Objective To establish a method for the determination of biotin in formula food for special medical purposes by high performance liquid chromatography-post column derivatization. Methods The biotin in the sample was dissolved in water and extracted by enzymatic hydrolysis with amylase and papain at 60 ℃ for 1 hour in a water bath. Using Zorbax SB-AQ chromatographic column separation and entering the post column reaction device, the biotin was derived from fluorescein isothiocyanate labeled avidin. Derivatives were detected using a fluorescence detector with an excitation wavelength of 495 nm and an emission wavelength of 525 nm. The results were quantified by the external standard method. Results Under the optimized conditions, the biotin showed good (r²>0.999) linear relationships within the concentration range of 5.00‒75.00 ng/mL. The average recoveries were 97.5%‒100.1%, and the relative standard deviations were 0.86%‒2.9%. The limit of detection was 12 μg/kg, and the limit of quantification was 41 μg/kg. The relative standard deviations of the biotin standard solution and the sample solution to be tested within 24 h were 0.68% and 1.08%, respectively. There was no significant difference between the results of this method and GB 5009.256—2016 National food safety standard-Determination of biotin in food. Conclusion This method has simple pretreatment, high recovery, good sensitivity and precision, and can be used for the determination of biotin content in formula food for special medical purposes.

Mercury is a global environmental pollutant that poses potential threats to ecosystems and human health. Among the various chemical forms of mercury, methylmercury is of particularly concern due to its neurotoxicity and carcinogenicity. The consumption of aquatic products is a significant source of human exposure to mercury. To ensure food safety, stringent regulations have been established by different countries and regions, specifying the maximum allowable levels of mercury species such as total mercury and methylmercury in aquatic products, as well as the corresponding detection methods. This paper provided a comprehensive summary of the current international regulations on the maximum allowable levels of total mercury and methylmercury in aquatic products, and compared the standard detection methods for methylmercury in different countries. Through comparative analysis, investigated the characteristics of various extraction methods, including acidic, organic reagent, and distillation methods in depth. Additionally, this paper evaluated the advantages and disadvantages of common separation techniques, such as liquid and gas chromatography, summarized the performance of various detection methods, including liquid chromatography-atomic fluorescence spectrometry (LC-AFS), liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS). These analyses not only revealed the limitations of existing detection methods but also provided a scientific basis and reference for the development and standardization of future methylmercury analytical techniques. This article further outlined the future direction of methylmercury determination in seafood, with the goal of enhancing the precision, accuracy, and sensitivity of detection methods to better support food safety.

Objective To establish a method for the determination of 25 kinds of illegal additives in candy by dispersive solid phase microextraction extraction coupled with ultra performance liquid chromatography-tandem mass spectrometry. Methods The samples were extracted with 50% methanol water, purified by dispersive solid phase microextraction extraction and separated by ACQUITY UPLC TSS T3 column. The samples were then eluted with ammonium formate aqueous solution and ammonium acetonitrile as mobile phase by gradient elution. The samples were determined by ultra performance liquid chromatography-tandem mass spectrometry and quantified by external standard method. Results The results showed that the 25 kinds of illegal additives had good linearity in the range of 2.00 to 50.00 µg/L with a correlation coefficient (r²) greater than 0.99, recoveries were between 65.1% and 99.3%, relative standard deviations were 1.1% to 5.0%, and limit of detection was 0.05 mg/kg and limit of quantification was 0.10 mg/kg. The method was applied to the detection of 105 batches of samples, in which one batch of compressed candy was found to contain xinlisita, and two batches of candy were found to contain dipropylphenidate. Conclusion The method is purified by dispersive solid phase microextraction extraction and detected by ultra performance liquid chromatography-tandem mass spectrometry. The method has good accuracy and high sensitivity, and can meet the detection requirements of 25 kinds of illegal additives in candy.

