Carbohydrate Polymers最新文献

High methyl-esterified citrus pectin (HMCP) is often used as a thickness in food products and is considered a poor emulsifier, especially in neutral pH solutions. Our previous findings show that the emulsifying capacity of HMCP could be significantly enhanced by calcium cations. Besides, the pH of the solution decreased in the presence of calcium cations. However, the impact of solution pH on HMCP emulsifying capacity in the presence of calcium cations is unclear. In this study, the pH of the HMCP solution was adjusted from 3.00 to 8.00 before adding calcium cations. The solution properties and emulsifying properties were analyzed in light of the existence of calcium cations. The results showed that the pH of the HMCP solutions decreased after bringing calcium cations into them. Calcium cations could change the solution rheological properties, particle size distributions and morphologies, and the particle microenvironmental hydrophobic areas in HMCP solutions while increasing the pH of HMCP solutions, contributing to improving the emulsifying capacity of HMCP. HMCP had the best emulsifying ability when the pH of the HMCP solutions was kept at a neutral level. This research gives us new ideas to adjust the emulsifying property of HMCP.

The low cost and environmental advantages of Xanthan gum make its production and application scale exceed that of other polysaccharides. However, the temperature resistance of Xanthan gum limits its application. In this study, polysaccharide supramolecular Xanthan gum network (XG-β-CD/AD) based on β-cyclodextrin and adamantane was prepared for enhanced oil recovery. The structure of Xanthan gum was characterized by Fourier infrared spectroscopy, nuclear magnetic resonance spectroscopy and thermogravimetric analysis. The rheological properties of the modified polysaccharide network in aqueous solution were systematically studied. The results showed that physical cross-linking of host-guest interacion enhanced the thickening ability of the polymer. Shear rheology, extensional rheology and dynamic modulus test proved that XG-β-CD/AD had excellent rheological properties. The micromorphology, dynamic light scattering and circular dichroism clarified the molecular conformation, the host-guest interaction can improve conformational transition temperature (Tm) and inorganic salt tolerance of Xanthan gum. Under harsh environment (90 °C, 30000 mg/L brine), the oil recovery of XG-β-CD/AD is 6 %–11 % higher than that of XG at the same conditions, showing a better ability to improve the recovery rate. This study provides a research idea for the selection, development and application of biomacromolecular materials.

This study investigated the influence of Konjac Glucomannan (KGM) with varying degrees of polymerization (DKGMx) on the gelatinization and retrogradation characteristics of wheat starch, providing new insights into starch-polysaccharide interactions. This research uniquely focuses on the effects of DKGMx, utilizing multidisciplinary approaches including Rapid Visco Analysis (RVA), Differential Scanning Calorimetry (DSC), rheological testing, Low-Field Nuclear Magnetic Resonance (LF-NMR), and molecular simulations to assess the effects of DKGMx on gelatinization temperature, viscosity, structural changes post-retrogradation, and molecular interactions. Our findings revealed that higher degrees of polymerization (DP) of DKGMx significantly enhanced starch's pasting viscosity and stability, whereas lower DP reduced viscosity and interfered with retrogradation. High DP DKGMx promoted retrogradation by modifying moisture distribution. Molecular simulations revealed the interplay between low DP DKGMx and starch molecules. These interactions, characterized by increased hydrogen bonds and tighter binding to more starch chains, inhibited starch molecular rearrangement. Specifically, low DP DKGMx established a dense hydrogen bond network with starch, significantly restricting molecular mobility and rearrangement. This study provides new insights into the role of the DP of DKGMx in modulating wheat starch's properties, offering valuable implications for the functional improvement of starch-based foods and advancing starch science.

