In-depth understanding of the effects of different molecular weight pullulan interacting with protein and starch on dough structure and application properties.

This work clarified the positive effects of pullulan on dough structure and application properties varied with its molecular weight. Pullulan with different molecular weights were introduced into dough system to explore their intervention effects on structural and technological properties of dough as well as physical and digestion properties of biscuits. Results showed that HPL (pullulan with molecule weight of 100- 300 kDa) could increase the intermolecular collisions, prompt the protein aggregation and limit the water migration in dough system, resulting in an integrate, continuous and dense network structure of the gel with strengthened elasticity and weakened extensibility, which caused an increase in biscuit thickness, hardness and crispness. On the contrary, LPL (pullulan with molecule weight of 3- 100 kDa) could go against the formation of stable and elastic dough through breaking down cross-linkage between protein and starch so as to provide biscuits with decreased hardness and crispness during baking. Both HPL and LPL delayed starch pasting and retrogradation process while HPL had the stronger retarding effect on starch digestibility of biscuits than LPL. These findings dedicated to a better understanding of pullulan function in dough system and provide suggestions for fractionation applications of pullulan in food field.

Green potassium fertilizer from enzymatic hydrolysis lignin: Effects of lignin fractionation on wheat seed germination and seedling growth.

Sustainably sourced lignin presents great potential as a green feedstock for fertilizer production but commercial fulfillment is still challenging owing to the mediocre fertilizer activity of lignin. To address this issue, an effective strategy to enhance the activity of lignin-based potassium fertilizer (LPF) is proposed through lignin fractionation. Three lignin fractions subdivided from enzymatic hydrolysis lignin (EHL) were adopted as the feedstock for LPF preparation, and the effect of lignin fractionation on wheat seed germination and seedling growth was investigated. Compared with the potassium fertilizer from unfractionated lignin, LPF-F1 showed significantly improved effects on promoting seed germination and seedling growth, which can be attributed to the high potassium content resulted from its abundant phenolic hydroxyl and carboxyl contents. Under the optimal treatment concentration (100 mg/L), LPF-F1 showed comparable promotion effect to commercial fulvic acid potassium on wheat seedling growth, suggesting the potential of LPF-F1 as commercial potassium fertilizer. Overall, this work reveals that lignin heterogeneity presents critical effects on the wheat seed germination and seedling growth of LPF, and the fertilizer activity of LPF can be substantially improved using fractionated lignin with low molecular weight as the raw material.

Chitosan entrapping of sodium alginate / Lycium barbarum polysaccharide gels for the encapsulation, protection and delivery of Lactiplantibacillus plantarum with enhanced viability.

To preserve the viability of probiotics during digestion and storage, encapsulation techniques are necessary to withstand the challenges posed by adverse environments. A core-shell structure has been developed to provide protection for probiotics. By utilizing sodium alginate (SA) / Lycium barbarum polysaccharide (LBP) as the core material and chitosan (CS) as the shell, the probiotic load reached 9.676 log CFU/mL. This formulation not only facilitated continuous release in the gastrointestinal tract but also enhanced thermal stability and storage stability. The results obtained from Fourier transform infrared spectroscopy and thermogravimetric analysis confirmed that the addition of LBP and CS affected the microstructure of the gel by enhancing the hydrogen bond force, so as to achieve controlled release. Following the digestion of the gel within the gastrointestinal tract, the released amount was determined to be 9.657 log CFU/mL. The moisture content and storage stability tests confirmed that the encapsulated Lactiplantibacillus plantarum maintained good activity for an extended period at 4 °C, with an encapsulated count of 8.469 log CFU/mL on the 28th day. In conclusion, the newly developed core-shell gel in this study exhibits excellent probiotic protection and delivery capabilities.

Soluble dietary fibers from solid-state fermentation of wheat bran by the fungus Cordyceps cicadae and their effects on colitis mice.

