To explore the variation patterns of rheological properties and microstructure of Chenopodium quinoa Willd. flour and Triticum aestivum L. flour mixed flour dough with different Chenopodium quinoa Willd. flour substitution ratios.

By measuring the thermomechanical properties, gelatinization characteristics, tensile properties, microstructure and dynamic rheological properties of mixed flour dough, the variation patterns were analyzed.

The formation time and stability time of the mixed flour dough increased first and then decreased with the increase of the amount of Chenopodium quinoa Willd. flour, the maximum value was reached when the addition of Chenopodium quinoa Willd. flour was 20%; the breakdown decreased first and then increased, the resistance to extension, extensibility and setback value of the mixed flour dough showed a tendency to decrease. The weakening degree of the mixed flour dough showed a maximum value, the gluten network structure was destroyed seriously, and the Triticum aestivum L. starch granules fell off obviously with 30% of Chenopodium quinoa Willd. flour proportion. Storage modulus (G′) and loss modulus (G′) were positively correlated with the addition of Chenopodium quinoa Willd. flour; during the creep and recovery stages, the strain and recovery of the mixed flour dough were negatively correlated with the addition of Chenopodium quinoa Willd. flour.

The thermomechanical properties, gelatinization characteristics and rheological properties of the mixed flour dough are better, and the gluten network structure is relatively complete when the addition of Chenopodium quinoa Willd.flour is between 10% and 20%. The research conclusion can provide guidance for the application of Chenopodium quinoa Willd. flour in staple dough and theoretical basis for the development of Chenopodium quinoa Willd.-Triticum aestivum L. mixed flour products.

To develop a novel composite gel packaging film capable of food preservation and visual freshness monitoring.

Ferulic acid was covalently grafted onto the backbone of carboxymethyl chitosan (CMCS) using the carbodiimide method to synthesize a carboxymethyl chitosan-graft-ferulic acid copolymer(CMCS-g-FA). Gelatin and agar were used as the film-forming matrix, and CMCS-g-FA together with anthocyanins was incorporated into the matrix at temperatures below 40 ℃. Finally, the composite film was prepared by the solution casting method. The chemical structure of the films was characterized by Fourier transform infrared spectroscopy(FTIR), and their mechanical properties were determined using a texture analyzer. Furthermore, its application efficacy in chicken preservation was evaluated by measuring total volatile basic nitrogen (TVB-N), total viable count, pH , drip loss and conducting sensory evaluation.

FTIR analysis indicated the successful grafting of CMCS with ferulic acid, and CMCS-g-FA together with anthocyanins could form a stable composite film structure with the gelatin/agar matrix. The composite film incorporated with CMCS-g-FA and anthocyanins exhibited optimal comprehensive properties. Specifically, its tensile strength significantly increased to 10.410 MPa, the elongation at break was 35.367%,and the moisture content and water solubility were 13.21% and 39.67%, respectively. Moreover, this film effectively inhibited microbial growth and TVB-N accumulation in chicken meat. With prolonged storage time, the TVB-N value of the treated chicken increased from the initial 4.3 mg/100 g to 23.36 mg/100 g on the 6th day, which was 18.83 mg/100 g lower than that of the blank control group without preservation measures. Additionally, the pH also showed corresponding changes, reflecting the various stages of chicken meat from freshness to spoilage.

This study successfully develops an intelligent packaging film with enhanced mechanical properties and preservation functions. The film can not only visually monitor the freshness of poultry meat products but also effectively extend their shelf life, providing a novel approach for the development of composite gel-type packaging materials.

To establish a method for the determination of pentachloroanisole in wooden food contact materials by QuEChERS-gas chromatography-tandem mass spectrometry.

The prepared samples were added with pure water and zirconia beads, followed by ultrasonic extraction. Acetonitrile and a salt package(magnesium sulfate and sodium chloride) were sequentially added, and the mixture was shaken and centrifuged. The upper extract was purified by dispersive solid-phase extraction, concentrated to near dryness under nitrogen flow, redissolved by shaking with n-hexane, and filtered through a 0.22 μm microporous membrane. Separation was performed on a DB-5MS quartz capillary column (30 m×0.25 mm, 0.25 μm), and detection was carried out using an electron ionization source in multiple reaction monitoring mode. Quantification was achieved by the external standard method.

