To enhance the efficiency and performance of acellular dermal matrix (ADM) derived from the skin of Oreochromis niloticus, optimize the preparation process.

A decellularization process for Oreochromis niloticus skin was developed by combining physical (ultrasound) and chemical (tributyl phosphate, TBP) methods to prepare a decellularized fish skin matrix. The process parameters were optimized using DNA content and mechanical strength as evaluation indices.

Oreochromis niloticus skin was decellularized for 3.70 h at a TBP concentration of 1.6% and an ultrasonic power of 200 W. The resulting ADM demonstrated good mechanical strength and satisfied the requirement for decellularized materials, which was a DNA content of less than 50 ng/mg.

The ultrasonication-assisted TBP method for preparing decellularized fish skin matrix has been shown to significantly reduce the decellularization time whilst concomitantly improving the physicochemical properties of the resultant decellularized matrix. This provides a valuable reference point for the high-value utilization of the by-product fish skin from the processing of Oreochromis niloticus, and its potential application in the field of biomaterials.

To establish a method for determining the content of 4 kinds of fusel alcohols, namely n-propanol, n-butanol, isobutanol and isoamyl alcohol in Baijiu by gas chromatography (GC) internal standard method.

The experiment employed a DB-WAX UI chromatographic column (30.0 m×0.25 mm, 0.25 μm) and selected tert-amyl alcohol as the internal standard. By systematically optimizing the instrument operating parameters, complete separation of each fusel alcohol from the internal standard and other components in the Baijiu matrix was achieved. The feasibility of the method was verified through method consistency analysis.

The determination coefficients (r²) for the 4 kinds of fusel alcohols within the set concentration range (0–500 mg/L) were all greater than 0.999. The limits of detection at 3 times the signal-to-noise ratio ranged from 0.073 to 0.128 mg/L, and the limits of quantitation at 10 times the signal-to-noise ratio ranged from 0.242 to 0.426 mg/L, meeting the detection requirements for low concentrations. The recovery rate ranged from 94.39% to 107.40%, demonstrating good precision and accuracy. The paired sample t-test revealed no significant difference (α=0.05, P>0.05) between the detection values obtained by this method and those determined according to GB/T 5009.48—2003 Methods for analysis hygienic standard of distilled wines and mixed wines. The method demonstrated good consistency.

This method is simple to operate, exhibits excellent separation efficiency demonstrates high stability and precision. It can effectively avoid systematic errors and meets the quantitative analysis requirements for fusel alcohols in Baijiu.

To compare the characteristics of antioxidant and antimicrobial activities of polyphenol-enriched extracts from 3 Lamiaceae plants—Perilla frutescens, Rosmarinus officinalis and Thymus vulgaris.

The polyphenol-enriched extracts of the 3 plants were prepared using macroporous adsorption resin. The content of total polyphenols and their common component-rosmarinic acid were determined. The antioxidant activities were evaluated by the scavenging capacities against 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) disodium salt positive ion radical (ABTS⁺·), as well as the ferric ion reducing capacity. The antimicrobial activities against Escherichia coli, Staphylococcus aureus and Aspergillus niger were evaluated by the minimum inhibitory concentration (MIC) and fungal inhibition rate.

After enrichment with macroporous resin, the content of rosmarinic acid in the polyphenol-enriched extracts of Perilla frutescens,Rosmarinus officinalis and Thymus vulgaris were (21.59±0.19)%, (20.56±0.03)% and (23.25±0.97)%, respectively. All 3 extracts exhibited strong antioxidant activities, which enhanced with the increase of total polyphenol and rosmarinic acid content; among them, the ferric ion reducing capacity of the Thymus vulgaris extract was particularly prominent, higher than that of the positive control group (vitamin C). Antimicrobial tests showed that the 3 extracts had certain inhibitory effects on Escherichia coli and Staphylococcus aureus, being particularly sensitive to Staphylococcus aureus. The MIC of the extracts from Perilla frutescens, Rosmarinus officinalis and Thymus vulgaris were 0.31, 0.63 and 0.31 mg/mL,respectively. In the antifungal test against Aspergillus niger, the Thymus vulgaris extract showed the best inhibitory effect, with an inhibition rate of (51.55±3.27)% on the 4th day, while Perilla frutescens showed no significant inhibitory effect.

The polyphenol-enriched extracts of the 3 Lamiaceae plants possess excellent antioxidant and antimicrobial activities, which are closely related to the enriched total polyphenols and rosmarinic acid. This provides a theoretical basis for the formulation development of plant-based natural food preservatives and preservation agents.

To optimize the processing technology of black tea made by Forsythia suspensa leaves, improve and enhance its flavor quality, and clarify the composition of its characteristic aroma substances.

Taking the comprehensive sensory evaluation score as the evaluation index, the effects of fermentation temperature, fermentation humidity and fermentation time on the flavor quality of black tea made by Forsythia suspensa leaves were explored through single-factor experiments, and the Box-Behnken response surface method was used to optimize the optimal fermentation process conditions. The headspace solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) technology was applied to analyze the volatile flavor components of samples, and the key aroma-active substances were screened based on odor activity value (OAV).

