Fucosidases play a key role in the biodegradation and functional exploration of fucoidan, yet their catalytic diversity and molecular mechanisms remain unclear. This study aimed to explore novel fucosidases from the marine microorganism Pontiella sulfatireligans, and to analyze their enzymatic characteristics and structural basis. The discovery of glycosidases was conducted through genomic comparison and annotation to identify enzymes involved in fucoidan degradation. The candidate α-L-fucosidase gene, PSf1, was cloned and expressed, and its hydrolytic activity and substrate affinity were measured using p-nitrophenyl fucoside as a substrate. Substrate specificity was assessed through a substrate spectrum analysis. The three-dimensional structure of PSf1 was resolved using X-ray crystallography, and molecular dynamics simulations were performed to analyze its binding mode and stability differences with different substrates. The results showed that when using pNP-Gal as a substrate, PSf1 exhibited a hydrolytic activity of 3 U/mg, with a K_m value of 337 μmol/L. Substrate specificity analysis revealed for the first time that PSf1 had dual activity, hydrolyzing both α-fucosidic bonds and β-galactosidic bonds. Structural analysis (2.8 Å, PDB ID: 8Z63) showed that the enzyme existed as a non-mirrored dimer in its active form, where the fucose moiety of the substrate and its structural analog, galactose, bound within the conserved active site via hydrogen bonds and other interactions. Molecular dynamics simulations further demonstrated that PSf1 exhibited higher binding stability and lower binding free energy for the fucose substrate, while its hydrolytic activity towards galactosidic bonds originated from recognition of structural similarity. PSf1 was a multifunctional glycoside hydrolase with both α-fucosidase and β-galactosidase activity. The discovery of this enzyme not only elucidates the metabolic mechanism by which P. sulfatireligans efficiently utilizes fucoidan, but also provides a novel enzymatic resource and theoretical foundation for the functional development of fucoidan and enzyme-based synthesis and modification of human milk oligosaccharides, with significant potential applications.

Using Han Yuan Nan Jiao as raw material, the supercritical CO₂ extraction (SFE) process was optimized, and the differences in physicochemical properties, sensory characteristics, volatile components, and numbing compound contents of Zanthoxylum oleoresin prepared by SFE, ethanol solvent extraction method (SEM), and cold pressing method (CP) were systematically compared. Results showed that the optimal SFE conditions were an extraction pressure of 30.4 MPa, temperature of 38.7 ℃, and time of 1.9 h, achieving a Zanthoxylum oleoresin yield of 12.72%. The SFE product exhibited pure and intense numbing sensation (8.3 points) with mild aromatic notes (rosin and citrus), achieving the highest comprehensive sensory score. A total of 83 volatile components across 5 categories were detected in the Zanthoxylum oleoresin, with limonene, myrcene, linalool, and linalyl acetate being the predominant compounds across all three methods. The total numbing compound content of the SFE sample (597.75 mg/g) was significantly higher than those of SEM (438.60 mg/g) and CP (384.52 mg/g) samples. Among the 10 numbing amides, hydroxyl-α-sanshool, hydroxyl-β-sanshool, and hydroxyl-γ-sanshool were the most abundant. This study provides technical support for the industrial production of high-quality Zanthoxylum oleoresin and confirms the comprehensive advantages of supercritical CO₂ extraction in flavor and functional properties.

Objective: This study aimed to develop a green and efficient formula for a composite phosphorus-free water retention agent to enhance the water-holding capacity of frozen Sebastes schlegelii fillets. Methods: The optimal ratio was derived from the optimization method of orthogonal experiments based on one-way experiments, using the soaking weight gain rate, thawing loss rate, and cooking loss rate as evaluation indices of water retention. This approach allowed for the determination of the optimal compound phosphorus-free water retaining agent formula. The water retention effect, texture characteristics, microstructure, and sensory quality of the fish fillets treated with the optimal compound non-phosphorus water retaining agent formula were analyzed. Results: The results indicated that the optimal combination of the formula consisted of 2.5% sodium bicarbonate, 2.0% sodium citrate, and 1.5% alginate. Following treatment with this compound phosphorus-free water retention agent, the soaking weight gain rate of Sebastes schlegelii fillets increased from 5.46% to 19.2%, while the thawing loss rate and cooking loss rate decreased from 9.23% and 30.6% to 1.28% and 14.0%, respectively. These results were comparable to those of fillets treated with the compound phosphate water retention agent in terms of texture and structure. Microstructural analysis revealed that this formula helped maintain the integrity of the muscle fibers in the fillets, reducing the destruction of muscle fibers after thawing, while also effectively improving sensory quality and mitigating the negative sensory impacts associated with phosphate treatment. The composite phosphorus-free water retention agent formula developed in this study demonstrated its feasibility as a replacement for traditional phosphates. This achievement provides a theoretical basis for the industrial application expansion of phosphorus-free water retention technology in the processing of Sebastes schlegelii products.

