To explore the effects of high voltage electrostatic field treatment on the storage quality and postharvest physiology of Pyrus ‘Yu Lu Xiang’.

Using Pyrus ‘Yu Lu Xiang’s as material, experiments were conducted under conditions of 24 °C and 85%–90% relative humidity. The 3 electric field intensities (50, 100 and 150 kV/m) were applied, with treatment durations of 1, 2 and 3 h, respectively, followed by storage for 45 d. A control group received no treatment. Indicators including fruit firmness, soluble solid content, color difference,respiration rate and ethylene release were measured on 9, 18, 27, 36 and 45 d of storage.

The 100 kV/m treatment was most effective in maintaining fruit firmness and soluble solid content. The 50 kV/m treatment was most effective in suppressing the respiration rate and ethylene release. The treatment at 100 kV/m for 1 h effectively delayed the quality deterioration of Pyrus ‘Yu Lu Xiang’s and extended their storage period.

In summary, high voltage electrostatic field treatment can effectively maintain the storage quality of Pyrus ‘Yu Lu Xiang’. This study provides a practical and feasible protocol for the preservation and storage of Pyrus‘Yu Lu Xiang’.

To investigate the changes in the content of 4 kinds of andrographolide components in Andrographis herba decoction pieces before and after mold contamination, and analyze the impacts of different mold contamination degrees on the content of these 4 kinds of lactones.

According to the general principle 1108 microbial limit test for traditional Chinese medicine decoction pieces: Microbial enumeration tests in volume IV of the Chinese pharmacopoeia (2020 Edition), the method for enumeration of molds and yeasts was established and validated. The established method was used to count molds in Andrographis herba decoction pieces before and after mold contamination. High performance liquid chromatography was employed to determine the content of 4 kinds of andrographolide components in Andrographis herba decoction pieces before and after mold growth.

Andrographis herba decoction pieces showed weak inhibitory effects on Aspergillus niger and Candida albicans during the method suitability test. When the sample was diluted at 1:10, miscellaneous bacterial interference affected the detection. When the sample dilution reached 1:100, the interference was reduced, and the recovery ratios of the 2 kinds of test strains were both within the range of 0.5–2.0. Therefore, a sample dilution of 1:100 or higher could be used for the enumeration of molds and yeasts, with the plate pour plate method adopted for the test. In the high performance liquid chromatography determination of the 4 kinds of andrographolide components under the established chromatographic conditions, the 4 kinds of components exhibited good linearity in their respective concentration ranges (r>0.9999), with recoveries ranging from 95.31% to 104.14% and relative standard deviations less than 5% (n=6). After 20 batches of andrographolide slices were moulded, the content of dehydrated andrographolide was reduced by 62% on average, the content of new andrographolide was reduced by 69% on average, the content of andrographolide was reduced by 75% on average, and the content of deoxyandrographolide was reduced by 88% on average.

After mold contamination of Andrographis herba decoction pieces, the content of deoxyandrographolide decreases slightly, while the content of andrographolide, neoandrographolide and dehydroandrographolide decrease significantly. Therefore, regular monitoring during the storage of Andrographis herba decoction pieces is necessary to ensure they are free from microbial (mold) contamination and to guarantee the safety and effectiveness of medication. Meanwhile, this study on the impact of mold contamination on the content of active components in Andrographis herba decoction pieces provides a basis for establishing a more comprehensive quality standard for Andrographis herba decoction pieces.

To separate and identify the contaminated yeast that causes the fruit yogurt to bulge and establish a rapid detection method for the main contaminated yeast.

Yeasts were isolated from different samples of fermented yogurt and theirs gas production characteristics were also analyzed. Molecular biology methods were used to identify isolated strains. Specific primers were designed based on the 26S rDNA sequence, and real-time fluorescence quantitative polymerase chain reaction using SYBR Green I dye was applied for the rapid detection yeasts.

The 9 yeast strains were isolated from 3 samples of Vaccinium uliginosum L. yogurt, Mangifera indica L. fruit yogurt and Prunus persica ‘Yellow Peaches’ fruit yogurt. The 9 yeasts were identified as Wickerhammomyces anomalus, Pichia inconspicua, Clavispora lusitaniae and Pichia cactus through molecular biology methods. Among them, Clavispora lusitaniae was the main dominant yeast and had the strongest gas production ability. The primer designed based on the 26S rDNA gene had good specificity. The correlation coefficients of the constructed standard curves were all greater than 0.99. The sensitivity of this method for detecting yeast was 10² CFU/mL. The coefficient of variation within and between groups in the repeatability test was less than 2%, indicating that the method had good reliability and stability.

