In this study, a purified polysaccharide from Euodiae Fructus (EFP-40) was obtained by sequential water extraction, decolorization, and gradient ethanol precipitation. Chemical methods such as colorimetry and methylation, as well as instrumental techniques such as high performance gel permeation chromatography (HPGPC), gas chromatography-mass spectrometry (GC-MS), and high performance anion exchange chromatography coupled with an amperometric detector (HPAEC-PAD) were used to characterize its physicochemical properties and structural characteristics. An in vitro fecal fermentation model was established to determine the effect of EFP-40 on the gut microbiota and short-chain fatty acids (SCFAs) production. Results indicated that the molecular mass of EFP-40 was 9.7 × 104 Da, mainly consisting of rhamnose (4.36%), glucose (10.24%), arabinose (22.24%), galactose (24.79%) and galacturonic acid (33.36%). The degrees of methyl esterification (DM) and acetylation (DA) were 17.06% and 8.12%, respectively, and the polysaccharide was possibly a complex pectin containing structural domains such as RG-I (rhamnogalacturonan I) and homogalacturonan (HG). In addition, EFP-40 promoted the production of SCFAs, and regulated the gut microbiota by increasing the relative abundance of beneficial bacteria such as Bacteroidetes and Phascolarctobacterium, reducing the relative abundance of harmful bacteria such as Fusobacteriota and Proteobacteria, as well as the ratio of Firmicutes to Bacteroidetes. In conclusion, EFP-40 is a highly branched complex pectic polysaccharide, which can significantly regulate the gut microbiota, indicating its prebiotic potential.

We undertook this study to evaluate the structure and immunomodulatory activity of polysaccharides from dried Siraitia grosuenorii fruits. The crude polysaccharides were obtained by water extraction followed by alcohol precipitation and purified and separated into two homogeneous fractions: SGP-C2 and SGP-D1 through sequential Cellulose DE-52 and Sephadex G-200 column chromatography. The monosaccharide compositions and molecular masses of SGP-C2 and SGP-D1 were analyzed by pre-column derivatization with 1-phenyl-3-methyl-5-pyrazolone (PMP) followed by high performance liquid chromatography (HPLC) equipped with a refractive index detector (RID). Their structures were characterized by Fourier transform infrared spectrometer (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. Their immunomodulatory activity was evaluated by the neutral red colorimetric assay, their activity to induce the release of reactive oxygen species (ROS) from RAW264.7 cells was tested using 2’,7’-dichlorodihydrofluorescein diacetate (DCFH-DA) as the fluorescent probe, and their activity to induce NO production and the secretion of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in RAW264.7 cells was examined using a Griess kit and an enzyme-linked immunosorbent assay (ELISA) kit, respectively. SGP-C2 and SGP-D1 were heteropolysaccharides composed of glucuronic acid, rhamnose, galacturonic acid, glucose, galactose and arabinose with mole ratios of 0.78:1.84:26.57:1.31:0.49:0.06 and 1.37:2.00:20.79:0.61:0.12:0.25, respectively. Their relative molecular masses were 5.0 × 105 and 7.6 × 105 Da, respectively. NMR analysis showed that the backbone chain structure of SGP-C2 was →4)-α-D-GalpA-(1→ and →4)-α-D-GalpAMe-(1→, while that of SGP-D1 was →4)-α-D-GalpA-(1→. In the concentration range of 6.25–25 µg/mL, both polysaccharides promoted macrophage phagocytosis, NO production, and the secretion of TNF-α and IL-6. Besides, SGP-D1 significantly promoted the release of ROS. These results showed that SGP-C2 and SGP-D1 had immune-enhancing effects in vitro. This study provides the scientific basis for the development and application of polysaccharides from S. grosuenorii.

Schaftoside purified from the ethanol extract of Phyllostachys edulis shoot processing residues by gel permeation chromatography (GPC) was characterized structurally, and its inhibitory effect against pancreatic lipase (PL) was analyzed by enzymatic kinetics, ultraviolet (UV) spectroscopy, fluorescence spectroscopy, and molecular docking. The results showed that in the tested concentration range, schaftoside had a potent inhibitory effect on PL with half maximum inhibitory concentration (IC50) value of (76.3 ± 0.12) μg/mL in a reversible competitive manner. The fluorescence spectra indicated that schaftoside statically quenched the intrinsic fluorescence of PL with a binding constant (Ka) of 1.13 × 104 L/mol (at 293 K) and one binding site. The thermodynamic parameters showed that schaftoside could spontaneously combine with PL through hydrogen bonds and Van Der Waals force to form a stable complex. The synchronous fluorescence and 3D fluorescence spectra unveiled that schaftoside resulted in a red shift in the fluorescence emission wavelength of tyrosine (Tyr) and tryptophan (Trp) residues in PL and a decline in the quenching intensities, leading to enhanced microenvironmental polarity, decreased hydrophobicity, and increased hydrophilicity. Furthermore, molecular docking demonstrated that the carbonyl group in the C ring of schaftoside could combine with PL’s active sites including His264 through hydrogen bonds, hydrophobic force, and Van der Vaals’ force. Our findings provide a theoretical basis for the development of lipid-lowering functional foods based on P. edulis shoot extract.