Objective To study the Morchella eohespera mycelium extracellular polysaccharides (MEP), purify MEP-H and MEP-N by DEAE Sepharose Fast Flow column chromatography, and analyze their physicochemical properties, hypoglycemic activities, and antioxidant activities in vitro. Methods The physicochemical properties of MEP-H and MEP-N were studied by carbohydrate content determination, analysis of ultraviolet scanning, Fourier transform infrared spectroscopy analysis, and scanning electron microscopy. The hypoglycemic activities and antioxidant activities of MEP-H and MEP-N were evaluated by α-amylase inhibition rate, α-glucosidase inhibition rate, 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging ability, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) ammonium salt (ABTS) cationic free radical scavenging ability, reducing power and superoxide anion scavenging ability. Results The carbohydrate content of MEP-H and MEP-N was (78.12±0.14)% and (77.37±0.03)%, respectively. Hypoglycemic studies showed that at a mass concentration of 0.75 mg/mL, MEP-H and MEP-N had the highest α-amylase inhibition rates, which were (8.06±1.93)% and (11.08±1.05)%, respectively; at a mass concentration of 0.50 mg/mL, MEP-H and MEP-N had the highest α-glucosidase inhibition rates, which were (74.93±2.72)% and (69.48±2.97)%, respectively. Antioxidant studies showed that MEP-H and MEP-N achieved the best DPPH free radical scavenging activity at mass concentrations of 4 mg/mL and 2 mg/mL, with scavenging rates of (47.54±10.88)% and (47.16±6.91)%, respectively; at a mass concentration of 8 mg/mL, the maximum ABTS cationic free radical scavenging rates of MEP-H and MEP-N were (8.67±0.53)% and (17.00±4.21)%, respectively, the maximum reducing power absorbance values were 0.13±0.004 and 0.17±0.008 respectively, and the maximum superoxide anion scavenging rates were (40.95±6.02)% and (29.87±3.18)%, respectively. Conclusion Both MEP-H and MEP-N, the extracellular polysaccharides from the mycelium of Morchella eohespera, exhibit hypoglycemic and antioxidant activities. This study provides a theoretical basis for further research on liquid fermentation of Morchella eohespera.

Objective To explore the dose effects and molecular mechanism of B-type proanthocyanidins trimer, the main active component of Litchi chinensis Sonn pulp phenolics, on hepatocyte triglyceride (TG) deposition. Methods HepG2 cell steatosis model induced by oleic acid (OA) was treated with different mass concentrations (0.5-10.0 μg/mL) of B-type proanthocyanidins trimer. The content of TG and the expressions of genes related to lipid absorption, transport and oxidation, together with apoptosis of hepatocytes, were detected in oleic acid loaded hepatocytes. Results B-type proanthocyanidins trimer (0.5-10.0 μg/mL) all significantly inhibited TG accumulation in oleic acid-loaded hepatocytes, while no dose dependence was observed. Low-dose (1.0 μg/mL) B-type proanthocyanidins trimer inhibited hepatocyte apoptosis by increasing the relative expression ratio of Bcl-2 to Bax, thereby reducing TG accumulation in hepatocytes. In addition to the above-mentioned pathway, medium/high-dose (5.0 μg/mL, 10.0 μg/mL) B-type proanthocyanidins trimer also inhibited lipid absorption in hepatocytes by down-regulating CD36 and FATP2 expression, and promoted hepatocytes lipolysis by up-regulating ACSL1 and CPT1α expression, hence reducing TG accumulation in hepatocytes. Conclusion B-type proanthocyanidins trimer of Litchi chinensis Sonn pulp can inhibit lipid absorption, promote β-oxidation of fatty acids and inhibit excessive apoptosis of liver tissue cells, thereby improving lipid metabolism and preventing fatty liver.

Objective To establish a method for simultaneous determination the content of 4 kinds of human milk oligosaccharides [2'--fucosyllactose (2'-FL), 3'-sialic acid (3'-SL), 6'-sialic acid (6'-SL) and lactose-N-neotetraose (LNnT)] in milk powder by liquid chromatography-fluorescence method. Methods The samples were dissolved in water, enzymolized with amyloglucosidase or β-galactosidase, derived with 2-aminobenzamide (2-AB) and 2-methylpyridine borane (2-PB), and separated by amide bonding column, detected by fluorescence detector, and quantitated by internal standard methods. Results The 4 kinds of milk oligosaccharides had a good linear relationship in the concentration range of 10-600 μg/mL, and the correlation coefficients (r²) were more than 0.999. The limits of detection and quantification of 4 kinds of milk oligosaccharides were 0.94-2.31 mg/100 g and 3.12-7.69 mg/100 g, respectively; the recovery rates of 4 kinds of milk oligosaccharides were 97.7%-101.5%, and the relative standard deviations (RSD) (n=7) were 0.53%-3.09%. Conclusion This method does not have high requirements for people, equipments and environment for determining the content of 4 kinds of milk oligosaccharides in milk powder. The pre-treatment operation is simple, and it has good accuracy and precision. It can provide a reference for the quality control method of human milk oligosaccharides in milk powder.