In this study, the main contaminating yeast causing gas production in fruit milk is Clavispora lusitaniae. The developed detection method can be used for rapid detection of yeast in fruit fermented milk. It provides a technical support for the food safety of fermented fruit milk.

To analyze the nutritional composition and edible quality of the muscle of Centropristis striata cultured in factory.

A comprehensive analysis of the basic nutrients, amino acids, fatty acids, vitamins and mineral elements was conducted on farmed Centropristis striata under industrialized aquaculture conditions.

The muscle contained 71.0% moisture, 19.3% crude protein, 8.6% crude fat and 1.3% ash. A total of 17 kinds of amino acids were identified, with a total amino acid content of 18.85%. Essential amino acids accounted for 41.06% of the total amino acids, and the essential amino acid index was 96.20, indicating that Centropristis striata was a high-quality protein source. The fatty acid profile was well-balanced, with polyunsaturated fatty acids comprising 34.66% of the total fatty acids. The content of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were 4.14% and 2.98%, respectively, and the n-6/n-3 polyunsaturated fatty acid ratio was 2.48:1. The atherogenic index and thrombogenic index were 1.14 and 0.50, respectively. In addition, Centropristis striata was rich in vitamin E (497 μg/100 g) and selenium (0.720 mg/kg). Its mineral profile exhibited a “high potassium, low sodium” characteristic (potassium: 3901 mg/kg; sodium/potassium ratio: 0.116), suggesting that it is particularly suitable for the dietary needs of individuals with hypertension, hyperlipidemia or diabetes.

Centropristis striata possesses a balanced amino acid profile, abundant unsaturated fatty acids and high levels of vitamins and minerals, demonstrating high nutritional value and strong potential as a high-quality protein source.

To investigate the absorption effects of chondroitin sulfate (CS) with different molecular weights in the body and its effects on the health of knee joint cartilage.

The 50 healthy, clean-grade New Zealand male rabbits were randomly divided into 5 groups after 3 days of adaptive feeding, namely the control group(CON), the normal-dose macromolecule group (BH), the half-dose macromolecule group (BL), the normal-dose small molecule group (SH) and the half-dose small molecule group (SL). The CON group was gavaged with normal saline and the normal dose group and the halved dose group were given gavage at doses of 0.170 g/kg and 0.085 g/kg for 7 d, respectively.

Compared with the CON group, the SH group exhibited extremely significant increases in serum and articular cartilage tissue levels of CS (P<0.01) and significant increases in collagen type-II (COL-Ⅱ)content (P<0.05), and interleukin-17 (IL-17) levels in serum was extremely significantly decreased (P<0.01) and matrix metalloproteinase-3 (MMP-3) levels in articular cartilage tissue were extremely significantly reduced(P<0.01). Hematoxylin-eosin (HE) staining results showed that the chondrocytes in each CS group were evenly distributed, and there were no blood vessels or nerves in the cartilage, and no pathological changes were observed.The results of quantitative real time polymerase chain reaction (qPCR) revealed showed that the messenger RNA(mRNA) expression levels of matrix metalloproteinase-1 (MMP-1) and IL-17 in the SH group were significantly decreased (P<0.05) and MMP-3 were extremely significant decreased (P<0.01) , the mRNA expression levels of collagen alpha 1 (II) chain (COL2A1) and fibroblast growth factor-2 (FGF-2) were both significantly increased(P<0.01) and collagen type IX alpha 1 chain (COL9A1) was significantly increased (P<0.05).

CS can promote the content of COL-II and the mRNA expression of related genes through trophic deep chondrocytes, inhibit the expression of matrix metalloproteinases (MMPs), and reduce the content of inflammatory factors, thereby protecting the cartilage of the rabbit knee joint. Among them, the SH group has the best effect.

To investigate the effects of different cooking methods on the volatile flavor of rushan.

Raw rushan was processed by 3 kinds of cooking methods, including microwave irradiation, deep-frying, and pan-roasting, and analyzed by gas chromatography-mass spectrometry/olfactometry (GC-MS/O) combined with sensory evaluation.