The optimal fermentation process parameters for black tea made by Forsythia suspensa leaves were determined as fermentation temperature of 32 ℃, fermentation time of 3.8 h and fermentation humidity of 91%. The tea prepared under these conditions presented bright red liquor, elegant aroma and mellow taste, with significantly improved sensory quality. A total of 56 volatile flavor compounds were identified from the samples, belonging to 8 categories, mainly including aldehydes, alcohols, ketones, alkenes and phenols. Among them, 3-methylbutanal, 2-methylbutanal, phenylacetaldehyde, linalool, nonanal, phenethyl alcohol, α-terpineol, geraniol, eugenol and trans, trans-2,4-decadienal were the key aroma-active substances of black tea made by Forsythia suspensa leaves.

Appropriate fermentation process can significantly improve the sensory flavor of black tea made by Forsythia suspensa leaves. Aldehydes and alcohols are the core contributing components of its characteristic aroma. The optimized process in this study is stable and feasible, which can provide a certain reference for the large-scale production and flavor quality regulation of black tea made by Forsythia suspensa leaves.

To construct a Hylocereus polyrhizus-surimi composite gel system.

Hylocereus polyrhizus pulp was incorporate into surimi at mass ratios of 0%, 5%, 10%, 15% and 20% to prepare fish stick. The sensory quality, color, texture property, gel strength, water-holding capacity, cooking loss, pH, thermal stability of betacyanin and major nutritional components of the composite gels were systematically evaluate.

The addition of Hylocereus polyrhizus enhanced multiple quality attributes of the composite gels. At 10% addition, the fish stick gels achieved the highest sensory scores in color, odor and overall acceptability, exhibiting optimal color development and flavor harmony. Gel strength increased by 71.13 g·cm compared with the control group, cooking loss decreased to 4.64%, water-holding capacity reached 71.36%, and betacyanin retention rate was 88.57%, indicating the best thermal stability. Meanwhile, fat content decreased while moisture and protein content increased, resulting in an optimized nutritional profile.

The addition of 10% Hylocereus polyrhizus significantly improves the color, gel properties and nutritional composition of fish strips. The incorporation of an appropriate amount of Hylocereus polyrhizus promotes the densification of the composite gel network structure, which effectively enhances the thermal stability of the pigment, water-holding capacity and sensory quality of the product. This study provides a theoretical basis for the functional application of natural pigments in surimi products and offers a technical approach for developing nutritionally fortified surimi products.

To investigate the suitability of 3 kinds of tea plant varieties in Fuliang County for black tea production.

Fuliang black tea was produced using the Group variety, Zhuyeqi and Zhuye variety as raw materials. The sensory quality, biochemical components and flavor compounds of the 3 kinds of Fuliang black teas were systematically compared.

Sensory evaluation indicated that Zhuyeqi exhibited prominent golden tips, a pure red-yellow liquor color and the highest overall score; Zhuye variety produced the brightest liquor color. Physicochemical analysis revealed significantly higher water-soluble substances (43.53%±0.02%), caffeine (43.70mg/g), catechin gallate(0.67%±0.01%) and gallic acid (4.11 mg/g) in Zhuye variety; higher tea polyphenols (8.85%±0.13%) and catechins(0.37%±0.02%) in Group variety; and superior theabrownins (7.23%±0.05%) accumulation in Zhuyeqi. Analysis of the taste activity value (TAV) showed that caffeine was a common key bitter compound, while epigallocatechin and gallic acid contribute to astringency to varying degrees across different varieties. Specifically, epigallocatechin (TAV=1.08)was the key bitter compound in Group variety; epicatechin (TAV=1.15) was the key astringent compound in Zhuyeqi;and catechin gallate (TAV=1.22) was the key astringent compound in Zhuye variety. The aroma components varied significantly. Geraniol was the dominant aromatic component in Group variety (33.09%) and Zhuyeqi (29.91%),imparting rose-like and sweet fragrance notes, whereas Zhuye variety exhibited a balanced profile consisting of β-linalool (25.38%) and geraniol (17.24%).

This study clarifies the differences in sensory quality,characteristic flavors and aroma components among the 3 kinds of varieties, providing experimental basis for variety selection, targeted processing and quality control of Fuliang black tea.

To study the drug sensitivity and biofilm forming ability of Listeria monocytogenes isolated from instant delicatessen meats in Chaoyang District, Beijing.

A total of 41 strains of Listeria monocytogenes isolated from instant delicatessen meats were collected. Serotyping was performed by combining polymerase chain reaction (PCR) with serum agglutination. Drug sensitivity tests were conducted using the micro-broth dilution method, and the biofilm forming ability and genes related to biofilm formation were detected by 96-well plate crystal violet staining and PCR.