Ulcerative colitis is a chronic inflammatory disease with a complex pathogenesis for which there is no definitive therapeutic agent. Fermentation, as a green and efficient bioprocessing technique, has been shown to enhance the biological activity of food ingredients. Soluble dietary fiber isolated from plants is thought to have the potential to prevent and alleviate ulcerative colitis. This work was designed to study the differences in the chemical properties of the soluble dietary fiber from wheat bran fermented by Isaria cicadae Miq. (FSDF) and the unfermented soluble dietary fiber from wheat bran (UFSDF) and their effects on colitis mice. The results showed that FSDF and UFSDF differed in molecular weight, monosaccharide compositions, and surface morphology. In addition, supplementation with UFSDF and FSDF ameliorated the symptoms of DSS-induced colitis in mice by attenuating body weight loss, decreasing the disease activity index and splenic index, shortening the length of the colon, and attenuating colonic tissue damage. UFSDF and FSDF also increased the production of the anti-inflammatory cytokine IL-10 and inhibited the expression of IL-6, IL-1ß, and TNF-α. The results of gut flora and short-chain fatty acid analyses showed that UFSDF and FSDF improved the diversity of gut microbiota, up-regulated the abundance of some beneficial bacteria such as Akkermansia and Muribaculaceae, increased the levels of acetic acid, propionic acid, and butyric acid, and restored dextran sodium sulfate (DSS)-induced dysbiosis of the intestinal flora in mice. These findings provide guidance for the development of FSDF and UFSDF as functional foods for the relief of ulcerative colitis.

The Relationship between Preparation and Biological Activities of Animal-Derived Polysaccharides: A Comprehensive Review.

Polysaccharides are biomolecules found in microorganisms, plants, and animals that constitute living organisms. Glycosaminoglycans, unique acidic polysaccharides in animal connective tissue, are often combined with proteins in the form of covalent bonds due to their potent biological activity, low toxicity, and minimal side effects, which have the potential to be utilized as nutrition healthcare and dietary supplements. Existing studies have demonstrated that the bioactivity of polysaccharides is closely dependent on their structure and chain conformation. The characteristic functional groups and primary structure directly determine the strength of activity. However, the relationship between structure and function is still unclear, and the target and mechanism of action are not fully understood, resulting in limited clinical applications. As a result, the clinical applications of these polysaccharides are currently limited. This review provides a comprehensive summary of the extraction methods, structures, and biological activities of animal-derived polysaccharides that have been discovered so far. The aim is to promote developments in animal active polysaccharide science and provide theoretical support for exploring other unknown natural products.

Peanut oil odor enhances the immunomodulatory effect on immunosuppressed mice by regulating the cAMP signaling pathway via the brain-spleen axis.

The role of sniffing relative to immune function has attracted considerable attention. The present study investigated the immunomodulatory effects of peanut oil odor on cyclophosphamide (CTX)-induced immunosuppressed mice. The subset of mice subjected to prolonged (8 h) sniffing peanut oil odor (PL) demonstrated significantly elevated levels of agouti-related peptide, neuropeptide Y, and glutamate (p < 0.05), whereas it significantly down-regulated the level of γ-aminobutyric acid in the brain (p < 0.05). Furthermore, immunohistochemistry results indicated significantly increased expression of mGluR1/5 and decreased expression of GABABR in the hippocampus and hypothalamus (p < 0.05) of the PL group. Additionally, the PL group had significantly up-regulated expression levels of cAMP, Epac, Rap1, ERK1/2 and PKA (p < 0.05) and remarkably increased phosphorylation of CREB in the cAMP signaling pathway (p < 0.05), which influenced the central nervous system. Moreover, compared with CTX-induced mice, the percentages of peripheral blood T lymphocytes (CD3+CD4+ and CD3+CD8+) and the levels of splenic cytokines (IL-2, IL-4, and TNF-α) were significantly increased following PL treatment (p < 0.05). The PL group also showed significantly up-regulated expression levels of cAMP, p-p65, and p-IκBα in the spleen (p < 0.05) by western blot analysis. In summary, PL intervention significantly up-regulated the expression levels of cAMP in the brain (p < 0.05), with subsequent transfer of cAMP to the spleen which promoted phosphorylation of p65 and IκBα. This series of events enhanced the immunity of mice, which confirmed the regulatory effect of PL on the cAMP signaling pathway, thereby enhancing immune function via the brain-spleen axis.