This study was carried out in order to explore the anti-inflammatory constituents of the tuber of Gastrodia elata B1 and their mechanisms of action. The petroleum ether extract and its sequential fractions: dichloromethane, ethyl acetate, n-butanol and water-soluble fractions were determined for their active ingredients as well as assessed for their bioactivities. The bioactive ingredients were identified by ultra-high performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS/MS), and network pharmacology was utilized to predict the potential anti-inflammatory components of the selected fraction and their targets. Furthermore, molecular docking was used to investigate the binding of the potential anti-inflammatory components to the core targets for treating inflammation. The results showed that the ethyl acetate fraction possessed the highest content of bioactive ingredients, with total polyphenol, total flavonoid and polysaccharide contents of (164.69 ± 1.57), (64.81 ± 3.21) and (279.64 ± 3.11) mg/g, respectively. The ethanol extract and its fractions possessed strong in vitro antioxidant and anti-inflammatory activities, among which the ethyl acetate fraction demonstrated the strongest 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging capacity and in vitro anti-inflammatory activity. Correlation analysis showed that the total polyphenol content was significantly (P < 0.05) and highly significantly (P < 0.01) correlated with the half maximal inhibitory concentration (IC50) against DPPH radical and 2,2’-biazobis(3-ethylbenzothiazoline-6-sulfonic acid) cationic radical, with correlation coefficients of −0.587 and −0.873, respectively. The total flavonoid content was significantly (P < 0.05) and highly significantly (P < 0.01) correlated with the IC50 values against NO and the denaturation of bovine serum albumin (BSA), with correlation coefficients of −0.780 and −0.842, respectively. Meanwhile, a total of 164 chemical constituents were identified from the ethyl acetate fraction, and core active ingredients including 5-(5-methoxycarbonyl-5,8a-dimethyl-2-methylidene-3,4,4a,6,7,8-hexahydro-1H-naphthalen-1-yl)-3-methylpentanoic acid, 4,4,8,10,14-pentamethyl-17-(4,5,6-trihydroxy-6-methylheptan-2-yl)-2,5,6,7,9,15-hexahydro-1H-cyclopenta[a]phenanthrene-3,16-dione, and simvastatin and key targets including TP53, SRC, PIK3R1, PIK3CA, and AKT1, which were mainly involved in cancer-related signaling pathways as well as the mitogen-activated protein kinase (MAPK) and cyclic adenosine monophosphate (cAMP) signaling pathways, were obtained by network pharmacology. The results of molecular docking showed that the core active ingredients had good binding activity with the key targets.

In order to clarify the effect of vitamin C (VC) on physicochemical properties and digestibility of lotus seed starch (LSS) during freeze-thaw cycles, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to characterize the multi-scale structure of the starch, and its rheological properties and in vitro digestibility were determined. The results showed that the pore size of starch gels became lager and the syneresis decreased with increasing freeze-thaw cycles. VC addition promoted the formation of tighter gels during freeze-thaw cycles, resulting in lower syneresis and improved freeze-thaw stability. Overall, the degree of starch recrystallization increased with increasing freeze-thaw cycles. The addition of VC decreased the digestibility of frozen-thawed LSS. One potential reason may be that the addition of VC enhanced short-range ordered structure, double helix structure and relative crystallinity of LSS. In conclusion, VC can improve freeze-thaw stability of LSS and reduce the digestibility of frozen-thawed LSS.

In this study, the effect of transglutaminase (TGase)-Ca2+ crosslinking on the texture, water-holding capacity (WHC), rheological properties, and vitamin D3 (VD3)-loading capacity of soy protein isolate (SPI) emulsion gels was investigated. The results showed that with increasing SPI concentration (4%–12%), Ca2+ concentration (0–30 mmol/L) and TGase dosage (0–90 U), the hardness, elasticity, WHC and rheological properties of SPI emulsion gels first increased and then decreased or leveled off. Upon the addition of 10% SPI, 10 mmol/L Ca2+ and 30 U of TGase, the best gel characteristics were obtained. The emulsion gel prepared by TGase-Ca2+ crosslinking showed a denser microstructure and more uniform oil droplet distribution as observed by confocal laser scanning microscopy (CLSM). The results of in vitro simulated digestion showed that compared with free VD3, its mixture with medium chain triglycerides (MCT), and SPI emulsion-encapsulated VD3, SPI emulsion gel-encapsulated VD3 showed reduced release rate of free fatty acids (FFAs) and increased bioaccessibility of VD3. The results of this study provide a theoretical basis for the preparation of protein supplements and the application of hydrophobicity-enhancing substances in functional foods.

The effect of using tagatose as a substitute for sucrose in sponge cake on the microstructure and viscosity properties of batter and the texture, color and sensory quality of sponge cake was studied by optical microscopy, a rotary rheometer, a texture analyzer and a color difference meter. The results showed that the relative density of batter gradually increased (P < 0.05), and the viscosity gradually decreased (P < 0.05); the hardness of cake gradually increased (P < 0.05) with increasing level of tagatose replacement. Compared with the control group, 50% tagatose substitution resulted in no significant change in the foaming capacity or foam stability of whole liquid egg or the specific volume or elasticity of sponge cake (P > 0.05). In addition, with increasing level of tagatose replacement, the brightness of cake crust and crumb decreased, and the redness and yellowness increased (P < 0.05), indicating increased extent of Maillard reaction. In terms of sensory properties, the addition of tagatose did not significantly (P > 0.05) reduce the acceptability of sponge cake. Considering batter properties and baking quality, the replacement level of tagatose should not exceed 50%.

In this study, 65 strains of dominant bacteria were isolated from Sojae Semen Praeparatum (SSP) from different regions and screened for their fibrinolytic enzyme activity by enzyme-linked immunosorbent assay (ELISA). Bacillus velezensis 20-1 was selected from these strains for its high fibrinolytic enzyme activity, and its fibrinolytic enzyme gene was amplified and heterologously expressed in Pichia pastori. As a result, a recombinant strain with high fibrinolytic enzyme activity, P. pastoris pPIC9K-his-aprEBS2, was obtained. The results showed that the gene expression level of P. pastoris pPIC9K-his-aprEBS2 was 5.8 times as high as that of B. velezensis 20-1, and the enzyme activity reached (3 025.59 ± 201.27) U/mL after 48 h culture, which was 8.9 times as high as that of B. velezensis 20-1. The fibrinolytic enzyme activity increased to (8 698.24 ± 180.73) U/mL under optimized conditions. The acute toxicity test showed that the recombinant bacterium was non-toxic. SSP fermented by the recombinant bacterium was (17 287.02 ± 103.20) U/g. Physicochemical characterization, sensory evaluation and electronic tongue analysis demonstrated that the recombinant bacterium could improve the sensory quality and flavor of SSP. The thrombolysis rate of SSP fermented by it was (60.55 ± 1.58)%, which was higher than that of commercially available SSP.

