Objective To analyze Cyperus esculentus by near infrared spectroscopy, and trace geographical origin of Cyperus esculentus by the identification model in chemometrics. Methods A total of 408 samples of Cyperus esculentus samples from Hebei, Hunan, Shandong, Xinjiang, and Yunnan were analyzed for provenance tracing using near-infrared spectroscopy and chemometric software, 3 kinds of spectral preprocessing methods including multiplicative scatter correction, standard normal variate transformation and standard normal variate transformation & detrending, were used respectively, and 5 kinds of recognition modes such as support vector machine (SVM), soft independent modeling of class analogy (SIMCA), orthogonal partial least squares discriminant analysis (OPLS-DA), partial least squares discriminant analysis (PLS-DA), and K-nearest neighbor algorithm (KNN) were used to identify the geographical origin. Results The modeling recognition rates of the 5 kinds of modes including SVM, SIMCA, OPLS-DA, PLS-DA, and KNN were 91.89%, 94.47%, 62.37%, 65.32%, and 100.00% respectively. The KNN was selected as the origin identification model, and the impact of different preprocessing methods, data preprocessing and sample distance on the stability of the model prediction results were analyzed in order to select the optimal model parameters. The prediction set recognition rate could reach 100.00% by using multiplicative scatter correction spectral preprocessing method, one of data preprocessing methods including UV, Pareto, automatic, or centering, and block distance as the sample distance. Conclusion The technology of near infrared spectroscopy combined with KNN mode has the advantages of fast analysis speed, simple operation, easy sample pretreatment, non-destructive, on-line qualitative and quantitative analysis, etc., and has a certain application prospect.

Objective To establish a rapid colloidal gold card method for the determination of fumonisin and T-2/HT-2 toxin in Triticum aestivum L. and Zea mays. Methods The limit of detection, limit of quantitative, precision and accuracy of the method were evaluated in 6 laboratories. Results The limits of detection of fumonisin and T-2/HT-2 toxin methods were 150 μg/kg and 5 μg/kg, respectively. The limits of quantitation were 450 μg/kg and 11 μg/kg, respectively. When the fumonin content in Triticum aestivum L. and corn ranged from 426.39 to 3897.22 μg/kg, the relationship between the method repeatability standard deviation S_r and reproducibility standard deviation S_R and fumonin content was obtained, namely, repeatability standard deviation S_r=1.478m^0.600 and reproducibility standard deviation S_R=4.269m^0.591. When the T-2/HT-2 toxin content in Triticum aestivum L. and Zea mays ranged from 426.39 to 3897.22 μg/kg, the relation between repeatability standard deviation S_r and reproducibility standard deviation S_R and T-2/HT-2 toxin content m was as follows: Repeatability standard deviation S_r=3.1901m^0.218, reproducibility standard deviation S_R=0.2507m^0.492 (Triticum aestivum L. matrix). Repeatability standard deviation S_r=0.8357m^0.333, reproducibility standard deviation S_R=1.1231m^0.585 (Zea mays matrix). The recoveries of fumonisin and T-2/HT-2 toxin ranged from 95.42% to 101.90% and 83.30% to 118.20% respectively. There was no significant difference between the paired t test and the standard method. Conclusion The method has good accuracy and can be widely used for rapid and quantitative determination of fumonisin and T-2/HT-2 toxin in Triticum aestivum L. and Zea mays.

Objective To explore the optimal conditions of different deodorization treatment methods and compare the main flavor components of oyster raw materials, oyster enzymatic hydrolysates and the products obtained through different deodorization methods. Methods Taking the Crassostrea hongkongensis enzymatic hydrolysate as the research object, the changes in flavor after deodorization of the samples were investigated by means of single-factor experiments, sensory analysis and physicochemical analysis in combination. Results The optimal conditions for activated carbon deodorization were reaction time 50 min, reaction temperature 50 °C, and the amount of activated carbon addition was 1.0%. The optimal conditions for yeast deodorization were a fermentation temperature of 40 °C and a fermentation time of 60 min, and the yeast addition amount was 1.0%. Compared with oyster raw materials, the total free amino acid content in the enzymatic hydrolysate increased, both bitter and sweet amino acids increased, while the umami amino acids decreased slightly. Compared with the enzymatic hydrolysate, the sweet amino acids of the product treated with combined deodorization increased slightly, while the bitter and umami amino acids decreased slightly. The relative content of alcohols and acids increased by 21.50%. The relative content of ketones decreased by 8.49%, and the clam flavor and oil flavor decreased. Conclusion The combined deodorization of activated carbon and yeast effectively improves the flavor of Crassostrea hongkongensis enzymatic hydrolysate, providing valuable preliminary data for the development of oyster condiments.

