To prepare the Fe₃O₄@SA nanozyme gel microspheres with peroxide-like activity to construct a colorimetric sensor to detect the peroxide value (POV) of vegetable edible oils.

The standard curve of POVs of different types of vegetable edible oils was established by collecting the absorbance and the red,green, blue (RGB) information of the solution after color reaction with the microplate reader and smartphone, and the accuracy and practicability of the detection method were evaluated.

The POVs of 5 kinds of vegetable edible oils showed a good linear relationship in the range of 0–0.40 g/100 g. Compared with the results of the national standard method, the determination coefficient (R²) of the microplate reader colorimetric method and the smartphone digital image colorimetric method were both greater than 0.9500, and the root mean square error (RMSE) was less than 0.1.

The colorimetric detection system established based on the activity of Fe₃O₄@SA nanozyme gel microspheres has good accuracy and practicability, and the research results will provide a new idea for the analysis and detection of food safety factors.

To analyze, identify and quantitatively determine active components and nutrients in Meizhou Shatian pomelo flowers.

Ultra performance liquid chromatography-quadrupole/exactive-orbitrap high resolution mass spectrometry (UPLC-QE-Orbitrap-HRMS) combined with workstation TraceFinder 5.0 and its Chinese medicine database were used to analyze non-volatile components of Shatian pomelo flower. Active compounds and nutrients in pomelo flowers were determined by other various detection techniques.

A total of 51 kinds of non-volatile active components were identified in pomelo flowers, including 19 kinds of flavonoids, 11 kinds of coumarins, 8 kinds of terpenoids, 3 kinds of organic acids, 2 kinds of aldehydes, 2 kinds of amino acids, 2 kinds of nucleosides, 1 kind of phenol, 1 kind of alkaloid and 2 kinds of other compounds. Types and content of flavonoids in pomelo flowers were rich. Naringin, total saponins, fat, protein, dietary fiber, carbohydrate, 5 kinds of vitamins and 10 kinds of nutrient elements in dried pomelo flowers were determined quantitatively in this study. The content of naringin was high to 13.9 g/100 g. The content of saponins, vitamin C and vitamin E were relatively high.It also contained a variety of trace elements needed by human body.

Pomelo flowers are rich in active components and nutrients. This study provides a scientific basis for pomelo flowers related to the formulation of quality standards, the comprehensive utilization of resources and product development.

To establish a method for the simultaneous detection of benzoic acid, sorbic acid and dehydroacetic acid in pre-made meals by high performance liquid chromatography.

Sodium hydroxide solution was added to the sample for ultrasonic extraction. Protein was precipitated with potassium ferrocyanide and zinc acetate solution. Separation was carried out using an Agilent XDB-C₁₈ (4.6 mm×250 mm, 5 μm)chromatographic column. The mobile phase was ammonium acetate solution and methanol (93:7, V:V), with a flow rate of 1 mL/min and a column temperature of 30 ℃. The detection was carried out by a diode array detector with detection wavelengths of 230 nm and 293 nm. At the same time, the spectra of the standard solution and the sample solution were collected respectively by a diode array detector. By comparing the spectra of the target peak in the standard and sample solutions, the samples were further qualitatively confirmed.

The 3 kinds of preservatives had a good linear relationship within the range of 0.5–100.0 mg/L, with correlation coefficients (r)greater than or equal to 0.9994. The limits of detection were 1.7 mg/kg, the limits of quantitation were 5.0 mg/kg, the recovery rates were 92.0%–104.0%, and the relative standard deviations were 0.1–1.6%.

This method is simple, rapid, has good reproducibility and high recovery rate, and is suitable for the rapid detection of 3 kinds of preservatives, namely benzoic acid, sorbic acid and dehydroacetic acid in pre-made meals.

To develop a navel Citrus sinensis peel tea with suitable taste and unique flavor by inoculating the peels of Gan Nan navel Citrus sinensis with the Eurotium cristatum and conducting solid-state fermentation.

The single-factor experiment and response surface analysis method were adopted to optimize the fermentation process parameters of Gannan navel Citrus sinensis peel tea, and the sensory quality of the obtained product was comprehensively evaluated. Meanwhile, the in vitro antioxidant activity was evaluated by measuring the scavenging effects on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and 2, 2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) positive ion free radicals.

