To establish a method for determining caffeine content in tea by ultra performance liquid chromatography-triple quadrupole mass spectrometry.

The samples were separated on a BEH C₁₈ column(2.1 mm×50 mm, 1.7 μm) via isocratic elution with a mobile phase consisting of 0.1% formic acid in water and acetonitrile (80:20, V:V). The flow rate was set at 0.3 mL/min, with an injection volume of 5 μL and a column temperature maintained at 25 ℃. Quantification was performed using the external standard method. Mass spectrometric analysis was conducted in the positive mode with the quantitative ion pair being m/z 195.0/137.9, and the qualitative ion pairs being m/z 195.0/109.9 and m/z 195.0/82.9. The capillary voltage was set at 1.00 kV, the cone voltage was set at 50 V, the desolvation gas (N₂) temperature was set at 500 ℃, the desolvation gas (N₂) flow rate was set at 1000 L/Hr, the cone gas flow rate at was set 50 L/hr, and the collision gas was high-purity argon.

The results demonstrated a limit of detection was 0.25 ng/mL for caffeine. The method exhibited excellent linearity with in the mass concentration range of 1–2000 ng/mL, with a correlation coefficient (r) of 0.9994. The spike average recovery rates ranged from 101.6% to 106.6%, with relative standard deviation (RSD) between 1.47% and 3.12%(n=3). The precision, repeatability and stability results were all satisfactory.

This method is rapid, sensitive, offers high resolution and is well-suited for the quantitative analysis of caffeine in tea.

To investigate the inhibitory effect of purple sweet potato anthocyanins (PSPA) on oxidative stress, and elucidate its underlying molecular mechanism.

The potential targets of PSPA active components and oxidative stress were screened through public databases to obtain overlapping targets, which subsequently underwent gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses to preliminarily elucidate the underlying mechanisms. An oxidative stress model was established in BV2 microglial cells using lipopolysaccharide (LPS) induction. Cells were pretreated with low or high doses of PSPA. The levels of nitric oxide (NO), malondialdehyde (MDA), glutathione (GSH), and the activity of catalase (CAT), superoxide dismutase (SOD) were measured using enzyme-linked immunosorbent assay. Apoptosis was assessed via Hoechst staining and flow cytometry, and related protein expression was analyzed by Western blot.

The main active components of PSPA were identified as peonidin and cyanidin. Network pharmacology analysis identified 253 PSPA-related targets and 1178 oxidative stress-related targets, with 86 overlapping targets. Topological analysis suggested that PSPA might counteract oxidative stress by targeting key proteins such as protein kinase B alpha(AKT1), epidermal growth factor receptor (EGFR) and heat shock protein 90 alpha family class A member 1(HSP90AA1). Molecular docking confirmed strong binding affinity between PSPA and the top 3 core targets. GO and KEGG analyses indicated that PSPA was involved in regulating cellular components such as the cytosol and cytoplasm; biological processes including activation of the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signaling pathway and protein phosphorylation; and pathways related to chemical carcinogenesis–reactive oxygen species. Cellular experiments demonstrated that PSPA significantly reduced NO and MDA levels, increased GSH content and CAT and SOD activity, inhibited abnormal apoptosis, and modulated PI3K/AKT phosphorylation.

PSPA effectively alleviates LPS-induced oxidative stress damage in BV2 microglial cells, likely through direct activation of the PI3K/AKT signaling pathway.

To investigate the preparation process, physicochemical properties and flavor characteristics of soluble proteins from Stropharia rugosoannulata.

Ultrasound-assisted extraction was employed to prepare soluble protein from Stropharia rugosoannulata. The key process parameters-including ultrasonic power density, treatment time, extraction temperature and solid-to-liquid ratio-were optimized using single-factor and response surface methodology. The resulting protein extracts were systematically characterized in terms of amino acid composition (analyzed with an amino acid analyzer), secondary structure (determined by circular dichroism), thermal properties (measured via differential scanning calorimetry) and umami intensity (evaluated through sensory analysis).

After process optimization, the optimal conditions for preparing the soluble protein extract were determined: An ultrasonic power density of 375 W/L, an ultrasonic treatment time of 10 minutes, an ultrasonic extraction temperature of 30 ℃, and a feedstock-to-liquid ratio of 1:30 (g:L). Under these conditions, the protein content in the extract reached (431.20±2.67) mg/g, with essential amino acids accounting for(99.10±0.26) mg/g, and the umami amino acid glutamate accounted for 27.56%. The proportion of α-helix and random coils increased, and the denaturation temperature was 108.06 ℃. Umami evaluation results showed that the 8 mg/mL soluble protein extract exhibited equivalent umami intensity to 2 mg/mL monosodium glutamate.

The research can provide theoretical basis for the development and application of soluble protein products of Stropharia rugosoannulata.

