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 investigate false positive interference from spices in hot pot base materials during the detection of thebaine using mass spectrometry, identify interfering matrix components, and optimize analytical methods. Methods The 62 kinds of commonly used spices in hot pot bases were collected. The false positive issues screened by BJS 201802 Determination method of morphine, codeine, papaverine, noscapine and thebaine in food were further analyzed by Fourier transform ion cyclotron resonance mass spectrometry combined with positive pressure electrospray ionization full mass spectrometry scanning. The potential interfering substances were locked through ion fragment analysis and verified. Results The results showed that the detection found interference peaks with retention times similar to those of thebaine in the extracts of bay leaves and pepper, which could lead to false positive results. The molecular weight of the interfering substance was 311.3812 ([M+H]+), with a deviation of less than 2 ppm from the theoretical value of thebaine (311.375), suggesting that it was an isomer. Through the detection of the suspected interfering substance, it was verified that Launobine and Pisatin had no interfering activity. Conclusion The alkaloid substances in spices have significant interference with the detection of thebaine. It is suggested to improve the specificity and accuracy of the detection by optimizing the mass spectrometry conditions, introducing nuclear magnetic resonance technology and perfecting the pretreatment process to avoid false positive misjudgment.

Objective To establish a method for the determination of the migration of 14 kinds of ultraviolet absorbers in aqueous food simulants and chemical alternative solvents (95% ethanol aqueous solution and isooctane) by high performance liquid chromatography. Methods The ultraviolet absorbers migrated into the aqueous food simulants were extracted twice with n-hexane by vortexing and shaking, and the combined extract was evaporated to dryness under reduced pressure and re-dissolved in tetrahydrofuran. The ultraviolet absorbers migrated into the chemical alternative solvents were evaporated to dryness and re-dissolved in tetrahydrofuran. A C₈ column was used for separation, with acetonitrile and water as the mobile phase and gradient elution. Detection was performed using a ultraviolet detector at a wavelength of 300 nm. Results The limits of detection of 14 kinds of ultraviolet absorbers were as low as 0.008 mg/L, and the limits of quantitation were 0.020 mg/L. The correlation coefficients of the 14 kinds of target compounds were above 0.999 within the linear range of 0.20-5.0 mg/L. The 3 levels of ultraviolet absorbers (0.02, 0.05 and 0.50 mg/L) were added to the food simulants or chemical alternative solvents, and 6 replicate experiments were conducted. The results showed that the recovery rates of each compound at each level were within the range of 82.4%-108.0%, and the relative standard deviations were less than 10%. Conclusion This method is accurate, efficient and simple, and can be used to simultaneously determine the migration amounts of 14 kinds of ultraviolet absorbers in aqueous simulants and chemical alternative solvents.

Objective To investigate the effects of different degree of low substitution degree on the physicochemical properties of potato starch, and apply it to the hard capsule shell to observe the effect of potato acetate starch on its properties. Methods Potato starch was used as raw material and acetic anhydride as esterifying agent to prepare esterification modified starch with different low degree of substitution (0.0143-0.0570). The physical and chemical properties and structural changes of different starch with low substitution degree were investigated, and it was used in the preparation of hard capsule shells. Results Both potato starches with different low substitution degrees and the original starch were shear-thinning type pseudoplastic fluids. The energy storage modulus and loss modulus of modified starch showed an increasing trend, and the storage modulus was larger than that of original starch. Compared with the original starch, the transparency, gel strength and water holding capacity of modified starch were improved. The swelling degree and solubility increased. The esterification reaction of acetic anhydride with potato starch occurred mainly on the surface of starch particles, and did not change the crystallization type of potato starch. The modified starch paste of potato was used to prepare the hard capsule shell and all the indexes met the requirements of Pharmacopoeia of the People’s Republic of China (2020 edition). Conclusion The low substitution degree of acetate starch can improve the performance and application range of natural starch, which is in line with the national food safety standards. The preparation of plant hard capsules instead of gelatin capsules can make up for the shortcomings of natural starch in the preparation process, and it is in line with the standards stipulated in Chinese pharmacopoeia.

Agricultural product safety form the foundation of constructing food supply systems. Smart hydrogels exhibit promising application prospects in agricultural safety analysis due to their stimuli responsiveness, mechanical stability, biocompatibility, and adjustable pore size. This review focused on the classification, preparation methods, responsive mechanisms and applications of smart hydrogels in agricultural product safety. Based on synthesis methods, they could be divided into physically cross-linked and chemically cross-linked hydrogels, while stimulus-responsive types included temperature-responsive, pH-responsive, biomolecule-responsive, electric field-responsive and magnetic field-responsive hydrogels. This study summarized their applications in contaminants adsorption/separation, foodborne pathogen detection, mycotoxin detection, pesticide/veterinary drug residue analysis, illegal additive identification, and heavy metal detection for agricultural product assurance. Development prospects of smart hydrogels are further discussed to provide references for their expanded utilization in agricultural product safety.

