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Corbicula fluminea distillate as an important industrial by-product of C. fluminea during steaming process is rich in amino acids, proteins and polysaccharides, showing potential hepatoprotective effect. In this study, a polysaccharide (CFDP) was obtained from C. fluminea distillate by three-phase partitioning combined with (NH 4) 2 SO 4 precipitation at a saturation of 60 %. The structural characteristics, antioxidant activity in vitro , and hepatoprotection against mice CCl 4 -induced acute liver damage of CFDP were studied. Results demonstrated that CFDP was a water-soluble homogenous polysaccharide predominantly comprising glucose (>98 %), with a weight-average molecular weight of 1.4 × 107 Da, and exhibiting potent antioxidant benefits in vitro. CFDP had a backbone of (1 → 4)-α- d -glucopyranosyl (Glc p) and a small amount of (1 → 4, 6)-α-D-Glc p. The branch formed at C-6 comprised by (1→)-α-D-Glc p and (1→)-α-D- N -acetylglucosamine. CFDP possessed excellent hepatoprotective activity against acute liver damage caused by CCl 4 in mice, mainly by ameliorating weight reduction and organ injures, alleviating hepatic function and serum lipid metabolism, suppressing oxidative stress and inflammatory responses, as directly verified by histopathological examination. Moreover, CFDP improved gut microbiota by up-regulating the relative abundance of total bacteria and probiotics such as Firmicutes , Bacteroidete , Rumminococcaceae , Lactobacillaceae , accompanied by promoting short chain fatty acid production. Therefore, our findings indicated that CFDP can be developed as a healthy food supplement for the prevention of chemical livery injury. [ABSTRACT FROM AUTHOR]

In this study, Phellinus linteus polysaccharides (PLPS) and proteins were simultaneously separated from P. linteus mycelia by using an aqueous two-phase system (ATPS) based on choline chloride ([Chol]Cl)/K2HPO4, and the physicochemical and antioxidant properties of PLPS after ATPS extraction were evaluated. Results demonstrated that the maximal extraction efficiencies of 68.53% ± 0.29% PLPS and 82.37% ± 0.41% proteins were obtained when the cholinium-based ATPS contained 68.9% K2HPO4, 20% [Chol]Cl, 10.0 mg mL−1 crude water extract (1.0 mL), and distilled water (4.0 mL) at shaking time and temperature of 30 min and 21.2 °C, respectively. Compared with C-PLPS obtained using traditional ethanol precipitation and isolation protocols, PLPS had higher carbohydrate content (63.58% ± 1.12%), lower molecular weight (15.2 kDa, 80%), different monosaccharide compositions, and showed similar preliminary structural characterizations. Moreover, PLPS exhibited more evident scavenging effects on free radicals and in vitro antioxidant activities than C-PLPS. Therefore, the method of [Chol]Cl/K2HPO4 ATPS can be developed as an effective strategy for the separation/purification of highly bioactive polysaccharides. [ABSTRACT FROM AUTHOR]

In this study, the submerged culture conditions for exopolysaccharide (EPS) production by Ganoderma cantharelloideum M. H. Liu were screened and optimized, and the physicochemical and biological properties of EPS were investigated. Results showed that the glucose and tryptone were the best C and N sources for the maximum EPS production, respectively. Under the optimal culture conditions, the EPS production achieved 1.60 g/L at day 6 in a 5 L stirred tank reactor. Two purified fractions (i.e., Fr-I and Fr-II) were obtained from the G. cantharelloideum EPS by gel permeation chromatography. Fr-II had a higher yield (87.54%), carbohydrate (95.86%), and protein (3.07%) contents and lower molecular weight (74.56 kDa) than that of Fr-I. Both Fr-I and Fr-II were polysaccharide-protein complexes with different monosaccharide compositions and chemical structures. Fr-II also exhibited stronger radical scavenging abilities, antioxidant capacities, and α-amylase and α-glycosidase inhibitory activities in vitro than that of Fr-I. Therefore, Fr-II obtained from G. cantharelloideum EPS might be explored as potential natural functional components or supplements for applications in food, medicine, and cosmetics. [ABSTRACT FROM AUTHOR]