In order to improve the aroma and sensory quality of Fuji-Merlot wine, the mixing ratio between Fuji apple and Merlot grape juices was optimized and the mixed fruit juice was inoculated with non-Saccharomyces yeast and S. cerevisiae for mixed culture fermentation. The physicochemical indexes, color parameters and volatile aroma compounds of wine samples were determined, and the sensory scores were calculated using the fuzzy mathematical sensory evaluation method. The results showed that the mixing between grape and apple juices had a significant effect on the color saturation (C*) and volatile components of apple-grape wine. Notably, the wine made from a 50:50 (V/V) mixture of apple and grape juices were characterized by bright color (luminosity (L*) value of 76.24, red-green (a*)) of 31.24, and C* of 2.58) and high levels of volatile compounds including trans-nerolidol, β-damascenone, ethyl caproate, ethyl caprylate, and ethyl phenyl acetate. Non-Saccharomyces yeast had an insignificant effect on the color parameters of the wine. The wine fermented with a mixed culture of Torulaspora delbrueckii and S. cerevisiae had the largest number of volatile compounds (63) and significantly higher mass concentrations of isoamyl acetate, ethyl acetate, ethyl hexanoate, ethyl caprylate, phenethyl alcohol, 1-hexanol, and 1-heptanol than did pure S. cerevisiae fermentation and the other mixed culture fermentations. In addition, the wine had enhanced floral and fruity aromas with a sensory score of 7.605 5. In conclusion, the apple-grape wine co-fermented by T. delbrueckii and S. cerevisiae was superior to apple wine fermented by S. cerevisiae in terms of sensory quality.

We undertook this work in order to study the correlation between the microbial community composition and the characteristic flavor substances in stinky mandarin fish during the low-temperature fermentation process. 16S rDNA high-throughput sequencing was used to determine the microbial community composition. Gas chromatography-mass spectrometry (GC-MS) was used to evaluate the volatile flavor substances, and the characteristic flavor substances were identified by multivariate statistical analysis combined with odor activity value (OAV). The correlation between the microbial flora and the characteristic flavor substances was analyzed by Spearman correlation analysis. The results showed that Lactobacillus sakei, Hafnia alvei and Serratia plymuthica were the dominant microorganisms during the low-temperature fermentation process. A total of 81 volatile flavor substances were detected, and the characteristic flavor substances identified included 1-octen-3-ol, eucalyptol, linalool, hexanal, heptanal, nonanal, trimethylamine, D-limonene, and o-cymene. L. sakei showed a significant positive correlation with linalool and o-cymene (P < 0.05). H. alvei and S. plymuthica were significantly positively correlated (P < 0.05) with the aroma substances D-limonene and linalool as well as the odorous substance trimethylamine (P < 0.05). The results provide a theoretical basis for developing functional starters and regulating the flavor quality of stinky mandarin fish.

This study focused on the analysis of the microbial community structure and flavor substances of different layers of pit mud for Luzhou-flavor baijiu in spring and autumn using high-throughput sequencing and headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS), and it also used Spearman correlation analysis to examine the correlation between dominant microbial genera and flavor compounds. The results showed that for each layer of pit mud, the diversity of both prokaryotes and eukaryotes was higher in autumn than in spring. In all samples, 21 prokaryotic phyla, 45 classes, 82 orders, 128 families and 241 genera were detected, including 7 dominant phyla and 43 dominant genera; 7 eukaryotic phyla, 19 classes, 33 orders, 81 families and 134 genera were detected, including 5 dominant phyla and 34 dominant genera. The types and relative contents of flavor compounds in pit mud were significantly different between different seasons and layers, with both the types and relative contents of flavor compounds being higher in the middle layer of pit mud in spring. The correlation analysis showed that Caproiciproducens and Aspergillus were correlated with the production of a variety of flavor compounds, and microorganisms that were positively correlated with the key flavor compounds caproic acid and ethyl caproate in pit mud significantly varied between different seasons and layers. These results revealed the microbial composition of the pit mud and the correlation with flavor compounds from the dimensions of time and space, and provided theoretical references for the excavation of aroma-producing microorganisms in the pit mud.

To explore the antibacterial effect and mechanism of antimicrobial peptide LL-1 against Salmonella, the minimum inhibitory concentration (MIC) was determined by the doubling dilution method, and the antibacterial effect was evaluated by the growth inhibition curve. Then, the bacterial morphology was observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of LL-1 on the cell wall and cell membrane of Salmonella was evaluated by detecting the leakage of intracellular nucleic acids, proteins and alkaline phosphatase (ALP) as well as by conducting propidium iodide (PI) staining experiments. The binding of LL-1 to Salmonella DNA was detected by nucleic acid gel electrophoresis. Finally, the effect of LL-1 on the energy metabolism of Salmonella was evaluated by measuring the activities of intracellular succinate dehydrogenase (SDH), NADP-malate dehydrogenase (NADP-MDH) and ATP levels. The results showed that the MIC was 6.25 μg/mL, and LL-1 had a good antibacterial effect in dose- and time-dependent manners. Salmonella treated with LL-1 showed morphological changes such as cell shrinkage, cell membrane dissolution, and plasmolysis. LL-1 resulted in the leakage of intracellular nucleic acids, proteins and ALP and an increase in the fluorescence intensity of PI-stained bacterial cells. Additionally, LL-1 could bind to bacterial DNA. Increasing LL-1 concentration resulted in a decrease in the intracellular ATP content, SDH and NADP-MDH activities. In conclusion, LL-1 could exert its antibacterial activity against Salmonella by increasing the permeability of the cell membrane and cell wall, thereby causing the leakage of intracellular contents, binding to DNA, and affecting bacterial energy metabolism. This study lays the foundation for further research on the antibacterial mechanism and application of LL-1.

