Solving the problem of obesity has been globally recognized as a crucial public health challenge. Recent studies have shown that fucoxanthin and conjugated linoleic acid could work together to exert an anti-obesity effect. In this study, sodium alginate- and chitosan-modified fucoxanthin and conjugated linoleic acid complex liposome (S-C-L) was prepared and characterized. The anti-obesity effect and mechanism of action of S-C-L were evaluated by establishing an obese mouse model. The results indicated that S-C-L reduced the weight and fat content of obese mice and improved their oxidative stress state. It regulated the expression levels of mRNA and protein by activating the AMPK signaling pathway, thereby enhancing energy expenditure and inhibiting the differentiation of adipocytes, confirming its anti-obesity properties. Comprehensive analysis indicated that S-C-L had broad application potential in the development of anti-obesity foods and health products.

Kjellmaniella crassifolia is rich in polysaccharides and phenolics, yet the structural heterogeneity and antioxidant potential of its phenolic–polysaccharide complexes remain unclear. A K. crassifolia phenolic–polysaccharide complex (KCPPC) was extracted by an alkaline method optimized using response surface methodology and fractionated by DEAE-Sepharose Fast Flow chromatography. Under the optimized conditions of 2.5% alkali, a solid-to-liquid ratio of 1:55, 65°C, and 320 min, the KCPPC yield reached 4.60%, with 64.34% polysaccharides, 13.26% sulfate, and 2.90% phenolics. Three structurally distinct fractions were obtained. KCPPCF2 showed greater phenolic retention, lower molecular weight (284.56 kDa), and narrower polydispersity (2.86), whereas KCPPCF3 had the highest sulfate content (20.90%), fucose enrichment, and higher molecular weight (1567.16 kDa). KCPPCF2 showed the lowest IC₅₀ values for superoxide anion and hydroxyl radical scavenging (3.21 and 3.19 mg/mL), although the latter was nearly identical to KCPPCF3 (3.20 mg/mL). KCPPCF3 showed the lowest IC₅₀ values for ABTS radical scavenging and ferric reducing power (2.57 and 3.71 mg/mL). These findings demonstrate that structural heterogeneity governs assay-dependent antioxidant behavior and supports targeted fraction selection for functional food applications.

Brown algae are rich sources of bioactive compounds, including fucoxanthin (FX), which exhibits diverse biological activities, such as antioxidant, anti-inflammatory, antitumor, and metabolic regulatory effects. Processing critically influences these bioactivities, yet the structural transformations of FX and their biological consequences remain poorly understood. This review systematically summarizes the effects of processing methods (thermal treatment, drying, salting) and environmental factors (light, pH, oxygen) on FX content, structural integrity, and isomeric profile and discusses how these structural alterations-including isomerization, oxidation, and degradation-subsequently influence key bioactivities, including antioxidant defense, anti-inflammatory signaling, apoptosis induction, and lipid metabolism. Evidence indicates that specific isomers (e.g., 13-Z and 9'-Z) exhibit distinct functional properties. Therefore, optimizing processing conditions is essential for maximizing FX retention and functional efficacy. This review elucidates the processing-structure-function-mechanism relationship, providing a theoretical basis for high-value utilization of brown algae.