Fabrication modulation of lignin-derived carbon nanosphere supported Pd nanoparticle via lignin fractionation for improved catalytic performance in vanillin hydrodeoxygenation.

Nano-lignin presents great potential in advanced carbon materials preparation since it integrates the advantages of nanomaterials as well the preferable properties of lignin (e.g. high carbon content and highly aromatic structure). Herein, lignin-derived carbon nanosphere supported Pd catalysts (Pd@LCNS) were prepared via a two-step carbonization of Pd2+ adsorbed lignin nanospheres (LNS) and applied in vanillin hydrodeoxygenation. The effect lignin heterogeneity on the synthesis of Pd@LCNS as well as its catalytic performance was further investigated through the synthesis of Pd@LCNS using three lignin fractions with different molecular weight. The results showed that the three Pd@LCNSs exhibited significant differences in the morphology of both carbon support and Pd nanoparticles. Pd@LCNS-3 prepared from high molecular weight lignin fraction (L-3) presented stable carbon nanosphere support with the smallest particle size (∼150 nm) and the highest Pd loading amount (3.78 %) with the smallest Pd NPs size (∼1.6 nm). Therefore, Pd@LCNS-3 displayed superior catalytic activity for vanillin hydrodeoxygenation (99.34 % of vanillin conversion and 99.47 % of 2-methoxy-4-methylphenol selectivity) at 90 °C without H2. Consequently, this work provides a sustainable strategy to prepare uniformly dispersed lignin-based carbon-supported Pd catalyst using high molecular weight lignin as the feedstock and further demonstrate its superior applicability in the selective transfer hydrogenation of vanillin.

Lima bean (Phaseolus lunatus Linn.) protein isolate as a promising plant protein mixed with xanthan gum for stabilizing oil-in-water emulsions.

BACKGROUND: Lima bean protein isolate (LPI) is an underutilized plant protein. Similar to other plant proteins, it may display poor emulsification properties. In order to improve its emulsifying properties, one effective approach is using protein and polysaccharide mixtures. This work investigated the structural and emulsifying properties of LPI as well as the development of an LPI/xanthan gum (XG)-stabilized oil-in-water emulsion. RESULTS: The highest protein solubility (84.14%) of LPI was observed and the molecular weights (Mw ) of most LPI subunits were less than 35 kDa. The enhanced emulsifying activity index (15.97 m2 g-1 ) of LPI might be associated with its relatively high protein solubility and more low-Mw subunits (Mw < 35 kDa). The effects of oil volume fraction (ϕ) on droplet size, microstructure, rheological behavior and stability of emulsions were investigated. As ϕ increased from 0.2 to 0.8, the emulsion was arranged from spherical and dispersed oil droplets to polyhedral packing of oil droplets adjacent to each other, while the LPI/XG mixtures changed from particles (in the uncrowded interfacial layer) to lamellae (in the crowded interfacial layer). When ϕ was 0.6, the emulsion was in a transitional state with the coexistence of particles and lamellar structures on the oil droplet surface. The LPI/XG-stabilized emulsions with ϕ values of 0.6-0.8 showed the highest stability during a 14-day storage period. CONCLUSION: This study developed a promising plant-based protein resource, LPI, and demonstrates potential application of LPI/XG as an emulsifying stabilizer in foods. © 2023 Society of Chemical Industry.

Physical properties, phenolic profile and antioxidant capacity of Java tea (Clerodendranthus spicatus) stems as affected by steam explosion treatment.

