Objective To optimize the protein extraction process of Pectinidae. Methods A combination of composite enzymes and segmented enzymatic hydrolysis was employed, utilizing different protease enzymes with mode of enzyme digestion and cleavage sites. Significant factors were screened by single factor combined with Plackett-Burman and Box-Behnken model was used to optimize the one-stage protein extraction process, and the parameters of the two-stage enzymatic digestion process were optimized by orthogonal tests. Results The optimal extraction conditions for complex enzyme-assisted stepwise hydrolysis in protein extraction were as follows: The optimal extraction process parameters of the one-stage were as follows, solid-liquid ratio was 1:3.9 (m:V), enzyme digestion time was 80.0 min, compound enzyme addition was 1.1%, complex enzyme ratio (trypsin:alkaline protease) was 1:2 (m:m), enzyme digestion pH was 8.2, enzyme digestion temperature was 52.5 ℃; the optimal extraction parameters of the two-stage were as follows: Enzyme digestion pH was 7.0, enzyme digestion temperature was 50.0 ℃, neutral protease addition was 0.8%, and enzyme digestion time was 40 min. Under these conditions, the protein extraction rate was 76.3%. Conclusion Due to synergistic and complementary effects between the complex enzymes and segmented enzymatic hydrolysis, the protein extraction rate of Pectinidae is effectively improved, which provide some theoretical basis for the subsequent development and utilization of proteins from Pectinidae.

Objective To understand the levels of veterinary drug residues in chickens and eggs in the diet of Xinjiang residents, and analyze and assess the health risks associated with exposure to veterinary drug residues in this region. Methods Veterinary drug residues were detected in chicken and egg samples from supermarkets and farmers’ markets in Xinjiang Uygur Autonomous Region from 2021 to 2023 by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and then combined with the data on the food intake of the residents of Xinjiang Uygur Autonomous Region, and then assessed the risk of dietary exposure by point assessment method. Results The detection rate of 19 kinds of veterinary drug residues in chicken and egg samples in Xinjiang from 2021 to 2023 was 23.3% (63/270), and the exceedance rate was 6.3% (17/270), and the difference in the detection rate of florfenicol was statistically significant by chi-square test (P=0.002), and the differences in detection and exceedance rates in the Northern, Southern and Eastern regions of Xinjiang were not statistically significant. The food safety index for chicken meat in Xinjiang were much smaller than 1, and the food safety index for veterinary drug residues in eggs were all less than 1, but the food safety index for ofloxacin, enrofloxacin, ciprofloxacin, diclazuril and florfenicolide were much greater than 1. Conclusion The risk of dietary exposure to veterinary drug residues for chicken meats and eggs in Xinjiang is small and in the controllable range.

Objective To investigate the contamination of fungal toxins in locally produced rice in Harbin Area, and conduct a risk assessment. Methods The content of aflatoxin B₁ (AFB₁) and ochratoxin A (OTA) in commercially available locally produced Daohuaxiang No.2 rice were detected using liquid chromatography-tandem mass spectrometry. Through Monte Carlo simulation, non-parametric probabilistic assessment methods and point assessment methods were employed to evaluate the dietary exposure risk of different populations in Harbin to AFB₁ and OTA through the consumption of rice. Results A dietary exposure model for AFB₁ and OTA has been established. This study found that both AFB₁ and OTA pose a high risk to children, especially those with high consumption levels, who had a greater potential risk of developing liver cancer through rice consumption. Conclusion The overall health risk of AFB₁ and OTA exposure through rice consumption among residents in Harbin is relatively low. However, there is a significant potential health risk for high-consuming children, which requires much more attention. Apparent health risks were not found for other populations.

Objective To analyze the key factors affecting constant weight in the direct drying method and to optimize the experimental conditions for vacuum drying, distillation, and Karl Fischer methods as specified in the GB 5009.3—2016 National food safety standard-Determination of moisture in foods. Methods The determination of moisture content in samples was conducted according to GB 5009.3—2016. The study altered experimental conditions to explore key factors affecting constant weight in the direct drying method, optimized conditions for vacuum drying by adjusting vacuum pressure, and compared the effects of different reagents (xylene, Karl Fischer reagent) on detection results. Results In the direct drying method, sample temperature, cooling time in the desiccator and the degree of sample pulverization were identified as key factors affecting constant weight. For vacuum drying method, increasing the vacuum to -0.1 MPa and adding an effective desiccant to the drying box could rapidly evaporate moisture from the sample, improving detection efficiency. In the distillation method, the preparation and purification of analytical-grade toluene or xylene could be omitted. The Karl Fischer method could use a low-toxicity, pyridine-free Karl Fischer reagent. Conclusion The 4 detection methods in this standard are optimized separately to solve problems such as difficulty in achieving constant weight after repeated drying and the use of toxic and harmful reagents. The rationalization suggestions provide in this study have increased the operability of the standard and improved the testing efficiency of the laboratory.

