To study the immunogenicity of the novel outer membrane protein 5’-nucleotidase(5’-NT) from Vibrio parahaemolyticus.

Bioinformatics methods were used to analyze the sequence conservation, structure and B-cell epitopes of 5’-NT; the gene was cloned by polymerase chain reaction (PCR) and the recombinant plasmid pET-28a(+)-nutA was constructed and transformed into Escherichia coli for induced expression. The soluble recombinant protein was obtained by nickel-chelated nitrilotriacetic acid agarose affinity chromatography purification and gradient dialysis refolding; mice immunization, enzyme-linked immunosorbent assay, Western blotting, complement-mediated serum bactericidal assay and immunofluorescence confocal microscopy were used to systematically evaluate the protein’s surface exposure, immunological titer, cross-reactivity and immunoprotective effect.

The results showed that 5’-NT had high sequence conservation in the genus Vibrio. The recombinant plasmid of 5’-NT was successfully constructed and the high-purity recombinant 5’-NT was obtained through induced expression and purification. The antibody titer of 5’-NT against the whole-cell immune serum of Vibrio parahaemolyticus was 1:81k, which confirmed the surface exposure of this protein. The titer of 5’-NT immune serum against 5’-NT protein was 1:81k, and 1:3k against Vibrio parahaemolyticus. It had weak cross-reactivity with most other Vibrio species and the immune serum exhibited weak complement-dependent bactericidal activity (1:4). Western blot analysis demonstrated that the immune serum against recombinant 5’-NT could generate specific bands with whole-cell proteins of Vibrio parahaemolyticus and other Vibrio species. Confocal immunofluorescence microscopy analysis further confirmed that the recombinant 5’-NT immune serum specifically bound to Vibrio parahaemolyticus which also indicated that this protein possesses surface-exposed characteristics.

Although 5’-NT of Vibrio parahaemolyticus exhibits Vibrio-conserved and surface-exposed characteristics, its relatively low immune serum titer indicates limited exposure, immunogenicity, or expression abundance. This limits its application as a standalone vaccine or detection antigen. In subsequent studies, combination strategies can be adopted to explore its value in the prevention and control of Vibrio parahaemolyticus.This study reveals the surface exposure, immunogenicity, and serum protectivity of the outer membrane protein 5’-NT from Vibrio parahaemolyticus, providing a reference for the development of diagnostic antigens and subunit vaccines against this pathogen.

To improve the survival rate of probiotic cells and prepare microencapsulated compound probiotics.

In this study, microencapsulation technology was employed, using sodium alginate and skimmed milk powder as wall materials, and stachyose and konjac micro-powder as core materials to encapsulate probiotics. The effects of stachyose and konjac micro-powder on the survival rate and release rate of microencapsulated composite probiotics were investigated through room temperature storage and simulated gastrointestinal fluid treatment.

When the mass ratio of probiotics, stachyose, lactulose, isomalto-oligosaccharides and konjac micro-powder solution was 1:5:2:2:3, the probiotic composite microcapsules prepared in this way had a survival rate of 84.5% after being treated in gastric juice for 90 min, a release rate of 93.0% after being treated in intestinal juice for 90 min, a survival rate as high as 93.2% after being stored at room temperature for 30 d, and a survival rate as high as 90.0% after being stored at room temperature for 60 d.

The added stachyose, lactulose, isomalto-oligosaccharides and konjac micro-powder can increase the survival rate of microencapsulated probiotics during storage at room temperature, with good gastric acid resistance and excellent enteric effect.

To develop an intelligent, highly sensitive rapid detection platform for enrofloxacin (ENR) to address the issues of high cost and lengthy processing times associated with traditional detection methods, as well as the reliance on manual operation and insufficient identification accuracy of existing digital immunoassay technologies.

Based on automated imaging equipment and deep learning algorithms, a digital immunoassay system using polystyrene microspheres as signal carriers was constructed, combining immunoreaction and magnetic separation technologies to achieve quantitative detection. The system integrated a high-precision automated microdisplacement platform, adopted the Faster-RCNN algorithm to achieve rapid recognition of microspheres, and introduced the NAFNet image enhancement algorithm to improve the imaging quality.

The platform was capable of achieving high sensitivity detection of ENR (limit of detection 19.35 pg/ml, linear range 0.5–100.0 ng/mL), with test recoveries ranging from 104%–111%, and had made significant breakthroughs in detection efficiency, automation and anti-interference capability.

The study develops a deep learning-based automated immunoassay platform capable of stable image acquisition and accurate recognition of microspheres. The deep learning algorithm provides accurate and reliable counting, and the immunoassay system establishes features a wide linear range, low detection limit and high sensitivity. It performs well in the detection of milk samples and is suitable for the rapid automated detection of enrofloxacin in food.

To optimize the processing techniques for Zanthoxylum bungeanum tea, elucidate the mechanisms through which different methods influence its quality and bioactive components.