To investigate the correlation between the microbial community structure and composition and physicochemical indicators as well as the sources of microorganisms in fermented grains during the stacking and pit fermentation processes in the first round of jiang-flavor baijiu production, traditional culture methods and Illumina MiSeq sequencing were used to study the composition and succession of microbial communities in the fermented grains and the brewing environment, and their correlation with physicochemical factors was analyzed. Furthermore, the SourceTracker software was employed to determine the sources and proportions of dominant microorganisms in the fermented grains. The results showed that on the 6th day of stacking fermentation, both the total bacteria and yeast counts reached maximum values of (3.45 ± 0.15) × 106 CFU/g and (40.5 ± 2.50) × 104 CFU/g, respectively. Unclassified_Lactobacillaceae (91.23%–91.77%) and Pichia (32.84%–91.00%) were the absolute dominant bacterial and fungal genera. Unclassified_Lactobacillaceae showed a significant positive correlation with the moisture content and acidity of the fermented grains, and Pichia exhibited a significant positive correlation with the moisture content and reducing sugar content. The microbial source tracing analysis indicated that the dominant microorganisms on the 0th and 3rd day of stacking fermentation primarily originated from the ground (32.44%–57.37%) and production utensils (26.89%–50.74%). From the 6th day of stacking fermentation to 43rd day of pit fermentation, the dominant microorganisms mainly originated from surfaces such as window sills and walls (86.41%–87.31%). Specifically, unclassified_Lactobacillaceae mainly came from the ground (85.79%) across the stacking and pit fermentation processes and from windowsill and wall surfaces (91.96%–94.91%). There were more diverse sources of Pichia (1.32%–87.06%) in the brewing environment. Before the 6th day of stacking fermentation, its major sources were the air inside the workshop and the surface of production utensils, windowsills, and walls. During pit fermentation, its major sources were the inner wall of the pit, accounting for 18.21%–30.79%. This study provides a theoretical basis for elucidating the brewing mechanism of jiang-flavor baijiu.

This study aimed to investigate the changes in trimethylamine (TMA) levels in cecal contents, intestinal microflora structure and physiological homeostasis indicators in mice receiving dietary supplementation of choline, dietary supplementation of choline and arabinoxylan, dietary supplementation of choline and arabinoxylan plus interventions with inhibitors of key enzymes of glycolysis. 16S rRNA gene sequencing, metabolomics and enzyme-linked immunosorbent assay (ELISA) were used to explore the effect of dietary supplementation of arabinoxylan and interventions with glycolysis inhibitors on the contents of choline and its metabolites TMA and trimethylamine oxide (TMAO) in cecal contents, intestinal microbiota composition, and homeostasis indicators such as serum glucose, serum high-density lipoprotein cholesterol (HDL-C), interleukin-1 (IL-1) and interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). The results showed that compared with the choline supplementation group, addition of arabinoxylan and interventions with glycolysis inhibitors significantly increased the species richness and evenness of the gut microbiota (P < 0.05), increased the number of beneficial bacteria, reduced the levels of TMA and TMAO in the digesta (P < 0.05), significantly reduced the levels of serum glucose, IL-1, IL-6, and TNF-α levels (P < 0.05), and increased HDL-C levels. The findings of this study provide new insights for understanding how choline metabolites cause diseases and for the prevention and treatment of related metabolic syndromes.

The objective of this study was to investigate the effect of chlorophyll a versus b on the intestinal flora of mice induced by a high-fat diet (HFD) metabolomics combined with microbial diversity analysis. Results demonstrated that chlorophyll was transformed and degraded by the intestinal flora after 48 h culture in vitro. Its major derivatives included oxides (132-hydroxy chlorophyll a, 151-hydroxy-lactone chlorophyll b, and 132-hydroxy chlorophyll b) and magnesium-free derivatives (pheophytin a and 132-hydroxy pheophytin b). The reduced chlorophyll was degraded into non-fluorescent metabolites (m/z 666.289 5), fluorescent metabolites (m/z 614.273 5, 618.268 4, and 792.321 2) and pyrrole derivatives of propionate (m/z 223.071 3). Microbial diversity analysis showed that the addition of chlorophyll down-regulated Escherichia-Shigella and up-regulated Acinetobacter, and chlorophyll a and chlorophyll b had different effects on the microbial abundance and species. Targeted metabolomics showed no significant difference in fatty acid contents among the control and chlorophyll addition groups. Untargeted metabolomics showed that chlorophyll addition resulted in differences in fecal metabolites (both chlorophyll a and b led to the synthesis of more antibiotics). These metabolites were mainly enriched in the caprolactam degradation pathway and the macrolide biosynthesis pathway 12, 14 and 16 for the chlorophyll a and b groups, respectively, with 15 shared pathways being found between the two groups. The results of this study will help to understand the effect of chlorophyll supplementation on the gut microbiota of HFD-induced mice, and provide useful information for understanding the interaction between chlorophyll and the intestinal flora.

Objective: To study the composition of non-volatile small molecules in shrimp pastes from different geographical origins. Methods: Metabolomics based on ultra-high performance liquid chromatography-Q Exactive high field-mass spectrometry was used to detect metabolites in shrimp pastes from Shandong, Guangdong and Hebei. The characteristic metabolites of shrimp paste from each region were identified by orthogonal partial least square-discriminant analysis (OPLS-DA). Results: Shrimp paste was rich in amino acid and fatty acid metabolites, forming a large number of N-acyl compounds, with cinnamic acid, 11’-carboxy-α-chromanol and β-leucine being the major ones. It was found that shrimp paste also contained active neurotransmitters such as dopamine, norepinephrine, 6-hydroxymelatonin, and γ-glutamine-5-hydroxytryptophan. The major characteristic metabolites of Shandong shrimp paste were cinnamic acid and β-leucine. 12-Hete-T and N-oleyl taurine were the major characteristic metabolites in Guangdong shrimp paste. The major metabolites of Hebei shrimp paste were eicosapntemacnioc acid (EPA) and cyanidin-3-O-(6’-malonyl-arabinoside). Conclusion: Shrimp paste is rich in small molecules such as β-leucine, glutamic acid, proline-valine and leucine-glycine as well as bioactive ingredients such as taurine, norepinephrine and dopamine. The composition of metabolites in shrimp paste is region specific.