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 establish a method for determination the fat content in flavored fermented milk containing thickeners by papain-gravimetric method. Methods Papain was used to reduce the adsorption of fat by casein in dairy products. The amount of papain added was 0.5 g, the enzymatic hydrolysis temperature was 65 ℃, and the hydrolysis time was 20 min. A mixture of ether and petroleum ether with equal volumes [25:25 (V:V)] was used to extract fat twice from the flavored fermented milk hydrolysate containing thickening agents. The extraction solvent was evaporated in a water bath, and the fat content was quantified by gravimetric method after drying in an oven. Results The determination of fat content in flavored fermented milk with thickener flavor was consistent with the label value, with a relative standard deviation of 0.40% and a maximum deviation of 0.05 g/100 g, which met the precision requirements of GB 5009.6—2016 third method for determination of fat in foods. Conclusion This method is simple to operate and conform to the concept of green analytical chemistry, compared with GB 5009.6— 2016 third method, it reduces the total volume of mixed ethers used, thereby minimizing harm to human health and environmental pollution. With good reproducibility, it can effectively determine the fat content in flavored fermented milk containing thickeners, providing robust technical support for quality control of such products.

Objective To establish a pre-amplified quantitative real-time polymerase chain reaction (qPCR) method for the detection of Oncorhynchus mykiss source components. Methods The study developed an enhanced pre-amplified qPCR method, which was based on the validation and improvement of the existing standard qPCR method and compared the performance of both methods. Results Specificity testing of the standard qPCR method revealed cross-reactivity with closely related species, such as Coho salmon and Atlantic salmon. The established improved pre-amplified qPCR method, which incorporated a pre-amplification step, exhibited high specificity and no cross amplification was observed for Coho salmon, Atlantic salmon and other closely related species. The amplification efficiencies of the standard qPCR and the pre-amplified qPCR methods were 90.25% and 104.91%, respectively. The lowest limits of detection of the 2 kinds of methods were 2.99×10^-3 ng/μL (0.83-8.87 pg/μL, 95% confidence interval) for the standard qPCR and 1.50×10^-4 ng/μL (0.09-0.27 pg/μL, 95% confidence interval) for the pre-amplified qPCR. Conclusion The method established in this study has the characteristics of strong specificity, high sensitivity, and is suitable for authenticity and adulteration detection of Oncorhynchus mykiss source components in food products.

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 study and develop edible flower resources, evaluate their nutritional components and in vitro antioxidant activities. Methods The 6 kinds of edible flowers—Kanzan flower, loquat flowers, roses, chrysanthemums, jasmine flowers and honeysuckle—were selected as study subjects. The content of polysaccharides, polyphenols, total flavonoids, free amino acids, proteins, cyanidin and petunidin in the samples were measured. Principal component analysis and correlation analysis were used to compare the antioxidant activity of different edible flowers. Results The chemical compositions of the 6 kinds of edible flowers showed significant differences. The free amino acid (11.18%) and protein (22.06%) content of Kanzan flower were significantly higher than those of the other 5 kinds of flowers. The polysaccharide content of the 6 kinds of flowers was concentrated around 4%. The highest polyphenol and total flavonoid contents were found in roses (9.42%-13.94%) and Guangxi honeysuckle (3.62%), respectively. Petunidin and cyanidin were detected in Kanzan flower, loquat flowers, and roses. Except for Pingyin roses, the petunidin and cyanidin contents in roses were generally higher than those in Kanzan flower and loquat flowers. Antioxidant experiments showed that roses exhibited strong scavenging effects on 2,2-diphenyl-1-picrylhydrazyl radicals and hydroxyl radicals. Correlation analysis indicated that polyphenols, petunidin and cyanidin in edible flowers were positively correlated with antioxidant activity, with correlation coefficients all greater than 0.72, while no significant correlation was observed between total flavonoid content and free radical scavenging rates. Principal component analysis and comprehensive scoring revealed that roses ranked highest among the 6 kinds of flowers. Conclusion Overall, roses possess higher nutritional value as a food ingredient compared to the other five edible flowers. The research provide a scientific basis for the selection of food materials and the development of new food products in the field of edible flowers.

Objective To evaluate the residue dissipation dynamics and dietary intake risks of sodium dichloroisocyanurate (DCCNa), prochloraz and its metabolites in Myrica rubra Sieb. & Zucc. Methods The residue dynamics of DCCNa, prochloraz and its metabolite 2,4,6-trichlorophenol in Myrica rubra Sieb. & Zucc under room temperature and cold storage conditions were quantitatively analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS), dietary intake risks were further assessed. Results There was a positive correlation between the concentration and residual amount of DCCNa and prochloraz in fruit soaking, indicating that higher dipping concentrations resulted in greater initial residues. The dissipation dynamics of both pesticides in Myrica rubra Sieb. & Zucc followed the first-order kinetics. The half-lives of DCCNa were 0.5-0.9 days at room temperature and 0.8-1.1 days under refrigeration, while those of prochloraz were 1.1-1.3 days and 1.5-2.1 days respectively. Additionally, the content of 2,4,6-trichlorophenol, a metabolite of prochloraz, exhibited an increasing trend during storage. Dietary risk assessment demonstrated that when Myrica rubra Sieb. & Zucc were treated with DCCNa (15 mg/L and 60 mg/L) or prochloraz (45 mg/L and 180 mg/L) solutions for preservation respectively, the acute dietary exposure risks of both pesticides in at the highest residue levels remained within the acceptable limits. Moreover, acute dietary risk values of DCCNa and prochloraz in commercially available Myrica rubra Sieb. & Zucc were lower than those in the experimental treatment groups, with all acute dietary exposure risks below 100%, indicating controllable exposure levels. Conclusion This study clarifies the degradation patterns of sodium DCCNa, prochloraz and their metabolites during the storage and preservation process of Myrica rubra Sieb. & Zucc, providing a theoretical basis for the scientific and standardized use of fungicidal preservatives as well as quality and safety regulation.