In this work, the Panax notoginseng flower residue was mixed fermented with the kefir grains and kombucha consortium to investigate the effects of fermentation parameters on the functional properties of the soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) by single-factor and response surface experiments. The optimal fermentation conditions were as follows: the broth ratio of kefir grains and kombucha 2:1 (v/v), inoculation amount 8% (v/w), culture temperature was 28 ℃, and fermentation time 53 h. Under these optimized conditions, the fermented SDF (F-SDF) yield was 40.32%, and its functional group abundance had been significantly enhanced. For F-SDF and F-IDF, the water holding capacity (WHC), oil holding capacity (OHC), water swelling capacity (WSC), and cation exchange capacity (CEC) increased by 80.30% and 89.77%, 69.37% and 76.77%, 111.98% and 67.18%, and 58.82% and 122.22%, respectively. The adsorption capacities of glucose and sodium cholate increased by 61.18% and 72.66%, 22.50% and 22.61%, respectively. Under simulated gastrointestinal conditions, when the pH was 2.0, the adsorption capacities of cholesterol and nitrite were significantly increased by 24.77% and 20.65%, 21.48% and 19.28%; when the pH was 7.0, the adsorption capacities of cholesterol and nitrite were significantly increased by 22.67% and 29.45%, 19.27% and 24.90%, respectively. In conclusion, the mixed fermentation effectively modified the physical structure and functional properties of the dietary fiber derived from notoginseng flower residue. The results provide a theoretical basis for promoting the high-value application of notoginseng by-products.

Polyphenols have the ability to scavenge reactive oxygen species and protect tissues against oxidative damage. However, the extraction, enrichment mechanisms, and antioxidant activities of rouge radish polyphenols (RRP) remained poorly understood. This study aimed to elucidate the key factors in extraction, enrichment mechanisms, and the characteristics of antioxidant activity. Response surface methodology was employed to optimize the probe-type ultrasonic-assisted extraction process. Resin enrichment mechanisms were investigated through adsorption/desorption kinetics and isothermal adsorption model. Antioxidant activity of RRP before and after enrichment was analyzed using the DPPH, ABTS⁺, and ferric reducing antioxidant power assay to provide theoretical support for the efficient development and antioxidant research of RRP. Results indicated that probe-type ultrasound significantly enhanced RRP yield compared to plate-type ultrasound and shaking-bed extraction (P<0.05). Optimal parameters were: Extraction solvent concentration 60% ethanol, solid-to-liquid ratio 1:55 g/mL, extraction temperature 55 ℃, ultrasonic power 350 W, and extraction time 20 min, yielding 33.03±0.12 mg/g. The adsorption/desorption process of HPD-400 resin was conformed to be the pseudo-second-order model, and the intraparticle diffusion was primary but not the sole rate-limiting step. Temkin model was more suitable for describing the adsorption behavior, and lower temperature was beneficial for adsorption. After enrichment, the scavenging concentration values for RRP in scavenging 1,1-diphenyl-2-trinitrobenzene hydrazine radical and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radicals decreased to 35.5% and 83.0% of their pre-enrichment levels, respectively, while the ferric reducing antioxidant power assay value increased by 1.3-fold.