This study employed non-targeted metabolomics based on liquid chromatography-mass spectrometry (LC-MS) to analyze the differences in metabolites between camel milk and cow milk. Junggar bactrian camel milk and cow milk from the same pastoral area were collected for analysis of small-molecule metabolites. Multivariate statistical analysis methods including principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used in combination with the R language and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database for differential analysis. The results showed that a total of 984 metabolites were detected (572 and 412 in the positive and negative ion modes, respectively), the major ones being undefined metabolites, lipids and lipid-like molecules, and organic acids and their derivatives, which accounted for 30.39%, 27.13%, and 11.59% of the total number, respectively. Significant differences (P < 0.05) in small-molecule metabolites were found between camel and cow milk. Altogether, 67 differential metabolites predominated in camel milk, and 63 in cow milk. Compared with cow milk, the differential metabolic pathways in camel milk were primarily enriched in purine metabolism, phenylalanine metabolism, nicotinate and nicotinamide metabolism, vitamin digestion and absorption. These findings provide a scientific basis for the development of functional foods based on camel milk.

Tea shoots consisting of one bud and two leaves from three tea strains/varieties in Hunan Province, Rucheng Baimao 1 (RT1), Rucheng Baimao 2 (RT2), and Rucheng Baimao Quntizhong (group variety, QT3) were picked and separately processed into white tea using the same procedure involving withering and drying, whose aroma characteristics and volatile components were evaluated by quantitative descriptive analysis (QDA) and analyzed qualitatively and quantitatively by headspace-solid phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography-quadrupole time-of-flight mass spectrometry (GC × GC-QTOF-MS), respectively. Partial least squares-discriminant analysis (PLS-DA) and relative odor activity value (ROAV) were combined to identify the key aroma components of Rucheng Baimao white tea and to explore the impacts of different tea tree varieties on the aroma of white tea. The results showed that the sensory aroma characteristics of the three varieties of Rucheng Baimao white tea differed from one another. Both RT1 and QT3 exhibited floral aromas; RT1 had a pronounced fresh aroma, while QT3 had a prominent tip aroma. RT2 exhibited a minty aroma. Multivariate statistical analysis showed that using variable importance in the projection (VIP) score > 1 with a P value < 0.05 as well as ROAV > 1.00 as the cutoff, 10 aroma components were identified as contributors to the differences in aroma among the three varieties of white tea. Benzaldehyde played a key role in the fresh aroma of all white tea samples. Hexanal was the key to the fresh aroma of RT1. Benzaldehyde, linalool oxide II, and linalool oxide I significantly contributed to the minty aroma of RT2. 1-Octen-3-ol, citral, and (Z)-4-heptenal were crucial for the tip aroma of QT3. This study provides a theoretical reference for the diversification of aroma types of Rucheng white tea and for understanding the material basis for the key aroma compounds in Rucheng white tea produced from different tea strains/varieties.

To investigate the mechanism for the effect of rice false smut on rice grain quality, this study used two high-quality japonica rice varieties, Liaogeng 433 and Liaogeng 2501, moderately susceptible to rice false smut. Through non-targeted metabolomics analysis, 271 metabolites were identified in rice grains, and the relative contents of 49 metabolites were affected by rice false smut. The relative contents of gallocatechin, 3-hydroxybenzoic acid, chlorogenic acid, sinapinic acid, spermine, α-tocopherol, nicotinamide, dodecanoic acid, and palmitic acid were significantly reduced, while the relative contents of 1-monoolein, 2-monoolein, 1-monostearin, fructose, erythritol, galactose, maltose, tagatose, shikimic acid, and α-ketoglutaric acid were significantly increased. These changes led to disorders in sugar metabolism, the tricarboxylic acid cycle, fatty acid synthesis and secondary metabolism in rice, thereby increasing the chalkiness or chalky gain percentage of rice and reducing the head rice percentage, antioxidant capacity and nutritional quality.

In this study, three varieties of sorghum (Hongyingzi, Lunuo 18, and Liangnuo 1), which vary in quality, were used to brew jiang-flavor base baijiu. The differences in the physicochemical factors of fermented grains and the important flavor compounds of base liquor from different rounds of fermentation were compared among the varieties. The results showed that the moisture content of fermented grains from Liangnuo 1 in the first 4 rounds of fermentation was significantly higher than that of any other group (P < 0.05). The acidity of fermented grains from Hongyingzi in the first 7 rounds was the highest, followed by Lunuo 18 and Liangnuo 1, with significant differences being observed (P < 0.05). Besides, the reducing sugar content of fermented grains from Liangnuo 1 after stacking fermentation and cellar fermentation was significantly higher than that of Hongyingzi and Lunuo 18 (P < 0.05). A total of 75 major volatile flavor compounds were quantitatively analyzed by gas chromatography with hydrogen flame ion detection (GC-FID) using an internal standard method, including 24 esters, 16 alcohols, 9 acids and, 13 aldehydes and ketones. A principal component analysis (PCA) plot showed clear separation of Liangnuo 1 base baijiu samples from the third, fourth and sixth rounds of fermentation according to their flavor composition, and the changes in the characteristic flavor compounds in fermented grains from Hongyingzi and Lunuo 18 were similar. A total of 33 flavor components were identified by odor activity value (OAV) analysis, and 17 important differential components were selected by orthogonal partial least squares-discriminant analysis using the cutoff of variable importance in projection (VIP) score > 1. This study systematically analyzed the differences between the fermentation parameters of different sorghum varieties and the flavor substances of base liquor, which could provide a theoretical basis for the screening of raw materials for liquor production.

