Objective To investigate the difference of hydrogen isotope ratio between whole grains and cereals flour and their components and the influence of drying conditions and moisture on the determination of hydrogen isotope ratio in grains and cereals. Methods High temperature cracking/elemental analysis-stable isotope ratio mass spectrometry (TC/EA-IRMS) was used to determine the δ²H values of whole grains and cereals flour (maize, rice, wheat and sorghum) and the fractions (starch, defatted portion, fat, crude fiber and protein). The effects of different drying conditions on the δ²H values of grain were analyzed, and the influence of exchangeable hydrogen on the determination of starch hydrogen isotope ratios was explored. Results The δ²H values of various fractions in the grains and cereals were different. Drying the grain samples at 105 °C to a constant weight was the best water removal effect. After being treated with different standard water samples under the optimal drying conditions, the maximum difference in δ²H of grains and starch was 12.11‰ and 18.41‰. This indicates that exchangeable hydrogen had a significant effect on the δ²H value of starch (P<0.001). Conclusion The isotopic fractionation of sugar, fat, protein and cellulose during the growth of grain makes the distribution of hydrogen isotopes in samples not uniform. Organic compounds contain exchangeable hydrogen, which will exchange isotopes with the water in the environment where the sample is located, affecting the accurate analysis. When measuring the hydrogen isotope ratio in grain, it is necessary to exclude the interference of water. This study provides an effective reference for the determination of hydrogen isotope ratios in grain starch and the study of grain traceability in the future.

Owing to the high protein content, low fat levels, and rich amino acid profile of Bos grunniens meat, market demand has been steadily increasing. Due tohigh breeding costs, low production yields, and widespread adulteration practices have hindered the industrial development of Bos grunniens meat. Analysis technologies have played a crucial role in ensuring the safety of the supply of Bos grunniens meat products. This paper reviewed the analytical techniques applied to Bos grunniens meat assessment over the past 20 years, namely chromatography, mass spectrometry (MS), biological and spectroscopic techniques. In particular, chromatography, MS and their coupled techniques had proven effective in characterizing the composition and structure of Bos grunniens meat. Biological techniques, notably polymerase chain reaction (PCR) technology, DNA sequencing (DNA-seq), and related methods, were applicable to species identification and genetic analysis. Furthermore, immunoassay (IA) demonstrate high sensitivity in monitoring veterinary drug residues, whileloop-mediated isothermal amplification (LAMP) could be employed for adulterant detection. Spectroscopic techniques exhibited outstanding performance in compositional analysis, freshness evaluation and geographical origin tracing. The integration of chemometrics with spectroscopic techniques showed great promise forrapid analysis and accurate identification of Bos grunniens meat components, driving the evolution of Bos grunniens analysis toward eco-friendly, non-invasive and automated paradigms. It provides comprehensive technical references and theoretical support for quality improvement, market supervision, scientific research, and the sustainable development of the Bos grunniens industry.

Objective To establish a method for the simultaneous determination of quinolones antibiotics (enrofloxacin, ciprofloxacin, norfloxacin, pefloxacin, ofloxacin, lomefloxacin) and doxycycline residues in prepared dishes by high performance liquid chromatography tandem mass spectrometry. Methods The 84% acetonitrile aqueous solution (1% ice acetic acid) was used as extraction solution, Oasis Prime-HLB solid phase extraction column was used to purify and concentrate, all the eluents were collected, nitrogen-blown to nearly dry, and 1 mL of complex solution 10% methanol aqueous solution (containing 1% ice acetic acid) was added to vortex dissolve, and 0.22 μm microporous filter membrane was taken as supernatant. The Waters ACQUITY UPLC TM BEH C₁₈ column (100 mm×2.1 mm, 1.7 μm) was separated, methanol and 0.1% formic acid aqueous solution were used as mobile phase, ionization mode was spray positive ion mode, and the analysis was performed by high performance liquid chromatography tandem mass spectrometry using multiple reaction detection mode. Results The linear correlation of the 7 kinds of antibiotics was good (r>0.9990). The limits of detection were 0.03-0.24 μg/kg and the limits of quantitatation were 0.09-0.72 μg/kg. The recoveries were 84.5%-114.0% and the relative standard deviations were 1.1%-4.1%. Conclusion The method established in this study is convenient, rapid, accurate and stable, and can be used for quantitative analysis of 6 kinds of quinolone veterinary drug residues and doxycycline residues in prepared dishes.

