To optimize the method for free astaxanthin detection and develop an extraction process for astaxanthin from Xanthophyllomyces dendrorhous powder.

By optimizing the detection time and mobile phase ratio, an analytical method for free astaxanthin based on high performance liquid chromatography (HPLC) was established. On this basis, using Xanthophyllomyces dendrorhous powder as raw material, the extraction process for astaxanthin from Xanthophyllomyces dendrorhous powder was developed via single-factor experiments, Plackett-Burman design, and response surface methodology, using astaxanthin extraction yield as the evaluation index.

The limit of detection was 0.55 μg/g, and the limit of quantitation was 0.16 μg/g. The spike recoveries ranged from 105.12% to 127.70%, and the relative standard deviation in the precision test was less than 0.14%. The extraction process for astaxanthin from Xanthophyllomyces dendrorhous powder was developed and optimized as follows: The average particle size of superfine Xanthophyllomyces dendrorhous powder was 0.55 μm;the water addition ratio was 3.30:1 (mL:g); the dimethyl sulfoxide (DMSO) addition ratio was 41.25:1 (mL:g); the acetone addition ratio was 137.50:1 (mL:g); the extraction was performed twice; after water addition, the mixture was incubated at 45  ℃ for 5 min; and after DMSO addition, it was incubated at 45  ℃ for 15 min. The extraction yield was 2.74  mg/g.

The established HPLC method for free astaxanthin is sensitive, accurate and reproducible, enabling rapid quantitative analysis of free astaxanthin in Xanthophyllomyces dendrorhous. The optimized extraction process is efficient, stable and environmentally friendly. This study provides technical support for the application of Xanthophyllomyces dendrorhous astaxanthin in aquaculture, food and other fields.

To establish a method for determining the content of ergothioneine in edible and medicinal fungi, screen out edible and medicinal fungi with high ergothioneine content, and explore their antioxidant activities.

High performance liquid chromatography (HPLC) was adopted for content determination. An Agilent ZORBAX NH₂ column (4.6 mm×250 mm, 5 μm) was used, and isocratic elution was performed with acetonitrile-5 mmol ammonium acetate (80:20, V:V), followed by detection with an ultraviolet detector. To conduct methodological investigation using linearity, precision, stability, repeatability and recovery as indicators. The scavenging rates of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) cationic radical and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO)radical were used as indicators to evaluate the antioxidant capacity of ergothioneine in various edible and medicinal fungi.

For the 24 kinds of species of edible and medicinal fungi, the standard curve showed a linear range of 0.0053–0.1060 mg/mL, with a good linear relationship (r²>0.999), and the average recovery rate was 99.35%.Screening of edible fungi with high ergothioneine content among Boletus edulis, Armillaria mellea, Pleurotus citrinopileatus, Pleurotus ostreatus and Flammulina velutipes. And these 5 kinds of edible fungi also exhibited good antioxidant capacity; while the ergothioneine content in medicinal fungi was relatively low.

This method features simple operation and high detection efficiency, and can be applied to the determination of ergothioneine content in edible and medicinal fungi. It provides a scientific and reliable detection method for the content evaluation, quality control and resource development of ergothioneine in edible and medicinal fungi.Screening reveal that Boletus edulis, Armillaria mellea, Pleurotus citrinipileatus, Pleurotus ostreatus and Flammulina velutipes exhibit high ergothioneine content. And there is a certain dose-effect relationship between their mass concentration and in vitro antioxidant activity. This study lays a foundation for the subsequent development of ergothioneine from edible and medicinal fungi in the food and cosmetics industries.

To establish a method for simultaneous determination of the content of beauvericin (BEA), enniatin A (ENN A), enniatin A₁ (ENN A₁), enniatin B (ENN B) and enniatin B₁ (ENN B₁) in Castanea mollissima Blume by QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry.