To address the application limitations of eugenol due to its poor water solubility and volatility, this study developed a novel delivery system based on an ultrasound-assisted whey protein isolate-low methoxyl pectin bilayer nanoemulsion (WPI-LMP BN). Box-Behnken design was employed to optimize key parameters (WPI/LMP concentrations, ultrasound power/time), with mean particle size and polydispersity index (PDI) as critical evaluation indicators. The microscopic morphology and intermolecular interactions of the emulsion were analyzed using scanning electron microscopy and Fourier transform infrared spectroscopy; its stability under pH, ionic strength, and temperature stress was systematically evaluated; and finally, agar diffusion assays were employed to compare its antibacterial activity with that of free eugenol. The optimal conditions were established as follows: 2.60% WPI, 1.20% LMP, 500 W ultrasound power, and 8 min ultrasound time. Under these conditions, the resulting WPI-LMP BN exhibited a particle size of 318.6 nm, a PDI of 0.227, and an encapsulation efficiency of 76.53%. Scanning electron microscopy revealed spherical and uniformly distributed droplets, while Fourier transform infrared spectroscopy confirmed the successful formation of a WPI-LMP composite interface. Stability studies indicated that the nanoemulsion maintained good physical stability under various environmental stresses, including a broad pH range (3~10), Na⁺ concentrations up to 250 mmol/L, and temperatures up to 80 ℃. Antibacterial assays showed that the inhibition zone diameters of WPI-LMP BN against Staphylococcus aureus and Escherichia coli were significantly increased by 43.11% and 41.81%, respectively, compared to free eugenol, demonstrating a substantial enhancement in antimicrobial efficacy. These findings indicate that the ultrasound-assisted WPI-LMP BN possesses excellent stability, effectively encapsulates eugenol, and markedly improves its antibacterial performance, offering a promising approach for developing stable and efficient plant essential oil-based antimicrobial delivery systems.

'Aijiao Oolong' is a distinctive type of Oolong tea from Fujian Province. To investigate the quality and flavor attributes of high-quality Aijiao Oolong tea, the Aijiao Oolong tea products from Jian'ou City were utilized as experimental materials, and classified samples with higher sensory quality scores into a high-quality group for analysis. The main taste and aroma compounds were analyzed using sensory evaluation, biochemical component analysis, and advanced technologies such as UPLC-QqQ-MS (Ultra-Performance Liquid Chromatography Triple Quadrupole Mass Spectrometry) and HS-SPME-GC-MS (Headspace Solid-Phase Microextraction-Gas Chromatography-Mass Spectrometry). The results demonstrated that the high-quality group of Aijiao Oolong tea had a distinct floral scent along with a rich, mellow, and fresh taste. Since the flavonoid content (1.50%±0.22%) was significantly lower than that of the ordinary group, the water extract (34.70%±1.36%), tea polyphenols (10.3%±0.69%), and caffeine (4.40%±0.32%) contents of high-quality Aijiao Oolong tea were all significantly higher than those of the ordinary group (P<0.05). The biochemical component results aligned with the tea soup's strong flavor and astringency trend in the high-quality group's sensory rating. Notably, 67.73% of the total amino acid content in the high-quality group was made up of umami amino acids. The fragrant arginine and the fresh, invigorating theanine were the primary distinguishing amino acid components, according to additional analysis using the OPLS-DA model. This could be the primary cause of the Jian'ou Aijiao Oolong tea soup's high freshness and sweet aftertaste. A total of 527 volatiles were identified in two group tea samples. Finally, 54 volatiles were screened as differential volatiles based on VIP≥1 and P<0.05. OAV and ACI analysis showed that mthyl salicylate, δ-decanolactone, geranyl acetate, and 2-ethyl-3-methylpyrazine were the main ingredients of the high-quality group, which mainly presented fruity and sweet flowery aroma, their content was significantly higher than that in the ordinary group. The findings can serve as a valuable foundation for investigating and determining the distinctive flavor and quality of high-quality Aijiao Oolong tea.