Objective To investigate the effects of different brewing conditions on the antioxidant activities and effective components of Taraxacum mongolicum tea soup. Methods The method used a controlled univariate design to study the extraction content of total flavonoids, total polyphenols, total polysaccharides, and total amino acids in dandelion tea under different brewing times, temperatures, tea water ratios, and water quality conditions by ultraviolet-visible spectrophotometry. The antioxidant activities of dandelion tea soup were explored using 2,2-diazine-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) cationic radical, 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical and nitroso scavenging rate, and ferric ion reducing antioxidant power (FRAP) as indicators. The relationships between its antioxidant activities and the content of total flavonoids, total polyphenols, total polysaccharides, and total amino acids in the dandelion tea soup were analyzed. Results When the brewing time was 5 min, the nitroso scavenging activity was the best, expressed as the equivalent concentration of vitamin C (VC) per gram of sample was 0.3938 mg VC/g, which was significantly correlated with the contents of total polyphenols, theanines, and glutamic acids, with correlation coefficients of 0.597, 0.598 and 0.616, respectively; When the brewing temperature was 94 ℃, the iron ion reduction capacity was the strongest, at 0.1784 mg VC/g, significantly correlated with the total polysaccharide content, with a correlation coefficient of 0.529; when the tea water ratio was 1:50 (g:mL), the DPPH radical scavenging activity was the strongest, at 0.2571 mg VC/g, significantly correlated with the contents of total theanines and glutamic acids, with correlation coefficients of 0.483 and 0.497, respectively; when the brewing water was tap water, the ABTS cationic radical scavenging activity was the strongest, at 0.2072 mg VC/g, significantly correlated with the total flavonoids and total polyphenols content, with correlation coefficients of 0.417 and 0.787, respectively. In summary, different brewing conditions affected the antioxidant activities and effective components of dandelion. The antioxidant activities of Taraxacum mongolicum tea were the results of the combined effects of various active compounds, including flavonoids, polyphenols, polysaccharides and amino acids. Conclusion To ensure the optimal antioxidant effects of Taraxacum mongolicum tea, when primarily considering antioxidant activities, it is recommended that the best brewing conditions are: A brewing time of 5 min, a brewing temperature of 94 ℃, a tea-to-water ratio of 1:50 (g:mL), and using tap water for brewing.

Objective To develop a method for the simultaneous determination of lutein, zeaxanthin, α-carotene, and β-carotene in infant formula milk powder and natural foods by online solid phase extraction-liquid chromatography (online SPE-LC). Methods Samples were saponified with 50% potassium hydroxide solution at 70 ℃ for 15 min. Saponified solution was diluted with 70% ethanol, and after high-speed centrifugation, the supernatant was directly analyzed. A styrene-divinylbenzene copolymer-based SelectCore PSS-packed chromatographic column was chosen as the online SPE column, using 80% methanol-water as the initial loading solvent and acetonitrile/methyl tert-butyl ether as the washing solvent. A ChromCore C₃₀ column (4.6 mm×250 mm, 3 μm) was used as the analytical column, with acetonitrile-methanol (26:74, V:V, 0.4 g/L of ascorbic acid) and methyl tert-butyl ether as the mobile phase for gradient elution. The flow rate was 1.0 mL/min, and the detection wavelength was 450 nm. Results The 4 target analytes in infant formula milk powder and natural foods were well separated. Linear correlation coefficients for all target analytes were greater than 0.9999. The limit of quantification of method for lutein, zeaxanthin, α-carotene, and β-carotene were 0.77, 0.72, 0.94, and 1.40 μg/100 g, respectively. Average recovery rates of infant formula milk powder were 99.76%, 103.51%, 99.16%, and 97.92%, respectively. The relative standard deviations of method repeatability for all the analytes were less than 2.5%. Conclusion This method is accurate, reliable, and reproducible and can meet the quantitative requirements of lutein, zeaxanthin, and α-carotene, β-carotene in foodstuffs. It can be applied to the determination of real samples.

Fungi are one of the more common microorganisms in our daily lives, and are closely related to our lives, with both advantages and disadvantages. Its harmful effects are manifested in a number of ways. For example, some fungi can cause crop diseases and reduce yield, accidental consumption of poisonous mushrooms can cause food poisoning and threaten people's lives, in addition, pathogenic fungi can also cause fungal infections and other diseases that are harmful to people's health, so it is very important to be able to quickly and accurately detect pathogenic fungi and identify poisonous mushrooms. Loop-mediated isothermal amplification (LAMP) is a nucleic acid amplification technique widely used in recent years, which uses DNA polymerase and specific primers to amplify nucleic acids with high efficiency in a short period of time under constant temperature conditions, compared with traditional molecular biology methods, this method does not require high instrumentation, and is characterized by rapidity, sensitivity and simplicity. At present, LAMP technology has been widely used in the detection of microorganisms such as bacteria, fungi and viruses, and this paper summarised the application of LAMP technology in the detection of fungi to provide a reference for related research.