Java tea (Clerodendranthus spicatus) has been favored for its various health benefits and abundance of phenolic substances. Steam explosion (SE) treatment was performed in the pretreatment of Java tea stems and the physical properties, phenolic profile and antioxidant capacity were investigated. Extraction kinetics study showed that the phenolics yields of Java tea stems treated at 2.4 MPa for 10 min reached the maximum in 40 min, which was approximately 3 times the yields of raw stems in 180 min. The antioxidant activities of the extracts of Java tea stems were also significantly increased after SE treatment (P < 0.05). In addition, 19 phenolics were detected in Java tea stems by HPLC/QTOF-MS/MS, and rosmarinic acid was found to be hydrolyzed to danshensu during the SE process. SE could be an efficient pretreatment technology to improve the extraction rates of phenolics and conversions of their high-value hydrolyzed products, which could facilitate further research of Java tea products.

Sodium alginate-sodium hyaluronate-hydrolyzed silk for microencapsulation and sustained release of kidney tea saponin: The regulation of human intestinal flora in vitro.

Kidney tea saponin (KTS) exhibits considerable efficacy in lowering glucose levels; however, it does not have widespread applications owing to its low intestinal utilization. Therefore, in the present study, we prepared sodium alginate (SA)/sodium hyaluronate (HA)/hydrolyzed silk (SF) gel beads for the effective encapsulation and targeted intestinal release of KTS. The gel beads exhibited an encapsulation rate of 90.67 % ± 0.27 % and a loading capacity of 3.11 ± 0.21 mg/mL; furthermore, the release rate of KTS was 95.46 % ± 0.02 % after 8 h of simulated digestion. Fourier transform infrared spectroscopy revealed that the hydroxyl in SA/HA/SF-KTS was shifted toward the strong peak; this was related to KTS encapsulation. Furthermore, scanning electron microscopy revealed that the gel bead space network facilitates KTS encapsulation. In addition, the ability of KTS and the gel beads to inhibit α-amylase (IC50 = 0.93 and 1.37 mg/mL, respectively) and α-glucosidase enzymes (IC50 = 1.17 and 0.93 mg/mL, respectively) was investigated. In vitro colonic fermentation experiments revealed that KTS increased the abundance of Firmicutes/Bacteroidetes and butyric acid-producing bacteria. The study showed that the developed gel-loading system plays a vital role in delivering bioactive substances, achieving slow release, and increasing the abundance and diversity of intestinal flora.

The Effects of Synbiotics on Dextran-Sodium-Sulfate-Induced Acute Colitis: The Impact of Chitosan Oligosaccharides on Endogenous/Exogenous Lactiplantibacillus plantarum.

In this work, Lactiplantibacillus plantarum (L. plantarum) isolated from mice feces (LP-M) and pickles (LP-P) were chosen as the endogenous and exogenous L. plantarum, respectively, which were separately combined with chitosan oligosaccharides (COS) to be synbiotics. The anti-inflammatory activity of LP-M, LP-P, COS, and the synbiotics was explored using dextran-sodium-sulfate (DSS)-induced acute colitis mice, as well as by comparing the synergistic effects of COS with LP-M or LP-P. The results revealed that L. plantarum, COS, and the synbiotics alleviated the symptoms of mice colitis and inhibited the changes in short-chain fatty acids (SCFAs), tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, IL-6, IL-10, and myeloperoxidase (MPO) caused by DSS. In addition, the intervention of L. plantarum, COS, and the synbiotics increased the relative abundance of beneficial bacteria Muribaculaceae and Lactobacillus and suppressed the pathogenic bacteria Turicibacter and Escherichia-Shigella. There was no statistically difference between LP-M and the endogenous synbiotics on intestinal immunity and metabolism. However, the exogenous synbiotics improved SCFAs, inhibited the changes in cytokines and MPO activity, and restored the gut microbiota more effectively than exogenous L. plantarum LP-P. This indicated that the anti-inflammatory activity of exogenous LP-P can be increased by combining it with COS as a synbiotic.

