BACKGROUND:Astaxanthin is widely recognized as one of the most potent natural antioxidants. However, the large-scale production of astaxanthin remains a significant challenge due to the limitations of current chemical and biosynthetic methods. To address these challenges, this study explores the use of nitrogen-doped carbon dots (N-CDs) to enhance the accumulation of astaxanthin precursors (such as β-carotene and zeaxanthin) in Limnospira platensis. RESULTS:The N-CDs exhibited excellent dispersibility, strong blue photoluminescence, and no detectable cytotoxicity. By optimizing cultivation parameters such as N-CDs concentration (10 mg L-1), temperature (26 °C), light intensity (4500 lx), and nitrogen-limited medium (NaNO3 1.25 g L-1), effective improvements in biomass yield and bioactive compound accumulation were achieved. Under these optimized conditions, the biomass yield (1.48 ± 0.06 g L-1), β-carotene accumulation (1.20 ± 0.01 g kg-1), and zeaxanthin accumulation (0.43 ± 0.02 g kg-1) increased by 140.32%, 96.72%, and 95.45%, respectively, compared to the control. CONCLUSION:These findings demonstrate that N-CDs can serve as a cost-effective strategy for enhancing bioactive compound production in Limnospira platensis, offering a novel and efficient approach for biotechnological applications related to natural antioxidant production. © 2026 Society of Chemical Industry.

Astaxanthin (AST) faces challenges in application due to its poor water solubility and low stability. This study successfully developed a novel O/W nanoemulsion utilizing Spirulina immunoactive peptides (IAP) and apple pectin (AP) as a composite emulsifier to enhance the stability and bioavailability of AST. The optimized AP/IAP/AST nanoemulsion exhibited a small particle size (187.80 nm), high encapsulation efficiency (85.40%), and significantly improved stability under various pH, ionic strength, and storage conditions compared to the AP/AST emulsion. Furthermore, the AP/IAP/AST nanoemulsion demonstrated a higher bioaccessibility (38.18%) in vitro. IAP and AST exhibited synergistic immunomodulatory activity by effectively suppressing LPS-induced NO production and reducing the levels of inflammatory cytokines (TNF-α, IL-6, IL-1β) in RAW264.7 cells, which was attributed to the inhibition of NF-κB pathway activation. This work provides an effective strategy for AST delivery and offers a novel approach for the high-value utilization of spirulina peptides.

Augmenting redox imbalance has become a promising strategy for effective cancer therapy. Selenium nanoparticles (SeNPs) have potential in this respect but are limited by instability. In this study, we constructed novel chitooligosaccharide-sodium alginate (COS-SA)-modified SeNPs (COS-SA-SeNPs) and optimized the synthesis process via response surface methodology for size control. The formation, morphology, physicochemical characteristics and stability mechanism were investigated. The results indicated that the COS-SA-SeNPs were orange‒red, had zero-valent Se, and were uniform spherical nanoparticles with an average diameter of 158 nm. Owing to the intermolecular forces between COS-SA and SeNPs, the heating and storage stability of the COS-SA-SeNPs were better. Moreover, the stable nanoparticles demonstrated potent antiproliferation activity in HepG2 cells. ROS overproduction, increased iron content, decreased antioxidant enzyme activity, and downregulation of ferroptosis-related genes (e.g., Nrf2/HO-1, SLC7A11, and GPX4) were observed, indicating the disruption of cellular redox homeostasis and the occurrence of ferroptosis. COS-SA-SeNPs exert antitumor effects by disrupting redox homeostasis and inducing ferroptosis through the simultaneous impairment of cellular antioxidant defenses. This study not only provides an alternative candidate for nutritional selenium supplementation but also offers fresh perspectives on ferroptosis-mediated cancer therapy through the enhancement of redox imbalance.