Laminaria japonica, a large perennial brown alga of medicinal and culinary value, thrives in cold marine environments. As a principal economic seaweed species in China, it is characterized by high productivity and exceptional nutritional density. However, the characteristic marine odor substantially compromises consumer sensory acceptance, posing a major constraint on the value-added processing and industrial exploitation of L. japonica-based products. Consequently, the investigation of efficient deodorization techniques and their underlying mechanisms is of considerable importance. The primary odorants of L. japonica are ketones, aldehydes, and alcohols. These volatile compounds can be effectively separated, identified, and quantified using analytical techniques, including gas chromatography-ion mobility spectrometry (GC-IMS), which integrates the superior separation capability of gas chromatography with the rapid detection characteristics of ion mobility spectrometry. This combined technique offers high sensitivity, operational simplicity, and cost-effectiveness and requires minimal sample preparation, making it extensively applicable for the analysis and identification of food flavor compounds. Current deodorization methods for L. japonica include physical, chemical, and biological approaches. Physical methods, such as masking, adsorption, and encapsulation, have limited deodorization efficiency. Chemical methods, including acid-base treatments or antioxidant immersion, although effective, often introduce chemical residues that are difficult to eliminate. Biological deodorization is an environmentally friendly, mild, and efficient approach that utilizes microbial metabolism to convert the odorous substances in L. japonica into non-odorous macromolecules. However, most existing biological deodorization processes use L. japonica pulp or fragments as raw materials, which impedes subsequent refining. This study used whole L. japonica blades for microbial fermentation-based deodorization to establish a superior raw material foundation for downstream processing and address this limitation. To investigate the sources of off-odors in salted L. japonica and the regulatory effects of yeast fermentation on its flavor profile, intact salted L. japonica (without comminution) was used as rawmaterial. Three yeast strains, Pichia kluyveri CICC 32844, Saccharomyces cerevisiae CICC 32883, and Wickerhamomyces anomalus CICC 33313, were selected for fermentative deodorization of both raw and cooked salted L. japonica. The sensory evaluation results indicated minimal and non-significant differences in texture and color among the samples fermented with the three strains. However, significant variations in deodorization efficacy were observed. W. anomalus demonstrated the highest deodorization efficiency and overall performance for raw salted L. japonica, whereas Saccharomyces cerevisiae exhibited optimal deodorization and comprehensive effects on cooked salted L. japonica. W. anomalus and S. cerevisiae were the most suitable strains for raw and cooked salted L. japonica, respectively. The two selected strains were used for flavoring and fermenting salted L. japonica. The volatile flavor compounds in the samples subjected to different treatment conditions were qualitatively and quantitatively analyzed using GC-IMS, enabling characterization of alteration in the flavor profile and comparison with commercial L. japonica products. The relative odds activity value (ROAV) method was used to comprehensively evaluate the flavor characteristics and identify key compounds across different sample groups. The results revealed that the off-odors of salted Laminaria japonica were predominantly attributed to aldehydes and ketones. Among these, 1-octen-3-one was identified as the most potent odor marker, whose mushroom and earthy notes contributed more significantly to the characteristic marine odor than traditionally recognized aldehydes, such as (E)-2-nonenal and propanal. Although thermal processing can generate pyrazine flavor compounds, such as 2,3,5-trimethylpyrazine, via the Maillard reaction, their actual flavor contribution remains minimal (ROAV<0.1), demonstrating limited masking effects. After fermentative flavoring, the sensory quality of salted L. japonica significantly improved. In raw salted L. japonica, the process generated compounds such as isovaleraldehyde and propyl acetate, which synergistically masked the off-odors. In cooked salted L. japonica, fermentative flavoring produced isovaleraldehyde and alcohols, including n-hexanol, which effectively concealed the marine odor while increasing the diversity of aroma compounds. Comparative flavor analysis of the experimental samples and the identified commercial products identified isovaleraldehyde, phenylacetaldehyde, p-methylbenzaldehyde, 1-octen-3-one, acetylpyrazine, and diallyl disulfide as the key flavor compounds common to all samples. Among these, isovaleraldehyde imparted a distinct chocolate and fatty aroma to L. japonica samples, contributing significantly to their overall flavor profile. Notably, significant differences in overall flavor composition were observed between the experimental and commercial samples. Following the fermentative flavoring treatment, 1-octen-3-one was no longer the dominant contributor to the flavor profile, demonstrating the feasibility and effectiveness of the fermentation-based flavor modulation process developed in this study. In this study, qualitative and quantitative analyses of the key flavor compounds in raw salted L. japonica and its seasoned or fermented derivatives were performed. By systematically investigating compositional differences and dynamic changes in volatile profiles before and after yeast-mediated fermentation, and by comparing them with commercial products, L. japonica products with distinctive flavor characteristics were successfully developed. This study reveals the dynamic transformation of flavor compounds during microbial fermentation, and offers novel strategic insights for the development of seaweed products and the optimization of microbial deodorization technologies.

