To investigate the antioxidant activity of lecithin by optimizing the process of ultrasonic-assisted ethanol extraction of lecithin from defatted egg yolk powder.

This study optimized the ultrasound-assisted ethanol extraction process using response surface methodology, investigating the effects of 3 factors: Ultrasonic time, ethanol concentration and solid-to-liquid ratio on the extraction efficiency of egg yolk lecithin. The resulting product was further purified via zinc chloride precipitation and acetone purification. The fatty acid composition, structure and antioxidant activity of the purified egg yolk lecithin were characterized.

The optimal extraction conditions were as follows: Ultrasonic time of 33 min, ethanol concentration of 94% and solid-to-liquid ratio of 1:22 (g:mL). Under these conditions, the lecithin content was 354.179 mg/g. Egg yolk lecithin was composed of 12 kinds of fatty acids, among which saturated fatty acids accounted for 53.32% of the total, and unsaturated fatty acids account for 46.68%. The infrared spectrum of egg yolk lecithin (in the wavelength of 4000–400 cm^–1) was basically consistent with that of standard. The same characteristic group stretching vibrations appeared at wave numbers of 1089.5, 1220 and 2851 cm^–1. High performance liquid chromatography analysis showed that the content of phosphatidylcholine (PC), phosphatidylinositol (PI) and phosphatidylethanolamine (PE) in the egg yolk lecithin sample were 268.9, 23.6 and 100.3 mg/g, respectively. The proportion of PC was approximately 89.65%, indicating that the prepared egg yolk lecithin had high purity. Lecithin exhibited good scavenging rates against 1,1-diphenyl-2-picryl-hydrazyl radical and superoxide anion free radicals, which were positively correlated with the sample concentration. The maximum scavenging rates were 52.02% and 82.2%, respectively, and the total antioxidant capacity was 80.81%.

The ultrasonic-assisted ethanol extraction method can extract egg yolk lecithin with high purity and good antioxidant activity from defatted egg yolk powder, which improves the utilization rate of defatted egg yolk powder.

To investigate the effects of different reheating times and temperatures of air fryer on the edible quality of pre-processed crispy pork.

This experiment analyzed the effects of air fryer reheating temperatures (160, 180, 200 ℃) and reheating times (8, 10, 12 min) on the oil content, moisture content, color difference, sensory properties, texture and flavor substances of conditioned crispy pork.

When the air fryer reheating temperature was 180 ℃ and the reheating time was 10 min, the moisture content of crispy pork was about 40.18%, and the oil content was about 19.34%; the L^* value was about 61.49, a^* value was about 11.49, b^* value was about 23.16; the total sensory score was 83.44; the hardness was at a moderate level, about 12.78 N. There were 33 kinds of volatile substances in this experimental group of crispy pork. Among them, the heterocyclic compound methylpyrazine and the aldehyde compounds 2-methylbutanal and hexanal contributed greatly to the flavor of crispy pork, and could endow it with nutty, baked, fruity and oily aromas.

Under this reheating condition, the crispy pork have crispy texture, unique flavor and good edible quality.

To study the physicochemical indicators of low-salt salted eggs in small packages and its gelation changes of egg white and egg yolk.

This study used the optimal process formula for low-salt salted eggs in small packages selected in previous work to pickle salted eggs. Replace some of the sodium salt with potassium salt, add Baijiu, spices, and use small packaging to pickle salted eggs. The changes in protein-related indicators of the gelation changes of egg white and egg yolk under the action of salt were detected.