BACKGROUND Pectin, as a functional ingredient, is best known as a gelling and thickening agent, stabilizer, and fat substitute in processed foods. The synthesis of pectin graft copolymers is considered one of the most fascinating ways to improve its physicochemical and functional properties. In this study, therefore, water‐soluble pectin or ultrasound‐treated pectins (UP30 and UP60) grafted with ferulic acid (FA) conjugates, pectin‐g‐FA, UP30‐g‐FA and UP60‐g‐FA, were synthesized via a free radical‐mediated grafting procedure, and their physicochemical, structural, and functional characteristics were investigated. Moreover, 2,2‐diphenyl‐1‐picryl‐hydrazyl (DPPH)‐radical scavenging activity, Trolox equivalent antioxidant capacity (TEAC) assay and ferric‐reducing ability of plasma (FRAP) assay were used to evaluate their antioxidant activities in vitro. RESULTS: Results showed that FA was covalently grafted onto pectin or ultrasound‐treated pectins, and the grafting ratios of pectin‐g‐FA, UP30‐g‐FA and UP60‐g‐FA were 65.43 ± 1.30, 82.55 ± 1.71 and 75.82 ± 0.89 mg FA/g, respectively. Although the molecular weights, apparent viscosities, and thermal stabilities of the three FA‐grafted pectin conjugates decreased and their surface morphologies were different from those of native pectin and ultrasound‐treated pectins, they possessed prominent DPPH‐radical scavenging ability [half maximal inhibitory concentration (IC50) of 0.32 to 0.89 mg mL−1) and antioxidant capacity (TEAC of 100.02 to 153.42 μmol Trolox/g sample; FRAP: 166.41 to 270.27 μmol FeSO4/g sample). Their antioxidant potentials were positively correlated with the grafting ratio. CONCLUSION: This study provided a promising strategy for the functionalization of pectin, and the prepared FA‐grafted pectin conjugates could be explored as functional ingredients that showed potential for applications in food and agriculture systems. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In this study, hot water, 0.9% NaCl, citric acid, and 1.25 M NaOH/0.05% NaBH 4 were separately used for the extraction of water-soluble H . erinaceus polysaccharides (HEPs; HEP-W, HEP-S, HEP-C, and HEP-A) from the fruit body of Hericium erinaceus . The physicochemical properties and biological activities were then investigated and compared. Results showed that the extraction solvents exhibited significant effects on the extraction yields, molecular weights, monosaccharide compositions, preliminary structural characteristics, microstructures of HEPs and on their contents, such as neutral sugar, uronic acid, protein, and β-(1 → 3)-glucan. In vitro antioxidant activity assays indicated that HEP-C extracted with citric acid solution showed stronger scavenging abilities on hydroxyl and DPPH radicals and antioxidant capacities than HEP-W and HEP-S. Moreover, HEP-C exhibited the strongest inhibitory effects on α-glycosidase and α-amylase activities. Therefore, HEP-C extracted with citric acid can be developed as a potential bioactive ingredient for applications in food, medicine, and cosmetics industries. [ABSTRACT FROM AUTHOR]

In this paper, three water-soluble polysaccharides (PS-D1, PS-D2, and PS-D3) isolated and purified from Pueraria lobata roots were characterized and their biological activities were evaluated. Results showed that PS-D1 was a neutral heteropolysaccharide comprised glucose and fructose in a molar ratio of 24.4:1.0 with a weight-average molecular weight ( M w ) of 62 kDa, while PS-D2 and PS-D3 were both acidic heteropolysaccharides consisting of glucose, fructose, arabinose and glucose, fructose, galactose, arabinose in a molar ratio of 54.5:1.0:1.0 and 61.0:1.0:2.7:2.4 with M w s of 159 and 385 kDa, respectively. Amongst of them, PS-D3 had the highest uronic acid content (∼12.4%), carbohydrate content (∼88.9%) and M w . All the three polysaccharides exhibited as random coils or large aggregates in aqueous solution. In vitro antioxidant activity tests indicated that PS-D3 showed the strongest scavenging capacities on hydroxyl (79.6%) and DPPH (60%) radicals at 3.0 mg/ml, and exhibited the highest antioxidant activity with a Trolox equivalent antioxidant capacity of 53.8 µmol Trolox/g and a ferric reducing ability of plasma of 56.9 µmol Fe 2+ /g. Moreover, the inhibitory activity on advanced glycation end-products (AGEs) formation of PS-D3 was 59.1% at 0.8 mg/ml. These results indicated that PS-D3 with prominent antioxidant capability showed pronounced non-enzymatic glycation inhibition activity in vitro . [ABSTRACT FROM AUTHOR]