Objective To achieve the geographical discrimination of Fuping goat milk using microwave digestion combined with inductively coupled plasma mass spectrometry (ICP-MS) and chemometric methods. Methods A total of 70 goat milk samples were collected from 7 regions in Shaanxi Province, including Baoji, Hanzhong, Jingyang County and Qian County (both in Xianyang), Weinan, Xi’an and Yan’an. They were lyophilized to milk powder, and after microwave digestion, the digested solution was analyzed using ICP-MS. Principal component analysis (PCA) and orthogonal partial least squares-discrimination analysis (OPLS-DA) were employed to discriminate goat milk from different origins. Results A total of 42 kinds of elements in the milk powder from 7 different origins were detected. The concentrations of K, Ca, Fe, Zn, Si and Na were relatively high, followed by B, Ti, Mg, Al, Cu and Ba, while other elements were found in lower concentrations, particularly the rare earth elements such as Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er, Tm, Yb, Lu, Ho and Y, which were present in negligible amounts. The 7 origins were divided into two groups based on distance: Group I (Baoji; Hanzhong; Weinan; Yan’an) and Group II (Jingyang County, Qian County of Xianyang; Weinan; Xi’an). OPLS-DA model was applied to both groups, with accuracy rates of 95.12% and 87.80%, respectively. Among them, the accuracy of samples from Fuping County-Weinan City was 100%. In Group I, the content differences of Ba, Mn, Si, Zn, Se, Na and B were the primary factors for origin discrimination. While in Group II, Se, B and Ni elements contributed significantly to the origin discrimination. Geographical distance was the most important factor to distinguish goat milk from different origins. While the data of 6 goat milk samples from Fuping County-Weinan City were imported into both Group I and Group II models for validation, the discrimination accuracy was 100% for both groups. Conclusion The established multi-element analysis combined with chemometrics could achieve rapid and accurate identification of Fuping goat milk from small-scale regions (>50 km).

Objective To establish and optimize conditions for the determination of octachlorostyrene residues in milk by high performance liquid chromatography (HPLC) method. Methods Milk samples were extracted with acetonitrile and cleared up by sodium chloride and anhydrous magnesium sulfate, filtered through a microporous membrane, and analyzed by the high performance liquid chromatography. The separation was performed on a Waters C₁₈ column (250 mm×4.6 mm, 5 μm) with gradient elution by using 0.3% trifluoroacetic acid solution (pH=3.2) and acetonitrile (20:80, V:V) as the mobile phase, and quantified by external standard method. Results The results indicated that the correlations were greater than 0.999 at the range of 0.1 to 2.0 ng/mL. The limit of detection of octachlorostyrene was 0.05 μg/kg, and the limit of quantitation was 0.1 μg/kg. The average recoveries of octachlorostyrene ranged from 70% to 90% at spiled levels of 0.1 to 0.4 μg/kg with relative standard deviation less then 10%. Conclusion The experiment show that the method is simple, rapid, high sensitivity, good reproducibility and suitable for detection of octachlorostyrene residues in milk. The method provide effective technical support to the government’s food and agricultural product quality supervision work.

In recent years, microcapsule technology has shown broad application prospects in food science and biomedicine due to its protection and controlled release characteristics of active ingredients. Among a variety of wall materials, whey protein has become a promising candidate due to its natural non-toxicity, biocompatibility and biodegradability. This paper first provided an overview of the putamen structure of whey protein-based microcapsules. Secondly, this paper mainly discussed the modification methods of whey protein wall materials: Building composite wall materials with other biological macromolecules; structural modification by physical or chemical methods, as well as improvement of interface properties by Maillard reaction. This paper analyzed the technical characteristics of spray drying, freeze drying and complex coacervation methods and their effects on the properties of whey protein-based microcapsules. The results showed that the embedding rate and stability of microcapsules could be significantly improved by precisely regulating the process parameters. Finally, in the field of application, whey protein-based microcapsules could not only effectively protect the activity of probiotics and achieve targeted delivery of active substances, but also showed application potential in biomedical fields such as controlled drug delivery systems and wound dressings.

Aflatoxins are of difuran cyclotoxins produced by Aspergillus flavus and Aspergillus parasiticus, and own good chemical stability, thermal stability, strong hepatotoxicity, carcinogenicity, teratogenicity and other toxicity to human body. Due to the low content of aflatoxins in food and the complex food matrix, these food samples contain a large number of carbohydrates, fats, proteins, food additives, etc., which have great interference to the accurate qualitative and quantitative detection of aflatoxins. Therefore, it is of great significance to explore new sample pretreatment techniques and establish rapid and practical detection methods for aflatoxins. This paper reviewed the application of aflatoxin pretreatment techniques (liquid phase extraction, solid phase extraction, ultrasonic microwave assisted extraction, immunoaffinity chromatography) and detection methods(thin-layer analysis, high performance liquid chromatography-mass spectrometry, enzyme-linked immunosorbent assay, immunochromatography, nucleic acid aptamer sensing) in the analysis of aflatoxins in food, prospected the development trends towards online combination, the integration of new technologies with traditional equipment, ease of operation, and low cost, providing reliable support for the development of mycotoxin detection.