Listeria monocytogenes was classified into 4 kinds of serotypes: 1/2a serotype 46.34% (19/41), 1/2b serotype 29.27% (12/41), 1/2c serotype 21.95% (9/41) and 4b serotype 2.44% (1/41). The resistant rates of erythromycin, tetracycline, penicillin, gentamicin, vancomycin were 9.76%, 7.32%, 4.88%, 4.88%, 2.44%. No resistant strains to ampicillin, ciprofloxacin and chloramphenicol were detected. The 90.24% (37/41) of the tested strains exhibited biofilm-forming capacity, among which weak, moderate and strong biofilm-forming isolates accounted for 70.73% (29/41), 14.63% (6/41) and 4.88% (2/41), respectively. All drug-resistant strains exhibited biofilm-forming ability. The positive rates of flaA, degU, motB, sigB, yneA, agrA, relA, luxS, bapL were 100.00% (41/41), 97.56%(40/41), 97.56% (40/41), 95.12% (39/41), 95.12% (39/41), 92.68% (38/41), 92.68% (38/41), 87.80% (36/41) and 41.46% (17/41). The distribution of agrA differed significantly among strains with varying biofilm-forming abilities(P<0.05), and strains with stronger biofilm-forming capacity showed a higher carriage rate of agrA.

Listeria monocytogenes isolates from instant delicatessen meats in Chaoyang District, Beijing is predominantly 1/2a serotype. Drug-resistant strains with biofilm-forming capacity are identified, which may increase the risk of persistent contamination by drug resistant strains.

To investigate the chemical composition of red raisins and their mechanism of anti-cerebrocardiac insufficieny by ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) combined with network pharmacology.

UPLC-Q-TOF-MS coupled with Insight Explore Ver4.0 screening platform was adopted for rapid qualitative analysis of chemical constituents in red raisin extracts. Network pharmacology was applied to explore the mechanism of red raisins against insufficient cerebral-cardiac blood supply.

A total of 55 chemical constituents were identified from red raisin extracts by UPLC-Q-TOF-MS, mainly polyphenols and flavonoids. A total of 392 functional target of red raisins were screened, among which 264 intersecting targets were shared with insufficient cerebral-cardiac blood supply. The core targets included EGFR, SRC, STAT3, HSP90AA1 and AKT1. The 10 key pathways such as PI3K-Akt, MAPK, lipid and atherosclerosis pathways were mainly regulated to exert therapeutic effects on ameliorating insufficient cerebral-cardiac blood supply.

Red raisins exert therapeutic effects against insufficient cerebral-cardiac blood supply through synergistic regulation of multi-components, multi-targets and multi-pathways. It plays therapeutic roles by improving vascular function, alleviating ischemic injury, inhibiting inflammation and oxidative stress. This study provides scientific basis and experimental support for the development of functional foods, dietary therapy products and processing utilization of red raisins.

To establish a method for the determination of iron tartrate in edible salt by ion chromatography.

The sample was dissolved in water, and excess sodium hydroxide was added to dissociate iron tartrate and release tartrate ions. After purification with Ag column to remove chloride ion interference, the tartrate was determined by ion chromatography using L-tartaric acid as standard substance, and the content of iron tartrate was calculated by molecular weight conversion.

L-tartaric acid showed good linearity in the mass concentration range of 0.1–1.5 mg/L with correlation coefficient r=0.9986. The detection results were measured in terms of iron tartrate. The limit of detection was 17 mg/kg and the limit of quantitation was 50 mg/kg. In 3 kinds of matrices including refined salt(iodized), refined salt (non-iodized) and low-sodium salt, the spiked recoveries ranged from 86.1% to 107.9% with relative standard deviations of 0.45%–2.71%.

This method is simple, sensitive and accurate, suitable for the determination of iron tartrate in edible salt and salt substitutes.

To systematically investigate the effects of corn starches with different amylose content, including normal corn starch, high-amylose corn starch and waxy corn starch, on the freeze-thaw stability of konjac gels.

The texture characteristics, water separation rate and water retention rate of the samples were determined. The water distribution characteristics were analyzed in combination with low-field nuclear magnetic resonance technology, and the microstructure and crystalline structure analyses were carried out to reveal the structure-water-performance relationship of the composite gel.

The addition of corn starch could all improve the freeze-thaw stability of konjac gel. Among them, the 5% waxy corn starch system performed the best. After 5 freeze-thaw cycles, the water separation rate was only 5.58%, the water retention rate remained at 89.94%, the proportion of retained water in the system was maintained at 96.40%, and the proportion of free water was less than 1.20%. Moreover, the variation range of hardness and chewiness was the smallest. The results of scanning electron microscopy showed that the waxy corn starch system still maintained a continuous and uniform porous network structure before and after freeze-thaw, with only slight pore expansion. The results of the crystalline structure showed that its crystallinity changed the least, and the low-temperature regeneration was significantly inhibited. The appearance remained intact and the color was bright.

The highly branched amylopectin structure in waxy corn starch can restrict the regular arrangement of recrystallization and molecular chains. Meanwhile, the abundant hydroxyl groups on its molecules can form hydrogen bonds with konjac and water molecules, maintaining a stable hydration state and reducing the freedom of water migration. This effectively inhibits water migration, phase separation and structural damage induced by freeze-thaw cycles, significantly improving the freeze-thaw stability of konjac gel.