The biological activities of fucoidan from brown algae have attracted considerable attention. Degradation to low-molecular-weight fucoidan reduces viscosity and improves bioavailability, enhancing antioxidant and anti-inflammatory effects. Fucoidan was degraded using acetic acid combined with 60Co γ-ray irradiation and fractionated by Bio-Gel P10 chromatography to obtain four fractions (AIF1-AIF4). The fractions were structurally characterized and assessed for in vitro radical-scavenging activity and modulation of oxidative stress markers in H2O2-induced RAW264.7 macrophages. Compared with the model group, all fractions significantly increased catalase (CAT) and superoxide dismutase (SOD) activities, with the highest increase of approximately 1.33 U/mgprot for CAT and 20.32 U/mgprot for SOD, while decreasing malondialdehyde (MDA) and intracellular reactive oxygen species (ROS) levels. Among the four fractions, AIF4, with the lowest molecular weight, exhibited the highest antioxidant activity. LMWF treatment also upregulated the mRNA expression of antioxidant-related genes (HO-1, SOD1, SOD2) and signaling molecules (PI3K and Akt), accompanied by increased protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and PI3K/Akt pathway components. These findings indicate that LMWF is closely associated with the regulation of the PI3K/Akt-Nrf2 signaling axis under oxidative conditions and support its potential application as a dietary antioxidant ingredient.

Current pharmacological treatments for colitis are often associated with adverse effects and the development of drug resistance. This study aimed to investigate the alleviative effect and mechanism of low-molecular-weight fucoidan (LMWF), extracted from Kjellmaniella crassifolia via acid degradation, on dextran sulfate sodium (DSS)-induced colitis in mice. The prepared LMWF exhibited low molecular weight and high sulfate content, which were crucial structural features closely related to its anti-colitis activity. Results showed that LMWF significantly attenuated DSS-induced weight loss, disease activity index, and colon shortening, while enriching gut microbiota. Mechanistically, LMWF modulated the expression of inflammatory mediators at both the mRNA and protein levels. LMWF treatment reduced pro-inflammatory cytokines (IL-6, IL-1 beta, TNF-alpha, NLRP3) and oxidative stress (MDA), while increasing anti-inflammatory (IL-10) and antioxidant markers (CAT, SOD, GSH-Px). Both F1 and F2 exhibited significant protective effects, and the high-dose F2H group (100 mg kg(-1) day(-1)) exerted relatively better therapeutic effects, owing to its slightly more pronounced trend in specific indicators

Ulcerative colitis (UC) is a form of inflammatory bowel disease (IBD), which is marked by severe abdominal pain, weight loss, perianal bleeding, and diarrhea. This study successfully isolated and purified four low-molecular-weight fucoidan oligosaccharides through acid hydrolysis and Bio Gel P10 gel filtration. The molecular weights were 2.9 × 104-1.36 × 105 Da, 182-1012 Da, 161-939 Da and 161-939 Da, respectively. A mouse model of colitis was induced using Dextran Sulfate Sodium (DSS). The results indicated that fucoidan and fucoidan oligosaccharides could ameliorate murine ulcerative colitis, with the oligosaccharides (200 mg/kg/d) demonstrating superior therapeutic effects. This superiority was likely attributed to the lower molecular weight and higher content of total sugars and fucose. The primary mechanisms involved the modulation of gene and protein expression levels associated with the Toll-like receptor 4, Myeloid differentiation primary response 88, nuclear factor kappa-light-chain-enhancer of activated B cells, p65, and Inhibitor of kappa light polypeptide gene enhancer in B cells, alpha (TLR4, MYD88, NF-κB p65, and IκB-α) signaling pathways, which reduce the production of inflammatory cytokines such as tumor necrosis factor-alpha, Interleukin-1 beta and Interleukin-6 (TNF-α, IL-1β, and IL-6). Additionally, these oligosaccharides alleviated oxidative stress, enhanced the levels of intestinal barrier proteins (Claudin family member 4 and Zonula occludens protein 1), regulated the abundance and diversity of the gut microbiota, and increased the levels of short-chain fatty acids (SCFAs) in the intestine. It is worth emphasizing that this study can only demonstrate that fucoidan oligosaccharides have a mitigating effect on intestinal inflammation in mice. Further research is needed in the future to investigate the structure-activity relationship of fucoidan oligosaccharides and their impact on human intestinal microbiota, in order to further elucidate their anti-inflammatory mechanisms.