The mass spectrometry conditions for 5 kinds of emerging mycotoxins were optimized. The optimal chromatographic column and mobile phase conditions based on the separation degree and peak shape of the chromatographic peaks were selected. The best extraction reagent and QuEChERS purification column through recovery rate indicators were determined. The matrix effects of Castanea mollissima Blume samples on 5 kinds of emerging mycotoxins were analyzed. Finally, a methodological experiment was conducted on the established method.

The method ultimately used acetonitrile-water (80:20, V:V) as the extraction reagent, selected QuEChERS column (primary secondary amine 50 mg, MgSO₄ 150 mg) for cleaning Treatment. The ACQUITY UPLC BEH C₁₈ column was used as the chromatographic column and acetonitrile-2 mmoL/L ammonium acetate was used as the mobile phase, the elution mode was gradient elution. Matrix effects of the method could not be ignored, the isotope internal standard method should be used for quantitative analysis. The limits of detection of BEA, ENN A, ENN A₁,ENN B and ENN B₁ were 0.03 μg/kg and the limits of quantatition were 0.1 μg/kg, the recovery rates were between 89.5% and 125.0%, the relative standard deviations were 1.6% to 8.4%, the correlation coefficients were all than or equal to 0.9990.

This method is simple, rapid, with the high accurates and ensitivity, which can be used for simultaneous determination of the content of BEA, ENN A, ENN A₁, ENN B and ENN B₁ in Castanea mollissima Blume.

To compare the analytical performance of high performance liquid chromatography with fluorescence detector and high performance liquid chromatography with diode array detector for determination of 9 kinds of biogenic amines in fermented wines.

Under identical pretreatment and chromatographic conditions, both methods were applied to determine 9 kinds of biogenic amines in fermented wines. A comprehensive evaluation was conducted based on linear range, sensitivity, precision, recovery and resistance to interference.

Both methods exhibited good linearity (r²≥0.9986) within the 1–50 μg/mL range, with precision (<3.00%)and accuracy meeting detection requirements. The fluorescence detection method exhibited higher sensitivity than the diode array detection method for most biogenic amines, with a detection limit as low as 0.05 μg/mL; however, its sensitivity for histamine, octopamine, and tyramine was comparable to that of the diode array detection method; The diode array detection method provided a more uniform response across different biogenic amines, whereas the fluorescence detection method demonstrates superior resistance to interference in complex matrices..

The high performance liquid chromatography-fluorescence detector is suitable for high-sensitivity detection of trace biogenic amines, whereas high performance liquid chromatography-diode array detector holds practical value for balanced screening and routine analysis of multiple biogenic amines.

To establish a method for determination the 4 kinds of androgen residues, namely testosterone, methyltestosterone, trenbolone and 17 β-trenbolone acetate in pork by QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry.

The pork samples were homogenized after comminution. Subsequently, water and acetonitrile solution were added sequentially for extraction by oscillation.Anhydrous magnesium sulfate and sodium chloride were introduced for dehydration, followed by centrifugation. The supernatant was collected and purified by adsorption using anhydrous magnesium sulfate and neutral alumina.The purified solution was dried under nitrogen in a water bath at 45 ℃, then redissolved by vortexing in an acetonitrile-water mixture (1:1, V:V). After filtration through a 0.22 μm microporous membrane, the solution was ready for analysis. For the determination of analytes, an ACQUITY UPLC BEH C₁₈ column (2.1 mm×100 mm,1.7 μm) was adopted. Acetonitrile and 0.1% formic acid aqueous solution were used as the mobile phase for chromatographic separation. Data acquisition was performed in the electrospray ionization positive mode with multiple reaction monitoring, and quantification was carried out via the external standard method.

The target compounds exhibited good linearity in the concentration range of 0.1–100.0 ng/mL, with all correlation coefficients (r²) greater than 0.999. The limits of detection were 0.1–0.3 μg/kg, and the limits of quantitation were 0.2–1.0 μg/kg. At the spiking levels of 2, 8 and 20 μg/kg, the recoveries were between 84.12% and 109.75%, with the relative standard deviations varying from 1.72% to 9.62%.