The content of acids and esters in rushan treated with microwave irradiation increased significantly increased. Compounds including butyric acid, hexanoic acid and ethyl hexanoate exhibited high odor activity values (OAV) and flavor dilution factors (FD), which were identified as the odor-active compounds in microwaved rushan, contributing to enhanced sour and fruity notes. In deep-fried rushan, compounds such as cis-2, 4-decadienal were generated via processes like the Maillard reaction, with high OAV and FD factors; sensory evaluation indicated prominent oily and roasted notes. For pan-roasted rushan, compounds including trans-2-dodecenal and 2-heptanol showed high OAV and FD factors, imparting increased oily and wine-like aromas to the product.

Sensory attributes and volatile flavors of rushan were altered by different cooking methods. The findings provide a reference for consumers to select preferred cooking methods, and also lay a theoretical foundation for the further processing of rushan and the development of ready-to-eat rushan products.

To investigate the characteristic volatile component differences among premium grade(YK-T), second grade (YK-A) and fourth grade (YK-B) raw Pu-erh tea storage samples.

Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) combined with principal component analysis (PCA) validation, orthogonal partial least squares discriminant analysis and calculation of relative odor activity value (ROAV) were used to analyze and screen key aroma components of the 3 grades of raw Pu-erh tea storage samples.

A total of 92 volatile compounds were detected across the different grade samples, primarily consisting of aromatic hydrocarbons, alcohols, esters and hydrocarbon compounds. The differences in the number of volatile components among the 3 grades of aged raw Pu-erh tea samples were relatively small. However, the total volatile content in the YK-T sample was significantly higher than in the other 2 grades.Additionally, after long-term storage, the ester content in the volatile components of the YK-T aged raw Pu-erh tea sample was significantly higher than in the other 2 grades. Based on variable importance projection (VIP)>1 and P<0.05, 19 kinds of volatile compounds were identified as key differentiators: Pinene acetate, (+)-limonene, (S)-α-pinene, linalool, methyl linoleate, 2, 2, 6-trimethyl-6-vinyl-tetrahydro-2H-furan-3-ol, camphene, methyl salicylate, 1, 10-decanediol, and 1, 2, 3-trimethoxybenzene as key differential volatile compounds among the three grades of stored raw Pu-erh tea samples. Further calculations yielded ROAV values for 14 kinds of volatile compounds, revealing that rosin acetate, (+)-limonene, (S)-α-terpineol, linalool, camphene, methyl salicylate, and 1, 2, 3-trimethoxybenzene exhibited ROAV>1, indicating these key aroma compounds contribute significantly to the flavor profiles of different grade raw Pu-erh tea storage samples.

The overall aroma profile of YK-T is dominated by floral, citrus, and aged notes presented by linalool, (+)-limonene and 1, 2, 3-trimethoxybenzene.Terpineol acetate, which exhibits a herbal aroma, is detected exclusively in YK-T, distinguishing this grade from the other 2. The volatile components of YK-A and YK-B primarily exhibit woody notes from camphene and floral notes from linalool. Notably, YK-A possesses the highest ROAV value for camphene among all key differentiating aroma compounds, resulting in its pronounced woody character. This study establishes a theoretical foundation for understanding quality differences among Pu-erh tea grades and provides data support for constructing discriminant profiles for raw Pu-erh tea of varying grades.

To investigate the feasibility of mineral element analysis for tracing the geographical origin of Salmon.

The content of 20 kinds of mineral elements in 40 Salmon samples from the Faroe Islands, Norway, Scotland and Xinjiang were determined by inductively coupled plasma mass spectrometry. The obtained data were processed with SPSS 27.0 software for variance analysis, principal component analysis and Fisher discriminant analysis.

The 11 kinds of mineral elements (Na, Mg, K, Ca, Fe, Cu, V, Cr, Co, As, Hg)showed significant differences among the different origins (P<0.05), while 6 kinds of elements (Zn, Sr, Sn, Sb, Pb,Mn) did not show significant differences (P>0.05). According to principal component analysis, the cumulative variance contribution rate of the 4 principal components was 80.864%, and it was determined that 11 kinds of mineral elements, namely Na, Mg, K, Ca, Fe, Cu, V, Cr, Co, As and Hg, were the characteristic factors of the differences in mineral elements among the Salmon from the 4 production areas. The discriminant model established based on these 11 kinds of mineral elements had an overall correct discrimination rate of 100.0% for the origin of fresh Salmon, and the correct rate of cross-validation results was also 95.0%.

Mineral element analysis is an effective method for tracing the geographical origin of fresh Salmon from the Faroe Islands, Norway, Scotland and Xinjiang,providing technical support for combating the misrepresentation of the geographical origin and label fraud of Salmon.