Through a comparative analysis of 3 kinds of typical processing techniques for black tea, green tea, and white tea, this study systematically evaluated their distinct impacts on the quality characteristics of Zanthoxylum bungeanum tea.

Among the 3 kinds of processing techniques evaluated, the green tea method exhibited the most favorable overall performance for producing Zanthoxylum bungeanum tea. Regarding sensory quality, this method effectively preserved the characteristic aroma and flavor profiles of Zanthoxylum bungeanum leaves, yielding a unique sensory profile characterized by a mild numbing sensation and a fresh, spicy aroma. In terms of nutritional and bioactive components, the content of water-soluble extracts (36.00%), vitamin B₂ (0.46 mg/100 g), vitamin C (154.00 mg/100 g) and β-carotene (1.31×10⁴ µg/100 g) were significantly increased (P<0.05). Functionally, the green tea method achieved a total flavonoid content of 9254.24 μg/g, which was significantly higher than that of Zanthoxylum bungeanum tea (Red) and Zanthoxylum bungeanum tea (White) by 206.30% and 93.90%, respectively. Moreover, the retention of numbing compounds, including hydroxy-α-sanshool and hydroxy-β-sanshool was optimal; their concentrations fell within the desirable threshold range for both flavor and bioactivity, without inducing any negative sensory effects. These advantages were attributable to the high-temperature fixation step inherent to green tea processing, which rapidly inactivated key enzymes such as polyphenol oxidase and amide hydrolase, thereby suppressing oxidative degradation. In contrast, during black tea processing and white tea processing, enzyme activity was not sufficiently inhibited, resulting in varying degrees of constituent transformation and degradation.

Through the modulation of enzyme activity during processing, the green tea method achieves the simultaneous preservation of sensory qualities, bioactive components, and characteristic flavor compounds in Zanthoxylum bungeanum tea. The resulting product thus exhibits both desirable flavor attributes and potential health benefits, establishing this method as the optimal approach for high-quality production. These findings provide a crucial technological foundation for the high-value utilization of Zanthoxylum bungeanum leaves.

To establish a rapid method for the determination of 21 kinds of mycotoxins in spices, including conventional mycotoxins and 5 kinds of emerging mycotoxins such as alternariol monomethyl ether by solid-phase extraction pretreatment coupled with ultra performance liquid chromatography-tandem mass spectrometry.

Sample extracts were purified by dispersive solid-phase extraction, separated on an HSS T3 column. Gradient elution was performed using a mobile phase consisting of aqueous solution containing 0.1% formic acid and 5 mmol/L ammonium acetate, and methanol solution containing 0.1% formic acid and 3 mmol/L ammonium acetate. Electrospray ionization was adopted with rapid switching between positive and negative ion modes. Multiple reaction monitoring mode was used for data acquisition, and external standard method was applied for quantitative analysis.

All 21 kinds of mycotoxins showed good linear relationships within a certain concentration range, and the correlation coefficients (r) were all no less than 0.99. The limits of detection were 0.10–6.00 µg/kg, and the limits of quantitation were 0.30–22.00 µg/kg. The average recovery rates of the target substances were 78.5% to 100.5%, and the relative standard deviations were 1.50% to 7.98%.

The method has excellent accuracy and precision, and can be used for rapid and accurate detection of many mycotoxins in spices.

To establish an analytical method for the detection of 11 kinds of preservatives content in short-shelf-life fruits by QuEChERS combined with high performance liquid chromatography-tandem mass spectrometry.

The samples were extracted with methanol, and 2.0 mL of the extract was transferred to a purification tube containing 100 mg of N-primary secondary amine (PSA) and 100 mg of C₁₈ powder. After vortex mixing for 1 min and centrifugation at 4500 r/min for 5 min, the supernatant was passed through a 0.22 μm organic microporous membrane. The sample was analyzed in multiple reaction monitoring mode using electrospray negative and postive ionization mode.

The results demonstrated good linearity for all 11 kinds of preservatives within their respective concentration ranges, with correlation coefficients (r) exceeding 0.99. The method exhibited limits of detection of 0.003–0.015 mg/kg and limits of quantitation of 0.01–0.05 mg/kg. For recovery studies in bayberry, mulberry and strawberry matrices at 3 spiked mass concentration levels, the average recoveries ranged from 76.4% to 98.9%, with relative standard deviations (RSDs) of 0.5%–9.8%. When applied to 20 batches of bayberry, mulberry and strawberry samples, natamycin was detected in 2 batches of mulberries and one batch of bayberries, with concentrations ranging from 4.5 to 11.9 mg/kg.

The method is simple, highly sensitive, and enables rapid determination of multiple preservatives, providing technical support for the simultaneous monitoring and evaluation of various preservatives in short-shelf-life fruits.

To establish a method for rapid detection oxytetracycline (OTC) residues in animal-derived foods by carbon dots (CDs) fluorescent probe.

Blue-emissive carbon dots (B-CDs) were synthesized via a one-step hydrothermal method using salicylic acid and o-phenylenediamine as precursors, and a fluorescent probe for OTC detection was constructed.