This study examined the yield, metabolome and antibacterial activity of the essential oil from the fruit peel (P1, P2 and P3) and seed (S1, S2 and S3) of Alpinia hainanensis K. Schum. at different maturation stages (29, 47, and 73 days after bloom (DAB)). The seeds at the three maturation stages were green, light brown and dark brown in color, respectively. The essential oil, extracted by supercritical CO2 extraction, was analyzed qualitatively and quantitatively by gas chromatography-mass spectrometry (GC-MS) based on retention index (RI). The obtained data were analyzed by multivariate statistical analysis. Finally, the potential quality markers for the antibacterial activity were identified by spectrum-effect relationship analysis. The results showed that the oil content of the seed was significantly higher than that of the peel. A total of 125 metabolites were identified by metabolomics, and the types of metabolites were similar in the peel and seed, the dominant ones being terpenoids. However, there was a significant difference in the content of terpenoids between the peel and seed, and the content of oxygenated diterpene metabolites in the peel was significantly higher than that in the seed. Hierarchical agglomerative clustering (HAC) and principal component analysis (PCA) results showed clear separation between the peel and seed, which became more pronounced with increasing maturity. Orthogonal partial least squares-discriminant analysis (OPLS-DA) identified 124 differentially accumulated metabolites (DAM) between tissues. At 29, 47, and 73 DAB, 91, 94, and 96 DAM were found between the peel and seed, respectively, all of which were dominated by oxygenated monoterpenes, sesquiterpenes, and oxygenated sesquiterpenes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of DAM revealed that the differential pathways were mainly related to stress resistance, which might affect the antibacterial activity. The results of antibacterial tests showed that the peel had significantly higher antibacterial activity against Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus, and Staphylococcus epidermidis than did the seed. The spectrum-effect relationship analysis identified 30 potential quality markers for the antibacterial activity of the peel, dominated by oxygenated monoterpenes, sesquiterpenes and oxygenated sesquiterpenes. In conclusion, the metabolome and antibacterial activity of the essential oil of A. hainanensis fruits exhibited significant spatiotemporal heterogeneity, highlighting the potential application value of the peel as Chinese herbal medicinal waste and providing a reference for the application of A. hainanensis fruits in the food and medicine industries.

To better evaluate the thermal stability of spices and enhance their practical value, a uniform evaluation method for the thermal stability of spices was established by combining thermogravimetric analysis-sample storage interface-gas chromatography-mass spectrometry (TGA-IST-GC-MS) with TGA and GC-MS. First, the method used TGA to obtain the optimal injection temperature of spices based on their volatility characteristics. Then, GC-MS and TGA-GC-MS chromatograms were obtained under different systems. By comparing the two chromatograms, the stability, cracking degree, and fragmentation degree were calculated as three important thermal stability indicators of spices. Finally, the aroma changes of spices before and after heating were investigated based on their thermal stability. The results indicated that using the peak temperature for maximum mass loss rate during spice volatilization as the optimal injection temperature for TGA-IST-GC-MS, the developed method had high response intensity and good repeatability. Comparing the GC-MS and TGA-GC-MS chromatograms, the influence of spice matrix background was effectively reduced, which improved the accuracy of the method, making it suitable for both single-component spices and multi-component natural spices. Based on the three indicators of thermal stability, it could further obtain the cracking intensity and the amount of new cracking products during the heating of spices, which is of great practical and guiding significance for aroma evaluation.

The purpose of this study was to explore the bioactive components of Fengdan peony pods and their mechanisms of action by using network pharmacology and molecular docking. A total of 88 components were identified by ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS), among which 17 were selected for network pharmacology, corresponding to 219 targets. Gene ontology (GO) analysis showed that the intersection targets were mainly involved in biological processes such as response to xenobiotic stimulus. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment signaling pathways mainly included the advanced glycation end products (AGE)-receptors for advanced glycation end products (RAGE) signaling pathway in diabetic complications, prostate cancer, the interleukin-17 (IL-17) signaling pathway, and the tumor necrosis factor (TNF) signaling pathway. The binding energies between the active ingredients and the key targets were all below −5.0 kJ/mol, indicating stable binding. In summary, peony pods participate in various biological processes through multiple components, multiple targets, and multiple pathways to exert anti-inflammatory and antibacterial effects, providing the basis for the development and utilization of peony fruit pods.

This study investigated the changes of natural pigments and volatile components in sunflower oil during the refining process. A high performance liquid chromatography (HPLC) method was established and optimized for the detection of natural carotenoids and flavonoids pigments in sunflower oil during the refining process (crude, deacidified, dewaxed, decolorized and deodorized oil). The results showed that the content of natural carotenoids in the crude oil was in the following order: lutein (1.44 μg/g) > β-carotene (0.55 μg/g) > zeaxanthin (0.51 μg/g) > lycopene (undetectable). The content of flavonoids was in the following order: fisetin (2.60 μg/g) > kaempferol (2.06 μg/g) > quercetin (2.00 μg/g) > isoquercitrin (1.58 μg/g) > luteolin (1.21 μg/g). In addition, the decolorization process was responsible for the loss of carotenoids and the deacidification process was responsible for the loss of flavonoids. Totally 264 volatile components were identified in sunflower oil, the dominant ones being terpenes and aldehydes, and the deodorization process had a significant effect on aroma components of sunflower oil, reducing the contents of terpenes, aldehydes, and alcohols by 99.27%, 81.10%, and 94.75%, respectively. The refining process decreased the antioxidant activity of sunflower oil, which may be attributed to the loss of natural pigments. This study provides a scientific basis for optimizing the traditional refining process of sunflower oil and improving its quality and nutritional value.