• Seven polysaccharides (BGPs) are extracted from barley grass at three growth stages. • Different growth stages obviously affected physicochemical properties of these BGPs. • These BGPs had similar structural characteristics but different thermal stabilities. • BGP-Z12 and BGP-Z21 obtained at seedling stage showed more excellent bioactivities. Barley grass polysaccharides (BGPs) are some of the major bioactive constituents of barley (Hordeum vulgare L.) grass (BG). They exhibit favorable biological activities and health benefits. In this study, seven BGPs were extracted from BG, which was harvested at three different growth stages (e.g., seedling, tillering, and stem elongation), by alkaline-extraction method. Their physicochemical properties, structural characteristics, and biological activities were investigated and compared. Results demonstrated that the extraction yields, chemical compositions, monosaccharide constituents, and molecular weights of the seven BGPs obtained at different growth stages varied obviously. These BGPs had similar preliminary structural characteristics but different microstructures and thermal properties. Furthermore, the BGPs (BGP-Z12 and BGP-Z21) obtained at the seedling stage possessed stronger in vitro antioxidant potentials, cholic acid binding activity, and immunological activity than other BGPs. Therefore, these results indicated that that the seedling stage of BG was the preferable harvest time for preparing highly bioactive BGPs. [ABSTRACT FROM AUTHOR]

Corbicula fluminea distillate (CFD), as an industrial sub-product of the steaming process of C. fluminea , is rich in polysaccharides, proteins, and amino acids and has important developmental value. In this study, therefore, three water-soluble polysaccharides (CFDPs: CFDP-D, CFDP-U, and CFDP-T) were extracted and separated from CFD through direct ethanol precipitation, ultrasound-assisted extraction, and three-phase partitioning (TPP), respectively. Results demonstrated that the three extraction methods had important influences on extraction yields, chemical compositions, molecular weights, monosaccharide and amino acid constituents, structural characteristics, and microstructures as well as biological activities of CFDPs. Specifically, CFDP-T had higher yield (60.92% ± 3.58%), carbohydrate content (91.05% ± 1.22%), and uronic acid content (8.55% ± 0.18%) and lower protein content (7.15% ± 0.15%) than CFDP-D and CFDP-U. The three CFDPs were acidic proteoheteroglycans combined through O -glycosidic bonds and had high molecular weights of 1.93–2.41 × 107 Da and the same monosaccharide and amino acid compositions but different contents. Compared with CFDP-D and CFDP-U, CFDP-T exhibited more excellent free radical scavenging and stimulating (1.57 ± 0.03 μM, 500 μg/mL) activities on RAW264.7 macrophages in vitro. Therefore, our findings suggested that CFDP-T obtained from CFD by TPP had the potential to be a functional food ingredient in food industry. • Three polysaccharides (CFDPs) were separately prepared from C. fluminea distillate. • Extraction methods have obvious effects on physicochemical characteristics of CFDPs. • CFDPs are proteoheteroglycans via O -glycosidic linkages with high molecular weights. • CFDP-T obtained by TPP shows stronger bioactivities in vitro than CFDP-D and CFDP-U. [ABSTRACT FROM AUTHOR]

Abstract: A novel polysaccharide designated EPS-1A with an average molecular weight around 40kDa was fractionated and purified by anion-exchange and gel-filtration chromatography from the crude exopolysaccharide (EPS) isolated from fermentation broth of Cs-HK1, a Tolypocladium sp. fungus isolated from wild Cordyceps sinensis. The structural characteristics of EPS-1A were determined with various methods (e.g. GC, GC–MS, FT-IR, 1H NMR and 13C NMR) and through acid hydrolysis, methylation, periodate-oxidation and Smith degradation. The results suggested that EPS-1A was composed of glucose, mannose and galactose at 15.2:3.6:1.0M ratio. EPS-1A was a slightly branched polysaccharide and its backbone was composed of (1→6)-α-d-glucose residues (∼77%) and (1→6)-α-d-mannose residues (∼23%). Branching occurred at O-3 position of (1→6)-α-d-mannose residues of the backbone with (1→6)-α-d-mannose residues and (1→6)-α-d-glucose residues, and terminated with β-d-galactose residues. [Copyright &y& Elsevier]