Phycocyanin, a natural edible blue pigment extracted from the cyanobacterium Limnospira platensis, possesses diverse physiological activities including anti-inflammatory, antioxidant, anticancer, antiviral, and immunomodulatory functions. However, its broader application remains limited due to low extraction efficiency and poor stability during storage and food processing. To address these issues, this study optimized the extraction process of phycocyanin, characterized its physicochemical properties, and evaluated its stability under various conditions. The optimal extraction parameters were determined as follows: extraction solution, 2

Diospyros lotus-derived peptide Pro-Pro-His-Gly (PPHG) and gallic acid (GA) exhibit synergistic thrombin-inhibitory activity but suffer from instability and premature gastric release during oral delivery. This study optimized synergistic ratios and developed a PPHG/GA-β-cyclodextrin (β-CD) co-encapsulation system. Checkerboard assays with Zero Interaction Potency (ZIP) modeling established an optimal 2.5:1 (w/w) PPHG:GA ratio. PPHG/GA-β-CD inclusion complexes (ICs) prepared at a 1:2 (w/w) core-to-wall ratio achieved encapsulation efficiencies of 81.15 ± 1.68% for PPHG and 80.52 ± 0.11% for GA. Structural characterization (SEM, XRD, FTIR, and 1H NMR) supported amorphous phase formation and the proposed “inner-inclusion/outer-assembly” architecture. Thermal analysis, interfacial charge measurements, molecular docking, and dynamic light scattering further indicated improved thermal behaviour and the formation of submicrometre aqueous assemblies with a smaller mean diameter and lower polydispersity than the physical mixture. The ICs demonstrated stability under environmental stresses (light, heat, pH) and food additives. In INFOGEST simulated digestion, the ICs reduced apparent gastric release by 28.74% and 34.83% for PPHG and GA, respectively, followed by gradual intestinal release. After simulated digestion, the ICs retained 75.8% of their initial thrombin-inhibitory activity, compared with 31.2% for the free PPHG + GA mixture, and showed 2.16-fold higher inhibition at the intestinal endpoint. This approach effectively stabilizes and delivers synergistic peptide-polyphenol combinations orally.

Astaxanthin, as a natural keto-carotenoid, demonstrates remarkable antioxidant properties. However, the naturally occurring trans-structured free astaxanthin is limited by restricted natural availability and low industrial production yield. Furthermore, its molecular architecture rich in unsaturated double bonds and inherent hydrophobicity critically undermines its stability and bioavailability. In this study, an integrated strategy spanning from production enhancement to functional delivery was established. Xanthophyllomyces dendrorhous, a red yeast, was used to ferment Limnospira platensis, with fermentation parameters systematically optimized to promote astaxanthin accumulation. Subsequently, astaxanthin produced from the optimized fermentation process was extracted and formulated into two types of astaxanthin-loaded nanoparticles, whose antioxidant activities were systematically evaluated using a Caco-2 cell oxidative stress model. The results showed that supplementation with Limnospira platensis promoted a metabolic shift of carotenoids toward astaxanthin biosynthesis in Xanthophyllomyces dendrorhous, thereby increasing astaxanthin accumulation from 0.88 +/- 0.08 mg/g to 1.03 +/- 0.07 mg/g. Moreover, the two astaxanthin-loaded nanoparticles exhibited distinct physicochemical properties and delivery behaviors, and their antioxidant effects were mainly achieved through scavenging excessive intracellular reactive oxygen species. By integrating production enhancement with functional delivery, this study effectively improved the yield, stability, and bioavailability of astaxanthin. These findings provide further support for its potential applications in functional foods and nutraceutical delivery systems.