BACKGROUND:Aquatic products are highly valued for their rich nutrient content and unique flavors. However, they are particularly vulnerable to microbial contamination during transportation and storage, which can lead to spoilage. Fucoidan exhibited a broad spectrum of biological activities. Nevertheless, research on its application as an antifreeze agent remains limited. The practical application of high-molecular-weight fucoidan is constrained to some extent by its high viscosity and poor solubility. Conversely, low-molecular-weight fucoidan (WIF) prepared via physical, chemical, or enzymatic degradation methods may offer superior permeability and biological activities, making it a promising, novel, and highly efficient cryoprotectant. RESULTS:In this study, WIF was prepared through irradiation degradation using fucoidan as the material. The relative molecular weights of WIF obtained via 50 kGy γ-ray irradiation ranged from 4.97 × 103 to 3.25 × 104 Da. It was found that the irradiation degradation method reduced the molecular weight and altered the original chemical composition. Following irradiation, the protein content decreased from 0.94% ± 0.02% to 0.24% ± 0.04%, whereas the reducing sugar content increased from 0.69% ± 0.01% to 6.25% ± 0.36%. Results indicated that soaking treatments with various concentrations of WIF solution exhibited excellent cryoprotective properties and water holding capacity in frozen Litopenaeus vannamei. Notably, after 180 days of frozen storage, the group treated with 15 g L-1 WIF maintained a myofibrillar protein Ca2+-ATPase activity of 0.0338 U mg-1 prot and a total sulfhydryl content of 30.06 μmol g-1 prot, both of which were significantly higher than those of the other groups (P < 0.05). Furthermore, at day 180, the surface hydrophobicity of the 15 g L-1 WIF group was 61.35 μg mg-1 prot, significantly lower than that of the control groups (P < 0.05). CONCLUSION:These findings demonstrate that WIF effectively inhibits the decline of Ca2+-ATPase activity, the oxidation of sulfhydryl groups, protein carbonylation, the exposure of hydrophobic residues, and the accumulation of malondialdehyde. In conclusion, WIF with lower molecular weight shows superior antifreeze and water retention abilities compared to high-molecular-weight fucoidan. © 2026 Society of Chemical Industry.