Herein, the effects of temperature cycling (4 °C/50 °C/100 °C) on the recrystallization, physicochemical properties, and digestibility of debranched starch (DBS) were investigated. Temperature cycling involved heating DBS to 100 °C to dissociate weak heat-sensitive crystalline structures and cooling to 4 °C to induce the rapid growth of crystal nuclei, followed by maintaining the temperature at 50 °C to promote orderly crystalline growth. This procedure aimed to increase the degree of crystalline structure in recrystallized DBS, thereby resulting in DBS that was heat- and digestion-resistant. Temperature cycling increased the dissociation temperature of DBS, and temperatures of up to 114.8 °C were attained after five cycling times. With increasing cycles, the crystalline structure of DBS transitioned from B-type to the more robust and compact A-type, and the crystallinity increased to ∼81.9 % (after seven cycles). Raman and Fourier transform infrared (FTIR) spectra indicated that temperature cycling enhanced the short-range ordered structure of DBS. Moreover, in vitro digestion experiments demonstrated that the resistant starch content of DBS increased to ∼61.9 % after eight cycles. To summarize, this study demonstrated a green and effective method for preparing heat-and digestion-resistant recrystallized DBS, which can be used for developing dietary supplements and low gastrointestinal staples.

The healing of chronic diabetic wounds remains a formidable challenge in modern times. In this study, a novel traditional Chinese medicine microneedle patch was designed based on the physiological characteristics of wounds, with properties including hemostasis, anti-inflammatory, antioxidant, antimicrobial, and induction of angiogenesis. Initially, white peony polysaccharide (BSP) with hemostatic properties and carboxymethyl chitosan (CMCS) with antimicrobial capabilities were used as materials for microneedle fabrication. To endow it with antimicrobial, procoagulant, and adhesive properties. Among them, loaded with ROS-sensitive nanoparticles of Astragalus polysaccharides (APS) based on effective components baicalein (Bai) and berberine (Ber) from Scutellaria baicalensis (SB) and Coptis chinensis (CC) drugs (APB@Ber). Together, they are constructed into multifunctional traditional Chinese medicine composite microneedles (C/B@APB@Ber). Bai and Ber synergistically exert anti-inflammatory and antimicrobial effects. Microneedle patches loaded with BSP and APS exhibited significant effects on cell proliferation and angiogenesis induction. The combination of composite polysaccharides enabled the microneedles to adhere stably to wounds and provide sufficient strength to penetrate the biofilm and induce dispersion. The combination of composite polysaccharides enabled the microneedles to adhere stably to wounds and provide sufficient strength to penetrate the biofilm and induce dispersion. Therefore, traditional Chinese medicine multifunctional microneedle patches offer potential medical value in promoting the healing of diabetic wounds.

The dissolving pulp preparation from bleached kraft pulp while realizing the high-value application of hemicellulose fraction is of great significance for improving the overall economics of the process. This work proposed a two-step cascaded process of deep eutectic solvent (DES) pretreatment combined with mechanical refining for the co-production of dissolving pulp and arabinoxylan (AX) from bleached bamboo pulp. Results showed that using alkaline DES composed of quaternary ammonium hydroxide and urea prepared high-quality dissolving pulp (α-cellulose content of 97.7 %) while selectively extracting high-quality AX. The mechanical refining rapidly opened up the cellulose structure to increase its Fock reactivity to over 70.0 %. When 100 g bleached bamboo pulp was subjected to this technology route, the high yields of dissolving pulp (63.8 g) and AX (13.0 g) were respectively obtained. It was proposed that the tailored DES with different alkalinity could specifically produce dissolving pulp or AX which were more favorable for downstream application through distinct action pathways. The swelling effects of DES on the cellulose surface facilitated the subsequent mechanical fibrillation, allowing a synergistic enhancement of the reactivity. Thus, the integrated process provided a sustainable alternative for dissolving pulp upgrading while adding attractiveness by co-producing AX product stream.