Zeaxanthin, a vital carotenoid, is synthesized through a series of enzymatic reactions, with β-carotene hydroxylase serving as a key rate-limiting enzyme facilitating the conversion of β-carotene to zeaxanthin. This study aimed to investigate the feasibility of cloning and transferring the β-carotene hydroxylase gene (LpcrtR) from Limnospira platensis into Escherichia coli for the efficient production of zeaxanthin. Firstly, the LpcrtR gene was successfully extracted from the L. platensis genome, which contains 906 base pairs and encodes 301 amino acids. Through comparison, it was found that the LpCRTR protein shares high amino acid sequence homology with β-carotene hydroxylases from different species and possesses the "HXXXXH" and "HXXHH" motif structures. After constructing the gene expression vector pGEX-6p-1-LpcrtR, the recombinant plasmid was transformed into E. coli. The results of SDS-PAGE and Western blotting validated the expression of the LpcrtR protein (LpCRTR) in the bacterial system. Additionally, HPLC results revealed that LpCRTR can partially catalyze the conversion of β-carotene to zeaxanthin within E. coli. Notably, the zeaxanthin and β-carotene yield in recombinant E. coli were 81.7 ± 0.4

This study prepared, characterized, and applied synergistic antibacterial complexes of mulberry leaf peptide (MLP) and gallic acid (GA) for grape preservation. The complexes were formed through non-covalent binding (GA-MLP N), alkaline treatment (GA-MLP A), and free-radical grafting (GA-MLP F) to address the high usage concentration of MLP. The minimum inhibitory concentration of MLP in the synergistic combination was reduced by 87.5

BACKGROUND:Bovine blood is a protein-rich by-product of the meat industry, yet its potential as a source of bioactive peptides remains underexplored. Pancreatic lipase (PL) is a key enzyme in lipid digestion, and its inhibition represents a promising strategy for managing obesity. This study aimed to identify and characterize novel PL inhibitory peptides derived from bovine blood and to elucidate their binding mechanisms through molecular docking. RESULTS:Bovine blood proteins were hydrolyzed using a multi-enzyme system, 592 peptides were identified using liquid chromatography coupled with tandem mass spectrometry. Through virtual screening based on docking energy, toxicity prediction, and PeptideRanker scores, the peptides TQRFF and FTPVF were prioritized for analysis. Subsequently, molecular docking analysis revealed that TQRFF stabilized the PL complex through hydrogen bonding as well as cation-π, π-π, π-alkyl and alkyl interactions. Meanwhile, FTPVF formed salt bridges and demonstrated hydrogen bonding, cation-π interactions, π-π interactions and alkyl interactions. Molecular dynamics simulations revealed greater conformational stability in the FTPVF-PL complex, whereas TQRFF was found to induce protein compaction and form stronger hydrogen bonds. Finally, in in vitro experiments conducted after synthesizing these two key peptides, both TQRFF and FTPVF exhibited potent in vitro PL inhibitory activity, with half maximal inhibitory concentration (IC50) values of 260.02 ± 17.01 μg mL-1 and 760.04 ± 59.03 μg mL-1, respectively. CONCLUSION:The bovine blood-derived peptides TQRFF and FTPVF are novel PL inhibitors with promising anti-obesity potential. Their binding modes involve key interactions with the active site residues, supporting further development as functional food ingredients. © 2026 Society of Chemical Industry.

Anthocyanins (ATCs), as the primary economically active constituents in natural rose juice, encounter stability challenges under adverse storage conditions. Our aim was to investigate how encapsulation in (3-cyclodextrin ((3-CD) enhanced the light, thermal and oxidation stabilities of ATC, and assays were performed to assess its physicochemical properties and degradation kinetics in model rose juice during 70 days of storage. Characterization confirmed that the ATCs in the ATC-loaded (3-CD complexes were encapsulated in the cavity of the (3-CD. Compared with free ATCs, encapsulation significantly increased retention rates by 9.24%, 9.21%, and 2.57% under high temperature, light exposure, and strong oxidant exposure, respectively. As the same time the introduction of (3-CD imparted a discernible level of thermal resistance and favorable color stability to rose juice. The kinetics of ATC degradation was best-fitted by the first-order reaction model. The encapsulated juice, with Ea values ranging from 41.6 to 42.8 kJ/mol and zG values varying from 80.1 to 86.4 kJ/mol, indicates that the ATCs encapsulated within (3-CD exhibit better stability under adverse storage conditions. Furthermore, encapsulation greatly enhanced the shelf life of rose juice compared to the control sample. Thus, rose juice process technology using (3-CD encapsulation was feasible to obtain juices with superior hue and ATC stability.