Hyperbranched polyglycerols(HPG)represent an emerging class of dendritic polyethers characterized by a highly branched,three-dimensional architecture and a multitude of terminal hydroxyl groups.This distinctive structural configuration confers exceptional hydrophilicity,bio-compatibility,and a high density of modifiable surface functionalities,thus establishing HPG as highly promising materials for the development of advanced chromatographic stationary phases.Their application is particularly relevant for the separation of polar and hydrophilic analytes,which has long posed a significant challenge in conventional reversed-phase liquid chromatography.The in-tegration of such hyperbranched polymers with robust inorganic substrates,such as silica gel,has recently gained traction as a sophisticated materials strategy.This approach synergistically combines the superior mechanical strength and pressure resistance of the inorganic matrix with the rich surface chemistry and tunable hydrophilicity of the polymer,thereby addressing critical limitations of traditional stationary phases in hydrophilic interaction liquid chromatography(HILIC)applications.In the present study,a novel HILIC stationary phase,designated HPG-Sil 3,was synthesized through the in-situ ring-opening polymerization of glycidol monomers from the surface of aminopropyl-functionalized silica microparticles.The synthesis commenced with a meticulous silanization step to graft(3-aminopropyl)triethoxysilane(APTES)onto the silica surface,thereby introducing a uniform layer of primary amine groups.These amine functionalities served as initiation sites for the subsequent grafting-from polymerization,ensuring the formation of a covalently anchored,robust HPG layer.This covalent immobilization strategy is critical for mitigating stationary phase degradation and polymer leaching under prolonged chromatographic use,thereby guaranteeing long-term op-erational stability.The successful fabrication of the HPG-Sil 3 material and its physicochemical properties were thoroughly characterized using a suite of analytical techniques.Elemental analysis indicated a substantial increase in carbon and hydrogen content post-modification,providing quantitative evidence of organic polymer grafting.Fourier-transform infrared(FTIR)spectroscopy further corroborated this result,revealing signature absorption bands associated with the stretching vibrations of O-H and C-O-C ether linkages,which are characteristic of the HPG polyether structure.Thermogravimetric analysis(TGA)demonstrated the material's excellent thermal resilience,with the onset of HPG decomposition occurring above 200℃,a temperature window far exceeding the operational range of typical HILIC analyses.Textural properties,evaluated via nitrogen physi-sorption,showed a predictable decrease in specific surface area and pore volume relative to the unmodified silica substrate.This reduction is attributed to the partial filling of the mesoporous silica network by the grafted HPG chains.Importantly,the material retained a sufficiently open porous structure to facilitate efficient mass transfer of analytes during chromatographic runs.To system-atically investigate the chromatographic behavior and retention mechanism of the HPG-Sil 3 phase,a set of model polar compounds,including thymine,uracil,hypoxanthine,and adenosine,was selected.The influence of critical mobile phase parameters on the analyte retention factor(k)was examined,including the acetonitrile(ACN)content,the concentration of ammonium acetate buffer,and the buffer pH.The observed retention trends were unequivocally indicative of a dominant HILIC mechanism.A pronounced increase in retention with increasing ACN content was observed for all analytes,consistent with the enhanced partitioning of solutes into a water-rich layer immobilized on the hydrophilic stationary phase surface.Conversely,an increase in buffer concentration led to a decrease in retention,a phenomenon explained by the competitive adsorption of buffer ions with the analytes for polar interaction sites on the HPG layer.Furthermore,the retention of ionizable analytes,namely hypoxanthine and adenosine,was demonstrably influenced by the buffer pH,as pH variations alter their ionization state and thus their overall hydrophilicity and interaction strength with the stationary phase.Under the optimized chromatographic conditions,all four model analytes were baseline separated within a 10-min runtime,exhibiting excellent peak symmetry and high repeatability.The practical utility of the HPG-Sil 3 stationary phase was further demonstrated through the efficient separation of alginate oligosaccharide homologs with degrees of polymerization(DP)ranging from 2 to 7.The elution order followed increasing DP,which aligns perfectly with the HILIC retention principle,as larger oligosaccharides possess more hydroxyl groups and exhibit stronger hydrophilic interactions.The stationary phase also demonstrated remarkable operational stability,with no observable changes in retention times or chromatographic efficiency over 10 consecutive injections,underscoring its robustness for routine analytical applications.In conclusion,the HPG-Sil 3 stationary phase synthesized in this work exhibits outstanding hydrophilic separation per-formance,a well-understood HILIC retention mechanism,and excellent long-term stability.These attributes position it as a highly competitive and promising material for the analysis of a wide array of polar compounds,including nucleosides,carbohydrates,and polar pharmaceuticals,across diverse fields such as metabolomics,biopharmaceutical analysis,and food chemistry.Future re-search will focus on the precise control of polymer parameters,including molecular weight,branching density,and post-functionalization,to fine-tune the properties of the HPG layer for tailored selectivity towards specific applications.Furthermore,a systematic evaluation of its per-formance using complex biological and environmental matrices will be conducted to assess its practical applicability.

Fucoxanthin (Fx), a natural carotenoid predominantly found in brown algae and certain microalgae, has garnered significant attention in recent years for its potent antioxidant and anti-inflammatory properties. As inflammation and oxidative stress represent fundamental physiological responses that play pivotal roles in disease pathogenesis, their intricate interplay has become a focus of scientific investigation. This study employed an LPS-induced THP-1 cell inflammation model to elucidate the anti-inflammatory mechanisms of fucoxanthin and its interaction with oxidative stress pathways. Our findings demonstrate that fucoxanthin effectively suppresses the LPS-induced secretion of pro-inflammatory mediators, including IL-1β, IL-6, iNOS, COX-2, and TNF-α, in THP-1 cells. Mechanistically, this effect is achieved through the inhibition of IκB-α phosphorylation, thereby blocking the activation of the NF-κB p65 signaling pathway. Concurrently, fucoxanthin exhibits robust antioxidant activity, as evidenced by enhanced catalase (CAT) and superoxide dismutase (SOD) activities coupled with reduced malondialdehyde (MDA) production. Furthermore, fucoxanthin activates the Nrf2 signaling pathway, leading to upregulated heme oxygenase-1 (HO-1) expression and the consequent attenuation of reactive oxygen species (ROS) generation. These results collectively indicate that fucoxanthin exerts dual protective effects through anti-inflammatory action mediated by NF-κB pathway inhibition and antioxidant activity via Nrf2/HO-1 pathway activation. The observed crosstalk between these pathways suggests that fucoxanthin’s therapeutic potential stems from its ability to simultaneously modulate interconnected inflammatory and oxidative stress responses. Our study provides compelling evidence that fucoxanthin’s antioxidant and anti-inflammatory activities are functionally interrelated, with the Nrf2 signaling pathway serving as a critical node in this protective mechanism against LPS-induced cellular damage.