Pentachloroanisole showed a good linear relationship in the concentration range of 0.2–10.0 μg/L (r²=0.999). The limit of quantitation was 0.5 μg/kg, and the limit of detection was 0.2 μg/kg. Wooden samples were spiked with pentachloroanisole at 3 concentration levels, with 6 replicates at each level. The recoveries ranged from 85.3% to 97.4%, and the relative standard deviations were 3.0%–3.6%.

The method is simple to operate, with high sensitivity, specificity and precision, and is suitable for the determination of pentachloroanisole in wooden food contact materials.

To test 31 kinds of inorganic elements in fresh, traditionally dried and vacuum-sealed dried Lycium barbarum from 4 major producing regions (Qinghai, Ningxia, Gansu and Xinjiang) in China, analyze and compare the content variations across different geographical origins and processing techniques.

Microwave digestion coupled with inductively coupled plasma mass spectrometry was employed to determine the concentrations of 31 kinds of inorganic elements in Lycium barbarum. WPS 12.1.0.26375 was used to organize data, and one-way analysis of variance was performed using R software to analyze the differences in inorganic elements among Lycium barbarum from different regions and processing methods.

The elements with the highest content in Lycium barbarum,ranked in descending order, were K, Na, Mg, Ca, Fe, Al, Zn, B, Cu, Mn, Sr and Rb. For the 12 kinds of aforementioned elements in fresh Lycium barbarum from the 4 regions, all except Rb showed statistically significant differences(P<0.05), while Rb exhibited no significant variation (P>0.05). In Ningxia samples, the content of Na, Fe, and Al in traditionally dried Lycium barbarum were 5.2–6.4 times those in fresh ones, whereas in vacuum-sealed dried Lycium barbarum these elements were 1.8–2.8 times higher than in fresh ones.

The microwave digestion-inductively coupled plasma mass spectrometry method is accurate and reliable, enabling simultaneous analysis of macroelements,microelements and trace elements in Lycium barbarum, and is suitable for high-throughput analysis of inorganic elements in Lycium barbarum across multiple scenarios. The traditional drying process leads to abnormal enrichment of Na and Al in Lycium barbarum, which can be mitigated by the vacuum-sealed drying process. Special attention should be paid to health education on Lycium barbarum consumption for vulnerable populations such as the elderly.

To evaluate the molecular epidemiological characteristics and potential risks of foodborne Listeria monocytogenes in Jiayuguan City, Gansu Province.

This study analyzed the population structure,virulence factor profiles, and genetic evolutionary relationships of local strains at the genomic level. Whole-genome sequencing was performed on 4 strains of Listeria monocytogenes isolated from food in Jiayuguan City. Bioinformatics methods were used for molecular typing and serotype prediction, systematic screening of virulence and resistance genes,and through average nucleotide identity (ANI) analysis and the construction of core genomic phylogenetic trees, the genetic similarity and evolutionary localization among strains were analyzed.

The 4 strains belonged to 4 sequence types: ST8, ST121, ST91 and ST9. All strains carried complete core virulence gene clusters and the invasion gene inlA. The ST121 strain exhibited deletion of the actA gene and an incomplete LIPI-1 virulence island. Average nucleotide identity and phylogenetic analysis showed that the ST9 strain formed a tight clonal group with specific reference strains; the ST8 strain was highly homologous to a clinical strain (ANI: 99.78%) and clustered closely on the phylogenetic tree.

This study confirmes the genetic diversity of foodborne Listeria monocytogenes in Jiayuguan City and their possession of complete core virulence gene clusters. Among them, the ST8 clone showes high homology with clinical strains, indicating a clear risk of food-to-human transmission. The findings provide critical data support for establishing a genomics-based prospective early warning system for food safety risks in the region.

To optimize the preparation process of Ziziphi Spinosae Semen peptide-zinc chelate(ZSSP-Zn) and characterize its structure.

This study optimized the preparation of ZSSP-Zn used a combination of single-factor experiments and response surface methodology. The structures and compositions of ZSSP-Zn were characterized using ultraviolet spectroscopy, Fourier transform infrared spectroscopy, amino acid analysis, scanning electron microscopy and size distribution. The stability of the ZSSP-Zn was investigated through in vitro simulated gastrointestinal digestion.