Cellulose nanofibrils (CNFs) from non-woody biomass, including citrus peel (CpCNFs), are promising naturally occurring nanomaterials; however, their properties depend on the composition of non-cellulosic components, including pectin. In this study, the effects of pectin modifications on CpCNFs were examined, including demethylesterification using alkaline treatment and enzymatic degradation of pectin using pectinase. CpCNFs could be redispersed in water with little aggregation after drying; however, the redispersibilities of both alkaline-treated (AT-CpCNFs) and pectinase-treated CpCNFs (PT-CpCNFs) were improved. Both AT-CpCNFs and PT-CpCNFs exhibited higher viscosity than untreated CpCNFs (UT-CpCNFs); redispersion in water after drying further increased the viscosity. A quartz crystal microbalance revealed that interactions between AT-CpCNFs were barely detectable, and interactions between PT-CpCNFs were stronger than those between UT-CpCNFs. The increase in the carboxylate groups of pectin due to demethylesterification in AT-CpCNF may have increased the viscosity and reduced the interactions between AT-CpCNFs, explaining the improved redispersibility. The increase in the viscosity of PT-CpCNFs may be attributed to the increased purity of CNFs, which is assumed to be more viscous than pectin. Our results show that the properties of CpCNFs are affected by the structure, properties, and content of pectin and can be controlled by pectin modification.

Dihydrazide (ADH) and dioxyamine (PDHA) were assessed for their efficacy in coupling chitosan and dextran via their reducing ends. Initially, the end-functionalization of the individual polysaccharide blocks was investigated. Under non-reducing conditions, chitosan with a 2,5-anhydro-D-mannose unit at its reducing end exhibited high reactivity with both PDHA and ADH. Dextran, with a normal reducing end, showed superior reactivity with PDHA compared to ADH, although complete conversion with ADH could be achieved under reductive conditions with NaBH₃CN. Importantly, the oxime bond in PDHA conjugates exhibited greater stability against hydrolysis compared to the hydrazone bond in ADH conjugates. The optimal block coupling method consisted in reacting chitosan with an excess of dextran pre-functionalized with PDHA. The copolysaccharides could be synthesized in high yields under both reducing and non-reducing conditions. This methodology was applied to relatively long polysaccharide blocks with molecular weight up to 14,000 g/mol for chitosan and up to 40,000 g/mol for dextran. Surprisingly, block copolysaccharides did not self-assemble at neutral or basic pH; rather, they precipitated due to hydrogen bonding between neutralized amino groups of chitosan. However, nanoparticles could be obtained through a nanoprecipitation approach.

Konjac glucomannan (KGM) molecular chains contain a small amount of acetyl groups and a large number of hydroxyl groups, thereby exhibiting exceptional water retention and gel-forming properties. To meet diverse requirements, KGM undergoes modification processes such as oxidation, acetylation, grafting, and cationization, which reduce its viscosity, enhance its mechanical strength, and improve its water solubility. Researchers have found that KGM and its derivatives can regulate the polarization of macrophages, inducing their transformation into classically activated M1-type macrophages or alternatively activated M2-type macrophages, and even facilitating the interconversion between M1 and M2 phenotypes. Concurrently, the modulation of macrophage polarization states holds significant importance for chronic wound healing, inflammatory bowel disease (IBD), antitumor therapy, tissue engineering scaffolds, oral vaccines, pulmonary delivery, and probiotics. Therefore, KGM has the advantages of both immunomodulatory effects (biological activity) and gel-forming properties (physicochemical properties), giving it significant advantages in a variety of biomedical engineering applications.

Microcarriers for large-scale cell culture have a broader prospect in cell screening compared with the traditional high cost, low efficiency, and cell damaging methods. However, the equal biological affinity to cells has hindered its application. Therefore, based on the antifouling strategy of zwitterionic polymer, we developed a cell-specific microcarrier (CSMC) for shielding non-target cells and capturing mesenchymal stem cells (MSCs), which has characteristics of high biocompatibility, low background noise and high precision. Briefly, [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide and glycidyl methacrylate were grafted onto polygalacturonic acid, respectively. The former built a hydration layer through solvation to provide an excellent antifouling surface, while the latter provided active sites for the click reaction with sulfhydryl-modified cell-specific peptides, resulting in rapid immobilization of peptides. This method is applicable to the vast majority of polysaccharide materials. The accurate capture ratio of MSCs by CSMC in a mixed multicellular environment is >95 % and the proliferation rate of MSCs on microcarriers is satisfactory. In summary, this grafting strategy of bioactive components lays a foundation for the application of polysaccharide materials in the biomedical field, and the specific adhesive microcarriers also open up new ideas for the development of stem cell screening as well.