As consumer awareness of food quality and its grading continues to increase, there is a growing focus on developing effective, reliable and non-destructive methods for assessing food freshness. Aquatic product freshness indicators are typically constructed from sensitive materials and fixed carriers. These materials react with specific substances generated during the degradation process of aquatic product freshness, converting the chemical reaction results into signals that are easily observable and interpretable by consumers, such as color changes, electrical signals, or fluorescence signals. This review summarized the common sensitive materials used in aquatic product freshness indicators and their application progress. It particularly explored various preparation methods for these indicators, along with their advantages and limitations, including solution casting, spin coating, impregnation-drying, electrospinning, 2D printing, and 3D printing technologies. Additionally, strategies to enhance the performance of freshness indicators were discussed from multiple perspectives. The use of functional additives, encapsulation techniques, and chemical modifications could improve the stability of the indicators, while methods like dye blending, metal ion complexation, and colorimetric arrays had proven effective in enhancing their sensitivity. Finally, the article outlined the opportunities and challenges for future research in food freshness, aiming to provide insights for the development of intelligent food packaging freshness indicators.

As the demand for meat products has risen sharply, ensuring the quality and freshness of meat has become a major challenge for the industry. It is known that meat spoilage is a complex biochemical process involving the action of microorganisms and the accumulation of various compounds, during which many characteristic substances are produced, such as biological amines, volatile basic nitrogen, hypoxanthine, hydrogen sulfide, etc. However, the traditional methods of freshness assessment are time-consuming and not precise enough to provide accurate detection results. Therefore, this review focused on introducing some emerging detection technologies, including biosensors, gas sensors, electronic noses, electronic tongues and spectroscopic techniques, covered their principles and applications. These technologies could not only rapidly and non-destructively assess the freshness of meat but also provided clear information on the overall safety and quality of meat products, reducing waste caused by spoilage. Finally, the review discussesed the trends of future meat freshness detection technologies, which were expected to become more advanced, intelligent and user-friendly providing more efficient and intelligent solutions for the food industry.

With the continuous extension and increasing complexity of the global food supply chain, coupled with the rapid emergence of new business models, novel foods and innovative commercial practices, food fraud has become a growing concern and a global issue. In recent years, the risks posed by food fraud to food safety, public health and consumer confidence have been widely reported. This paper systematically reviewed the various definitions and classifications of food fraud currently recognized internationally, with a particular focus on analyzing the functionalities and applications of major global food fraud databases. It also summarized and analyzed mitigation measures for food fraud, guidelines and standards for vulnerability assessments, and related evaluation tools. Furthermore, the paper elaborated on the research progress in food fraud detection technologies, highlighting the applications and limitations of traditional detection methods, and explores the prospects of emerging technologies. Special emphasis was placed on the importance of integrating multiple detection technologies, big data, and artificial intelligence in enhancing detection efficiency and accuracy. Finally, the paper provided relevant recommendations, aiming to offer insights and references for addressing food fraud issues in China.

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.

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 study and screen the novel vardenafil derivative in food, and establish a quantitative method. Methods A compound with similar structure to vardenafil was detected in food by ultra performance liquid chromatography-quadrupole-exactive orbitrap-high resolution mass spectrometry. The molecular structure and fragmentation law of the vardenafil structure analogue were inferred from the fragment ions of high-resolution mass spectrometry. The compound name was clarity compared with the custom-synthesized reference substance. Quantitative analysis was carried out in a multiple reaction monitoring by high performance liquid chromatography-tandem triple quadrupole mass spectrometry with the external standard method. Results The novel vardenafil derivative in food was identified as propoxyphenyl hydroxy-vardenafil. The results showed that good linearity was observed for propoxyphenyl hydroxyvardenafil within the concentration range of 2-50 ng/mL. The limit of detection was 0.03 mg/kg, and the limit of quantitation was 0.10 mg/kg. The average recoveries and relative standard deviations (RSD) of coffee, confectionery, jelly and plant-based drinks were 87.6%-102.6% and 0.5%-6.3% respectively. The reproducibility and stability of the method were good (RSD<5%). The method was applied to measure the real samples, and 34 batches of positive samples were found with the content range of 1.60×10³-2.62×10⁴ mg/kg. -Conclusion This method is fast, accurate and high sensitivity, can be used for screening and quantitative determination of the derivative propoxyphenyl hydroxyvardenafil in food, and can provide technical support for the supervision of the illegal addition of vardenafil derivatives.

Objective To establish a detection method for soybean allergens in plant-based protein products based on ultra performance liquid chromatography-tandem mass spectrometry, and conduct research on the quantification and authenticity determination of allergy protein in plant-based protein products. Methods After the soybean protein isolate was hydrolyzed by trypsin, the data were collected by high resolution mass spectrometry and matched with the Uniprot database to screen out the soybean specific allergen peptides. The response surface design was adopted to optimize the extraction conditions of the allergen protein, thereby constructing the quantitative method of allergens. Actual sample tests were conducted on commercially available plant-based protein products to preliminarily obtain the content of soybean allergy proteins in different plant-based protein products. Results The 6 kinds of soybean quantitative peptides with good linearity and correlation coefficients above 0.995 were selected. The limits of detection and the limits of quantification of the method were 0.182-2.08 µg/g and 0.607-6.920 µg/g. The spiked recoveries were 97.1%-126.6% and the intra-day and inter-day precisions were 5.17%-10.20% and 5.02%-11.70%. Conclusion This method has strong specificity and high sensitivity, and can well detect plant-based protein products, achieving accurate quantification of soybean allergens without isotope-labeled peptide segments. It has a good application prospect in the detection of allergen in plant-based protein products. Meanwhile, it can achieve the identification of adulteration in plant-based protein products and the discrimination of allergic information on food labels.

