Dandelion is a medicinal and food plant in China, with a wide range of sources and rich nutritional and pharmacological values. Dandelion polysaccharide is one of the important functional active ingredients, and domestic and international studies have found that it has a variety of biological activities. This paper systematically reviewed the extraction and purification methods of Dandelion polysaccharides, analyzed the primary structural features of Dandelion polysaccharides, such as molecular weight, monosaccharide composition and chemical structure, and summarized and analyzed the biological activities and related mechanisms of Dandelion polysaccharides, such as antioxidant, anti-bacterial, immune regulation, hypoglycemia, anti-inflammatory and anti-tumor, etc., and explored the conformational relationship between the structure of Dandelion polysaccharides and its biological activities, which is aimed to provide the basis for the deep development of Dandelion polysaccharides in food and medicine. This study aims to provide important theoretical references for the development and application of Dandelion polysaccharides in food and medicine.

Objective To establish an analytical method for the determination of flonicamid residues in tea and assess the dietary intake risk of flonicamid in tea. Methods Flonicamid residues in tea were extracted using acetonitrile, followed by dehydration and salting out with anhydrous MgSO₄ and sodium acetate. The supernatant was purified using anhydrous MgSO₄, C₁₈, primary-secondary amine (PSA), and graphitized carbon black (GCB) as adsorbents. Analysis was performed using ultra performance liquid chromatography-tandem mass spectrometry in multiple reaction monitoring mode with positive ionization. Quantification was achieved using matrix-matched external standards. Dietary intake risk assessment was conducted based on residue trial results and the dietary structure of the Chinese population. Results Flonicamid had a good linear relationship (r≥0.9999) within a certain concentration range. At levels of 0.01, 0.50, 20.00 and 30.00 mg/kg, the average recovery rates of tea (dry and fresh) ranged from 83.9%-93.6%, with relative standard deviations of 1.1%-5.3%. The limit of quantitation was 0.01 mg/kg. The final residue test and degradation test showed that the residual amount of flonicamid on tea was mainly affected by the combined effects of application dose and harvesting interval. The half-lives of flonicamid in fresh and dry tea in various regions were between 0.8-4.0 d and 0.8-5.1 d, respectively, indicating that it was an easily degradable pesticide. The results of the dietary assessment showed that the estimated daily intake of flonicamid through tea consumption for adults over 18 years old was between 0.74-0.81 μg/(kg·bw·d), which accounted for 1.05% to 1.16% of acceptable daily intake; combining the registration status of pesticides in China and the existing residue limits, the national estimated daily intake of flonicamid for the general population was 58.5193 μg/(kg·bw·d), which accounted for 83.6% of the acceptable daily intake. Flonicamid had low acute toxicity, and the probability of causing acute dietary risk was minimal. Therefore, there was no need to conduct an acute dietary risk assessment. Conclusion This method has simple pretreatment steps, high accuracy and high sensitivity, and can be used for the detection of flonicamid residues in tea. Upon evaluation, it has been determined that flonicamid does not pose an unacceptable risk to the general population.

Objective To establish a method for the simultaneous determination of 11 kinds of synthetic colorants in beverages by automated solid-phase extraction-liquid chromatography. Methods The 2 g of the beverage sample was taken, it was extracted with an ammonia ethanol solution, and operations such as activation, sample loading, washing, eluting and collection were performed in turn with the help of a fully automatic solid-phase extraction instrument. After nitrogen blowing and redissolution, the liquid chromatography instrument was used for on-line determination [diode multi-wavelength multi-channel simultaneous detection, detection wavelengths 415 nm (citrus yellow and quinoline yellow), 520 nm (new red, amaranth red, carmine, sunset yellow, temptation red, acidic red, and red algae), 610 nm (indigo and bright blue); mobile phase: A 20 mmol/L ammonium acetate solution, B methanol, flow rate 1 mL/min, gradient elution]. Results In the range of 0.2-10.0 μg/mL, the mass concentration of 11 kinds of synthetic colorants showed good linear relationship with peak area, and the linear correlation coefficients were all greater than 0.99, the limit of detection met the requirements of GB 500935—2023 National food safety standard-Determination of synthetic colorants in food. In the standard addition method recovery test, the recovery rates were between 91.3% and 106.0%, and the relative standard deviation of the determination value (n=6) was less than 5.0%. This method was applied to the ability verification of sunset yellow and carmine in beverages in food testing institutions in the Yangtze River Delta. The content of carmine was 5.86 mg/kg, and the content of sunset yellow was 4.31 mg/kg. The other synthetic colorants were not detected. Conclusion This method achieve good enrichment effect, high automation degree, simple operation, good stability, short time, high efficiency, good sensitivity, high accuracy and good reproducibility, and is suitable the determination and analysis of synthetic colorants in a large number of beverages.