To assess the toxicological safety of Cornu cervi pantotrichum-Ganoderma lucidum liquor.

According to GB 15193—2014 National food safety standard-Acute oral toxicity test, the safety of Cornu cervi pantotrichum-Ganoderma lucidum liquor was evaluated through acute oral toxicity test on mice, 3 genetic toxicity tests and 28-day oral toxicity test.

The maximum tolerated dose (MTD) of Cornu cervi pantotrichum-Ganoderma lucidum liquor for both male and female mice was greater than 42 mL/kg, indicating it was a practically non-toxic sample. No mutagenic effects were found in the genetic toxicity test. In the 28-day oral toxicity test, Cornu cervi pantotrichum-Ganoderma lucidum liquor at all doses had no significant impact on the body weight, food utilization rate, urine indicators and organ-to-body weight ratio of rats. The hemoglobin and hematocrit values of female rats in the low-dose group were significantly reduced compared to base liquor control group, but no abnormal changes related to the sample were found in the histopathological examination. The no-observed-adverse-effect level of Cornu cervi pantotrichum-Ganoderma lucidum liquor for both male and female rats in the 28-day oral toxicity test was 42 mL/kg.

Cornu cervi pantotrichum-Ganoderma lucidum liquor does not show general toxicity or genetic toxicity at the doses studied in this research, indicating a high level of edible safety. This study provides a scientific basis for the development and utilization of Cornu cervi pantotrichum-Ganoderma lucidum liquor.

To investigate the effects of cold acclimation treatment on the storage performance and storage quality of 6 kinds of common edible pepper varieties.

Peppers were cold acclimation treatment at 0 ℃ and 4 ℃ and then stored at 10 ℃. The decay rate, decay index, chilling injury index, color change index, physiological quality and nutritional value of peppers during storage were analyzed.

Cold acclimation treatment could effectively inhibit decay and color change in most edible pepper varieties, especially bell peppers. Untreated peppers exhibited rot and color change indices of 19.23% and 43.59%, respectively, while peppers subjected to 0 ℃ for 5.25 h and 4 ℃ for 0.75 h showed no color change or rot. Cold acclimation treatment at 4 ℃ for 0.75 h delayed water loss, reduced respiration rate, inhibited malondialdehyde accumulation and delayed the degradation of chlorophyll and vitamin C during storage.

Cold acclimation represents a cost-effective, chemical-free preservation strategy that effectively inhibits quality deterioration in most edible peppers during storage. It significantly extends the shelf life of bell peppers and maintains their postharvest quality. This approach offers clear industrial value in mitigating postharvest losses and ensuring the supply of high-quality vegetables.

To understand the pollution status of phenolic endocrine disruptors in aquatic products in Shanghai and evaluate the dietary exposure risk of phenolic endocrine disruptors among Shanghai residents.

Based on the monitoring data of phenolic endocrine disruptors in aquatic products sold in Shanghai from 2024 to 2025, combined with the aquatic product consumption data of Shanghai residents in 2024, a simple distribution assessment method was used to evaluate the dietary exposure of phenolic endocrine disruptors in aquatic products.

The overall detection rate of 5 kinds of phenolic endocrine disruptors in 340 aquatic product samples sold in Shanghai was 98.2%. Among them, the detection rate of nonylphenol in aquatic products was 77.4%, the average content was 20.20 μg/kg, and the maximum value was 380.19 μg/kg. The detection rate of bisphenol A in aquatic products was 3.5%, with an average content of 2.29 μg/kg and a maximum value of 190.31 μg/kg. The detection rate of 4-tert-octylphenol in aquatic products was 95.9%, with an average content of 14.14 μg/kg and a maximum value of 345.02 μg/kg. Both 4-n-nonylphenol and 4-n-octylphenol were not detected in aquatic products. According to the analysis of aquatic product types, the average content of nonylphenol in freshwater crabs (39.13 μg/kg) was the highest, followed by marine crabs (34.44 μg/kg). The average content of bisphenol A in freshwater fish (4.69 μg/kg) was the highest, followed by shellfish (3.10 μg/kg). The average content of 4-tert-octylphenol in marine crabs (22.76 μg/kg) was the highest, followed by freshwater shrimps (16.88 μg/kg). The mean daily exposure and P₉₅ exposure of nonylphenol through aquatic products for Shanghai residents aged ≥3 years old were 3.25×10^–2 μg/kg bw and 9.15×10^–2 μg/kg bw, respectively, both of which were much lower than the tolerable daily intake (TDI) of 5 μg/kg bw. The mean daily exposure and P₉₅ exposure of bisphenol A through aquatic products for Shanghai residents were 4.11×10^–3 μg/kg bw and 1.45×10^–2 μg/kg bw, respectively, which were much less than the temporary ADI (4 μg/kg bw). The mean daily exposure and P₉₅ exposure of 4-tert-octylphenol through aquatic products for Shanghai residents were 2.52×10^–2 μg/kg bw and 7.01×10^–2 μg/kg bw, respectively.