Objective To identify flavor compounds in Douzhir and Ma Tofu and analyze their characteristic components based on purge and trap-gas chromatography/mass spectrometry (PT-GC/MS) combined with the national institute of standards and technology (NIST) database. Methods Weigh 2.0 g of sample into a 40 mL brown spiral sample bottle, add 10 mL of experimental water and a tetrafluoroethylene magnetic stirrer, heat the sample at 40 ℃, and analyze it by PT-GC/MS. Results A total of 260 kinds of flavor compounds were identified across 34 batches, including sulfur-containing compounds, alcohols, aldehydes, ketones, esters, etc. Raw and cooked Douzhir exhibited significantly higher relative abundances of sulfur-containing compounds compared to Ma Tofu, which showed greater diversity but lower similarity in flavor profiles. These identification data could to some extent reflect sensory evaluation results, but there was a possibility that some flavor compounds might be more prominent or interfered with by other odors. In addition, this study used principal component analysis (PCA) method to identify the overall distribution of samples and deviations from samples, and attempted to analyze the reasons for deviations. Further, using orthogonal partial least squares discriminant analysis (OPLS-DA), based on the screening conditions [P<0.05, variable importance in the projection (VIP)>1], 31 kinds of characteristic flavor compounds of raw and cooked Douzhir were selected, which could be used for the differentiation and identification of raw and cooked Douzhir. Conclusion The study confirms that PT-GC/MS combined with multivariate statistical method can effectively analyze the flavor compounds of Douzhir and Ma Tofu, screen the characteristic compounds, and provide a basis for the subsequent optimization and improvement of product flavor.

Objective To optimize the ultrasonic-assisted extraction process of proanthocyanidins from Polygonum aviculare by response surface method, to obtain the best extraction conditions. Methods The main factors affecting the extraction amount were investigated through single-factor experiments. Based on the results of the single-factor experiments, the Box-Behnken design and response surface methodology were used to optimize the single factors, including the volume fraction of ethanol, ultrasonic time, and solid-liquid ratio, which had an impact on the extraction amount of proanthocyanidins from Polygonum aviculare. The optimal extraction process conditions were obtained. Results The optimized results of the optimal process conditions for ultrasonic-assisted extraction of proanthocyanidins from Polygonum aviculare were as follows: The ultrasonic time was 34 min, the volume fraction of ethanol was 65%, and the solid-liquid ratio was 1:46 (g:mL). Under these process conditions, the final extraction amount of proanthocyanidins reached 2.18%, which was consistent with the model validation value of 2.12%. Conclusion This study shows that the process condition parameters optimized by the response surface methodology are effective and feasible. The response surface methodology is successfully applied to optimize the extraction parameters of ultrasonic-assisted extraction of proanthocyanidins from Polygonum aviculare, providing a research basis for the later promotion and application of proanthocyanidins from Polygonum aviculare.

Objective To optimize the fermentation process of pear residue soluble dietary fiber (PSDF) modified by Aspergillus niger and study its characteristics. Methods Using single factor experiments to optimize the inoculation amount, fermentation temperature, and fermentation time of Aspergillus niger, and determine the optimal fermentation process; determine the characteristics of the modified PSDF: The water holding capacity (WHC), oil holding capacity (OBC), fructose, glucose, arabinose, xylose and xylose content, 1,1-diphenyl-2- picrylhydrazyl radical (DPPH) free radical scavenging ability, 2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) cationic radical scavenging ability, glucose adsorption capacity (GAC) and cholesterol adsorption capacity (CAC).Results By optimizing the fermentation process, the optimal inoculation amount, fermentation temperature, and fermentation time of Aspergillus niger were determined to be 8%, 36 ℃ and 7 d. Based on the optimal fermentation process, the characteristic analysis of PSDF was conducted: WHC was 15.89 g/g, and OBC was 4.02 g/g; the content of glucose and arabinose increases, while the content of fructose, xylose and xylose decreases; the DPPH radical scavenging ability and ABTS cationic radical scavenging ability were significantly improved; GAC increased to 0.77 mg/g, and CAC increased to 0.56 mg/g. Conclusion Modifying PSDF with suitable fermentation processes can help improve yield. The use of Aspergillus niger modified pear pomace dietary fiber effectively improve its physiological activity and health function.