In order to explore the interaction between lipid and protein in film-forming solutions and films, the effects of linoleic acid concentration (0%, 10%, 20%, 30% and 40% relative to protein mass) on the viscosity of 11S globulin film-forming solutions, and the microstructure and physicochemical properties of the resulting films were studied. Confocal laser scanning microscopic (CLSM) images showed that the size of oil droplets in the film-forming solution increased with increasing linoleic acid concentration, and it further increased after drying. According to the results of scanning electron microscopy (SEM), oil droplets accumulated on the upper surface of the smooth and dense protein films after adding linoleic acid, while the lower surface became rough without accumulation of oil droplets on it. After adding 40% linoleic acid, the glass transition temperature, tensile strength and water vapor permeability of the film decreased from 53.50 ℃, 12.67 MPa and 2.52 × 10−10 g/(m·Pa·s) to 50.38 ℃, 7.30 MPa and 1.83 × 10−10 g/(m·Pa·s), respectively, while the elongation at break increased from 95.58% to 198.15%. Molecular dynamics simulation showed that 11S globulin did not interact with linoleic acid below 200 ns. The proportion of ionic bonds and disulfide bonds in the 11S globulin film decreased with the addition of linoleic acid, while the proportion of hydrophobic interactions and non-disulfide covalent bonds increased. These results suggest that the addition of linoleic acid can change the chemical interactions among proteins, thus affecting the physicochemical properties of the film. This finding provides a theoretical reference for studying the mechanism of film formation of soybean protein emulsion films.

The digestibility of myofibrillar proteins (MP) extracted from yak meat cooked to different internal temperatures of (40, 50, 60, 70 and 80 ℃) was determined during in vitro gastrointestinal digestion, and total carbonyl content, total sulfhydryl content and Schiff base content before and after digestion were measured. Ultraviolet (UV) absorption spectroscopy, endogenous fluorescence spectroscopy and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were used to investigate the oxidation and digestion patterns of yak meat proteins during gastrointestinal digestion. The results showed that total protease hydrolysis of MP from yak meat cooked to 60 ℃ was the highest after simulated gastric and intestinal digestion (88.64%). The rates of pepsin hydrolysis and total protease hydrolysis of MP from yak meat cooked to 80 ℃ decreased by 34.10% and 22.47%, respectively, and the rate of trypsin hydrolysis increased by 75.34% compared with MP from raw yak meat. The total carbonyl content after simulated gastric and intestinal digestion increased by 81.42% and 77.40%, respectively, and the total sulfhydryl content decreased by 30.02% and 36.43%, respectively, compared with raw MP. With an increase in cooking temperature, the Schiff base content gradually increased, the UV absorbance was significantly enhanced, and the endogenous fluorescence intensity was significantly reduced. The SDS-PAGE patterns showed that the protein bands were severely degraded and even disappeared after digestion. It was found that the digestibility of MP from yak meat cooked to 60 ℃ was the highest. The degree of protein oxidation in yak meat cooked to 80 ℃ was the strongest and increased during gastrointestinal digestion.

Postmortem mutton longissimus dorsi was minced and treated separately with phosphatase inhibitor, kinase inhibitor, S-nitrosoglutathione and nitric oxide synthase (NOS) inhibitor to control the degrees of phosphorylation and S-nitrosylation. The effect of interaction between protein phosphorylation and S-nitrosylation on mutton tenderness during postmortem storage were investigated by analyzing the changes in the phosphorylation level, S-nitrosylation level, pH, myofibrillar fragmentation index (MFI), desmin and troponin-T degradation of the treated mutton samples during storage at 4 ℃. The results indicated that phosphorylation levels were significantly higher (P < 0.05) in the phosphorylation-controlled group than in the phosphorylation and S-nitrosylation-controlled group in the early (0–12 h) and late (48–72 h) stages of storage, suggesting that protein S-nitrosylation inhibited its phosphorylation. When phosphorylation and S-nitrosylation modifications acted simultaneously, phosphorylation modification was dominant in affecting pH and its effect could be further enhanced by S-nitrosylation. On the contrary, S-nitrosylation played a major role in destroying the internal structure of myofibrillar proteins in mutton longissimus dorsi. When they occurred simultaneously, protein phosphorylation inhibited its S-nitrosylation; conversely, protein S-nitrosylation may promote the inhibitory effect of protein phosphorylation on desmin degradation. During postmortem storage, the interaction between protein phosphorylation and S-nitrosylation varied at different reaction periods, but both ultimately resulted in a decrease of troponin-T degradation. In conclusion, the interaction between protein phosphorylation and S-nitrosylation negatively influences the tenderness of mutton during postmortem aging.