Objective To develop a sensitive and stable dual signal output indicator label and realize real-time monitoring of the freshness of Litopenaeus vannamei. Methods Based on polyvinyl alcohol (PVA)/agar composite matrix combining anthocyanins (ACNs), silver coated gold nanoparticles (Au@AgNPs) and the metal organic framework material UiO-66, the dual signal output indicator labels were prepared by casting method. Next, the stabilizing effect of UiO-66 on the labels was investigated by storage stability, ultraviolet stability and anti-migration experiments. Ammonia, dimethylamine and trimethylamine were used as characteristic volatile markers to evaluate the gas sensitive response performance of the labels. Ultimately, the label was applied to real-time monitoring of the freshness of Litopenaeus vannamei. Results Compared to labels without UiO-66, the addition of UiO-66 effectively immobilized the anthocyanins and improved the UV stability and storage stability of the label. In addition, the label showed excellent responsiveness to ammonia and amine gases. In the application of freshness monitoring of Litopenaeus vannamei, the color of the indicator label gradually changed from purplish-red to bluish-green with the change of freshness of Litopenaeus vannamei. The partial least squares regression (PLSR) model based on the surface-enhanced Raman scattering (SERS) signals showed excellent prediction performance for the total volatile basic nitrogen (TVB-N) values, with a correction set coefficient of calibrated coefficient of determination (R²_C) of 0.951, cross-validated coefficient of determination (R²_CV) of 0.899, predicted coefficient of determination (R²_P) of 0.966, and residual prediction deviation (RPD) of 4.765. Conclusion A colorimetric-SERS dual-signal output indicator label is developed in this study. The label enable simultaneous visual identification of the freshness of Litopenaeus vannamei and high-sensitivity prediction of TVB-N values, providing a reference for the design of novel intelligent food packaging systems.

Objective To explore the optimal fermentation process of Vatica wine and analyze its flavor substances. Methods The fermentation conditions of Vatica wine were optimized by single factor experiments and Box-Behnken response surface analysis. The effects of yeast addition amount, fermentation temperature and fermentation time on the fermentation of green plum wine were analyzed. The flavor components of green plum wine were analyzed by headspace solid-phase microextraction and gas chromatography-mass spectrometry to determine the optimal process conditions. Single-factor experiments. Results The optimal technological conditions were as follows: Fermentation temperature 25 ℃, yeast addition 0.5 g/L, fermentation time for 8 days. Among them, 25 kinds of volatile flavor substances were detected. The main flavor active ingredients were alcohols, esters, aldehydes and ketones, terpenes, etc. They accounted for 59.28%, 9.07%, 17.00% and 0.96% of flavor substances, respectively. Conclusion The Vatica wine fermented by this condition is sweet and sour and has the unique fragrance of Vatica, which provides theoretical support for the industrialization upgrading and quality improvement of Vatica wine.

Objective To establish a method for rapid detection of toltrazuril and other veterinary drug residues in milk using ultra performance liquid chromatography-tandem mass spectrometry based on solid-phase extraction purification technology. Methods The samples were ultrasonically extracted with a 0.1% acetic acid-acetonitrile solution and purified using an solid phase extraction column (HMR-Lipid). Separation was achieved on a BEH C₁₈ chromatographic column with 0.1‱ acetic acid in water-acetonitrile as the mobile phase. The target compounds were ionized in the negative ion mode of electrospray ionization and detected in multiple reaction monitoring mode, with quantification performed using the internal standard method. Factors such as extraction, purification and chromatographic conditions of the target compounds in the samples were optimized. Results The target compounds had good linearity in the mass concentration range of 0.5-50.0 ng/mL, with correlation coefficients all greater than 0.999. The limits of detection were 0.23-0.52 μg/kg, and the limits of quantitation were 0.23-1.45 μg/kg. The spiked recoveries ranged from 92.4% to 105.2%, and the precisions were between 0.32% and 7.00%. Conclusion The sample pretreatment could be completed within 15 minutes. This method is simple, rapid, highly sensitive and accurate for both qualitative and quantitative analysis, and is suitable for the detection of toltrazuril and other veterinary drug residues in milk.

Objective To screen salt-tolerant esterase-producing strains from yellow water and analyze their metabolic products. Methods Esterase-producing strains were isolated from yellow water and identified using morphological, physiological, biochemical and molecular biological methods. Results The 9 esterase-producing strains were screened from yellow water, among which CZ-1, CZ-5 and CZ-8 were Paenibacillus dendritiformis, CZ-9 was Paenibacillus cookii, CZ-10, CZ-13 and CZ-15 were Bacillus velezensis, and CZ-3 was Saccharomyces cerevisiae, P5-5 was Pichia manshurica. All 9 strains had good salt tolerance and could grow at pH 2.0-11.0, and 7 strains had salt tolerance up to 120 g/L. Experiments showed that when using caproic acid as the substrate, the esterifying enzyme activities of strains CZ-1, CZ-3, CZ-5, CZ-8, CZ-9, CZ-13, CZ-15 and P5-5 were 69.93, 70.62, 6.01, 67.65, 35.31, 48.51, 69.24 and 71.45 U/mL respectively, and strain CZ-10 had no esterifying enzyme activity. Gas chromatography-mass spectrometer analysis showed that 12 kinds of volatile components of alcohols, 7 kinds of volatile components of aldehydes, 1 kind of volatile component of ethers, 3 kinds of volatile components of amines, 11 kinds of volatile components of ketones, 9 kinds of volatile components of esters, 3 kinds of volatile components of acids and 22 kinds of other volatile components were detected in the fermentation broth. Conclusion The 9 esterifying enzyme-producing strains are screened from yellow water, all of which have good salt and alkali tolerance and esterifying enzyme activity. P5-5 has the highest esterifying enzyme activity and the most types of volatile components, which provides a theoretical basis for the subsequent treatment and application of yellow water.