This study investigated the effect of cold atmospheric plasma (CAP) at different combinations of power (0, 150, and 250 W) and time (0, 30 and 90 s) on the decay incidence, percent mass loss, respiration rate, total phenolic content, anthocyanin content, malondialdehyde (MDA) content, and H2O2 content of raspberry fruits during postharvest storage. The aim was to explore the effect and mechanism of CAP on the postharvest preservation of raspberry fruits. The results showed that CAP at 250 W, 90 s extended the storage life of raspberry fruits by 2–5 days. On the 5th day of storage, the decay incidence and percent mass loss of the treated fruit were 22.61% and 35.97%, which were both lower than those of the control group; however, there was no significant difference in juice yield or total soluble solid content between the two groups. Besides, the treatment maintained the titratable acid (1.16%), soluble protein (204.5 mg/100 g) and anthocyanin (107.7 mg/L) contents, increased the synthesis of total phenols (85.72 mg/100 g), inhibited the respiration rate (5.683 mg/(kg·h)), decreased the contents of malonaldehyde (30.99 mmol/g) and H2O2 (6.858 mmol/L), and improved the superoxide anion free radical scavenging capacity (4.21 U/g). Therefore, CAP is effective in extending the shelf life of raspberry fruits while maintaining its quality.

The effect of combined treatment with ultrasound and different NaCl concentrations (0, 15, 30, 45, and 60 mmol/L) on the fibrillation of whey protein isolate (WPI) was examined. Changes in the morphology, aggregation process, turbidity, emulsifying activity, and emulsion stability of different WPI fibrillar aggregates were investigated using transmission electron microscopy (TEM), fluorescence spectrophotometry, ultraviolet visible (UV-Vis) spectrophotometry, and laser scanning confocal microscopy (LSCM). The results showed that the combined treatment changed the morphology and polymerization kinetics of WPI fibrillar aggregates. Compared with WPI, ultrasound combined with 15 mmol/L NaCl increased the maximum rate of increase in fluorescence intensity, resulting in maximum fluorescence intensity of 985.213. Ultrasound combined with 60 mmol/L NaCl reduced the lag time to 0.784 h. The kinetic changes in fibrillar aggregation might be the reason for the morphological changes in fibrillar aggregates. The fibrillar aggregates formed by ultrasound combined with 30 mmol/L NaCl had the best morphology and the highest emulsifying activity index (1.44 m2/g) and emulsion stability index (73.21%). The fibril aggregates could evenly wrap around the surface of oil droplets.

In this study, using a one-step dynamic numerical analysis and optimization method, a tertiary model describing the growth of total viable count in sauced pig head meat was developed for real-time freshness prediction under fluctuating temperature (2–35 ℃). The validation results showed that the root mean square error (RMSE) of the prediction model for total viable count was 0.26 (lg(CFU/g)), and the residual mean and standard deviation were −0.047 (lg(CFU/g)) and 0.125 (lg(CFU/g)), respectively, which were within the normal experimental error range. The results of this study can be used to predict the changes of total viable count during cold chain and temperature abuse, and obtain a real-time freshness prediction model for pre-packaged sauced pig head at 2–35 ℃, thereby providing a theoretical basis for the real-time monitoring of the freshness of prepackaged sauced pig head at fluctuating temperatures.

To clarify the key material basis for the rapid softening of shrimp muscle during refrigeration, this study established a specific histological detection method for cytoskeletal proteins and analyzed the correlation between the degradation of cytoskeletal proteins and texture deterioration. By comparing the effects of different fixatives, dehydration modes, clarification times, and staining parameters on the staining of cytoskeletal proteins, it was found that the suitable fixative solution for shrimp muscle tissue was Carnoy’s fixative; the specific staining process encompassed five steps: 1) 15 h fixation at room temperature, 2) dehydration with a series of gradient ethanol concentrations, 3) sequential clarification with a mixture of xylene and ethanol followed by xylene, 4) paraffin embedding for sectioning, 5) and Masson’s trichrome staining, clearly showing the morphology of nuclei, myofibrils, and collagen fibers. The pathological results showed that the gap between muscle fiber bundles increased with refrigeration time, and the structure of myofibrillar bundles was partially destroyed. The color of stained collagen fibers became gradually lighter indicating a decrease in its amount. Quantitative analysis showed that refrigeration led to a significant decrease in the volume fraction of collagen fibers and myofibrils in muscle tissue (P < 0.05). The volume fraction of myofibrils in cross-section and longitudinal sections decreased from (91.03 ± 1.37)% and (93.39 ± 0.91)% to (41.14 ± 3.78)% and (24.36 ± 3.67)%, respectively, over a 5-day refrigeration period. The cross-sectional and longitudinal areas of shrimp myofibrils and collagen fibers were significantly positively correlated with muscle hardness and elasticity (P < 0.05), indicating that the reduction in myofibril and collagen contents during refrigeration was closely related to texture deterioration. The significant correlation between the structural degradation of cytoskeletal proteins and texture deterioration revealed their key role in texture preservation and was an important target for early monitoring and intervention of muscle softening.

To explore a simple, rapid and sensitive method for the detection of doxycycline hydrochloride (DOX), metronidazole (MTZ) and sulfadimidine (SM2) in pork and milk, a porphyrinic zirconium metal-organic framework (MOF) material, PCN-225, was synthesized as a fluorescence probe and used to construct a fluorescence sensor to determine the concentrations of DOX, MTZ and SM2. First, the morphology, structure and properties of PCN-225 were characterized and optimized, and the sensing mechanism of PCN-225 was analyzed by fluorescence spectroscopy and ultraviolet-visible (UV-Vis) absorption spectroscopy. Second, the sensing performance of PCN-225 for detecting the three antibiotics was studied. The results showed that the developed method showed excellent selectivity and sensitivity for the detection of DOX, MTZ and SM2, with detection limits of 4.70, 5.30 and 4.84 nmol/L, respectively. Finally, the sensor was used to detect DOX, MTZ and SM2 in pork and milk. The recovery rates ranged from 94.7% to 110.8%, with relative standard deviations (RSDs) not higher than 1.1%. In conclusion, this method shows great potential for the detection of DOX, MTZ and SM2 in a simple, efficient, sensitive and rapid manner.