In order to explore the effects of different combinations of spice essential oils on the quality and safety of air-dried catfish sausages, sausages were prepared from marinated catfish surimi added with a 1:1 (m/m) blend of clove and star anise (CA), clove and perilla (CP), star anise and perilla (AP) or clove, star anise and perilla essential oil (CAP) at 0.03% or none as a control. Moisture content, water activity (aw), pH, color difference, thiobarbituric acid reactive substance (TBARS) value, biological amine content, N-nitrosamine content, and microbial load were measured. Microbial community structure was analyzed by 16S rDNA high-throughput sequencing. The results showed that the moisture content of the AP group was 27.13%, and the aw value was 0.765. The L* and a* values of the CA group were high, indicating typical characteristics of air-dried sausages. The pH of the four treatment groups was higher than that of the control group, and followed the descending order of CAP > AP > CA > CP. There was no significant difference in the inhibition of fat oxidation among different essential oil combinations (P > 0.05), but the TBARS value of air-dried sausages was significantly reduced by all combinations (P < 0.05). The contents of biogenic amine and N-nitrosamine in the AP group were low. The total number of bacteria, and the number of Enterobacteriaceae and Aeromonas were significantly lower in the AP group than in the control group (P < 0.05). High-throughput sequencing results showed low species richness in the AP and CAP groups and low relative abundance of pathogenic bacteria in the AP group. Overall analysis showed that AP was superior to the other groups in improving the quality and safety of air-dried catfish sausages.

In order to reduce the content of NaCl in shrimp surimi while improving its gelation properties, the effects of different levels of NaCl substitution with CaCl2 combined with sodium alginate (SA) on the protein structure and gelation properties of shrimp surimi as characterized by 3D printing characteristics, gel strength, water-holding capacity (WHC), texture properties, rheological properties, protein secondary structure, and and molecular chemical forces were investigated under the same ionic strength. The results showed that the hardness, gel strength, β-sheet content, and hydrogen bond content of shrimp surimi increased significantly (P < 0.05) with increasing level of CaCl2 substitution, while WHC of surimi gels showed a gradual decreasing trend (P < 0.05), and the 3D printing supportability became worse. The high concentration of Ca2+ (0.5%) caused excessive protein aggregation, which was unfavorable to the formation of a good gel structure, thereby leading to a decrease in WHC. The addition of SA improved the WHC of shrimp surimi gels, and the results of protein secondary structure and chemical force showed that substitution of CaCl2 had no significant effect on the protein secondary structure of shrimp surimi, but increased the hydrogen bond content and hydrophobic interaction of the surimi gels, promoted the formation of gel networks, and improved the quality of the surimi gels. The above results indicate that incorporation of CaCl2 combined with SA can improve the gel characteristics and quality of shrimp surimi, which provides a reference for the development of low-salt shrimp surimi products.

A deoxynivalenol-degrading enzyme DepB was successfully expressed in Bacillus subtilis RIK 1285 in this study, but the fermentation level of DepB was low, which hinders its application in food and feed processing. Thus, an integrative strategy of transcriptional and translational regulation was explored to enhance the expression level of DepB. First, nine single strong promoters were selected to replace the original promoter P43, among which the recombinant bacteria mediated by the promoter PspoVG gave the highest enzyme activity of 29.59 U/mL after fermentation. Second, four promoters (P43, PsacB, PspoVG, and PaprE) with relatively high DepB expression levels were chosen to construct a dual-promoter system. DepB mediated by the dual promoter PaprE-PspoVG reached the highest activity of 48.87 U/mL. Moreover, the DepB activity of Mutant-5 with optimized core region (-35 and -10 boxes) of PaprE-PspoVG reached 69.17 U/mL, which was 4.79 times higher than that of the original strain (14.45 U/mL). Finally, DepB expression level was further improved by optimizing the ribosome binding site (RBS) sequence of the promoter PspoVG, and the enzyme activity of RBS15 reached 115.15 U/mL, which was 7.97-fold higher than that of the original strain. The results suggest that combined transcriptional and translational regulation is an effective strategy to improve the fermentation level of recombinant proteins.