Pesticide application is one of the effective measures to prevent crop diseases and insect pests in agricultural production. However, large-scale use of pesticides also brings food pesticide residues, which brings safety risks to human health. It is of great significance for food safety to clarify the spatial distribution and metabolic transfer pathway of pesticides in food. Traditional detection and analysis methods can only perform qualitative and quantitative analysis of pesticides, unable to directly observe their distribution in food. The emergence of mass spectrometry imaging technology has enabled visual analysis of pesticide residues in food, with advantages such as high sensitivity, high spatial resolution and ease of operation. It has become an important analytical tool for pesticide residue detection. This paper summarized the research progress of mass spectrometry imaging technology for pesticide residue detection in food over the past 5 years, both domestically and internationally. It focused on outlining the principles, characteristics and differences between various types of mass spectrometry imaging techniques. Additionally, it reviewed the application studies of mass spectrometry imaging technology in detecting pesticide residues in food (including different sources of food and different types of pesticides), finally analyzed the deficiencies and challenges of mass spectrometry imaging technology in pesticide residue detection, and proposed the future prospects. This paper aims to provide a reference for the research and innovation development of mass spectrometry imaging technology in pesticide residue detection.

Objective To establish a method for the rapid determination of 45 kinds of pesticides residues in Vitis vinifera by gas chromatography-tandem mass spectrometry (GC-MS/MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Methods The Vitis vinifera samples were first extracted with acetonitrile by vibration and ultra-sonic. Then the mix adsorbents were used in dispersive solid phase extraction to purify the extract. After high speed centrifugation and filtration, the samples were detected by GC-MS/MS using selected reaction monitoring (SRM) mode, and LC-MS/MS using multiple reaction monitoring (MRM) mode. Results Deltamethrin exhibited good linearity within the concentration range of 0.1 to 1.0 mg/kg, while captan showed linearity within the range of 0.2 to 3.0 mg/kg, 28 kinds of pesticides including metalaxyl showed good linear relationships within the concentration range of 0.04-1.00 mg/kg, and 15 kinds of pesticides including emamectin benzoate showed good linear relationships within the concentration range of 0.1-1.0 mg/kg, with correlation coefficients reached 0.99 or above. The limits of detection were in the range of 0.00020-0.05000 mg/kg, the limits of quantitation were in the range of 0.00050-0.15000 mg/kg. The spiked recoveries at 3 levels of 45 kinds of pesticides were in range of 70.3%-117.0%, the relative standard deviations were in range of 0.01%-14.30%. Conclusion With features such as accuracy and easy operation, this method can be used to fast determination of 45 kinds of pesticides in Vitis vinifera without any special samples pretreatment apparatus, and also satisfies the requirement of pesticide routine analysis.

Objective To investigate the effects of carboxymethyl pachymaran on the stability, structure, physicochemical properties and biological activity of casein at different ratios. Methods Pachymaran was derivatized with carboxymethyl groups to enhance its solubility, and its structural features were studied; carboxymethyl pachymaran was mixed with casein in different ratios, and the turbidity, zeta potential, protein solubility, and phase diagram of the complex were evaluated at different pH values; the aggregation degree and physicochemical properties of different casein-based samples were studied under acidic conditions using confocal laser microscopy and rotational rheometer; free radical scavenging ability and non-enzymatic glycation product inhibition ability of different casein-based samples were compared. Results The molecular weight of carboxymethyl pachymaran obtained in this study was 2.43×10⁵ g/mol. The successful preparation of carboxymethyl pachymaran was determined by the degree of substitution (0.84) and the characteristic absorption peak of carboxymethyl group. When carboxymethyl pachymaran was mixed with casein, it could effectively affect the pH stability and reduce the turbidity of casein under acidic conditions, and its solubility was also enhanced. This might be due to the electrostatic interactions between polysaccharides and proteins affecting the surface charge distribution of the molecules. Among them, the best stabilizing effect was observed when carboxymethyl pachymaran was mixed with casein at 5:1 (w/w). Subsequent studies on the structure and physicochemical properties of the complex showed that with the introduction of polysaccharides, especially when they were mixed at a ratio of 5:1 (w/w), the aggregation degree, apparent viscosity and modulus of the complex were lower, indicating that its gel network structure had better stability. The biological activity results showed that the complex, especially when they were mixed at a ratio of 5:1 (w/w), exhibited the strongest antioxidant activity and non-enzymatic glycation product inhibition ability. Conclusion The carboxymethyl pachymaran-casein complex obtained in this study has better structural stability and biological activity in acidic environments, providing a theoretical basis and technical support for the development and processing of stable acidic dairy products.