Abstract: An exopolysaccharide (EPS) fraction isolated from mycelial culture of a Cordyceps sinensis fungus, designated EPS-1 with an average molecular weight (MW) of 38kDa, was hydrolysed in dilute sulphuric acid solution at pH 1 and 90°C, yielding two major MW fractions, 3.0kDa and 30kDa, respectively. While the proportion of lower MW fraction increased with the hydrolysis period (18% in 0.5h and 92% in 10h), the polydispersity (M w/M n) of EPS decreased steadily (from 1.47 initially to 1.10 in 10h). The IR spectra of hydrolysed EPS fractions showed changes only in the C–O–C and C–O–H band peaks from that of EPS-1. These results suggest that the hydrolysis of EPS in the acidic solution caused the EPS degradation mainly by cleaving the glycosidic linkage but no change in the primary molecular structure. The hydrolysed EPS fractions had much higher (30–80%) antioxidant and radical-scavenging activities. [Copyright &y& Elsevier]

Abstract: An optically active poly(phenylacetylene), poly{2-(R)-methyl-2-[4′-(tetradecyloxy)biphenyl-4-yloxy]propyl 4-ethynylbenzoate} (P1) is synthesized in a high yield with a high molecular weight (1.3×106 g/mol) by [Rh(nbd)Cl]2 catalyst. The chemical structure of the polymer is characterized by IR and NMR spectroscopies with satisfactory analysis data. The polymer is soluble in many common organic solvents. It shows circular dichroism (CD) band in the absorption region of the polyacetylene backbone, indicating that P1 is chiroptical owing to the formation of helical conformation with an excess screw sense. Combining the results of CD and light scattering experiments, we find that addition of poor solvent can induce the neighboring helical segments within a single polymer strand to become closer, resulting in exciton coupling prior to polymer precipitation. The exciton coupling can be kept in the solid state after solvent evaporation. [Copyright &y& Elsevier]

• Citrus pectin at different pH values was treated by ultrasonic irradiation. • Ultrasound at pH 10.0 led to pronounced reductions in the [ η ], M w , and DM of pectin. • Ultrasound did not cause noticeable influences on the main chain of pectin. • The degradation of pectin under ultrasound fitted to a second-order kinetics model. • Ultrasound at pH 10.0 caused obvious changes in rheological properties of pectin. Ultrasonic degradation has become a promising strategy for producing modified pectin (MP). In this study, the impact of ultrasonic treatment at various pH values (4.0, 7.0, and 10.0) on the macromolecular, structural and rheological characteristics of citrus pectin was investigated. Results demonstrated that ultrasonic irradiation at the higher pH led to larger reductions in the intrinsic viscosity and weight-average molecular weight of pectin. The degradation kinetics of pectin at different pH values under ultrasound well fitted to a second-order reaction kinetics model. Acoustic cavitation, β-elimination, and demethylation led to the breakage of glycosidic linkages of side chains and methoxyl groups of pectin, but did not have noticeable influences on the main chain of pectin. The ultrasonic treatment at a high pH led to an apparent change in the rheological characteristics of pectin. Therefore, ultrasonic treatment at various pH values can be developed as a viable means to prepare desirable MP. [ABSTRACT FROM AUTHOR]

• Three-phase partitioning (TPP) and gradient ethanol precipitation (GEP) are applied. • Polysaccharides (GPSs) were orderly prepared from raw garlic bulbs by TPP and GEP. • GPS80 had high carbohydrate and uronic acid contents, and low molecular weight. • GPS80 showed the stronger in vitro biological activities than the other three GPSs. In the present study, three-phase partitioning (TPP) coupled with gradient ethanol precipitation (GEP) was developed for the first time to extract and isolate polysaccharides (GPSs) from raw garlic (Allium sativum L.) bulbs. Four kinds of fructose polymers, namely, GPS35, GPS50, GPS65, and GPS80, were obtained at the final ethanol precipitation concentrations of 35%, 50%, 65%, and 80% (v / v), respectively, and their physicochemical characteristics and in vitro biological activities were investigated. Results indicated that GPS80 had higher carbohydrate (86.68% ± 0.90%) and uronic acid (12.89% ± 0.09%) contents, lower weight-average molecular weight (8.93 × 103 Da), and looser surface morphology than the other three GPSs. Furthermore, among the four GPSs, GPS80 exhibited the strongest antioxidant capacities, inhibitory effects on α-amylase and α-glycosidase, and nitric oxide stimulatory activity on RAW264.7 macrophage cells in vitro. Therefore, this study provides a simple and feasible technological strategy for producing bioactive polysaccharides from raw Allium vegetables. [ABSTRACT FROM AUTHOR]