Lignin-coordinated highly dispersed PdZn alloy nanocluster supported on N-doped nanolayer carbon and its application in hexavalent chromium detoxification.

As a renewable and low-cost biomacromolecule with high aromaticity and carbon content, lignin is a promising raw material for preparation of versatile carbon materials. Herein, we present a facile one-pot approach to prepare PdZn alloy nanocluster catalysts supported on N-doped lignin-derived nanolayer carbon through facile pyrolysis of melamine-mixed lignin-Pd-Zn complex. The dispersion of the PdZn alloy nanoclusters could be effectively modulated by varying the addition of melamine and the molar ratio of Pd and Zn salts. PdZn alloy nanocluster catalysts (Pd-Zn29@N10C) with ultra-small particle size (about 0.47 nm) were prepared when 10 times of melamine (relative to lignin weight) was added and the molar ratio of Pd and Zn salts was 1:29. Thereby, the catalyst presented superior catalytic activity for reduction of Cr(VI) to harmfulless Cr(III), significantly better than the two references Zn@N10C (without Pd addition) and Pd-Zn29@C (without N doping), as well as the commercial Pd/C. In addition, thanks to the strong anchoring of the PdZn alloy on the N-doped nanolayer support, the Pd-Zn29@N10C catalysts also exhibited good reusability. Consequently, the current study provides a straightforward and feasible method for producing highly dispersed PdZn alloy nanoclusters by lignin coordination, and further demonstrates its excellent applicability in hexavalent chromium reduction.

Extrusion Modification of Wheat Bran and Its Effects on Structural and Rheological Properties of Wheat Flour Dough.

The study investigated the extrusion modification of wheat bran and its effects on structural and rheological properties of wheat flour dough. Extruded bran showed better solubility of dietary fiber and structural porosity, leading to higher hydration and swelling power. Addition of extruded bran to dough caused water redistribution as an intensive aggregation of bound water to gluten matrix with reduced mobility. The bran-gluten interaction influenced by water sequestering caused partial gluten dehydration and conversion of ß-turn into ß-sheet, which demonstrated the formation of a more polymerized and stable gluten network. Farinographic data confirmed the promotion of dough stability with extruded bran addition at lower gluten content, while viscoelastic data suggested improved dough elasticity at all gluten contents by increasing elastic moduli and decreasing loss tangent. This study would be useful for interpreting the modification effect and mechanism of extrusion on cereal brans and provide valuable guidance for applying it as an effective modification technology on the commercial production of cereal bran and its flour products.

Effects of social support, anxiety, and hope levels on cognitive bias in patients with nasogastric/nasoenteric tubes.

BACKGROUND: Unplanned extubation is a common adverse event and an important indicator of quality and safety of care. It is well recognized that the incidence of unplanned extubation of nasogastric/nasoenteric tubes is higher than that of other devices. Theory and previous research have suggested that cognitive bias in conscious patients with nasogastric/nasoenteric tubes may lead to unplanned extubation, and that social support, anxiety, and hope are influencing factors of cognitive bias. Therefore, the objective of this study was to investigate the effects of social support, anxiety, and hope levels on cognitive bias in patients with nasogastric/nasoenteric tubes. METHODS: In this cross-sectional study, 438 patients with nasogastric/nasoenteric tubes were selected from 16 hospitals in Suzhou from December 2019 to March 2022 by convenience sampling method. The participants were assessed using the General Information Questionnaire, Perceived Social Support Scale, Generalized Anxiety Disorder-7, Herth Hope Index, and Cognitive Bias Questionnaire for patients with nasogastric/nasoenteric tubes. The structural equation model was established with AMOS 22.0 software. RESULTS: The cognitive bias score of patients with nasogastric/nasoenteric tubes was 2.82±0.61. Patients' perceived levels of social support and hope were negatively correlated with their cognitive bias (r=-0.395 and -0.427, respectively, P<0.05), and anxiety was positively correlated with cognitive bias (r=0.446, P<0.05). Structural equation model analysis showed that anxiety had a direct positive effect on cognitive bias, with an effect value of 0.35 (P<0.001), and hope level had a direct negative effect on cognitive bias with an effect value of -0.33 (P<0.001). Social support had a direct negative effect on cognitive bias and was also shown to indirectly affect cognitive bias through anxiety and hope levels. The effect values were -0.22, -0.12, and -0.19 (P<0.001), for social support, anxiety, and hope, respectively. Social support, anxiety, and hope explained 46.2% of the total variation in cognitive bias. CONCLUSIONS: Moderate cognitive bias is noted in patients with nasogastric/nasoenteric tubes, and social support significantly affects cognitive bias. Anxiety and hope level play a mediating role in social support and cognitive bias. Positive psychological intervention and the obtention of positive support could improve the cognitive bias of patients with nasogastric/nasoenteric tubes.

