Search Results (86)

Background: Polysaccharide–iron complexes (PICs) are widely used oral iron supplements, but their gastrointestinal tolerability varies and remains incompletely understood. As typical non-biological complex drugs (NBCDs), PICs exhibit structural heterogeneity, and their functional performance may be linked to higher-order structural attributes. Methods: In this study, two commercial PIC preparations (test samples A and B) were comparatively investigated to explore their structure–function relationship using a multi-dimensional approach. Structural properties were characterized by gel permeation chromatography (GPC), mass spectrometry (MS), Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy, along with monosaccharide composition analysis. Functional behaviors and physiological relevance were further evaluated through in vitro acid-stress release studies and in vivo rat gastrointestinal tolerability assessments. Results: The results revealed that test sample A exhibited a glucose-only detectable monosaccharide profile but a higher and broader apparent molecular-weight distribution, indicating monosaccharide compositional uniformity together with macromolecular heterogeneity. In contrast, test sample B showed detectable glucose and mannose, a lower and narrower apparent molecular-weight distribution, higher measured free iron, and greater iron release under the tested acidic conditions. An exploratory 7-day rat gastrointestinal tolerability study (n = 4 per group) indicated that these distinct profiles may impact mucosal tolerability. Structurally stable test sample A allowed intestinal iron accumulation while maintaining mucosal integrity. Conversely, the rapid dissociation of test sample B induced observable mucosal injury, despite lower local iron retention. Conclusions: These findings suggest that the gastrointestinal tolerability of PICs may be associated with their structural attributes and release behavior, rather than total iron content alone. Overall, this exploratory study highlights a potential relationship between multi-dimensional PIC structure and functional performance, emphasizing the need for broader, structure-informed frameworks in the quality evaluation of complex iron therapies. Full article

Calcium-induced polysaccharide hydrogels have attracted growing interest in food science because of their mild gelation conditions, tunable structures, and compatibility with food-grade formulation. This review focuses on edible Ca²⁺-mediated polysaccharide hydrogels and related composite networks, focusing on alginate, low-methoxyl pectin, gellan gum, and carrageenan. Rather than treating all calcium-containing polysaccharide materials as well-defined complexes, we distinguish direct coordination, ionic bridging, charge screening, helix stabilization, and composite-assisted network regulation. Current evidence indicates that Ca²⁺-mediated assembly is governed by polysaccharide fine structure, calcium-release behavior, pH, ionic strength, and processing conditions, thereby determining crosslinking density, digestibility gel strength, water distribution, rheological properties, release behavior, and texture-related functionality. For texture-modified foods for older adults, these hydrogels may provide a useful material basis for designing swallowing-friendly matrices, sustained nutrient-delivery systems, and soft composite foods. However, available evidence is still largely derived from model gels, in vitro characterization, and static digestion models, while validation in real food matrices, dynamic gastrointestinal conditions, oral processing, sensory acceptance, and older-adult populations remains limited. Future studies should establish structure–function–population evidence chains linking molecular assembly to reliable geriatric food performance. Full article

Sodium caseinate (SC)-stabilized emulsions are highly susceptible to flocculation and phase separation near the protein isoelectric point (pI), limiting their application in acidified food systems. In this study, high acyl gellan gum (HA) was introduced to construct pH-responsive protein–polysaccharide complexes to modulate the interfacial assembly and stability of SC emulsions. Results demonstrated that HA interacts with SC primarily through electrostatic attraction and multi-site hydrogen bonding. This interaction induces protein conformational rearrangement and, as evidenced by combined structural and computational analyses, facilitates the assembly of a denser, interconnected composite network. The formation of HA–SC complexes significantly enhanced interfacial adsorption, reduced oil–water interfacial tension. Rheological and microrheological analyses revealed the composite system formed an elasticity-dominated weak gel network, restricting droplet mobility and suppressing aggregation. Consequently, HA–SC emulsions exhibited markedly improved pH tolerance and physical stability compared to SC-only emulsions, particularly near the pI, evidenced by reduced droplet size, lower Turbiscan stability indices, and more homogeneous microstructures. Crucially, utilizing a well-defined mechanistic model of fixed HA and SC concentrations, this study quantitatively links molecular interactions, interfacial network reconstruction, and macroscopic emulsion stability across a broad pH continuum. Rank-correlation analysis of pH-resolved descriptors shows the molecular charge state co-varies monotonically with the interfacial network and macroscopic stability, and is inversely coupled to droplet mobility. These findings provide new insights into protein–polysaccharide interfacial engineering, establishing the essential physical-stability foundation for the future rational design of acid-tolerant food emulsions and functional delivery systems. Full article