Oligosaccharides possess characteristics such as low molecular weight, good solubility, and high bioavailability, which make them better absorbed than fucoidan. This study hypothesizes that fucoidan oligosaccharides can be absorbed by intestinal epithelial cells and quickly enter the bloodstream, with a rapid absorption rate. In this study, fucoidan oligosaccharides were obtained through acid degradation and Bio Gel column separation. By analyzing the chemical composition and molecular weight, oligosaccharides with smaller molecular weights and simpler monosaccharide compositions were selected for further research. A cell model and pharmacokinetic studies in mice were established to analyze the absorption patterns of the oligosaccharides. The results showed that after acid degradation and column separation, high-molecular-weight oligosaccharides SPF1 with a molecular weight range of 1.63 × 104 to 2.14 × 105 Da and the low-molecular-weight oligosaccharides SPF2 with a molecular weight range of 244.22 to 1545.36 Da were obtained. In cell transport and uptake experiments, the transport of SPF1 and SPF2 was positively correlated with time and negatively correlated with concentration. The transport rates of SPF1 and SPF2 ranged from 20% to 70%, with Papp values greater than 1 × 10−5 cm/s. In the pharmacokinetics study, the blood concentration of the oligosaccharides in mice was simulated and analyzed using DAS 2.0, which indicated that the fucoidan oligosaccharides exhibited good absorption characteristics in vivo and in vitro. Therefore, fucoidan oligosaccharides with smaller molecular weights are more easily absorbed, which provides a theoretical basis for the application of fucoidan oligosaccharides.

This study investigated the effects of the polyphenol-polysaccharide complex (HPC) and its purified components (PC1 and PC4), obtained from Hizikia fusiforme, on the human gut microbiota during in vitro simulated digestion and fecal fermentation. Results showed a gradual increase in reducing sugar content for HPC, PC1, and PC4 during simulated digestion, accompanied by a slight decrease in molecular weight, indicating that these complexes were not completely digested during oral-gastrointestinal digestion. However, following fermentation, the molecular weights of HPC, PC1, and PC4 decreased significantly, and the molar ratios of monosaccharide compositions changed considerably compared with prefermentation values. Thus, these complexes were degraded and used by the intestinal microbiota to produce short-chain fatty acids, which decreased the pH. In addition, after fecal fermentation, beneficial bacteria such as Bacteroides, Parabacteroides, and Bifidobacterium became more abundant, whereas the amount of harmful bacteria such as Fusobacterium and Escherichia/Shigella decreased, revealing the regulation by the complex on the intestinal microbiota. In conclusion, the polyphenol-polysaccharide complex improves the composition and abundance of the human gastrointestinal microbiota, thereby supporting gut health.

To solve the problem of poor selectivity of oligosaccharide separation, a new functionalized silica stationary phase, SPTM(THMA-co-MBAAm), was prepared with N-[tris(hydroxymethyl)methyl]acrylamide (THMA) and N, N-methylenebisacrylamide (MBAAm) containing hydroxyl groups as functional monomers. This stationary phase was used to do hydrogen bonding-based oligosaccharide compound separation. The stationary phase SPTM was successfully prepared, and the functional monomers were bonded onto an SiO2 matrix. The separation of nucleobases and nucleosides on SPTM conformed to the multiple retention mechanism (i.e., a distribution mechanism supplemented by an adsorption mechanism). As a result of the hydrophilic hydroxyl groups on the outermost layer of the phase of stagnation, a layer rich in water was created. The bonds of hydrogen and electromagnetic attraction in addition to repulsion were additionally involved in retention. SPTM was applied to the separation of samples of alginate oligosaccharides with optimized mobile-phase conditions.