The content of ionic bonds in the egg yolk protein of low-salt salted eggs in small packages increased to a maximum of 122.47 mg/100 g on the 14th day of pickling and then decreased. The content of hydrophobic interactions showed a trend of first increasing and then decreasing. The hydrophobic interaction content of fresh egg yolks increased from 7.95 mg/100 g to 16.62 mg/100 g after 21 days of pickling. The content of hydrogen bonds and disulfide bonds decreased, and the free sulfhydryl groups in the egg yolk showed a trend of first increasing and then decreasing. Both β-pleated sheets and β-turns showed an upward trend, while the content of α-helical structure decreased. The content of low-density lipoprotein decreased from 0.211 mmol/g to 0.110 mmol/g. Compared with fresh egg whites, the relaxation time and bound water changes of pickled egg white were not significant, the immobile water significantly decreased, and the free water significantly increased (P<0.05). The α-helical content of egg white gradually decreased from 20.36% to 16.33%, both β-pleated sheets and β-turns exhibited a trend of first increasing and then decreasing, and the random coil changes were not significant.

The introduction of salt alters the structure of egg white and egg yolk, causing the egg yolk particles to become more compact, oil to seep out, and cross-linking to occur. The free water in egg whites increases, the spatial structure changes, and the protein molecular structure unfolds, leading to the thinning of egg whites.

To investigate the composition of the volatile oil of Dracocephalum moldavica L. and its antioxidant capacity, and clarify the active substance basis and application potential of this plant.

The volatile oil of Dracocephalum moldavica L. was extracted by supercritical carbon dioxide extraction method. The volatile oil was systematically analyzed by gas chromatography triple quadrupole mass spectrometry. The percentage content of each component was calculated by peak area normalization method. The in vitro antioxidant capacity of the volatile oil of Dracocephalum moldavica L. was tested by cationic free radical scavenging methods, such as 1,1-diphenyl-2-picrylhydrazyl(DPPH) and 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺).

Using a gas chromatography-triple quadrupole mass spectrometry instrument, 24 kinds of compounds were identified from the volatile oil of Dracocephalum moldavica L. Among them, the fatty amide type ER erucic acid amide accounted for the highest proportion, and the types of ester compounds were the most numerous. Further in vitro antioxidant activity studies were conducted on the volatile oil, indicating that it had certain scavenging effects on DPPH free radicals and ABTS cationic free radicals, and the ABTS cationic free radicals scavenging ability [(median inhibition concentration, IC₅₀)=1.44 mg/mL] was superior to that of DPPH (IC₅₀=2.58 mg/mL). Through Ward clustering analysis, it was found that the higher the content of ER erucic acid amide, the stronger the antioxidant activity of the volatile oil.Statistical verification showed F=242 and (P<0.001), indicating that the differences in IC₅₀ values among the 3 groups were extremely significant, presenting a gradient change characteristic of antioxidant activity from strong to weak.

This research not only overcame the limitations of traditional extraction methods, but also clearly demonstrate that the volatile oil of Dracocephalum moldavica L. has significant in vitro antioxidant activity. It provides a solid scientific basis and reliable data support for the subsequent in-depth research and industrial processing and utilization of the volatile oil of Dracocephalum moldavica L..

To develop a method for the rapid quantitative detection of ochratoxin A in grain, oil crops and nuts by quantum dot fluorescence.

Using polystyrene microsphere quantum dot loading technology, a quantum dot microsphere probe with high fluorescence intensity was constructed by covalent coupling, ochratoxin A monoclonal antibody was coupled to the probe surface by activation coupling method, and the quantum detection system of ochratoxin A was constructed.

Through the optimization of experimental parameters, the established quantum dot fluorescence detection system showed excellent analytical performance for ochratoxin A.The linear relationship was good in the range of 1–20 ng/mL (r²>0.99), and the limits of detection and limits of quantitation were as low as 0.5 ng/mL and 2.0 ng/mL. The method had strong specificity, there was not significant cross reaction with common mycotoxins such as deoxynivalenol and zearalenone. The method was validated by methodology according to the standard of LS/T 6142—2023 Evaluation protocol for rapid detection method of mycotoxins in grains, spiked recovery rates were 90.3%–114.5%, and the relative standard deviation was less than 15%, the method of accuracy and precision met the requirements of the detection specification about ochratoxin A.