To establish a grading method for green Arabica coffee bean based on the lightweight YOLOv8-FasterBlock model, a total of 500 g of first-grade, second-grade, third-grade and defective green Arabica coffee bean from Yunnan were collected and mixed for acquirement of RGB images as the dataset for coffee bean grading. The YOLOv8n model was improved by replacing the BottleneckBlock in the C2f module with the FasterBlock module in FasterNet, resulting in a new lightweight YOLOv8-FasterBlock model. The improved model took 2.4 ms, on average, to discriminate different grades of coffee beans with accuracy, recall, and average precision of 98.4%, 94.3%, and 97.4%, respectively. Comparison, ablation, lightweighting, and adherent bean tests proved the superiority and structural validity of the YOLOv8-FasterBlock model. The YOLOv8-FasterBlock model improved the feature extraction capacity and inference speed for green Arabica coffee bean while having reduced complexity, enabling rapid grading of coffee bean. The results of the study provide a reference for the deployment of vision module in green Arabica coffee bean grading equipment, and also provide theoretical support for the grading of other agricultural products.

A rapid precolumn derivatization combined with high performance liquid chromatography (HPLC) with fluorescence detection method for the determination of the 1-deoxynojirimycin (DNJ) content in functional milk powder. Samples were extracted with 60% methanol in water. In pH 8.5 borate buffer solution, o-phthalaldehyde was added as a derivatizing agent to remove the interference from primary amines. DNJ in samples reacted with 9-fluorenylmethoxycarbonyl chloride to form a complex with fluorescence absorption. The separation was performed on a C18 column (150 mm × 4.6 mm, 2.7 μm). Mobile phase A was 10 mmol/L sodium acetate buffer solution, and mobile phase B was acetonitrile. Gradient elution was performed at a flow rate of 1.5 mL/min. The column temperature was 45 ℃. The excitation wavelength was 275 nm. The emission wavelength was 320 nm. Good separation of DNJ from other components was achieved. The detection limit was 4 ng/mL, and the calibration curve was linear in the range of 0.01 to 50 μg/mL, with a determination coefficient (R2) > 0.999. The recovery rates ranged from 101.8% to 104.1%. The method was validated to be stable and reliable, and could be used as an effective method for determining the content of DNJ in milk powder.

Chlorophyll imparts a green color to vegetables and possesses antioxidant, antimicrobial, immunomodulatory, and anticancer functions. However, it is unstable during thermal processing and easily degraded, resulting in loss of its bioactivity, thereby affecting the color and nutritional quality of vegetables. In plants, chlorophyll is normally degraded by pheophorbide oxygenase and also oxidized and degraded by chlorophyll peroxidase in the presence of phenolic substances. During thermal processing, chlorophyll is degraded through enzymatic and non-enzymatic reactions, the latter including the destruction of cell structure and chemical degradation reactions caused by heating. Additionally, factors such as temperature, pH, oxygen concentration and processing methods influence chlorophyll degradation during thermal processing. Physical, chemical, and biological methods are currently employed to prevent the degradation of chlorophyll through various mechanisms such as inactivating enzymes, enhancing the stability of chlorophyll by metal ions, promoting the formation of chlorophyll aggregates, and improving antioxidant capacity. This paper summarizes recent research on the degradation pathways and kinetics of chlorophyll in vegetables during thermal processing, and reviews and analyzes the techniques used to preserve chlorophyll during thermal processing.

As a new non-thermal food sterilization technology, pulsed light has gradually become a research focus for its advantages of high efficiency, convenience and environmental friendliness. Pulsed light has a strong penetration ability and a wide sterilization spectrum, which has found wide application. Pulsed light can maintain food texture, flavor and taste, making it highly promising for research. However, there is currently a lack of systematic research on the mechanism of pulsed light sterilization; although a wide range of methods have been applied, the synergistic mechanisms between different effects are still not clear. In this context, this paper reviews the mechanism of pulsed light sterilization and its application in the field of foods. First, using VOS viewer software and bibliometric, the current status of research on pulsed light sterilization is analyzed to provide accurate information and clues for understanding the research trends and development directions in the field of pulsed light sterilization technology. Secondly, from the perspectives of its biophysical, photothermal and photochemical effects the process of multi-target, multi-core and multi-system action of pulsed light on bacteria is elucidated to enhance our understanding of the mechanism of pulsed light sterilization. Finally, the application of pulsed light sterilization to different food categories is summarized. In the future, further understanding of the mechanism of pulsed light sterilization and its combination with other sterilization technologies will expand the application scope of food sterilization.

Food anti-counterfeiting and traceability are important ways to ensure food safety. In response to the upgrading of counterfeiting means, a variety of identification technologies have been gradually developed, which play a crucial role in the field of food quality and safety. In recent years, relying on the advantages of DNA molecules, more advanced and precise identification and tracking technologies have been developed, which provide new ideas for the establishment of an efficient anti-counterfeiting and accurate traceability system for food safety monitoring. This paper outlines the development process of DNA storage technology and DNA traceability code, describes the current status of and latest progress in the application of DNA traceability code in food anti-counterfeiting and traceability, and discusses the necessity of interdisciplinary cooperation in promoting the development of DNA traceability technology, as well as sustainability and safety issues that may be encountered in the implementation process. Finally, future trends in the development of DNA traceability technology are envisioned, and possible solutions are proposed for the current challenges, aiming to provide more scientific and efficient means for food authenticity identification and origin tracing.

The decline in meat freshness can result in resource waste and even pose high risks to human health. Therefore, development of effective evaluation technologies for meat freshness is crucial for ensuring food safety. Nanozymes, as a new generation of artificial enzymes, offer several advantages, including convenient preparation, low cost, high stability, and robust catalytic performance. Consequently, various nanozymes have been extensively applied in sensors for evaluating meat freshness. This paper first systematically summarizes five representative nanozymes and the signal generation mechanisms of different types of sensors (e.g. colorimetric, fluorescent, electrochemical, and surface-enhanced Raman spectroscopy (SERS) sensors) from the perspective of signal transduction in nanozyme-based freshness sensors. Furthermore, it focuses on the application of various nanozyme-based sensors in evaluating meat freshness. Finally, the challenges facing the application of nanozymes in detecting meat freshness are discussed. Our aim is to provide new ideas for advancing the development of nanozyme-based sensing technology for the detection of meat freshness.