Mycotoxins are secondary toxic metabolites produced by fungi during their growth and reproduction. They are widely found in various kinds of grain and oil and their products, and can cause serious threat to human health. Mycotoxin contamination has become a common phenomenon and problem in many countries and regions. Mycotoxin detection is the key link to build a mycotoxin prevention and control system. Furthermore, mycotoxins content is one of the health indicators that must be detected in raw grain and its products. It is of great significance to establish accurate and efficient detection methods for mycotoxins in grain, oil and food to ensure food safety. This paper summarized and analyzed the common detection methods of mycotoxins in grain, oil and food, and mainly introduced the different detection techniques and methods and their application characteristics, such as chromatography analysis, spectral analysis and immunoassay. Futhermore, this paper prospected the development trend and related requirements of mycotoxins detection, so as to provide references for the detection and safety supervision of mycotoxins in grain, oil and food.

Objective To establish a method for simultaneous determination of 13 kinds of illegally added azo industrial dyes (Sudan red I, Sudan red II, Sudan red III, Sudan red IV, Sudan red B, rhodamine B, Sudan red G, Sudan red 7B, para red, Sudan orange G, basic orange 2, basic orange 21, and basic orange 22) in spices using ultra performance liquid chromatography tandem mass spectrometry. Methods After the sample was soaked with water, it was extracted with acidified acetonitrile (containing 1% acetic acid) by ultrasonic extraction, and purified with anhydrous magnesium sulfate and sodium chloride. After concentration, acetonitrile-0.10% formic acid aqueous solution was used as mobile phase, gradient elution, C₁₈ chromatographic column (2.1 mm×150 mm, 1.7 µm) separation, electrospray multi reaction monitoring and positive ion mode determination were used to qualitatively determine 13 kinds of azo industrial dyes in spices, and external standard method was used for quantitative determination. Results The 13 kinds of azo industrial dyes showed good linear relationships within the mass concentration ranges of 0.5-50.0, 1-50, or 4-100 ng/mL, with correlation coefficients (r²) all greater than 0.99; the limits of detection could reach 1.0-10.0 µg/kg, and the limits of quantification could reach 3.0-30.0 µg/kg. The average spiked recovery rates at 1-fold, 2-fold, and 10 fold concentration levels were 75.7% to 102.4%, with relative standard deviations below 10% (n=6). Conclusion This method has the advantages of simple pretreatment, rapid, accurate, and sensitive, and is suitable for rapid screening and quantitative detection of 13 kinds of azo industrial dyes in spices, in order to provide strong technical support for the supervision of illegal addition of azo industrial dyes.

Objective To explore the effects of harvesting periods on nutritional quality, processing properties and antioxidant activities of different parts of Fagopyrum tataricum. Methods The harvesting period was determined based on the first flowering time, and the flavonoid content, protein content, dietary fiber content, water holding capacity, oil holding capacity and antioxidant activity of seeds, stems, flowers and leaves of Fagopyrum tataricum at different harvest periods were determined measured and analyzed. Results The seeds, stems, leaves, and flowers of Fagopyrum tataricum all include the rich nutrients and the biological activity ingredient, with excellent processing properties. The flavonoid content, protein content, dietary fiber content, water and oil holding capacity of Fagopyrum tataricum seeds showed a downward trend, while the dietary fiber content of Fagopyrum tataricum stems and flowers generally showed an upward trend. The flavonoid and protein content of Fagopyrum tataricum stems and leaves decreased. The dietary fiber content of Fagopyrum tataricum leaves, flavonoid content and total antioxidant activity of Fagopyrum tataricum flowers increased first and then decreased. The total antioxidant capacity and flavonoid content of Fagopyrum tataricum flowers were significantly higher than other parts of tartary buckwheat. The highest total antioxidant capacity and flavonoid content were found 14 days after flowering, at 369.42 μmol/g and 7.83%, respectively, which were 6.2 and 8.8 times that of Fagopyrum tataricum seeds. Conclusion As food processing raw materials, different parts of Fagopyrum tataricum have the potential and value for food development and processing, and can be fully utilized. The nutrition and functional components of different parts of Fagopyrum tataricum are directly affected by harvest period, and the reasonable harvest period shall be determined based on the purpose in production.

Objective To investigate the contamination level of Vibrio parahaemolyticus (VP) in the production chain of the Liuzhou river snails rice noodles, promptly assess the risk of VP in the production chain. Methods From 2023 to 2024, a total of 487 simlpes, including snails and snail meat, semi-finished soup packets, and pre-packed Liuzhou river snails rice noodles final products, were randomly collected from Liuzhou agricultural markets and manufacturing enterprises in Liuzhou. A conbination of culture-based methods and real-time fluorescent polymerase chain reaction (PCR) was used to detect VP. Results Among 70 snails samples from agricultural market with a detection rate of 38.6% and an average contamination level of 16.1 MPN/g in 44 snails samples. In the 41 snails and snail meat sample from manufacturing enterprises showing the detection rate of 2.4%; no VP was detected in the semi-finished soup package or final product. Conclusion Although VP contamination is relatively common in snails at the retail trade, the contamination rate of snails and snail meat in the enterprise is low. Furthermore, the repeated boiling in Liuzhou river snails rice noodles production can effectively control VP. Therefore, the risk of VP contamination in the Liuzhou river snails rice noodles production chain is relatively low.