The optimal fermentation process parameters of Gannan navel Citrus sinensis peel tea were determined as follows: Inoculation Eurotium cristatum amount of 2.7%, fermentation temperature of 27 ℃, and fermentation time of 7 days. Under these conditions, the sensory score of the Gannan navel Citrus sinensis peel tea reached 91.29. The in vitro antioxidant results showed that the in vitro antioxidant results showed that, with vitamin C (VC) as the reference, the fermented Gannan navel Citrus sinensis peels inoculated with Trichosporon cutaneum and the unfermented Gannan navel Citrus sinensis peels both before and after fermentation had the ability to scavenge free radicals DPPH and ABTS⁺. When the concentration was lower than 5 mg/mL, the scavenging ability of the fermented Gannan navel Citrus sinensis peels inoculated with Trichosporon cutaneum and the unfermented Gannan navel Citrus sinensis peels on DPPH and ABTS⁺ free radicals was lower than that of VC; when the concentration was 5 mg/mL, the scavenging ability of the fermented Gannan navel Citrus sinensis peels inoculated with Trichosporon cutaneum and the unfermented Gannan navel Citrus sinensis peels on DPPH and ABTS⁺free radicals was comparable to that of VC; the half scavenging rates of these three for DPPH free radicals before and after fermentation were (2.1892±0.0583), (0.7345±0.0052), (0.0024±0.0002) mg/mL, respectively, and for ABTS⁺ free radicals were (2.2372±0.0672), (0.7461±0.0048), (0.0026±0.0002) mg/mL, respectively. The numerical differences were significant, indicating that the Gannan navel Citrus sinensis peels after Trichosporon cutaneum fermentation have stronger antioxidant activity, but their antioxidant activity is still lower than that of VC.

This study successfully develop a navel Citrus sinensis peel fermented tea with excellent quality, good taste and strong antioxidant function. The process formula is stable and feasible, which can provide theoretical and methodological technical support for the market industrialization promotion of navel Citrus sinensis peels.

To evaluate the hypoglycemic effect of novel composite soluble dietary fiber (NCSDF) on db/db mice, and explore whether it exerts its hypoglycemic action through the gut microbiota-short-chain fatty acids(SCFAs)-glucagon-like peptide-1 (GLP-1) signaling axis.

The 8 weeks-old male db/db mice were divided into a model group, low-, medium- and high-dose NCSDF treatment groups, and a control group of db/m mice, with 10 mice in each group. After continuous administration for 8 weeks, fasting blood glucose, insulin and GLP-1 levels were measured in each group. The gut microbiota structure and metabolite levels were analyzed using 16S rRNA sequencing and SCFAs detection.

NCSDF intervention reduced fasting blood glucose levels, improved insulin resistance, and upregulated serum GLP-1 levels in db/db mice. Additionally, NCSDF intervention modulated the gut microbiota structure, increasing the abundance of SCFA-producing bacterial genera such as Bacteroides, Lachnospiraceae and Prevotellaceae, and elevated the concentrations of acetic acid, propionic acid, butyric acid, isobutyric acid and valeric acid in the intestinal content.

NCSDF may promote GLP-1 release and enhance insulin sensitivity in peripheral tissues by modulating the gut microbiota-SCFAs-GLP-1 signaling axis, thereby exerting its hypoglycemic effect.

To establish a method for the determination of dilauryl thiodipropionate (DLTP) in foods by gas chromatography-tandem mass spectrometry (GC-MS/MS).

Samples were extracted with acetonitrile. For lipid-rich samples, a solvent system composed of hexane-saturated acetonitrile was employed for defatting and purification. The resulting extract was then subjected to centrifugation, dehydration and filtration through a microporous membrane to complete sample preparation. The established GC-MS/MS method, combined with an external standard calibration approach, was applied to determine DLTP in various food matrices, including fruits, vegetables, puffed foods, fried nuts and seeds and fried flour-based products.

DLTP exhibited good linearity in the mass concentration range of 0.1–2.0 mg/L, with correlation coefficients all greater than or equal to 0.996. At different matrixes and different spiked concentration levels, the method demonstrated recoveries ranging from 81.8% to 107.8%, with relative standard deviations of 0.59%–5.75% (n=6). The limit of detection was 0.3 mg/kg, and the limit of quantitation was 1.0 mg/kg.

The developed method is simple to perform, accurate and exhibits satisfactory sensitivity. It is suitable for the quantitative determination of DLTP in foods and can provide reliable technical support for the safe use and regulatory oversight of this food additive.

To develop a Orah lactic acid bacteria fermented beverage with both excellent taste and health-promoting functions, and to conduct a comprehensive quality analysis thereof.

Single-factor experiments were conducted to investigate the effects of material-liquid ratio, white sugar addition amount, strain compound ratio, inoculation amount, fermentation time and temperature on the fermentation process. Basic parameters were screened by combining fuzzy comprehensive evaluation, and response surface methodology was further used for optimization and to establish a sensory evaluation prediction model.

The optimized optimal process parameters were determined as follows: Inoculation amount of 3%, fermentation temperature of 35 °C and fermentation time of 6 h, under these conditions, the fuzzy comprehensive evaluation value reached 0.9397. The physicochemical indexes of the fermented beverage were: Total acid content of 1.12 g/100 mL, total sugar content of 10.6 g/100 mL, pH 3.54 and soluble solid content of 12.4°Brix.

This study develope Orah lactic acid bacteria fermented beverage complies with GB/T 31121—2014 Fruit and vegetable juices and beverages. The research provide a theoretical basis for the development of high-value-added products from deep processing of Orah.

To establish a method for determination of 9 kinds of biogenic amines in aquatic products by tandem ion chromatography-ultraviolet detection (IC-UV).