• Polysaccharides (BPSs) were obtained from fresh bitter gourd by TPP and UAE methods. • TPP and UAE greatly affected the physicochemical and biological properties of BPSs. • BPS-W had excellent antioxidant, α-amylase and α-glycosidase inhibitory activities. • BPS-A with the lowest M w s showed the best bile acid-binding capacity among the BPSs. In this study, polysaccharides (BPSs) were obtained from fresh bitter gourd (Momordica charantia L.) by room temperature extraction techniques, including three-phase partitioning (TPP) and ultrasonic-assisted extraction (UAE) performed in different solvents. The results showed that the extraction methods had significant influence on the extraction yield, chemical composition, weight-average molecular weight (M w), monosaccharide composition, preliminary structural characterization and microstructure of the BPSs. The BPS-W sample obtained from the bitter gourd residue via UAE in distilled water had a higher uronic acid content (24.22%) and possessed stronger antioxidant capacities and α-amylase and α-glycosidase inhibitory activities than BPS-C extracted with UAE in citric acid, BPS-A extracted with UAE in 1.25 mol/L NaOH/0.05% NaBH 4 , and BPS-J extracted from bitter gourd juice by TPP. Moreover, BPS-A, which had the lowest M w s, showed the best bile acid-binding capacity among the four BPSs. This study had great potentials for the preparation of bioactive polysaccharides from fresh vegetables. [ABSTRACT FROM AUTHOR]

Curdlan is insoluble in water at ambient temperatures due to its rigid triple helix structure, which greatly limits its applications in the food industry. Alkali-neutralization (AN) treatment is a promising strategy for curdlan dissolution. In this study, the changes in macromolecular behaviors, microstructures, structural characteristics and rheological properties of curdlan before and after AN treatment at different alkali and acid concentrations (0.1–1.0 M) were analyzed and evaluated. Results showed that the AN-treated curdlans in aqueous solutions underwent conformation transitions from ordered triple helices to loose triple helices and then random coils with increased water solubility and reduced intrinsic viscosity, molecular weight, and rheological property. These findings were attributed to the breakdown of intra-/inter-molecular hydrogen bonds. Compared with untreated commercial curdlan, AN treatment significantly affected the microstructure, crystallinity, and thermal property of the AN-treated curdlans but hardly changed their (1 → 3)-β-D-glucopyranosidic linkages. Therefore, this study would provide a theoretical basis for gaining insight into the AN treatment for curdlan and further give a feasible and effective way for improving solubility of water-insoluble curdlan to expand its potential applications in food industry and biomedicine. Image 1 • AN-treated curdlans at various concentrations underwent conformation transitions. • AN treatment enhanced water solubility of curdlan, but hardly altered its structure. • AN treatment affected structural characteristics and functional properties of curdlan. • AN treatment influenced steady flow and viscoelastic behaviors of curdlan. • The breakdown of hydrogen bonds of curdlan was the main force during AN treatment. [ABSTRACT FROM AUTHOR]

In this study, a three-phase partitioning (TPP) system with dimethyl carbonate (DMC) as organic phase and sodium citrate (SC) as salt phase was used for partitioning of exopolysaccharide (EPS), namely, EPS-D, from fermentation broth of Phellinus baumii. Results showed that the maximum extraction yield (EY) of EPS-D was 71.02% under the following modified optimal conditions: DMC to fermentation broth ratio 0.5:1.0 (v/v), SC concentration 19% (w/v), temperature 30 °C, and pH 4.0. EPS-D had higher EY, carbohydrate, and uronic acid contents compared with the EPS, designated as EPS-T, obtained from the TPP system with t -butanol and ammonium sulfate. EPS-D and EPS-T had different chemical compositions and molecular weights; however, their preliminary chemical structures basically remained unchanged. Moreover, EPS-D exhibited stronger free radical-scavenging capability and total antioxidant capacity than EPS-T. Therefore, the TPP system with DMC as an alternative solvent for t -butanol has great potential for efficient partitioning of natural biomolecules. • TPP system with DMC and SC was used for partitioning of Phellinus baumii EPS-D. • The highest extraction yield of EPS-D was 71.02% under the optimal conditions. • EPS-D showed excellent free radical-scavenging capability and antioxidant capacity. • TPP with DMC and SC has great potential for partitioning of natural biomolecules. [ABSTRACT FROM AUTHOR]