This study investigated how different extraction parts of raw materials and different flocculation methods affect the extraction yield, structure, and properties of sodium alginate. The aim was to improve the quality of sodium alginate and provide theoretical guidance for upstream enterprises. In this study, Lessonia nigrescens (LN) was used as a raw material. The alkali treatment conditions were optimized. The optimal extraction conditions were determined to be a 2% sodium carbonate concentration, a duration of 4 h, a material-to-liquid ratio of 1:40, and a temperature of 60 °C, achieving an extraction yield of 43.03%. LN was categorized into blades, stipes, holdfasts, and whole seaweed for comparative analysis, and sodium alginate was flocculated using the acid, calcium, and ethanol methods. Structural and physicochemical analyses showed that the mannuronic acid/guluronic acid (M/G) ratios of the twelve sodium alginate samples ranged from 5.73 to 8.76. The LN part had a greater influence on the M/G ratio than the flocculation method. The relative molecular weight (2343–3074 kDa) and viscosity (170–331 mPa·s) exhibited consistent trends. For the same part, the effect of the flocculation method on the molecular weight followed the order ethanol > acid > calcium. The physicochemical properties of the extracted sodium alginate met the requirements specified in the physicochemical index standard GB 1886.243-2016 of China.

Anti-aging research represents a significant and challenging frontier in biomedical science. While rhodoxanthin, a naturally occurring carotenoid, has demonstrated preliminary antioxidant properties, its precise antiaging mechanisms remain poorly understood. This study systematically investigated the antiaging effects of rhodoxanthin in a D-galactose-induced murine aging model with particular focus on elucidating its underlying molecular mechanisms. Our findings revealed that rhodoxanthin administration significantly attenuated oxidative damage in both brain and liver tissues, as evidenced by reduced lipid peroxidation and enhanced activities of key antioxidant enzymes. At the optimal dosage (80 mg/kg rhodoxanthin), antioxidant enzyme activities were restored to 84.3% (CAT), 66.7% (SOD), and 145% (GPX) of model control levels in the liver and 61.36% (CAT), 4.2% (SOD), and 22.2% (GPX) in the brain. Mechanistic studies indicated that rhodoxanthin's antiaging effects were mediated through modulation of the nuclear factor erythroid-related factor ‌Nrf2 and PI3K/Akt signaling pathways. Quantitative analysis demonstrated significant upregulation of Nrf2, PI3K, and Akt expression in both hepatic and cerebral tissues of aging mice, and behavioral assessments confirmed that rhodoxanthin not only served as a potent natural antioxidant but also improved memory retention and cognitive function in aged subjects. These results collectively established rhodoxanthin as food-functional component, with dual protective effects against both oxidative damage and cognitive decline. Rhodoxanthin could be used as a natural antioxidant in the food industry.

The fishy odor of salted kelp, mainly derived from halogenated hydrocarbons, sulfur-containing compounds, and free fatty acids, limits its sensory quality and market value. This study evaluated microbial deodorization using six food-grade strains—Pichia kluyveri, Saccharomyces cerevisiae, Wickerhamomyces anomalus, Lactiplantibacillus plantarum, Limosilactobacillus fermentum and Pediococcus pentosaceus—in single and co-fermentation systems. GC-IMS, relative odor activity values, and sensory evaluation identified 1-octen-3-one as the dominant off-odor compound. Fermentation significantly reduced 1-octen-3-one while increasing aroma-active volatiles such as isovaleraldehyde, isopentanol, and isopropyl propionate, likely through enzymatic degradation and microbial biosynthesis. Sensory analysis confirmed improvements in aroma and overall acceptability with minimal changes in color and texture. These findings clarify microbial modulation mechanisms of kelp flavor and support the development of value-added fermented kelp products.