Fish samples were ultrasonically extracted with 0.2 mmol/L methanesulfonic acid solution then protein was precipitated with acetonitrile, and analyzed after filtration through a membrane. The 9 kinds of biogenic amines and coexisting ions in the samples were separated on an IonPac CS17 cation exchange chromatographic column (250 mm×4 mm, 7 µm). The experimental conditions, including eluent condition, column temperature and detector wavelength range, were optimized to achieve optimal performance.

The 9 kinds of biogenic amines exhibited wide linear ranges: Octopamine, tyramine and tryptamine showed good linearity in the mass concentration range of 0.2–20.0 mg/L, putrescine, cadaverine, spermidine and spermine in the mass concentration range of 0.02–20.00 mg/L; and histamine and phenethylamine in the mass concentration range of 0.10–20.00 mg/L; with linear correlation coefficients (r²)≥0.9960 and satisfactory recoveries (83.8%–122.9%). The limits of detection for putrescine, cadaverine, histamine, phenethylamine, spermidine, spermine, octopamine, tyramine and tryptamine were 0.23, 0.30, 1.63, 1.56, 0.21, 0.26, 1.97, 2.50 and 2.88 mg/kg, respectively.

This method is simple, eliminates the complex derivatization pretreatment, and offers excellent selectivity and high sensitivity, making it suitable for the detection and analysis 9 kinds of biogenic amines in aquatic products.

To explore the effects of different modified atmosphere packaging on the freshness and microbial community structure changes of chilled beef during storage.

This study established 4 treatment groups: Modified atmosphere packaging group 1 (LAR) (20% O₂, 10% N₂, 70% CO₂+absorbent pad), modified atmosphere packaging group 2 (ARAB) (20% O₂, 10% N₂, 70% CO₂+self-made antibacterial absorbent pad), modified atmosphere packaging group 3 (MAR) (45% O₂, 10% N₂, 45% CO₂+absorbent pad), and modified atmosphere packaging group 4 (HAR) (60% O₂, 20% N₂, 20% CO₂+absorbent pad). The 4 kinds of different types of chilled beef in modified atmosphere packaging were stored at 4 ℃ for 10 days. The sensory properties, pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARs), drip loss rate and total viable count of the chilled beef during the storage period were regularly measured, and the changes in the microbial community structure were analyzed simultaneously.

During the 10 d storage period, all the samples treated with modified atmosphere packaging remained at the first grade of freshness, and the TBARs did not exceed the standard limit. On the 10th day of storage, all the samples showed unacceptable conditions such as unpleasant odors. The total number of colonies increased to varying degrees from 0 to 6 days and then tended to stabilize. TVB-N did not exceed the limit (15 mg/100 g) within the 6-day storage period. The drip loss rate increased in all groups during the storage period, with the MAR group showing the smallest rate of change. At the beginning of storage, the dominant phyla in all modified atmosphere packaging treatment groups were Firmicutes, Actinobacteriota, Proteobacteria and Bacteroidota. As the storage time increased, the dominant phyla also changed. In the high oxygen content treatment group HAR, the dominant phyla were Firmicutes and Proteobacteria, while in the other groups, they were all Firmicutes. At the genus level, the dominant genera in the HAR treatment group were Leuconostoc, Lactobacillus, Lactococcus, Serratia and Pseudomonas, while in the other treatment groups, the dominant genera were Leuconostoc, Lactobacillus and Lactococcus.

In this study, different modified atmosphere packaging has certain effects on the freshness and microbial community of chilled beef during storage. It is worth noting that the dominant bacterial genera in the LAR, ARAB and MAR groups are all lactic acid bacteria, while in the HAR group with an oxygen content of 60%, the dominant bacterial genera are Pseudomonas, Serratia and other genera.

To establish a method for the simultaneous determination of 38 kinds of organic ultraviolet absorbents (OUVAs) in pork by ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).

The target compounds were extracted with acetonitrile and purified by pass-through solid-phase extraction EMR-Lipid, followed by gradient elution with 2 kinds of mobile phase systems:Methanol-0.1% formic acid aqueous solution and methanol-0.1% ammonia aqueous solution. The separation was performed on an Acquity UPLC BEH C₁₈ column (100 mm×2.1 mm, 1.7 μm). Mass spectrometry analysis was conducted using positive and negative electrospray ionization sources in multiple reaction monitoring mode, with targeted quantification performed by the internal standard method.

Within their respective mass concentration range, 38 kinds of OUVAs showed good linear relationships (r²≥0.9958), with the limits of detection ranging from 0.002 to 0.300 μg/kg and the limits of quantitation from 0.005 to 0.900 μg/kg. At 3 fortification levels in blank matrices, recoveries ranged from 61.2% to 128.2%, with relative standard deviations all below 11.8%. This method was applied to 19 commercially available pork samples, identifying 17 kinds of OUVAs. The concentration levels of ΣOUVAs ranged from 4.28 to 30.39 μg/kg.

This method is portable, efficient, reproducible and capable of multiple target compounds, making it suitable for the trace determination of 38 kinds of OUVAs in pork.