In this study, the genomes of 19 Latilactobacillus curvatus and 40 L. sakei strains were comparatively analyzed. Average nucleic acid identity (ANI) and genome-wide colinearity indicated that the genomes of L. curvatus and L. sakei had weak nucleotide sequence homology, allowing them to be used as indicators to distinguish the two species. Pangenomes for these species were constructed, whose core gene functions were annotated. The results showed that the core genomes of L. curvatus and L. sakei were mainly involved in their basic metabolism. Analysis of individual genomes of the strains revealed that 1) both L. curvatus and L. sakei contained a wide range of genes encoding glycoside hydrolases, which are abundant genetic resources for catabolizing and metabolizing dietary fiber such as polysaccharides, lactose utilization, and lignocellulose; 2) antibiotic resistance genes were annotated in the genomes of three strains, which originate from horizontal gene transfer; 3) the unique arginine deiminase pathway of L. sakei, the serine dehydratase and guanine deaminase pathways of L. curvatus, and the glutamate decarboxylase pathway of several strains were identified, revealing that the acid tolerance mechanisms of these two species are different; and 4) genes encoding cold stress proteins were discovered, which endow the two species with good cold processing properties. Moreover, the genomes of some L. sakei strains contained gene clusters related to the biosynthesis of lactocin S and condensin. In conclusion, this study established taxonomic criteria for the two species and information on individual differences between their strains, which will provide a basis for the study of the physiological, biochemical, molecular genetic mechanisms of L. curvatus and L. sakei and their industrial applications.

As an extension of the previous research, this study aimed to comprehensively characterize the genome of Bacillus subtilis SNBS-3. Illumina second-generation sequencing technology and the third-generation high-throughput Pacbio sequencing platform were used for whole-genome sequencing of B. subtilis SNBS-3 isolated from traditional bean paste to obtain the key information of genome characteristics, gene function annotation and classification, phylogenetic evolution, and secondary metabolites. The results showed that the genome of SNBS-3 was a closed circular DNA of 4 076 387 bp in length containing 4 000 protein-coding genes. A total of 3 209, 2 824, 2 560, 147, 12 and 4 functional genes were annotated in the Clusters of Orthologous Groups (COG), Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Carbohydrate-Active Enzymes (CAZyme), Comprehensive Antibiotic Resistance Database (CARD) and Virulence Factor Database (VFDB), respectively. Using the online software AntiSMASH and Bagel4, we found that it contained genes related to the synthesis of surfactin, mycosubtilin, plipastatin, bacilysin and bacillaene, as well as a complete gene cluster for the synthesis of the bacteriocin subtilosin A. Based on the results of antimicrobial test and proteinase K test, it was hypothesized that B. subtilis SNBS-3 had the ability to synthesize subtilosin A. In conclusion, the whole genome sequencing results of B. subtilis SNBS-3 show that it can produce a variety of bacteriostatic substances and thus have biocontrol potential. The results from this study provide a theoretical basis for further development and application of various bacteriostatic substances including the bacteriocin subtilosin A.

A biotransformation system (LSBT) consisting of Lactococcus lactis and Streptococcus lactis was used to eliminate the yeasty odor of eight yeast extracts with different characteristics (FG10, FM88, FM31, KU012, FIG12LS, F58, FIG03 and KA02) with a focus on flavor substances and amino acids. Meanwhile, the applicability and universality of LSBT were evaluated. All yeast extracts had no longer any yeasty flavor after being treated with LSBT, and FG10 and FM88 were provided with a fermented sauce flavor. Producing no indole was found to be one of the key factors for the success of LSBT. At the same time, the lactic acid content of the transformed yeast extract should not be less than 10.00 g/L. The difference of raw materials played an important role in the LSBT. In particular, the deficiency of aspartic acid and excessive accumulation of threonine in raw materials were likely reasons for the unsuccessful conversion of LSBT. Overall, LSBT is applicable to most yeast extracts, but other microbial combination techniques or fermentation conditions need to be explored for specific yeast extracts such as F58, FIG03 and KA02.

In order to obtain efficient engineered strains for oil production, the desaturase gene from Bacillus subtilis HB1310, an endophytic bacterium isolated from walnut, was expressed in Escherichia coli BL21 (DE3), the single-gene-expression strains BL21(DE3)/pET-de1 and BL21(DE3)/pET-de2 and the co-expression strain BL21(DE3)/pET-de were constructed. The results showed that the desaturase gene was highly expressed in E. coli BL21(DE3), and the desaturase activities of the three engineered strains were higher than that of the wild-type strain after induction for up to 60 h, and they reached their maximum after 24 h, which were enhanced by 1.38, 1.48 and 1.75 times compared with that of the wild-type strain at the same time point, respectively. The overexpression of exogenous desaturase gene led to changes in oil yield and fatty acid components in E. coli. The oil yields of the engineered strains were significantly improved compared with that of the wild-type strain, and reached 0.57, 0.58 and 0.72 g/L after 24 h, respectively. The contents of saturated fatty acids were increased by 72.26%, 66.93% and 123.21%, respectively, and unsaturated fatty acids by 112.18%, 44.18% and 134.30%, respectively in the engineered strains compared with the wild-type strain. This study provides a valuable strain source for the development and application of engineered bacteria for oil production.