The effects of live and pasteurized Akkermansia muciniphila on DSS-induced ulcerative colitis, gut microbiota, and metabolomics in mice.

Akkermansia muciniphila (A. muciniphila) plays an important role in intestinal regulation, while it is presently unclear whether live or pasteurized A. muciniphila has different effects on the intestinal health. In the present study, live or pasteurized A. muciniphila was administered to dextran sulfate sodium (DSS)-induced ulcerative colitis mice to investigate its influences on the host intestinal health, gut microbiota, and metabolomic phenotype. The results showed that pasteurized A. muciniphila alleviated the symptoms of colitis in mice more efficiently by encouraging the proliferation of beneficial intestinal bacteria, increasing the production of short-chain fatty acids, and inhibiting intestinal inflammation. Moreover, pasteurized A. muciniphila increased the abundance of Parasutterella and Akkermansia and thus affected the metabolism of lipid and lipid-like molecules associated with lysophosphatidylcholines (LysoPCs). Notably, prophylactic supplementation of pasteurized A. muciniphila increased the relative abundance of the anti-inflammatory microbe Dubosiella, thereby activating intestinal sphingolipid metabolism to alleviate intestinal damage. In conclusion, pasteurized A. muciniphila showed a more effective amelioration of DSS-induced colitis by repairing the dysbiosis of gut microbiota and intestinal metabolism compared to live A. muciniphila, providing a potential strategy to explore the protective effect of A. muciniphila on host intestinal health.

Black garlic melanoidins inhibit in vitro α-amylase and α-glucosidase activity: the role of high-molecular-weight fluorescent compounds.

BACKGROUND: Black garlic (Allium sativum L.) melanoidins (MLDs) are produced by Maillard reaction under high temperature and high humidity, and has a variety of biological activities. The aim of this study was to analyze the structural characteristics and investigate α-amylase and α-glucosidase in vitro inhibitory activity of black garlic MLDs. RESULTS: Spectroscopic and chemical analysis revealed that black garlic MLDs were heterogeneous macromolecular polymers with a skeletal structure similar to sugar chains. Molecular weight distribution and 3DEEM fluorescence showed that black garlic MLDs were composed of high-molecular-weight colorants with strong fluorescence properties. The polarity of black garlic MLDs was related to the fluorescence groups. The results of physicochemical properties proved that the polarity difference of black garlic MLDs was related to the elemental composition, resulting in differences in fluorescence, thermodynamic and apparent characteristics. MLDs with higher levels of fluorescent intensity (BG20 and BG40) had stronger inhibitory effects on α-amylase and α-glucosidase than BGW, and hydrolysis of fluorescent groups attenuated the inhibitory activity. The median inhibitory concentration (IC50 ) of black garlic MLDs against enzymes was positively correlated with the concentration, and the kinetic results detected non-competitive and mixed types of inhibition. CONCLUSION: High-molecular-weight fluorescent components of black garlic MLDs played a crucial role in the inhibitory activities of α-amylase and α-glucosidase, and the inhibitory ability was positively correlated with concentration. Black garlic MLDs had the potential to block postprandial glucose rise. © 2023 Society of Chemical Industry.