BACKGROUND:Walnut meal is a by-product of walnut oil extraction. Its fermented product exhibits antibacterial activity against Staphylococcus aureus, mainly due to the produced peptides during fermentation. This study aimed to identify antibacterial peptides from fermented walnut meal (FW) targeting S. aureus, focusing on cell membrane and energy metabolism effects. RESULTS:FW reduced the aerobic plate count of tomato juice by 75.45%. Peptides with a net positive charge and mean hydrophobicity greater than 0 accounted for 63.7% and 35.92%, respectively. Molecular docking identified three antibacterial peptides - HAAPK (HK-5), TYFPH (TH-5), and WVSK (WK-4) - that bind penicillin-binding proteins and critical membrane protein amino acids via hydrogen bonds, hydrophobic interactions, and π-π conjugate interactions. HK-5 exhibited the highest antibacterial activity. Structural analyses using Fourier transform infrared and circular dichroism spectroscopy revealed that HK-5 predominantly adopts β-sheets (45.0%) in solid state and random coils (51.2%) in aqueous environments. Treatment with 1.0 minimum inhibition concentration of HK-5 reduced intracellular protein, pyruvate, and β-galactosidase activity by 55.0%, 76.84%, and 68.57%, respectively, while lipase activity increased by 18.25%, indicating membrane damage. Additionally, adenosine triphosphate content and the activities of succinate dehydrogenase and malate dehydrogenase decreased by 93.28%, 82.63%, and 86.89%, respectively, whereas isocitrate dehydrogenase activity leakage nearly doubled, pointing to energy metabolism disturbances. Scanning and transmission electron microscopy confirmed morphological and ultrastructural damage caused by HK-5. CONCLUSION:These findings highlight FW as a promising source of antibacterial agents, providing a sustainable use for agricultural waste. © 2025 Society of Chemical Industry.

The emerging technology of inhibiting polyphenol oxidase (PPO) is crucial for preventing enzymatic browning in food. This study aimed to investigate the effects of 4.5 kJ/m2 ultraviolet (UV)-C radiation and 0.02 mg/mL L-cysteine (L-cys) treatment on the enzyme activity, physico-chemical properties, thermal properties, structure, and molecular microstructure of PPO. UV-C/L-cys decreased PPO activity and had the highest aggregation index and turbidity of PPO. UV-C/L-cys further reduced the denaturation temperature point and increased the denaturation enthalpy of PPO. UV-C/L-cys turned the α-helix to random coil of PPO and destroyed the tertiary structure. This combined treatment aggregated the microstructure of PPO, which led to covering the active center of the enzyme, leading to its inactivation. Molecular docking simulation confirmed that L-cys bound to PPO through hydrogen bonding and ionic contact. This study established a foundation for the application of UV-C radiation and L-cys treatment to control food browning.

Fermented walnut (FW) meal exhibits antifungal activity against Penicillium victoriae (the fungus responsible for prickly pear spoilage), which is mainly attributed to the synergistic effect of antimicrobial peptides and salicylic acid (SA). This study aimed to investigate the synergistic mechanism between YVVPW (YW-5, the peptide with the highest antifungal activity) and SA against the cell membrane of P. victoriae. Treatment enhanced prickly pear’s rot rate, polyphenol concentration, and superoxide dismutase (SOD) activity by 38.11%, 8.11%, and 48.53%, respectively, while reducing the microbial count by 19.17%. Structural analyses revealed β-sheets as YW-5′s predominant structure (41.18%), which increased to 49.0% during SA interaction. Molecular docking demonstrated YW-5′s stronger binding to β-(1,3)-glucan synthase and membrane protein amino acids via hydrogen bonds, hydrophobic forces, and π-π conjugate interactions. Spectroscopic analyses demonstrated SA’s major role in YW-5 synergy at the interface and polar head region of phospholipids, enhancing lipid chain disorder and the leakage of cell components. Malondialdehyde and SOD levels increased nearly two-fold and six-fold when treated with YW-5/SA, and YW-5 showed a more pronounced effect. Scanning electron and transmission electron microscopy confirmed that SA caused greater damage to spore morphology and cell ultrastructure. These findings support this formulation’s functions as an efficient antifungal substance in fruit storage.