Complete synthetic minimal media for Zygosaccharomyces rouxii growth were designed for high temperature (40 ℃, HTS) and high salt stress (18% NaCl, HSS) in this study, and the difference in the nutritional requirements of Z. rouxii cells under long-term adverse environmental conditions was analyzed. The differences in the metabolism and gene expression of organic acids, amino acids and sugars during the period from the growth adaptation stage to the early logarithmic stage were highlighted between HSS and HTS conditions. The results showed that Z. rouxii cells exposed to HSS needed more exogenous amino acids, vitamin and amino acid supplementation alleviated HTS-induced damage in yeast cells. The adversity transcription gene MSN4 and the hypertonic regulatory protein gene HOG1 responded to high salt, while the heat shock regulatory protein gene HSF1 and the superoxide dismutase gene SOD1 responded to high temperature. In summary, different strategies for organic acid, amino acid and sugar metabolism were adopted by Z. rouxii in response to HSS and HTS. This study deepens the understanding of the mechanism of temperature tolerance in salt-tolerant Z. rouxii, which will contribute to the development of new brewing yeast cells with tolerance to both high salt and temperature.

In this study, changes in the molecular mass of alginate were investigated during its enzymatic degradation and the processing parameters for the enzymatic preparation of alginate oligosaccharides were explored. Furthermore, the in vitro immunological activity of degraded products with different molecular mass was evaluated. The results showed that the molecular mass of alginate decreased significantly after degradation by alginate lyase, and three degradation products with different molecular mass were obtained through gradient ethanol fractionation. Their weight-average molecular masses were 13.4, 5.73 and 3.85 kDa, respectively. Using single factor experiments, the optimal processing parameters were determined as pH 7.0, alginate lyase dosage 15 U/g substrate, and hydrolysis time 24 h, giving a yield of 28.05%. All alginate and its degraded products had immunoenhancing activity in mouse macrophages, and among them, the effect of the product with a weight-average molecular mass of 5.73 kDa was most pronounced and more pronounced than that of alginate oligosaccharides. By adding TAK-242, a blocker of macrophage Toll-like receptor 4 (TLR4), it was verified that the degraded products of alginate regulated macrophage immune activity by inducing the secretion of TLR4 and consequently causing cascade reactions to increase the secretion of NO, TNF-α and IL-6. These results can provide a theoretical basis for the high-value utilization of alginate.

SlCCD1A-OE lines of cherry tomato CI1005 and large-fruited tomato AC were selected to investigate the effect of SlCCD1A on tomato flavor quality. The transgenic plants were identified by real-time polymerase chain reaction (PCR), and the volatile components and major quality traits of the transgenic lines were determined. The results showed that SlCCD1A-OE mainly cleaved lycopene and β-carotene in tomato fruit, and increased the contents of 11 volatile isoprene compounds, including 6-methyl-5-heptene-2-one, compared with the wild type (WT). The total amount of these isoprene compounds was the highest in strain OE-3 from CI1005, which was 5.68 times of that in WT, and it increased 1.88 times in OE-8 from AC compared with WT, significantly enhancing the floral, fruity, and sweet aroma. The soluble solid content, total sugar content, and sugar/acid ratio in strain OE-3 from CI1005 increased to 6.2%, 37.34 mg/g, and 10.37, while the contents of total acid and vitamin C (VC) decreased to 0.36 mg/L and 42.10 mg/L, respectively. The soluble solid content, total sugar content, and sugar/acid ratio in strain OE-7 from AC increased to 4.77%, 20.03 mg/g, and 5.23, while the total acid and VC contents decreased to 0.38 mg/L and 37.10 mg/L, respectively, resulting in high-sweet and low-sour taste. The SlCCD1A gene is beneficial for enhancing the content and richness of carotenoid-derived volatiles in tomato fruit and increasing the contents of soluble solids and total sugars, thereby improving the flavor quality.