The quantum dot fluorescence detection system for ochratoxin A has the advantages of high sensitivity, good specificity, simple operation and rapid analysis, it is suitable for rapid and accurate quantitative detection of ochratoxin A in grain, oil crops and nuts, it provides an effective technical means for the field screening and monitoring of mycotoxins in agricultural products.

To investigate the contamination status of Listeria monocytogenes in the production and processing of Flammulina velutipes in Lianyungang City.

Samples were collected from the production and processing chain of Flammulina velutipes in Lianyungang City. Isolation, identification and multilocus sequence typing of Listeria monocytogenes were performed.

A total of 67 samples were positive for Listeria monocytogenes among 359 samples collected from the production and processing chain of Flammulina velutipes, with an overall detection rate of 18.66%. The differences in the detection rate of Listeria monocytogenes among different sampling years and sampling locations were statistically significant (P<0.05), whereas no significant difference was observed among different sample types (P>0.05). The contamination rate in 2024 was relatively high(24.71%), and the positive detection rate of samples from the mycelium scraping room (38.46%) was much higher than that from other sampling sites. Environmental samples showed the highest contamination rate (25.32%).Sequence typing (ST) of the 67 Listeria monocytogenes isolates revealed that ST87 (32 isolates) and ST8 (31 isolates)were the dominant sequence types.

Listeria monocytogenes contamination exists in the production and processing chain of Flammulina velutipes in Lianyungang City, with the scraping room and harvesting and packaging area being the most heavily contaminated sites. It is essential to strengthen monitoring and supervision in these links, and formulate targeted prevention and control measures focusing on highly contaminated areas and environmental management.

To identify the influence mechanisms of Solanum tuberosum L. storage and transportation management (packaging method, storage temperature and sprout inhibition measures), slice thickness and soaking time on the comprehensive quality of potato chips, and determine the optimal combination of process parameters.

Experiments were conducted by varying Solanum tuberosum L. bagging methods, storage temperatures, sprout inhibitor(chlorobenzylamine) dosage, firmness levels, slice thickness and soaking time. These factors were systematically evaluated for their effects on Solanum tuberosum L. storage traits and final potato chip quality indicators.

Experimental results indicated that using ton-sized packaging bags, maintaining storage temperatures between 9–11 ℃, and applying 43 mL/t of chloramphenicol as a sprout inhibitor effectively delayed Solanum tuberosum L. sprouting while reducing mechanical damage and storage losses. Additionally, Solanum tuberosum L. maintained optimal firmness within 30 days post-harvest. Processing during this period, combined with maintaining a slice thickness of no less than 2.7 mm, yielded potato chips with excellent color, crispness and oil absorption rates.

This combination of process parameters effectively safeguards Solanum tuberosum L. quality during storage and transportation while significantly enhancing the edible quality and safety of the final potato chips. It provides clear guidance for practical production, helps enterprises reduce raw material losses and improves potato chip product quality.

To establish a method for the determination of multiple mycotoxins in wheat and its products by direct extraction-ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Samples (2 g) were extracted with 10 mL 80% acetonitrile-water solution (containing 1% formic acid).After ultrasonic extraction, centrifugation, nitrogen blow-drying and reconstitution, the analytes were detected using an electrospray ionization (ESI) source in both positive and negative ion modes. Quantification was performed using the external standard method calibrated with a wheat flour matrix-matched standard curve.

The linear relationship of the 7 kinds of mycotoxins was good within a certain mass concentration range, with a determination coefficient (r²) greater than 0.998. The limits of quantitation were 0.40–7.70 μg/kg. The spiked recovery rates at the 3 levels were 77.9%–109.2%, and the relative standard deviations were 0.9%–9.0% (n=6).

The method has excellent precision and high sensitivity, it is suitable for the determination and high-throughput screening of mycotoxins in wheat and its products.