This method can simultaneously determine 4 kinds of androgens and the pretreatment is simple. It has high sensitivity, repeatability and accuracy and can provide a reference for related detection.

To establish an analytical method for detection of residual tildipirosin in raw milk by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).

The sample was extracted with acid acetonitrile, purified by enhanced matrix removal (EMR) purification column, and then separated by BEH C₁₈. The target compound was analyzed by a positive electrospray ion multiple reaction monitoring mode and quantitative analysis using matrix matching isotope internal standard method for quantification.

The calibration curves were linear in the range of 2.5–100.0 ng/mL with correlation coefficients more than 0.99. The limit of detection was 2.5 μg/kg, limit of quantitation was 5.0 μg/kg. The average recoveries at different addition concentrations ranged from 78.2% to 97.6%, with the relative stand deviations of the determination results ranged from 6.02% to 7.69%.

This method is accuracy, sensitive stability, simple and easy to operate, which can be used to determinate of residual amounts of tildipirosin in raw milk.

To investigate the targeted addition of Qiongbei red rice pigment into starch-based foods for modifying their nutritional and functional properties.

This study systematically examined the effects of red rice pigment on the physicochemical and digestive characteristics of starch using iodometry, scanning electron microscopy and rapid viscosity analysis.

Red rice pigment significantly influenced the physicochemical and digestive properties of starch (P<0.05). The addition of the pigment increased the pH of starch suspensions,reduced chroma, elevated a^* and b^*, and resulted in a reddish-brown appearance. It also significantly decreased the iodine blue value of wheat starch, altered the microstructure of starch granules, and increased granule size. In vitro digestion experiments showed that as pigment concentration increased from 0% to 1.0%, resistant starch content increased from 48.11% to 63.71%, while rapidly digestible starch decreased from 42.41% to 28.27%. Hydrolysis sensitivity values generally declined, and the predicted glycemic index of starch dropped from 94.40 to 73.81.

Red rice pigment reduces the iodine-binding capacity of starch in a dose-dependent manner. It interacts with starch through non-covalent bonds, affecting the spatial distribution and arrangement of starch chains, and disrupting the crystalline structure of starch granules. Consequently, the sensitivity of starch to hydrolytic enzymes decreases, leading to a reduced hydrolysis rate and inhibited in vitro digestibility.

To explore the distribution characteristics of amino acids and elements in Yiwu brown sugar, as well as the influences of flavor substances on its quality.

The 6 representative batches of brown sugar from the main producing areas of Yiwu were selected. The content of 16 kinds of amino acids, such as aspartic acid, threonine and serine, were determined using an automatic amino acid analyzer. The content of 17 kinds of elements, such as potassium, sodium and iron were measured using inductively coupled plasma mass spectrometry.Volatile flavor substances, such as decanal and nonanal, were detected using gas chromatography-mass spectrometry.

The maximum content of potassium, sodium elements in Yiwu brown sugar could reach 1.43×10⁴ mg/kg and 928 mg/kg, respectively. The total amino acid content of Yiwu brown sugar ranged from 0.452 to 1.390 g/100 g, and the total content of 7 kinds of essential amino acids ranged from 0.0875 to 0.187 g/100 g.Dihydro-3-hydroxy-4,4-dimethyl-2(3H)-furanone, nonanal, decanal and acetic acid were identified as key contributing components to the flavor of brown sugar.

Yiwu brown sugar exhibits significantly higher potassium and sodium content, with this high-potassium and low-sodium elemental distribution pattern playing a decisive role in its mineral nutritional value. The notable differences in total amino acid content and essential amino acids directly influence the flavor complexity and nutritional quality of the sugar. Key flavor contributors such as dihydro-3-hydroxy-4,4-dimethyl-2(3H)-furanone, nonanal, decanal, and acetic acid demonstrate that their compositional variations constitute the core factors shaping Yiwu brown sugar’s distinctive aroma profile. In summary, the quality characteristics of Yiwu brown sugar are collectively determined by the synergistic distribution patterns of its elemental composition, amino acids, and volatile flavor compounds..