Highlights • Cellulose has the highest soluble portion (SP) yield, followed by hemicellulose and lignin. • The SPs were detailedly analyzed with a GC/MS and FTICRMS. • GC/MS analysis shows that compositions of the SPs are quite different. • The most abundant class species in cellulose-, hemicellulose-, and lignin-derived SPs are O 5 , O 5 , and O 2 , respectively. • ADBE and OAN of O 4 - O 10 class species in the SPs have a negative correlation. Abstract Methanolysis of the three biomass components was conducted to afford soluble portions (SPs) and residues. Cellulose has the highest SP yield, followed by hemicellulose and lignin. The relatively volatile or less polar species in the SPs were analyzed with a gas chromatograph/mass spectrometer (GC/MS) and the polar species were identified with a negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometer (FTICRMS). According to analysis with GC/MS, sugars, esters, and phenols are the predominant compounds in cellulose- and hemicellulose-, and lignin-derived SPs, respectively. The analysis with FTICRMS shows that the molecular masses in the SPs range from 100 to 500 u and those in cellulose-/hemicellulose-derived SPs dominate from 250 to 300 u but in lignin-derived SP concentrates from 300 to 350 u. The identified compounds were assigned to O n class species with double bond equivalent (DBE) values of 1–14 and carbon atom numbers of 5–35. The most abundant class species in cellulose-, hemicellulose-, and lignin-derived SPs are O 5 , O 5 , and O 2 , respectively. The van Krevelen diagrams of O n class species suggest that primary species in lignin-derived SP are mainly located in a relatively narrow region with atomic ratio of O/C 0.0–0.3 and atomic ratio of H/C 1.0–1.3, while those in cellulose- and hemicellulose-derived SPs are principally located in a wider region with atomic ratio of O/C 0.2–0.8 and atomic ratio of H/C 0.8–1.5. The oxygen atom numbers of O 4 − O 10 class species was negatively correlated with the average DBE value, which indicates a cyclic structure or double bond will be generated (opened or saturated) with the removal (addition) of oxygen atoms. [ABSTRACT FROM AUTHOR]

• Glycosylation of glycinin with κ-carrageenan and guar gum was comparatively studied. • K-carrageenan was more susceptible to glycinin glycosylation than guar gum. • Both polysaccharides improved emulsifying properties of glycinin after glycosylation. • Glycinin grafted with κ-carrageenan exhibited greater viscosity and viscoelasticity. Molecular structure and functional properties of glycinin conjugated to κ-carrageenan and guar gum using a dry-heating method were comparatively analyzed. Glycosylation was confirmed by analyzing the degree of grafting, protein subunit composition, infrared absorption profile, and changes in contents of protein secondary structures. K-carrageenan was proven to possess a greater susceptibility to be grafted to glycinin than guar gum due to its relatively low molecular weight and negatively charged characteristics. The improvement of solubility by glycosylation with guar gum near the isoelectric point of glycinin was better than that by glycosylation with κ-carrageenan. Glycinin glycosylated with both polysaccharides exhibited enhanced emulsifying activity and stability. The enhanced apparent viscosity, elastic modulus, and viscous modulus also demonstrated that glycosylation promoted the appearance of stable elastic network structure. In summary, glycosylation with these two polysaccharides conferred glycinin superior emulsifying and rheological properties, and κ-carrageenan exhibited a better performance compared to guar gum. [ABSTRACT FROM AUTHOR]

• Ultrasound at various frequencies was used to extract okra polysaccharides (OPSs). • Frequency affected extraction efficiency and physicochemical properties of the OPSs. • Frequency had minor impacts on chemical structure and thermal stability of the OPSs. • The OPS extracted by ultrasound at 40/60 kHz had the best antioxidant, CAC and NIAC. • The OPS extracted by ultrasound at 20 kHz had the most bile acid-binding capacity. In this study, single- (SFU) and dual-frequency (DFU) ultrasounds were used to extract polysaccharides from okra (Abelmoschus esculentus (L.) Moench) pods (OPSs), and the physicochemical characteristics, functional properties, and in vitro biological activities of the OPSs were comparatively evaluated. Results showed that ultrasonic extractions at different frequencies led to remarkable variations in extraction yields, chemical components, monosaccharide compositions, molecular weights (MWs), surface morphologies, and rheological properties of the OPSs but hardly affected their preliminary structural features and thermal stabilities. The OPS obtained through DFU at 40/60 kHz with the lowest MWs (0.85–14.93 × 105 Da) and highest polyphenol content (7.38%) as well as loosest network structures showed superior antioxidant, cholesterol absorption and nitrite ion absorption capacities than the other OPSs, and the OPS extracted through SFU at 20 kHz with the highest carboxylate content (76.08%), MWs (7.28–32.83 × 105 Da) and degree of esterification (30.7%) exhibited higher bile acid-binding capacity than the other OPSs. [ABSTRACT FROM AUTHOR]