At present, the demand for acaricides in agricultural production in China ranks second only to insecticides. As an important chemical pollutant affecting the safety of agricultural products, acaricides, represented by heterocyclic compounds, have relatively stable structures, long half lives, are not easily degraded, and are more likely to remain on the surface or inside of food, causing serious food safety problems. The development of economically effective detection methods for heterocyclic acaricides has become a current research trend, which is of great significance for ensuring the safety of public vegetable baskets, promoting green ecological agriculture, and advancing high-quality agricultural development. Immunoassay methods are widely used in the field of pesticide residue detection due to their fast, simple, efficient, and sensitive characteristics. This paper reviewed the research progress of immunological analysis methods for heterocyclic acaricides pesticides from the aspects of synthesis of haptens, preparation of antibodies, and their detection applications in agricultural product matrices, analyzed the challenges and future development prospects of immunoassay methods, which have certain reference value for the detection of heterocyclic acaricides residues.

Objective To optimize the decolorization process of Cistanche deserticola polysaccharides and explore their antioxidant activity. Methods Using activated carbon as a decolorizing agent, the effects of 4 factors including activated carbon dosage, decolorization temperature, decolorization time, and pH on decolorization rate and polysaccharide recovery rate were investigated. Based on single factor experiments, the decolorization process of Cistanche deserticola polysaccharide extract was optimized using response surface methodology. Using an in vitro antioxidant activity evaluation method, the free radical scavenging ability of 1,1-diphenyl-2-picrylhydrazine (DPPH), total reducing ability, hydroxyl radical scavenging ability, and 2,2'-azino bis(3-ethylbenzothiazole- 6-sulfonic acid) diammonium salt (ABTS) cation free radical scavenging ability of the polysaccharides from Cistanche deserticola were determined. Results The optimal decolorization process conditions for the extract of polysaccharides from Cistanche deserticola were as follows: Active carbon dosage 20%, decolorization temperature 37 ℃, decolorization time 49 min, pH 5.03. Under these optimal conditions, the decoloizration rate and polysaccharide recovery rate were 62.66% and 96.16%, respectively. After decolorization, the capabilities of scavenging DPPH radical and hydroxyl free radical was significantly increased, while the capabilities of scavenging ABTS anion radical was significantly decreased. Conclusion The decolorization process is easy to operate, with good decolorization effects and polysaccharide recovery rate. It has important application value and provides basis for the later research and development of Cistanche deserticola polysaccharide.

Objective To prepare colloidal gold immunochromatographic test strips for the rapid detection of acetamiprid residues in vegetables. Methods The immunogen was obtained through hapten synthesis, and a highly sensitive and specific monoclonal antibody against acetamiprid was developed using animal immunization and hybridoma technology. Based on this antibody, parameters such as membrane-coating conditions were optimized to prepare immunocolloidal gold test strips. These test strips, combined with colorimetric analysis, were applied for the quantitative detection of acetamiprid residues in various vegetables. Results Under optimal working conditions, the established method achieved a limit of detection of 0.23 μg/kg for acetamiprid, with a linear range of 0.42-18.38 μg/kg. The recovery rates for actual sample detection ranged from 70.0% to 88.3%, and the coefficients of variation (CV) for intra-batch and inter-batch experiments were below 12.00% and 11.03%, respectively. Conclusion The rapid test strips can be directly applied for high-throughput on-site screening of acetamiprid residues in vegetables. Additionally, with the assistance of a colorimetric analyzer, quantitative acetamiprid detection can also be achieved.

Objective To establish a method for the simultaneous determination of functional components in extracts from 7 kinds of medicinal and food homologous substances: Pueraria lobata, Sophora japonica, Lonicera japonica, Cistanche deserticola, Siraitia grosvenorii, Panax ginseng and Hovenia dulcis by high performance liquid chromatography (HPLC). Methods The analysis was conducted using an Agilent Eclipse XDB-C₁₈ column (4.6 mm× 250 mm, 5 μm) with a mobile phase gradient elution of acetonitrile-0.1% phosphoric acid at a flow rate of 0.6 mL/min, a column temperature of 30 ℃, a detection wavelength of 210 nm, and an injection volume of 5 μL. This method was employed to quantify the content of puerarin, rutin, chlorogenic acid, echinacoside, verbascoside, mogroside V, ginsenoside Re and dihydromyricetin. Results The results demonstrated that 8 kinds of functional components exhibited excellent linear relationships within their respective concentration ranges, with correlation coefficients (r²) exceeding 0.999. The limits of detection ranged from 0.02 to 1.88 mg/L, and the limits of quantification ranged from 0.08 to 3.62 mg/L. The precision experiment results showed that the relative standard deviation (RSD) was less than 3%, the average recoveries of spiked samples ranged from 95.49% to 109.87%. Conclusion This method is simple, rapid and highly accurate, making it suitable for the qualitative and quantitative analysis of the functional components in the aforementioned 7 kinds of medicinal and food homologous substances.