The as-prepared B-CDs exhibited near-spherical morphology, uniform size distribution, good water dispersibility and stable fluorescence. The fluorescence of B-CDs could be selectively quenched by OTC. Under optimized conditions, the fluorescent probe exhibited good linear response and sensitivity for OTC in the range of 0–1.00 mg/kg (Y=1070.95–673.35X, r²=0.9959), with a limit of detection as low as 3.60 μg/kg and a limit of quantitation of 11.99 μg/kg. In spiked recovery tests using real samples, recoveries ranged from 94.00% to 102.00%, with relative standard deviations between 0.17% and 2.25%.

The proposed method is simple to operate, highly sensitive, reliable and cost-effective, demonstrating promising potential for rapid screening of OTC residues in food samples.

To evaluate the quality of Camellia sinensis cv Baohongcha. green tea in Kunming, and identify its key quality indicators.

A total of 9 quality indicators, including water extract, tea polyphenols, catechins, free amino acids (calculated as glutamic acid), theanine, caffeine, theaflavins, polysaccharides (calculated as glucose) and total flavonoids (calculated as rutin), were determined in 31 batches of Camellia sinensis cv Baohongcha. green tea samples collected from Yiliang County, the main producing area of Kunming. Pearson correlation analysis, hierarchical cluster analysis and principal component analysis were adopted for data analysis.

The 9 individual indicators were integrated into 2 independent comprehensive components F1 and F2 by principal component analysis. The contribution rates of F1 and F2 were 41.33% and 15.20%, respectively, with a cumulative contribution rate of 56.53%. The 6 key evaluation indicators were screened out, namely water extract, tea polyphenols, catechins, caffeine, free amino acids and theanine.

The 6 key quality indicators of Camellia sinensis cv Baohongcha. green tea are analyzed in depth. The results shows that the overall quality indicators of Camellia sinensis cv Baohongcha. tea are excellent, which endows the tea with typical characteristics of high-aroma green tea: Yellowish-green and bright liquor color, fresh and brisk taste with sweet aftertaste, and rich fragrance. It is suggested to further construct and optimize the standard system for the whole industrial chain of Camellia sinensis cv Baohongcha. tea.

To establish an analytical method for the simultaneous determination of 12 kinds of organic acids (tartaric acid, hydroxycitric acid, lactic acid, citric acid, succinic acid, fumaric acid, gallic acid, protocatechuic acid, chlorogenic acid, caffeic acid, syringic acid and ferulic acid) in Hibiscus sabdariffa L. wine by solid-phase extraction and high performance liquid chromatography.

Mixed-mode strong anion exchange polymeric anion exchange (PAX) solid-phase extraction cartridges were used for purification and enrichment. The samples were eluted with 0.1% formic acid in water and methanol as mobile phases and separated on a CAPECELL PAK ADME C₁₈ liquid chromatography column (4.6 mm×250 mm, 5 μm), and a diode array multi-wavelength detection were employed.

The 12 kinds of organic acids were effectively separated; there was a good linear relationship within the linear range of various mass concentrations, with correlation coefficients (r) all above 0.9998;the average spiked recovery rates ranged from 82.78%–101.52%, with relative standard deviations of 0.90%–4.79%. The limits of detection were 0.00047–0.49392 mg/L and the limits of quantitation were 0.00157–1.64640 mg/L.

This method is simple to operate, good separation effect, accurate data and high sensitivity, making it suitable for the quantitative and qualitative detection of organic acids in Hibiscus sabdariffa L. wine.

To explore the efficient extraction method and biological activity of black Crabapple polysaccharides (BCP).

Using black Crabapple as the raw material, the extraction conditions of BCP were optimized through single-factor experiments combined with response surface methodology. The monosaccharide composition was analyzed by high performance liquid chromatography, and its in vitro antioxidant activity was evaluated based on the scavenging rates of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) radicals,2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonate acid) diammonium salt cation (ABTS⁺) radicals and hydroxyl radicals.

The optimal extraction process for BCP was a liquid-to-solid ratio of 20:1 (mL:g), extraction temperature of 72 ℃ and extraction time of 45 min, yielding a polysaccharide recovery rate of (19.98±0.25)%. BCP consisted of 8 kinds of monosaccharides, including glucose, galactose and arabinose, confirming its identity as an acidic heteropolysaccharide. Antioxidant experiments demonstrated that BCP exhibited concentration-dependent scavenging capabilities against DPPH radicals, ABTS⁺ radicals and hydroxyl radicals. At a mass concentration of 1.0 mg/mL, the inhibition rates for these 3 kinds of radicals were (84.70±0.38)%, (71.20±0.91)% and (92.40±0.51)% respectively, indicating its favorable in vitro antioxidant activity.

This study optimizes the extraction process of BCP and proves its excellent antioxidant properties, providing a theoretical reference for promoting the high-value development of black Crabapple.