In this study, inhibition kinetics, fluorescence spectroscopy and molecular docking simulation were used to systematically investigate the inhibitory effect and mechanism of EA on mushroom tyrosinase. The in vitro study and kinetic results showed that EA significantly inhibited tyrosinase activity with a half maximal inhibitory concentration (IC50) of 0.05 mg/mL in a reversible mixed-type manner; the binding constant KI was smaller than KIS, indicating that EA bound more tightly to the free enzyme than to the enzyme-substrate complex. The fluorescence of tyrosinase was quenched statically by EA, and they combined to generate a complex through a spontaneous endothermal process, with hydrophobic interaction being the main force; there was only one binding site or class of binding sites. Simultaneous and three-dimensional fluorescence spectroscopy analysis showed that EA increased the polarity of the microenvironment of tyrosinase, decreased the hydrophobicity, and brought the Trp residues of tyrosinase closer to the binding site. Molecular docking simulation analysis further complemented and validated the above results by showing visually that EA was a mixed-type tyrosinase inhibitor, binding to the free enzyme or enzyme-substrate complex mainly through hydrophobic interactions and hydrogen bonding, ultimately leading to reduced enzyme activity. This study is of reference significance for the application of EA as a preservative in the food industry.

To clarify the binding characteristics of human norovirus (HuNoV) with histo-blood group antigens (HBGAs)-like substances from Pacific oysters, this study used an Escherichia coli expression system to clone and express HuNoV GI.5 and GII.4 P proteins, and analyzed the binding characteristics of HuNoV P proteins with salivary HBGAs and HBGAs-like substances from Pacific oysters using enzyme-linked immunosorbent assay. The results showed that HuNoV GII.4 exhibited good binding characteristics with blood type A, B, AB, and O salivary HBGAs, while GI.5 HuNoV exhibited weak binding characteristics with blood type B salivary HBGAs but had significant advantage in binding with type O salivary HBGAs. HuNoV GI.5 and GII.4 could be bioaccumulated in the gills, digestive gland, and mantle of Pacific oysters, with the highest bioaccumulation in the digestive gland. Both types of HuNoV were mainly bound to type A and H1 HBGAs-like substances; HuNoV GII.4 had different degrees of binding with type Lea, Leb, Lex, and Ley HBGAs-like substances, while HuNoV GI.5 had weak binding with type Leb HBGAs-like substances but significant advantage in binding with type H1 HBGAs-like substances. In summary, different types of HuNoV have different binding characteristics with HBGAs or HBGAs-like substances. Specifically, HuNoV GII.4 shows broad-spectrum binding characteristics whereas HuNoV GI.5 shows selective binding characteristics.

This study was performed to explore the differences in the composition of astringent substances in different tissues of fresh lotus seeds and the expression of key enzyme genes involved in the synthesis of astringent compounds. The contents of soluble tannins, insoluble tannins and proanthocyanidins in lotus seed coat, lotus seed pulp without coat and lotus seed plumule were determined. Meanwhile, the activity and gene expression of key enzymes in the tannin synthesis pathway were detected. Sensory evaluation and electronic tongue analysis were performed on lotus seed samples. The data obtained was analyzed by orthogonal partial least squares discriminant analysis (OPLS-DA) and correlation analysis. Results showed that the major substance contributing to the astringency of lotus seeds was soluble tannins. Tannins had a positive effect on its excellent flavor at the waxy ripeness stage. Anthocyanin reductase was a key enzyme affecting the astringency intensity of lotus seeds. SnANR9 played a role in regulating the astringency of different tissues of lotus seeds.

The surface characteristics and adhesion properties of Lacticaseibacillus paracasei ZY-1, derived from Tibetan kefir grains, and L. paracasei S-NA5 and S-NB, isolated from Xinjiang traditional fermented milk, were evaluated in vitro, and whole genome sequencing was performed to compare the difference among adhesion-related genes in the three strains. The gastrointestinal tolerance and adhesion properties of L. paracasei S-NB to Caco-2 cells were superior to those of S-NA5 and ZY-1. Moreover, two exopolysaccharide (EPS) synthesis gene clusters were found in each strain, and the EPS cluster 1 of strain ZY-1 differed significantly from that of S-NA5 and S-NB. Meanwhile, genes involved in lipoteichoic acid (LTA) synthesis and related domains of protein adhesins were predicted. The secondary structure prediction of the products encoded by the adhesion protein genes in S-NB showed that the secondary structure of 11 adhesion proteins was dominated by α-helix and random coil. Additionally, the complete metabolic pathways of lactose, galactose, fructi-oligosaccharide, inulin and human milk oligosaccharides were found in the three strains, which were all highly conserved.