Curcumin has a wide range of application prospects, with various bioactivities in the food industry and in the biomedical field. However, curcumin has poor water solubility and is sensitive to pH, light and temperature. In this study, curcumin-chitooligosaccharide (CUR-COS) complexes were prepared via mechanochemical methods, and the CUR-COS complex was more soluble after freeze-drying (up to 862-fold greater than that of curcumin). The complex was characterized by SEM, XRD, FT-IR and thermal analysis, and its stability against pH, light and thermal treatment was evaluated. COSs could serve as carriers for curcumin delivery. Additionally, the antibacterial activity of the formed complex was determined. As a result, CUR-COS exhibited significantly better water solubility, enhanced stability, and stronger antibacterial properties than did pure CUR, offering a promising pathway for the extensive application of lipophilic natural products in foods, especially water-based products.

Thrombin is a core enzyme in the coagulation system, and inhibiting its activity can improve the hypercoagulable state of blood, playing a crucial role in the prevention and treatment of thrombotic diseases. The main objectives of this study were to isolate and characterize a thrombin-inhibitory peptide from Diospyros lotus(D. lotus) pomace and to evaluate its synergistic effect with gallic acid (GA) through in vitro assays. After enzymatic hydrolysis of proteins from D. lotus pomace followed by ultrafiltration purification, a total of 266 peptides were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), from which virtual screening identified the most bioactive peptide, Pro-Pro-His-Gly (PPHG). Although PPHG exhibited a relatively high IC₅₀ of 30.69 ± 0.54 mg/mL against thrombin compared to conventional bioactives, its combination with GA (4 mg/mL) at 10 mg/mL produced a marked synergistic effect, enabling a reduction in the effective dose of PPHG. Fourier-transform infrared spectroscopy (FTIR) revealed the formation of hydrogen bonds between PPHG and GA, Circular dichroism (CD) spectroscopy demonstrated that PPHG and GA affected thrombin activity by altering its secondary structure, with a stronger effect when combined. These results indicate that PPHG and GA have a synergistic anticoagulant effect, holding promise for application in the treatment of thrombotic diseases and the development of functional foods.

Fermented walnut meal (FW) has antifungal activity against Penicillium victoriae, a fungus responsible for Rosa roxbughii Tratt spoilage. This study characterized and applied ultrasonic-assisted antifungal film loaded with FW to preserve R. roxbughii Tratt during near-freezing temperature (NFT). Results showed that O2 and CO2 transmission rates decreased by 80.02% and 29.05%, respectively, and antimicrobial properties were improved with ultrasound at 560 W for 5 min and 1% FW. Fourier transform infrared spectroscopy and X-ray diffraction results revealed ultrasound improved hydrogen bonds and inductive effect via ─NH, ─OH, and C═O bonds. The addition of FW led to the formation of CMCS-GL-FW polymer via C═O bond. Thermogravimetric analysis and transmission electron microscope results demonstrated thermal degradation process was decomposed by ultrasound, and the internal structure of P. victoriae was accelerated by the addition of FW. Compared to the U-CMCS/GL group, the vitamin C content, peroxidase, and catalase activities of U-CMCS/GL/FW were enhanced by 4.24%, 8.52%, and 14.3% during NFT (-0.8 to -0.4°C), respectively. Particularly, the fungal count of the U-CMCS/GL/FW group did not exceed 105 CFU g-1 at the end of storage, and the relative abundance of P. victoriae decreased to 0.007%. Our findings provide an effective route for agricultural waste as natural antifungal compounds in the active packaging industry. PRACTICAL APPLICATION: In this study, the barrier and antimicrobial properties of film were successfully improved by ultrasonic treatment and loaded fermented walnut meal. The ultrasonic-assisted antifungal film loaded with fermented walnut meal effectively delayed the degradation of nutrients and reduced microbial invasion of Rosa roxburghii Tratt. These results provide a theoretical basis for the application of agricultural waste in the food packaging industry.