Novel metal-lignin assembly strategy for one-pot fabrication of lignin-derived heteroatom-doped hierarchically porous carbon and its application in high-performance supercapacitor.

The conversion of renewable lignin with low-cost and high carbon content properties into porous carbon materials for supercapacitor applications has caught considerable interest. Herein, two dimensional lignin-derived carbon nanosheets (N-LHPC) with hierarchically porous structures were facilely synthesized via a novel metal-lignin assembly strategy and their performances for supercapacitor applications were investigated. During the carbonization process, the uniformly distributed Zn facilitates the coordinating development of micropores structure and the generated MgO embedded in the carbon matrix acts as a template to produce mesoporous structure after acid washing. Moreover, the melamine addition promotes the development of mesopores by formation of lamellae structure and realizes the N doping in the carbon materials. Therefore, the obtained N-LHPC presents an excellent specific capacitance of 235.75 F/g at 0.5 A/g owing to its hierarchical pore structure as well as the N/O functional groups. Moreover, at the power density of 450 W/kg, the N-LHPC achieves a maximum energy density of 14.75 Wh/kg, showing great application potential in energy storage. The metal-lignin assembly strategy followed by N-doping proposed in this paper provides N-LHPC materials with hierarchical nanostructure, good electron/ion transfer properties, and abundant pseudocapacitive active species, which improve the capacitance performances of the N-LHPC.

Identification of a Novel Walnut Iron Chelating Peptide with Potential High Antioxidant Activity and Analysis of Its Possible Binding Sites.

Peptide iron chelate is widely regarded as one of the best iron supplements for relieving iron deficiency. In this study, a new type of walnut peptide iron (WP-Fe) chelate was prepared using low molecular weight walnut peptides (WP) as raw materials. Under the conditions of this study, the chelation rate and iron content of the WP-Fe chelate were 71.87 ± 1.60% and 113.11 ± 2.52 mg/g, respectively. Fourier transform infrared spectroscopy (FTIR), zeta potential, amino acid composition, and other structural analysis showed that WP-Fe is formed by the combination of carboxyl, amino and carbonyl with Fe2+. The WP-Fe chelate exhibits a honeycomb-like bulk structure different from that of WP. In addition, we predicted and established the binding model of ferrous ion and WP by molecular docking technology. After chelation, the free radical scavenging ability of the WP-Fe chelate was significantly higher than that of the WP. Overall, the WP-Fe chelate has high iron-binding capacity and antioxidant activity. We believe that peptides from different sources also have better iron binding capacity, and peptide iron chelates are expected to become a promising source of iron supplement and antioxidant activities.

Identification of high iron-chelating peptides with unusual antioxidant effect from sea cucumbers and the possible binding mode.

Iron deficiency anemia (IDA) is a common nutritional disease affecting 2 billion people. To develop a new iron-fortified food, we designed a novel type of iron-chelating peptide [Sea cucumbers peptides (SCP)-Fe] from sea cucumbers. SCP can chelate ferrous ions. The neutral protease hydrolysate have the highest iron chelating activity (117.17 ± 2.62 mg/g). Single factors including pH, material ratio, and molecular weight, had a significant effect on the iron chelating activity. The characterization of the SCP-Fe chelate revealed a loose and blocky structure with increased particle size. The amino acid composition, peptide identification and molecular docking indicated that Asp, Glu, Gly and Pro played an important role in binding to ferrous ions. After chelation, SCP-Fe chelate had dual nutrition effects of stronger radical scavenging ability and potential high-efficiency iron supplementation ability. These results might provide insights into the methods for developing functional foods such as iron-fortified seafood.