In order to enhance the product quality of tank-fermented broad bean chili paste, this study investigated the effects of inoculating Zygosaccharomyces rouxii on the physicochemical indexes, free amino acids and volatile flavor compounds during the fermentation process of broad bean paste and the fermentation process of broad bean chili paste at a constant temperature of 35 ℃. The results showed that during the fermentation process of broad bean paste, taking the broad bean paste without inoculation as the control group, the enhanced fermentation group showed higher total acid content and amino acid nitrogen content of 1.52 g/100 g and 0.85 g/100 g, respectively. It increased by 10.14% and 8.97% respectively. The content of reducing sugar was only 53.78% of the control group in enhanced fermentation group. The total free amino acids increased by 23.40% compared to the control group, especially glutamic acid content increased by 30.14%. Furthermore, the relative content of volatile substances reached 290.67 mg/kg, which was much higher than that of the control group at 144.92 mg/kg. The dominated flavor compounds were esters and alcohols. During the fermentation of chili paste, the content of total acid, amino acid nitrogen, reducing sugar and free amino acid mainly proline showed a decreasing trend. Volatile substances were mainly esters and alcohols. During the fermentation process of broad bean chili paste, the enhanced group had lower reducing sugar content in the early stage, then tended to be consistent. Total volatile contents reached 644.23 mg/kg, which increased 17.73% compared to control group. Through sensory evaluation and flavor analysis, the broad bean chili paste of the enhanced group had significant enhancement in mellow, sour, floral and fruity. In conclusion, inoculation with Zygosaccharomyces rouxii had a big influence on the quality indexes of tank-fermented broad bean paste, while the effect on broad bean chili paste fermentation of physicochemical indexes was relatively small. However, it led to a marked increase in flavor compounds. This study results have important instructive significance for improving the tank fermentation process of broad bean chili paste, which can effectively solve the problems of weak flavor and product quality degradation of tank-fermented broad bean chili paste.

To rapidly determine anthocyanin content in red radish (Raphanus sativus L.) and improve raw material screening efficiency for pigment production, color parameters (L^*, a^*, b^*, C^*, and H^*) were measured at different positions on red radish using a colorimeter. Ultra-performance liquid chromatography-mass spectrometry was employed to analyze content of individual anthocyanin. A significant positive correlation was observed between a^* values and anthocyanin contents. Linear regression models based on a^* values achieved a 68.4% prediction accuracy for total anthocyanin content and from 28.9% to 52.6% for major individual anthocyanins. Eight machine learning algorithms were employed to optimize the color parameter-based prediction model of anthocyanin content. The Lasso regression model demonstrated strong predictive performance for total anthocyanin content, achieving a prediction accuracy of 87.5%. The Decision Tree regression model achieved prediction accuracies of 75% for both pelargonidin-3-(feruloyl)diglucoside-5-(malonyl)glucoside and pelargonidin-3-(caffeoyl)diglucoside-5-glucoside, indicating its effectiveness in estimating specific anthocyanin compounds. Collectively, these findings indicate that combining colorimetric measurement with machine learning enables rapid prediction of anthocyanin content, which is conducive to raw material selection in red radish pigment production.

This study took the three selenium-enriched kiwifruit varieties 'Cui Xiang' 'Xu Xiang' and 'Qi Hong' grown in Hanyin County, Shaanxi Province as the research objects, and systematically analyzed their physicochemical properties, selenium content, functional components and biological activities. The results showed that the key quality indicators such as dry matter content, total soluble solids, total sugar, pH, and sugar-acid ratio presented significant differences among the three selenium-enriched kiwifruit varieties (P<0.05). The selenium content of the three selenium-enriched kiwifruits was all≥0.10 mg/kg, meeting the selenium content requirements of selenium-enriched fruits. The selenium content showed significant differences among different varieties and parts of the fruits (P<0.05), and the selenium distribution in the three fruits was peel>seeds>pulp, with 'Xu Xiang' having a significantly higher selenium accumulation ability than 'Cui Xiang' and 'Qi Hong'. Kiwifruit was rich in mineral elements such as potassium, calcium and magnesium. The total mineral content, V_C, polyphenols and antioxidant capacity of 'Cui Xiang' were significantly higher than those of the other varieties (P<0.05). In addition, the three selenium-enriched kiwifruit varieties all showed certain inhibitory activities against α-amylase, α-glucosidase and pancreatic lipase, among which 'Cui Xiang' had the strongest inhibitory effect on the three enzymes. This study provided a scientific basis for the development of functional foods from selenium-enriched kiwifruit by analyzing the component characteristics and biological activity differences among different varieties of selenium-enriched kiwifruit.