• Carboxylic curdlans were covalently grafted with ferulic acid (FA) via ester bonds. • Grafting with FA altered structure and functional properties of carboxylic curdlans. • FA-grafted carboxylic curdlan conjugates showed more excellent antioxidant benefits. • BC in Cur-8-g-FA Pickering emulsions had good storage stability against degradation. Grafting copolymerization of phenolic acids onto polysaccharides is an important strategy to improve their biological activities. In this study, ferulic acid (FA)-grafted carboxylic curdlan conjugates, namely, Cur-8- g -FA, Cur-24- g -FA, and Cur-48- g -FA, were synthesized by free radical-induced grafting. Results showed that FA was covalently grafted onto carboxylic curdlans via ester bonds. The grafting ratios of Cur-8- g -FA, Cur-24- g -FA, and Cur-48- g -FA were 223.03 ± 12.63, 115.63 ± 5.96, and 152.30 ± 4.57 mg FA/g, respectively, which were related with the carboxylate contents, molecular weights, and chain conformations of carboxylic curdlans. Compared with carboxylic curdlans, the FA-grafted carboxylic curdlan conjugates had lower thermal stability, molecular weight, and rheological property and looser surface morphology but had more prominent antioxidant benefits in vitro, which were proportional to their grafting ratios. Moreover, good storage stability against chemical degradation was exhibited by the β-carotene in Pickering emulsions stabilized by Cur-8- g -FA with a high grafting ratio and molecular weight. [ABSTRACT FROM AUTHOR]

• Ultrasound remarkably changed the structural and conformational features of pectin. • Ultrasound reduced the rheological properties and gel-formation capacity of pectin. • Ultrasonic-treated pectins had better emulsifying properties than untreated pectin. • Functional properties of pectin were largely determined by its M w and conformation. Ultrasonic degradation has become a fascinating strategy for preparing modified pectin, contributing to the improvement of pectin's functional characteristics. In this study, the impacts of structural and conformational characteristics of original and ultrasound-treated citrus pectins on their functional properties were examined. The results showed that compared with ultrasound-treated pectins, untreated pectin presented higher rheological and gelling properties primarily attributed to its larger weight-average molecular weight (M w), degree of methoxylation, amount of neutral sugar side chains, and z -average radius of gyration, as well as the more extended flexible-chain conformation. However, the ultrasound-treated pectins had better emulsifying properties than untreated pectin in an oil-in-water emulsion system. These properties, visually suggested by morphology analysis, including enhanced emulsifying capacity, emulsifying stability, reduced mean droplet size and negatively charged zeta potential. Moreover, the M w and chain conformation of untreated and ultrasound-treated pectins played more decisive roles in their functional properties than the others. [ABSTRACT FROM AUTHOR]

In this study, anionic carboxylic curdlans (Cur-8, Cur-24 and Cur-48) with different molecular properties and chain conformations were employed for the fabrication of carboxylic curdlan-coated zein nanoparticles (ZNPs) to overcome the poor colloidal stability of plain ZNPs. The results showed that the nanosized carboxylic curdlan-coated ZNPs prepared with 1.0 mg/mL ZNPs, 0.5 mg/mL carboxylic curdlans, and a 1:1 ZNP/carboxylic curdlan volume ratio (v / v) at pH 4.0 exhibited spherical shapes and negative zeta potentials. These carboxylic curdlan-coated ZNPs exhibited improved salt, thermal, and storage stability and good redispersibility compared with bare ZNPs. The carboxylate contents, molecular weights (MWs), and chain conformations of carboxylic curdlans considerably affected the particle sizes, electrical characteristics, microstructures, and colloidal stabilities of carboxylic curdlan-coated ZNPs. Specifically, compared with Cur-8, Cur-24 and Cur-48 with lower MWs, higher carboxylate contents and more extended flexible chains coated on the outer layer of ZNPs exhibited more pronounced colloidal stability. Moreover, electrostatic interactions, hydrogen bonds and hydrophobic effects contributed to the stabilization of ZNPs after coating with carboxylic curdlans, together with enhanced surface hydrophilicity. Thus, carboxylic curdlan-stabilized ZNPs can be developed as novel nanocarriers for various lipophilic nutrient delivery applications. • Zein nanoparticles (ZNPs) were coated by carboxylic curdlans for enhanced stability. • Carboxylic curdlans-coated ZNPs had spherical shapes and negative zeta potential. • Coating improved salt, thermal and storage stability and redispersibility of ZNPs. • Molecular properties and chain conformations affected the stability of coated ZNPs. • Electrostatic interactions and hydrogen bonds contributed to the stability of ZNPs. [ABSTRACT FROM AUTHOR]