This study reports the fabrication of Pickering emulsion gels stabilized by zein and curdlan (CU) and systematically elucidates the regulatory mechanisms of oil fraction and shearing parameters (temperature and duration) on their microstructure, mechanical properties, and stability. Results indicated that excessive oil content triggered pronounced flocculation and structural collapse, primarily attributed to insufficient interfacial coverage and compromised network continuity. An optimal dense network with superior cohesiveness was established at a shearing temperature of 60 °C, effectively entrapping oil droplets within the continuous phase. Furthermore, extending the shearing duration enhanced long-term stability by reducing droplet size, yielding a maximum oil binding capacity (OBC) of 78.9%. These emulsion gels exhibited remarkable stability against diverse environmental stressors, including thermal treatments, pH variations, and freeze-thaw cycles. This work expands the application of protein-polysaccharide complexes in food colloid science and provides a theoretical foundation for the development of novel low-fat food formulations based on emulsion gel systems. Full article

To address the challenge of purifying bioactive polyphenols from the complex matrix of Ziziphus jujuba Mill. var. spinosa pulp, this study established an integrated purification protocol combining Deep Eutectic Solvent (DES) extraction with macroporous adsorption resin (MAR) enrichment. Among five screened resins, AB-8 exhibited superior selectivity, achieving a maximum adsorption capacity of 62.48 mg polyphenols/g dry resin and a desorption ratio of 83.40%. Kinetic analysis revealed that the adsorption process strictly followed a pseudo-second-order model (R² = 0.999), indicating a mechanism dominated by chemisorption. Through dynamic optimization, optimal column parameters were determined as a loading concentration of 2.4 mg/mL, a flow rate of 1.0 mL/min, and elution with 70% (v/v) ethanol. Structural characterization via UV-Vis and FT-IR confirmed the effective removal of polysaccharide and protein impurities, while High-Performance Gel Permeation Chromatography (HPGPC) indicated a low-molecular-weight distribution (M_w approx. 1073 Da). Furthermore, HPLC-MS profiling definitively identified eight key constituents, including chlorogenic acid, catechin, rutin, and quercetin. Collectively, this work elucidates the adsorption mechanism and provides a scalable, efficient technical foundation for the high-purity preparation of jujube polyphenols. Full article

Protein–polyelectrolyte entities (complex, coacervates, flocs, gels, etc.) are of great interest due to their potential applications in biological and medical fields. This study focuses on investigating the interactions between a model protein, human serum albumin (HSA) and a newly synthesized hybrid thermoresponsive copolymer based on chitosan polysaccharide grafted with poly(N-isopropylacrylamide) synthetic polymer chains (Chit-g-PNIPAM), in aqueous media, by mixing the individual component aqueous solutions. Depending on the mixing molar ratio and the order of addition of the two components (protein and copolymer), either stable nanostructured suspension or macrostructures’ phase separation have been observed. Dynamic light scattering (DLS) results reveal that the Chit-g-PNIPAM/HSA_x (molar ratio 5:x, where x = 1, 2, 3, 5, 10 and 15) nanostructures’ and HSA/Chit-g-PNIPAM_x (molar ratio 100:x, where x = 1, 2, 3, 10, 20, 30, 40 and 50) structures’ formation depend on the molar ratio of the two components as well as on the order of addition, with first component amount being kept constant in aqueous solution and second component solution added drop-by-drop in the solution of the first component. Additional information regarding the thermoresponsiveness and stability vs time of the formed (nano)structures were acquired using turbidimetry and DLS measurements. Full article

The application of natural polysaccharides and their sulfated derivatives have already been successfully implemented in the pharmaceutical and food industries, in particular. The present study is concerned with modifying a predominant polysaccharide in the composition of spruce wood, galactoglucomannan (GGM), by sulfation via a urea-sulfamic acid complex in a 1,4-dioxane medium. By varying the sulfation process duration from 30 to 180 min, six novel GGM sulfate samples with different degrees of substitution (DS) of 0.4–1.2 were obtained and studied with a combination of modern physicochemical methods: elemental analysis, Fourier transform infrared (FTIR) spectroscopy, and gel permeation chromatography (GPC). It has been revealed that the sulfation of GGM proceeds without degradation of the main polymer chain, as evidenced by the shift in the main peak toward the high-molecular-weight region in the GPC curves. Moreover, modification of the polysaccharide leads to a significant transformation of the molecular conformation from a dense sphere to a random coil (α from 0.30 to 0.76). Furthermore, it has been determined that sulfate-substituted groups of the GGM tended to decrease the scavenging capacity of the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals. However, the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assay showed an increase in the free radical inhibitory capacity of sulfated polysaccharides. This is attributed to the structural and conformational properties of the polysaccharide sulfate derivatives. The maximum anticoagulant activity (ACA) of sulfated GGM (SGGM) is 21.19 ± 2.89 IU/mg and increases with increasing sulfation duration. Full article