The health risks for Shanghai residents from ingesting nonylphenol and bisphenol A solely through aquatic product consumption are relatively low.

To explore the differences in sensory quality and biochemical components of Pu-erh tea under different storage environments.

High performance liquid chromatography was used to quantitatively detect more than 20 active components such as catechins, flavonoids and amino acids in 3 kinds of sun-dried green tea stored in Kunming and Dongguan and 3 kinds of Pu-erh (ripe tea) stored in Kunming and Guangzhou, and the sensory quality was evaluated.

The main substances affecting the quality differences of 3 kinds of sun-dried green tea stored in 2 places were catechins and amino acids. There were significant differences in the content of gallocatechin gallate, gallic acid, glutamic acid, tyrosine, valine and aspartic acid in the sun-dried green tea samples stored in Dongguan and Kunming. The content of epicatechin gallate and gallocatechin gallate in 3 kinds of sun-dried green tea samples stored in Kunming were higher than those in the tea samples stored in Dongguan. The different components of Pu-erh (ripe tea) stored in Guangzhou and Kunming were mainly manifested in amino acids and catechins. The content of theanine, methionine and phenylalanine in the tea samples stored in Kunming were higher than those in the tea samples stored in Guangzhou. Epigallocatechin, catechin gallate, epigallocatechin gallate, arginine, histidine and leucine were higher in Kunming warehouse than in Guangzhou warehouse. Gallic acid and rutin were lower in Kunming than in Guangzhou. The results of sensory evaluation showed that the scores of sun-dried green tea samples in Kunming warehouse were higher than those in Dongguan warehouse, and the sensory quality scores of Pu-erh ripe tea samples stored in Guangzhou were slightly higher than those in Kunming warehouse.

Different storage environments have an important impact on the quality components such as gallic acid and amino acids in Pu-erh tea. The main influencing substances are gallocatechin gallate, gallic acid and glutamic acid, theanine, etc.

To optimize the alkali deastringency process of Phyllanthus emblica L. dried fruit and develop a unique and standardized composite tea bag containing Phyllanthus emblica L. dried fruit and black tea.

Using Phyllanthus emblica L. dried fruit as the raw material, alkali deastringency was performed with NaHCO₃ solution. Firstly, through single factor and orthogonal experiments, the solid-liquid ratio, NaHCO₃ mass fraction, deastringency temperature and deastringency time were optimized using deastringency rate as the indicator. Subsequently, based on the optimal deastringency process and using sensory evaluation as the evaluation criterion, the formula ratios of Phyllanthus emblica L. dried fruit, black tea, red dates and licorice in the composite tea bag were optimized.

The optimization experiment of the deastringency process showed that the optimal conditions were a solid-liquid ratio of 1:3 (g:mL), NaHCO₃ mass fraction of 2.5%, deastringency temperature of 35 ℃ and deastringency time of 35 min. Under these conditions, the deastringency rate reached 71.38%. The optimal formula for the composite tea bag was determined through formula optimization experiments to be 50% Phyllanthus emblica L. dried fruit, 30% black tea, 20% red dates and 10% licorice. The sensory score of the product produced based on this was 87.2 points, with a smooth taste, prominent fruit aroma and a long aftertaste. All indicators of the product comply with the GB/T 24690—2018 Bagged tea standard.

This study successfully establishes an efficient deastringency process for Phyllanthus emblica L. dried fruit, and developes a composite tea bag with excellent sensory quality and huge market potential, providing reliable theoretical basis and technical support for its industrial production and market promotion.

To study the toxicological safety of arabica coffea pulp.

The acute oral toxicity tests, 90-day oral toxicity tests, teratogenicity tests and 3 genetic toxicity tests were conducted on arabica coffea pulp in accordance with GB 15193.3—2014 National food safety standard-Acute oral toxicity test and other toxic test methods.

No obvious signs of poisoning symptoms appeared when the experimental animals were given 15.0 g/(kg·BW) of arabica coffea pulp in one time, and there was no death during the observation period, which indicated that the lethal dose of 50% of coffee pulp for experimental animals was more than 15.0 g/(kg·BW);during the 90-day oral toxicity test in rats, the rats were able to move freely, their growth and development were in good condition, and there was no death, there was no obvious change in rats, the blood routine and other indicators were within the normal value range, and there was no statistically significant difference (P>0.05); no specific damage and typical pathological and histological changes were observed in anatomical and pathological studies; at a dose of 10.0 g/(kg·BW), the rats showed no obvious embryotoxicity and teratogenic effects; the results of the 3 genetic toxicity tests were negative, and noagenic effects were seen.

The arabica coffea pulp has no genetic, no teratogenic and no toxic under the given test conditions, and has high safety in food development.