The optimal chelation conditions for ZSSP-Zn included peptide-to-zinc ratio of 3:1 (m:m), pH 6, chelation time of 2 h and a chelation temperature of 60 ℃. Under these conditions, the chelation rate was (41.97±0.82)%. After chelation, the ultraviolet absorption peak shifts to the blue.Amino nitrogen atoms, carboxyl oxygen atoms, carbonyl oxygen atoms and hydroxyl oxygen atoms served as key binding sites for zinc ions. Chelation led to formation of loose granular structures with reduced particle size. The in vitro simulated gastrointestinal digestion analysis indicated that the ZSSP-Zn chelate exhibited good stability.

The optimized ZSSP-Zn preparation process in this study is stable and reliable, with a more uniform particle size distribution of the chelate complex. These results provide technical references for the development of traditional Chinese medicine-based zinc supplements.

To analyze the amino acid composition of 12 kinds of dishes from Hunan Province and evaluate their nutritional value.

Following the National Food Composition Monitoring Work Plan, 12 kinds of representative local dishes were collected from Hunan Province. Protein content was determined using a Kjeltee 2300 automatic nitrogen determinator kjeldahl apparatus, while amino acid composition and content were analyzed using a membra Pure GmbH A300 automatic amino acid analyzer. The nutritional value of the dishes was comprehensively evaluated using the amino acid score, chemical score and amino acid ratio coefficient score.

Among the 12 kinds of dishes, Wugang braised tofu had the highest protein content (27.99 g/100 g), while Xinhua sanhe soup had the lowest (6.04 g/100 g). The highest total amino acid content was also found in Wugang braised tofu (23.34 g/100 g), and the lowest in Xinhua sanhe soup (3.18 g/100 g). The 17 kinds of amino acids were detected in steamed smoked fish,stir-fried pepper with oil residue, Wugang braised tofu and braised giant salamander (farmed), while methionine was not detected in the remaining dishes. Glutamic acid and aspartic acid were generally abundant, serving as the primary umami amino acids. Among the essential amino acids, leucine and lysine were relatively abundant. Lysine content was notably high in most dishes, exceeding the World Health Organization/Food and Agriculture Organization reference pattern (55 mg/g protein) and the ovalbumin pattern (55 mg/g protein) in 8 kinds of dishes, with the exceptions being sausage (39.00 mg/g protein), bee pupae (42.98 mg/g protein), baogusuan (34.59 mg/g protein) and Wugang braised tofu(50.73 mg/g protein). Nutritional evaluation identified methionine, isoleucine, valine, threonine and phenylalanine+tyrosine as limiting amino acids. The standard reference coefficient for amino acid values ranged from 58.04 to 81.90 for most dishes, except for sausage (40.46) and baogusuan (43.32), indicating a relatively balanced amino acid composition and high nutritional value for these foods.

The 12 kinds of local specialty dishes from Hunan are rich in protein, with generally high lysine content and favorable nutritional value. It is recommended to combine these dishes with foods rich in methionine, isoleucine, valine, threonine, phenylalanine and tyrosine to enhance overall protein utilization in the diet.

To understand the drug use and drug residue pollution characteristics in the farmed process of Rana catesbeiana in Yunnan Province and scientifically evaluate the dietary health risk.

Based on the monitoring data of the special project on the quality and safety of key farmed varieties in Yunnan Province, the single factor pollution index method and the drug hazard quotient method were used to calculate the veterinary drug residue pollution level and dietary health risk of bullfrog.

Among the 105 batches of Rana catesbeiana monitored this time, banned drugs such as malachite green and chloramphenicol were not detected and the detection rate of drug residues of conventional drugs enrofloxacin and florfenicol was relatively high. The detection rates of enrofloxacin,florfenicol and sulfonamides were 77.14%, 68.57% and 14.28%, respectively. Based on the dietary exposure assessment of general consumption, the estimated daily intake of Rana catesbeiana products with the maximum exposure of veterinary drug residues was lower than the allowable daily intake for adults and children.

The overall dietary exposure risk of Rana catesbeianas in Yunnan is relatively low, However, the illegal use of common antibiotics such as enrofloxacin, florfenicol and sulfonamides (including overdosage and failure to observe the withdrawal period)is a prominent problem, it should be given special attention. It is necessary to continue to optimize the grid management of Rana catesbeiana and build a safety defense line for the quality and safety of Rana catesbeiana products.