Polyethylene (PE) films, as the mainstream packaging material for Rosa roxburghii Tratt, have weak preservation abilities leading to serious waste. In this study, PE films coated with carboxymethyl chitosan (CMCS), sodium alginate (SA), and nisin (CSN-PE) were prepared as novel packaging materials to extend the shelf life of Rosa roxburghii Tratt. CSN-PE films had excellent mechanical, optical, barrier, and thermal properties. When compared to PE films, CSN-PE films improved firmness, soluble solids, titratable acidity, ascorbic acid, total phenol, and antioxidant enzyme activities (superoxide dismutase and peroxides) and decreased decay rate and browning enzyme activity (polyphenol oxidase) during storage (1 +/- 0.5 degree celsius for 70 d). The shelf life models for R. roxburghii Tratt were established based on ascorbic acid content. Our results emphasized the practicability of CSN-PE films, and we concluded that CSN-PE films can significantly extend the freshness period of R. roxburghii Tratt by 28 days.

AbstractMulberry (Morus alba L.) leaf can effectively inhibit the digestion of starchy foods, and α‐glucosidase (AG) is its main target. This study employed an untargeted metabolomics approach combined with molecular docking to identify AG inhibitors. Subsequently, inhibition kinetics, fluorescence spectroscopy, and interaction force analysis were utilized to investigate the inhibitory mechanism. Results indicated that vitexin exhibited significant reversible inhibition of AG through competitive inhibition, with an IC50 value of 105.50 ± 1.30 μg/mL. Molecular docking revealed hydrogen bonding as the main interaction force between vitexin and AG, and quenching mechanism analysis showed that they underwent static quenching driven by entropy. The results of the combined experiment showed that 1‐deoxynojirimycin (DNJ), a known bioactive component in mulberry, has a synergistic effect of inhibiting AG activity with vitexin. This study elucidates the potential mechanism of vitexin in inhibiting AG activity and provides theoretical evidence for utilizing vitexin‐DNJ complexes as functional components of AG inhibitors.

Diospyros lotus L., which belongs to the Ebenaceae family, is used in folk medicine for treating anemia, fatigue, insomnia, and hepatitis. In the present study, supercritical CO2 fluid extraction (SFE) was used to extract Diospyros lotus L. essential oil, and its antioxidant, antimicrobial, and cytotoxic activities were investigated. The chemical composition of the essential oil was investigated using GC/MS. The antioxidant capacity was evaluated via 1,1diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging and hydroxyl radical scavenging. The minimum inhibitory concentration (MIC) using the broth microdilution method was applied to investigate antimicrobial activities. The cytotoxic activity of the essential oil was measured using a standard 3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide (MTT) assay. The GC-MS analysis showed that Diospyros lotus L essential oil contained 25 components, mainly including 5-hydroxymethylfurfural (50.90%), 2-methylhexadecan-1-ol (19.97%), 2-cis-9-octadecenyloxyethanol (5.46%), dibutyl phthalate (4.84%), and n-hexadecanoic acid (4.20%). The IC50 values of the essential oil in the DPPH assay and hydroxyl radical scavenging activity were 46.46 +/- 1.70 mu g/mL and 0.551 +/- 0.0267 mg/mL, respectively. Furthermore, at concentrations below 50 mu g/mL, the evaluation of cell viability showed no cytotoxicity in the human embryonic kidney cell line 293T. The results show that Diospyros lotus L. essential oil has antimicrobial and antioxidant effects, and has no toxicity on 293T cells at low concentrations, indicating potential health benefits.