Objective To establish a method for the determination of 8 kinds of benzodiazepines residues, including diazepam, oxazepam, midazolam, clonazepam, lorazepam, triazolam, alprazolam and nitrazepam in aquatic products by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Methods The sample was extracted by 80% acetonitrile aqueous solution containing 0.2% formic acid, purified by Waters PRIME HLB solid phase extraction column, concentrated by nitrogen blowing in water bath. The residue contents were separated by C₁₈ chromatographic column, eluted by 0.1% formic acid aqueous solution-methanol mobile phase systems, and analyzed by electrospray ion source in positive ion multi-reaction monitoring mode. The quantitative information was obtained by matrix-added calibration with external standard. Results The correlation coefficient of calibration curves of 8 kinds of benzodiazepines residues were above 0.999. The limits of detection were 0.064-0.226 μg/kg, the recovery rates of the method were 70.4%-107.0%, and the relative standard deviations were 2.1%-10.2%. Conclusion The method is rapid, simple and accurate, and it is suitable for the determination of benzodiazepine sedative drug residues in aquatic products.

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 optimize the subcritical water extraction process of Pollen pini polysaccharides based on genetic algorithm-neural network (GA-NN) algorithm and further explore its anti-fatigue activity. Methods Using broken shell Pollen pini as raw material, a response surface was designed through Box-Behnken test on a single factor basis, and a network neural model was constructed and optimized using GA-NN algorithm. Under the optimal process conditions, the anti-fatigue effect of polysaccharides was evaluated through mouse weight-bearing swimming test. Results The relative error and coefficient of determination (R²) of the constructed neural network model were 0.03267 and 0.98476, respectively. The genetic algorithm was iterated 60 times for subcritical water extraction of polysaccharides, and the optimal parameters were obtained as follows: Temperature 148 ℃, time 28 min, liquid to material ratio 40:1 (mL/g), pressure 5 MPa, and polysaccharide yield of 23.7893 mg/g. After verification, there was no significant difference between the actual value and the predicted value, indicating good accuracy of the model. The study on anti fatigue activity showed that compared with the blank group, the high-dose group of mice had a certain degree of increase in body weight, while there was no significant difference in other groups (P>0.05). Compared with the blank group, the swimming time of mice in the polysaccharide group was prolonged, the levels of blood lactate and urea nitrogen were reduced, and the reserves of muscle glycogen and liver glycogen were significantly increased (P<0.05). Conclusion GA-NN can effectively optimize the subcritical water extraction process of Pollen pini polysaccharide, and the polysaccharide has a certain anti fatigue effect.

Food safety is crucial for national economic development and public health. With the development of science and technology, traditional detection methods is difficult to meet the supervision requirements of food safety in complex scenarios. In recent years, artificial intelligence (AI), with its high efficiency, high accuracy, powerful data processing capabilities, and precise identification and predictive analysis functions, has gradually been applied to research fields such as food flavor analysis, food safety risk assessment and early warning, and authenticity identification. The application of AI technology has improved the timeliness and reliability of food quality and safety testing, and has built a prevention and control system covering the entire industry for regulatory departments through intelligent decision-making assistance systems, becoming the core technical support for ensuring “safety on the tip of the tongue”. This paper mainly introduced the main algorithms of machine learning and deep learning algorithms, and reviewed the research progress of AI algorithms in food quality and safety. Additionally, it looks ahead to the existing problems and future research trends of the application of AI algorithms in food quality and safety. The aim is to offer references for further promoting the research and practice of AI technology in the field of food quality and safety, and to provide research ideas for the field of food quality and safety detection.

N-nitrosamines (NAs) are a class of strongly carcinogenic compounds with high contamination levels in aquatic products, posing significant risks to human health. Recent random inspections in China have revealed that excessive N-nitrosodimethylamine (NDMA) content has become a major factor disqualifying processed aquatic products, seriously hindering the healthy development of the aquatic product processing industry. Therefore, elucidating the formation mechanisms and influencing factors of NAs in aquatic products, along with controlling their levels through processing technologies and multidisciplinary approaches, has become a key research focus. This review systematically examined various formation pathways of NAs in aquatic products, pretreatment methods, and analytical techniques compliant with national food safety standards. It further summarized comprehensive strategies for NAs control, including reduction of NAs precursor intake, blocking of NAs formation pathways, and decomposition of existing NAs. The paper aimed to address the excessive NAs levels in aquatic products, thereby ensuring the quality and safety of aquatic products and promoting sustainable development of the industry.