Herein, we extracted a polyphenol-polysaccharide complex (HPC) from Hizikia fusiforme through enzyme-assisted alkali extraction. This complex had total phenol and carbohydrate contents of 57.99 mg GAE∙g-1 and 76.57 %, respectively. Subsequently, HPC1-5 fractions were purified on a diethylaminoethyl Sepharose Fast Flow anion exchange column. Fourier transform infrared and nuclear magnetic resonance spectroscopy showed the presence of telescopic vibrational peaks of polyphenolic and polysaccharide structures, indicating that HPC is an acetylated galactofucose predominantly composed of galactose. D-galactose was used to establish an aging model in mice. Administration of HPC delayed aging in these mice, as evidenced by the upregulation of antioxidant enzyme expression; suppression of peroxidation products and inflammatory factors; and activation of important signaling pathways, including Nrf2/Keap1 and NF-κB. In addition, HPC modulated the gut microbiota composition in aging mice. These findings highlight the potential therapeutic value of HPC and contribute to the advancement of research on natural antiaging interventions.

To investigate the effects of different processing methods on the characteristic flavor of Undaria pinnatifida, this study systematically compared the volatile flavor compositions of four sample groups, namely fresh U. pinnatifida from Dalian (WD), salted U. pinnatifida from Dalian (WY), dried U. pinnatifida from Dalian (WG), and fresh U. pinnatifida from Shantou (WS), using GC-IMS, combined with relative odor activity value (ROAV) analysis. The results showed that GC-IMS effectively distinguished the volatile profiles of samples subjected to different processing methods, identifying a total of 45 flavor compounds. Aldehydes emerged as the key flavor components, accounting for relative contents of 53.85% (WD), 41.12% (WY), 52.62% (WG), and 45.28% (WS), which were significantly higher than those of other compound classes. The ROAV analysis revealed that 1-octen-3-ol and 1-octen-3-one were the characteristic compounds shared by all four sample groups. Furthermore, distinct processing methods influenced the distribution of saturated aldehydes, esters, and furans, which could serve as key indicators to distinguish between different processing techniques. Multidimensional analysis, including GC-IMS fingerprint visualization and principal component cluster analysis, confirmed significant flavor differences among the samples from different processing methods and origins. This study provides a theoretical basis for the quality control and standardized production of algal-based foods by multidimensionally analyzing flavor evolution in U. pinnatifida during processing.

Carbohydrates play a vital role in food science,medicine science,life science and other fields.Carbohydrates can be divided into monosaccharides,oligosaccharides,and polysaccharides,among which monosaccharides and oligosaccharides are mostly soluble,which can not only serve as structural substances,but also have various biological activities such as antioxidant,anticancer,antibacterial,and antiviral activities.Hydrophilic interaction chromatography makes up for the deficiency of reversed-phase liquid chromatography in the separation of carbohydrates.This paper reviews the stationary phases including amino bonded stationary phase,amide bonded stationary phase,carbohydrate bonded stationary phase and zwitterionic bonded stationary phase used in hydrophilic interaction chromatography for the separation and analysis of monosaccharides and oligosaccharides during 2017-2022,and summarizes the effects of chromatographic separation conditions such as acetonitrile content,buffer salt concentration,mobile phase pH and column temperature on the hydrophilic separation efficiency so as to provide a reference for the separation and analysis of monosaccharides and oligosaccharides.

Aquatic product safety incidents have occurred frequently because of serious pollution in the farming environment,use of illicit veterinary drugs during the farming process,and the natural occurrence of pathogenic bacteria in aquatic products.However,due to the low content of target analytes,the complexity of aquatic product matrices,and the interaction between target analytes and food components,it is very difficult to separate and purify residual pollutants from aquatic products,so there is an urgent need for accurate and precise methods with a low limit of detection for the safety detection of aquatic products.Metal-organic frameworks(MOFs)are porous crystalline materials with large specific surface area,good thermal stability,and adjustable surface modification.MOFs have been successfully applied to the safety testing of aquatic products owing to the excellent adsorption properties.This article summarizes the major structure of MOFs,discusses the adsorption mechanisms of MOFs,and reviews the applications of MOFs in the safety detection of residual pollutants(fishery drugs,heavy metals,and organic pollutants)in aquatic products,in order to provide a reference for researchers engaged in the safety detection of aquatic products.