Objective To establish a method to simultaneously determine the content of 5 kinds of components of Lonicera japonica Thunb. herbs from Sandao real estate area (neochlorogenic acid, chlorogenic acid, isochlorogenic acid A, isochlorogenic acid B and isochlorogenic acid C) by quantitative analysis of multi-components by single marker. Methods Phenomenex Synergi Hydro-RP80A (250 mm×4.6 mm, 4 μm) column was used with acetonitrile (A)-0.1% phosphoric acid aqueous solution (B) as mobile phase, the detection wavelength was 327 nm, the column temperature was 20 ℃, and the flow rate was 0.7 mL/min. The injection volume was 2 µL. Results The linear ranges of neochlorogenic acid, chlorogenic acid, isochlorogenic acid B, isochlorogenic acid A and isochlorogenic acid C were 0.41-16.40, 7.22-289.00, 0.21-8.50, 1.65-66.00 and 0.37-14.80 μg/mL (r≥0.9993), respectively. The average recovery rate was 95.25%-100.42%, and the relative standard deviation (RSD) of precision, repeatability and stability were less than 2.0%. The content of neochlorogenic acid, chlorogenic acid, isochlorogenic acid A, isochlorogenic acid B and isochlorogenic acid C in 25 batches of samples was determined by external standard method, and there was no significant difference between the measured values and the calculated values of quantitative analysis of multi-components by single marker method. Conclusion This method is accurate, reliable and simple for the simultaneous determination of the content of 5 kinds of compounds in Lonicera japonica Thunb., which solves the bottleneck problem of lack of reference substances in the quality control of Lonicera japonica Thunb.. The content of caffeoylquinic acid in Lonicera japonica Thunb. from different origins varies greatly, and it is necessary to further strengthen the processing of Lonicera japonica Thunb.. This study provides an important basis for the identification, quality evaluation and formulation of quality standards of Lonicera japonica Thunb..

Objective To prepare edible gelatin-corn starch bio-based composite film loaded with lactive Lactiplantibacillus plantarum CXG9, and endow the film with antibacterial activity and excellent film properties. Methods Using gelatin and corn starch mixed film as substrate, the bacterial mud obtained by Lactiplantibacillus plantarum CXG9 centrifugation was mixed into gelatin-corn starch mixture, and the living bacteria edible composite film was prepared by solution casting method. By measuring the characterization of the film and its antibacterial activity in vitro, the effects of Lactiplantibacillus plantarum CXG9 on the properties of gelatin-corn starch film were studied. Results The elongation at break of the gelatin-corn starch composite film loaded with Lactiplantibacillus plantarum CXG9 increased by 35.51%, the moisture content decreased by 2.55%, and the water vapor permeability also decreased by 11.2%. This indicated that the ultraviolet barrier ability, water vapor permeability, elongation at break, and thermal stability of the film loaded with Lactiplantibacillus plantarum CXG9 had all been improved. On the other hand, the addition of live bacteria gave the film antibacterial properties, and it had different degrees of inhibition on Listeria monocytogenes, Shigella, Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and Pseudomonas aeruginosa. Conclusion In this study, gelatin-CXG9-corn starch antibacterial film loaded with Lactiplantibacillus plantarum CXG9 is successfully prepared by using gelatin-corn starch as substrate, which reduces the burden of traditional packaging materials on the environment and opens up a new way for the development of food packaging field.

Objective To establish a rapid detection method of viable Pediococcus pentosaceus in rose jam based on the combination of propidium monoazide (PMA) and quantitative real-time polymerase chain reaction (qPCR). Methods Primers specific for Pediococcus pentosaceus were designed according to the species-specific murI gene. The optimal PMA treatment conditions were determined by optimizing the PMA concentration, dark incubation time, and exposure time. Different ratios of Pediococcus pentosaceus dead/live bacterial mixtures were validated by the PMA-qPCR method to assess the sensitivity and limit of detection of the technique. Results The designed primers exhibited high specificity, and the optimal PMA treatment conditions were determined as 80 µg/mL PMA, 15 min of dark incubation, and 25 min of exposure. Under this condition, a standard curve with correlation coefficient (r²) of 0.9983 was constructed, and the lowest limit of detection was determined to be 3.98×10³ CFU/g. Conclusion The PMA-qPCR method established in this study enables the rapid and accurate quantification of viable Pediococcus pentosaceus in rose jam with high sensitivity, providing technical support for the quantitative detection of microorganisms in complex food matrices.