finally, during exposure to ozone, the formation rate of AOC showed a linear relationship with UV254 and total fluorescence intensity (TFI) and each regional fluorescence intensity (RFI) with slight interference by the presence of particulate organic matter (POM). This study provides useful information for variation of NOM and its associated bio-availability during conventional and advanced processes in full-scale water treatment plants.

Lignin/Carbohydrate Complex Isolated from Posidonia oceanica Sea Balls (Egagropili): Characterization and Antioxidant Reinforcement of Protein-Based Films.

A lignin fraction (LF) was extracted from the sea balls of Posidonia oceanica (egagropili) and extensively dialyzed and characterized by FT-IR and NMR analyses. LF resulted water soluble and exhibited a brownish-to-black color with the highest absorbance in the range of 250–400 nm, attributed to the chromophore functional groups present in the phenylpropane-based polymer. LF high-performance size exclusion chromatography analysis showed a highly represented (98.77%) species of 34.75 kDa molecular weight with a polydispersity index of 1.10 and an intrinsic viscosity of 0.15. Quantitative analysis of carbohydrates indicated that they represented 28.3% of the dry weight of the untreated egagropili fibers and 72.5% of that of LF. In particular, eight different monosaccharides were detected (fucose, arabinose, rhamnose, galactose, glucose, xylose, glucosamine and glucuronic acid), glucuronic acid (46.6%) and rhamnose (29.6%) being the most present monosaccharides in the LF. Almost all the phenol content of LF (113.85 ± 5.87 mg gallic acid eq/g of extract) was water soluble, whereas around 22% of it consisted of flavonoids and only 10% of the flavonoids consisted of anthocyanins. Therefore, LF isolated from egagropili lignocellulosic material could be defined as a water-soluble lignin/carbohydrate complex (LCC) formed by a phenol polymeric chain covalently bound to hemicellulose fragments. LCC exhibited a remarkable antioxidant activity that remained quite stable during 6 months and could be easily incorporated into a protein-based film and released from the latter overtime. These findings suggest egagropili LCC as a suitable candidate as an antioxidant additive for the reinforcement of packaging of foods with high susceptibility to be deteriorated in aerobic conditions.

Functional Features of Alginates Recovered from Himanthalia elongata Using Subcritical Water Extraction.

Subcritical water extraction of Himanthalia elongata and the subsequent acetone fractionation to precipitate crude fucoidans generated a liquid phase which was used to recover alginates with a wide range of viscoelastic features and other soluble extracts with potential biological activities. The precipitated alginate was converted to sodium alginate using an environmentally friendly treatment before being characterized by Fourier transform infrared attenuated total reflectance, nuclear magnetic resonance, high performance size exclusion chromatography and rheological measurements. The cell viability of three human cell lines (A549, HCT-116, T98G) in the presence of the extracts obtained before and after acetone fractionation was assessed. Fractionation with different acetone volumes showed a slight effect in the behavior of the different tested cell lines. Results also indicated a notable effect of the processing conditions on the block structure and molar mass of the extracted biopolymer, with the subsequent impact on the rheological properties of the corresponding gelled matrices.

Preparation and characterization of nanoparticles from cereal and pulse starches by ultrasonic-assisted dissolution and rapid nanoprecipitation

Starch nanoparticles (SNPs) were prepared for the first time via a combination of ultrasonic-assisted dissolution of starch and subsequent rapid nanoprecipitation. Purified starches from cereal (regular corn and wheat) and pulse (faba bean and field pea) grains that significantly differ in amylose content were used. The effects of starch source, concentration and amylose content as well as the ratio between antisolvent to solvent (i.e., aqueous starch solution) on the SNPs morphological, molecular, and physicochemical properties were investigated. The morphology was evaluated by scanning electron microscopy (SEM) to observe shape and surface details and dynamic light scattering (DLS) to analyze particle size and poly dispersity index (PDI). Molecular properties of the native starch and SNPs were determined by a high-performance size-exclusion chromatography equipped with a multi angle laser light scattering and a differential refractive detector (HPSEC-MALLS-RI). Physicochemical characterization of the SNPs was performed via measuring the crystallinity by X-ray diffraction (XRD), molecular order by Fourier-transform infrared spectroscopy (FTIR), and thermal properties by differential scanning colorimeter (DSC). Results showed that SNPs from all starches were spherical in shape, where pulse SNPs had smaller and more uniform size than cereal SNPs. Across all starch types, the molecular weight of amylopectin and amylose in SNPs was smaller and more uniform than in the respective native starches. Pulse SNPs with higher amylose content showed greater relative crystallinity, enhanced short-range molecular order, and better thermal stability. A schematic diagram has been proposed to explain the variations in SNP size, where amylose-amylopectin ratio plays an important role.

Physicochemical properties, preliminary characterization, and assessment of potential bioactivities of polysaccharide purified from the leaves of Avicennia marina

A low molecular weight polysaccharide, the AMLP was isolated from the leaves of Avicennia marina and sequentially purified using DEAE-Sepharose fast flow and size exclusion chromatography. Monosaccharide analysis suggested that AMLP is mainly composed of fucose (38.34 %), galactose (30.16 %), mannose (13.32 %), and rhamnose (18.18 %). IR spectroscopy and High-performance size-exclusion chromatography (HPSEC) analysis revealed that AMLP was a sulfated homogenous heteropolysaccharide, and their molecular weight observed was 1.31 kDa. The Spectroscopic analysis of AMLP comprised of (1,2)- α-L-Fuc p , (1,6)-β-D-linked galactan, α-rhamnose, and (1,4)-β-D mannose residues. AMLP has a loosely arranged granular bead-like appearance present on the surface and also with the presence of some porous structures. The rheological properties of AMLP exhibited pseudoplastic properties with shear-thinning flow behavior. Congo red test and X-ray diffraction (XRD) results indicated the semi-crystalline nature of AMLP with a triple-helical structure. Thermogravimetric and Differential scanning calorimetry (TGA-DSC) analysis of AMLP found was thermally stable and its degradation temperature observed was 280 °C. Furthermore, AMLP exhibited potential antibacterial and antibiofilm properties against bacterial pathogens such as Listeria monocytogenes, Escherichia coli , Klebsiella pneumonia , Salmonella typhimurium, and Staphylococcus aureus . The In vitro antioxidant activities such as DPPH scavenging, Superoxide radical scavenging, OH radical scavenging, and reducing power activities of AMLP were evaluated and the results revealed that the tested antioxidant activities of AMLP were significantly (P < 0.05) increased with increasing the concentrations. Overall, these findings suggested that AMLP could be used as a potential candidate in pharmaceutical, cosmetics, and food industry applications. • AMLP (polysaccharide) from the leaves of Avicennia marina mangrove plant was characterized. • The backbone of AMLP contains (1,2)-α-L-Fuc p , (1,6)-β-D-linked galactan, α-rhamnose and (1,4)-β-D mannose residues. • It shows pseudoplastic flow properties with shear thinning behavior in solution. • AMLP showed triple-helix conformation and high thermal stability with degradation temperature of 280 °C. • It showed promising antioxidant activity and antibiofilm activity against several pathogens.