Extrusion-based bioprinting is widely used for fabricating cell-laden constructs; however, its success is highly dependent on the rheological and biological performance of the bioink. Natural polysaccharide gums have emerged as promising bioink components due to their biocompatibility and tunable properties. Among them, tragacanth gum (TG), a complex anionic heteropolysaccharide composed of tragacanthin and bassorin fractions, has gained increasing attention for extrusion bioprinting applications. TG exhibits pronounced shear-thinning behavior, high water uptake, and spontaneous gel-forming ability, which collectively enhance the printability, shape fidelity, and structural stability of bioinks. This review critically summarizes recent advances in TG-based hydrogels and bioinks, with emphasis on their molecular characteristics, rheological and physicochemical properties, and biological performance in extrusion bioprinting systems. The role of TG as a functional component in composite bioinks, particularly in improving mechanical integrity, extrusion consistency, and cytocompatibility, is discussed. Finally, current challenges and future research directions are highlighted to support the development and clinical translation of TG-based bioinks for tissue engineering applications. Full article

This study explores the fabrication and characterization of Pickering high internal phase emulsions (P-HIPEs) stabilized by soy protein isolate (SPI) and coix polysaccharide (CP) complex. CP exhibited high purity (95.29%) with a molecular weight of 5.53 × 10⁵ Da and was predominantly composed of glucose, as confirmed by monosaccharide analysis and FT-IR spectroscopy. SPI/CP complexes formed well-dispersed nanoparticles with optimal stability at 2% CP concentration, demonstrated by minimal particle size and enhanced zeta potential. P-HIPEs stabilized by these complexes showed excellent physical stability without phase separation or oil leakage, with the creaming index decreasing as particle concentration increased, reaching optimal stability at 12% SPI/CP and pH 9. Particle size and zeta potential measurements indicated smaller, more uniform droplets and intensified electrostatic repulsion under these conditions, effectively preventing droplet coalescence. Confocal microscopy revealed a dense, multilayered interfacial network formed by SPI/CP complexes around oil droplets, enhancing emulsion stability. Rheological analyses confirmed that P-HIPEs exhibited elastic solid-like gel behavior with pronounced shear-thinning and superior thixotropic recovery at 12% SPI/CP and alkaline pH, highlighting improved gel strength and structural integrity. These findings demonstrate the critical influence of SPI/CP concentration and pH on the physicochemical, microstructural, and rheological properties of P-HIPEs, offering valuable insights for developing stable emulsions with enhanced performance and applicability in food systems. Notably, the results emphasize the critical role of SPI/CP concentration and pH in achieving optimal emulsion stability and rheological properties. Full article

Hydrogels based on gelatin–chitosan mixtures have great potential for practical application in the development of new materials in food technology and biomedicine. This study examines the effect of chitosan on the gelling properties, rheological, and structural characteristics of fish gelatin type A hydrogels in the acidic pH range of 3.2–3.9. It was shown that an increase in the chitosan-to-gelatin mass ratio up to 0.15 resulted in a growth in the hydrogel thermal stability and an increase in the elastic modulus, hardness, and yield stress. The structural strength of the fish gelatin–chitosan hydrogel increased due to the strengthening of the binding zones in the fish gelatin gel network in the presence of chitosan. According to scanning electron microscopy, the supramolecular microstructure of the gels demonstrated a significant compaction upon the addition of chitosan to fish gelatin. UV and IR spectroscopy data, as well as changes in zeta potential, showed the formation of supramolecular complexes of fish gelatin with chitosan as a result of hydrophobic interactions between biomacromolecules and the establishment of hydrogen bonds; in this case, electrostatic interactions between macromolecules of fish gelatin and chitosan are practically absent in the acidic pH region. The ability to form supramolecular complexes of different compositions at different mass ratios of polysaccharide-to-fish gelatin makes it possible to obtain hydrogels with high gelling properties, strength, elasticity, and thermal stability comparable to hydrogels of mammalian gelatin. Full article