In this study, carboxylic curdlans with different carboxylate contents, molecular weights (MWs), and chain conformations (Cur-8, Cur-24, and Cur-48) were developed as hydrophilic coatings for hydrophobic zein nanoparticles (ZNPs) to encapsulate curcumin. The results showed that the freshly prepared curcumin-loaded ZNPs (ZC) had spherical structures, a particle size of ~183.0 nm, a zeta potential of +17.7 mV, and an encapsulation efficiency of 66.7%. The anionic carboxylic curdlan coating on the surface of ZC affected the particulate and physicochemical characteristics of the encapsulated curcumin and effectively improved its water dispersibility, photo- and thermostability, and sustained release behavior in aqueous environments. These properties were correlated with the carboxylate content, MW, and chain conformation of the carboxylic curdlans. The observed improvements were attributed to hydrogen bonding, hydrophobic and electrostatic interactions among curcumin, ZNPs, and carboxylic curdlans. The curcumin encapsulated in the Cur-24-coated ZNPs exhibited stronger antioxidant capacity in vitro than the other samples. Therefore, carboxylic curdlan-coated ZNPs have considerable potential for use in hydrophobic nutraceutical encapsulation. Carboxylic curdlans with different molecular properties and chain conformations could serve as hydrophilic coatings of hydrophobic zein nanoparticles encapsulating curcumin and resulted in enhanced water dispersibility, photo- and thermo-stability, controlled release ability, and antioxidant activity in vitro. Image 1 • Carboxylic curdlan (CC)-coated zein nanoparticles were used to encapsulate curcumin. • Molecular properties and conformations of CC affected the encapsulation of curcumin. • Coating enhanced physicochemical and delivery properties of the entrapped curcumin. • Hydrogen bonds, hydrophobic and electrostatic interactions were main driving forces. • CC-coated zein nanoparticles served as desirable vectors for hydrophobic nutrients. [ABSTRACT FROM AUTHOR]

• Three-phase partitioning (TPP) and gradient (NH 4) 2 SO 4 precipitation (GNP) are used. • Polysaccharides (PS) from fresh okra pods were prepared via TPP coupled with GNP. • OPS-50 obtained by GNP at 50% (NH 4) 2 SO 4 had higher sugar and uronic acid contents. • OPS-50 had lower molecular weight, more flexible chain and less rheological nature. • OPS-50 showed more excellent in vitro antioxidant and hypoglycemic potentials. In this study, three-phase partitioning (TPP) coupled with gradient ammonium sulfate ((NH 4) 2 SO 4) precipitation (GNP) method was first used to extract and separate bioactive polysaccharides (OPSs) from fresh okra pods. Results showed that OPS-50 obtained by GNP at a saturation of 50% (NH 4) 2 SO 4 after TPP presented higher precipitation yield, carbohydrate (86.82%) and uronic acid (22.34%) contents with same monosaccharide composition and different molar ratios compared with OPS-30 and OPS-40 obtained via GNP at saturations of 30% and 40% (NH 4) 2 SO 4 , respectively. OPS-50 had lower weight-average molecular weight (3.65 × 106 g/mol), more flexible chain, and relatively looser surface structure compared with OPS-30, OPS-40, and the OPS obtained with TPP parallelized with decreased apparent viscosity and dynamic viscoelasticity. Furthermore, OPS-50 exhibited stronger DPPH radical-scavenging ability, antioxidant capacity, and α-amylase and α-glucosidase inhibitory activities in vitro than OPS, OPS-30, and OPS-40. [ABSTRACT FROM AUTHOR]