Plant-based natural polymers are gaining attention as ecofriendly alternatives to synthetic materials with applications in food, biomedical, pharmaceutical, and environmental science. Tragacanth gum (TG), a natural exudate obtained from Astragalus species, represents a unique polysaccharide with a complex molecular structure and distinctive rheological properties. It has been traditionally used for centuries as a stabilizer and emulsifier. Recent advances highlight its potential as a multifunctional biopolymer with industrial and biomedical potential. This review explores the structural characteristics, physicochemical properties, and modification strategies of TG, comparing it with other plant derived gums. Special emphasis is given to its applications in drug delivery, tissue engineering, wound healing, biodegradable packaging, and functional food formulation. Strengths such as biocompatibility and gel-forming ability but challenges remain including variability in quality, limited standardization, and issues with large scale production. Emerging trends, such as nanoformulations, hybrid polymer composites, and smart hydrogels, are also discussed. By positioning TG within the broader context of sustainable biomaterials, this review identifies key research gaps and proposes future directions to advance its role in the green polymer economy. Full article

Fresh coconut meat polysaccharides (FCMPs) are high-value natural active polysaccharides with both medicinal and edible uses, but their structural characteristics and potential biological activities have not been well studied. In this work, FFCMP was separated and purified by sequential application of water extraction and alcohol precipitation methods, the Sevag method, DEAE-52 cellulose column chromatography, and Sephadex G-100 gel column chromatography, yielding four components (FCMP 1-FCMP 4). High-performance liquid chromatography (HPLC) was used to determine their molecular weights as 343,016.9, 2279.4, 1363.2, and 2228.9 Da, respectively. Structural characterization and monosaccharide analysis revealed that the FCMP series primarily consists of mannose, glucose, galactose, arabinose, and rhamnose. Methylation experiments and nuclear magnetic resonance (NMR) indicated that FCMP 1 exhibits a complex topological structure with a β-1→4 main chain, β-1→6 branches, and an α-L-rhamnose terminal; FCMP 2 is a heteropolysaccharide with a β-(1→3)-mannan main chain containing β-(1→6)-galactose branches; the main chain of FCMP 3 consists of β-D-mannose and β-D -galactose, with side chains containing α-L-rhamnose and terminal α-L-arabinose and β-D-mannose; and FCMP 4 has a main chain primarily composed of glucose and mannose linked via 1→4 bonds, with some C6 positions exhibiting 1→6 branch structures. Molecular docking predictions suggest that the FCMP series of polysaccharides possess immunomodulatory, anti-inflammatory, and edema-treating properties, providing a theoretical basis for their application in pharmacology and food science research. Full article

In this work, the associative behavior of Gum Arabic in aqueous solutions was investigated through dynamic light scattering, nuclear magnetic resonance, and transmission and scanning electron microscopy. It was shown that in small associates, the spherical polysaccharide units have predominant sizes of 2–8 and 9–20 nm. The average hydrodynamic diameter of diffusing structural units, calculated on the basis of NMR experiment, turned out to be close to 20 nm, which corresponds with electron microscopy data. Based on geometric considerations and the composition and supramolecular structure of Gum Arabic, we calculated the parameters of branched chains of Gum Arabic. A possible “crown” model of polysaccharide chain association into spherical blocks is presented. The developed model allowed us to describe the effects observed during the time-extended association of Gum Arabic particles (molecules) in aqueous solutions, leading first to blocks’ swelling, then the appearance of local gelation, and only then to the creation of dense protective layers on the surfaces. It was established that the tendency of amphiphilic Gum Arabic molecules to form complexes both among themselves and with various surfaces and the possibility of forming viscous gel-like layers on the interfaces underly its use in many natural, food, technical, and technological applications, including emulsification. Full article

The root of Arnebia szechenyi Kanitz, known as “Mongolia Zicao,” has been widely used in traditional Chinese and Mongolia medicine. Herein, we aimed to characterize a pectin polysaccharide extracted from A. szechenyi Kanitz root (ASP), elucidate its structure, and evaluate potential immunomodulatory activities through in vitro assays. Sugar composition analysis and high-performance gel permeation chromatography (HPGPC) revealed that ASP is predominantly composed of GalA (45.44%), Gal (22.13%), and Ara (19.86%) with a homogenous molecular weight of 18.4 kD. ASP was identified as a typical pectin-like polysaccharide containing linear HG domains and potentially linked to complex branches with Ara and Glu residues. The monosaccharide analysis of the digestion product, D-ASP, supported this hypothesis. The Congo red test indicated the absence of a triple-helix structure in ASP and its digestion product D-ASP. ASP exhibited an irregular structure due to the branching fork, which disappeared after digestion, as observed by scanning electron microscopy. Additionally, ASP and D-ASP had certain antioxidant activities and significantly stimulated the release of cytokines (IL-1β, IL-6, TNF-a, NO), macrophage proliferation and phagocytic capability in RAW 264.7 cells in a dose-dependent manner. These findings outline the chemical and biological foundation for the development of novel drug candidates in the food and pharmaceutical industries. Full article