The microbial community succession of fermented mutton sausage during natural fermentation was determined using metagenomic technology, and the metabolic pathways of volatile flavor substances and the microorganisms and enzymes involved in the metabolism of volatile flavor substances were annotated and analyzed by using the Evolutionary Genealogy of Genes: Non-supervised Orthologous Groups (eggNOG) database, the Kyoto Encyclopedia of Genes and Genomes (KEGG) database and the Carbohydrate-Active Enzymes (CAZy) database. The results revealed that Haemophilus influenzae, Staphylococcus aureus, and Oenococcus oeni were the dominant species during the fermentation process, and the relative abundance of Staphylococcus saprophyticus and Staphylococcus equorum reached a peak of 16.52% and 10.53% after 14 days of fermentation, respectively. Among the samples fermented for 0, 5, 14 and 26 days, the samples fermented for 5 days had the highest number of genes annotated. Carbohydrate metabolism and amino acid metabolism were the most annotated metabolic pathways, and glycosidohydrolase and glycosyltransferase were the most abundant enzymes involved in carbohydrate metabolism. Totally 167, 217 and 92 genes encoding enzymes involved in amino acid metabolism, carbohydrate metabolism and fatty acid metabolism were found, respectively. The enzymes participating in the three metabolic pathways were mainly annotated in Staphylococcus, Leuconostoc, Pseudomonas, Psychrobacter, and Vibrio. The abundance of most of the enzymes attained a maximum after 14 days of fermentation. The results obtained in this study provide a significant reference for the analysis of the dynamic changes of microorganisms and the formation mechanism of volatile flavors in fermented mutton sausage.

To systematically elucidate how metal-binding antimicrobial peptide SIF4 exerts its antimicrobial activity by targeting DNA topoisomerase without destroying the cytoplasmic membrane, Escherichia coli was used as a model strain to investigate the binding mode of SIF4 with its genomic DNA and the impact of SIF4 on DNA topoisomerase I and II activities and intracellular nucleic acid biosynthesis. Results showed that SIF4 could bind to genomic DNA in a manner similar to ethidium bromide (EB) intercalation with strong inhibitory effect on topoisomerase I but weak effect on topoisomerase II, and catalyzed RNA transcription to exert antimicrobial activity by interfering with the unwinding of negative DNA supercoils and RNA polymerase binding. It was also found that the biosynthesis of intracellular DNA and RNA was inhibited to different degrees after 12 h treatment with SIF4, which exhibited a good dose-effect relationship. There was no significant difference in the amounts of intracellular DNA and RNA between the 1/2 minimum inhibitory concentration (MIC) group and the control group (P > 0.05), but there was a significant difference between the MIC and 2 MIC groups and the control group (P < 0.05). Our results may provide theoretical support for the application of SIF4 in the biocontrol of foodborne E. coli.

This study was conducted to isolate and identify Bifidobacterium from the feces of Kazakh school-age children in Yining, Xinjiang and evaluate the in vitro probiotic characteristics of B. longum subsp. longum isolates. By groEL gene sequencing and repetitive element sequence-based polymerase chain reaction (rep-PCR) fingerprinting, 416 Bifidobacterium strains were identified to belong to B. longum, B. bifidum, B. pseudocatenulatum, B. catenulatum and B. breve. According to the fingerprints of B. longum subsp. longum, 27 genotypes showed genetic differences between individual strains and the coexistence of multiple strains in the gut was found. The in vitro experimental results showed that out of 27 representative strains, strains 2B3-21, 1B23-11, 2B33-3, and 1B68-16 were optimal in acid and bile salt tolerance, strains 1B68-16, 2B13-5, 2B33-3, and 1B39-2 had broad-spectrum antibacterial properties, and strains 1B38-1, 2B33-3, 1B68-16, and 2B13-28 showed a strong antioxidant capacity. Considering the antibiotic resistance of all strains and their ability to utilize plant-derived glycans, strains 1B38-1 and 2B13-28 were selected to assess their in vivo probiotic potentials. This study may lay the foundation for the development of excellent probiotics and related products for populations from specific areas.

Salmonella pullorum phage Pu29 was comprehensively analyzed for its biological and genomic characteristics. A magnetic separation and enrichment technique for Salmonella was established using the phage Pu29 as a recognition element. The phage belonged to the genus Roufvirus and had an icosahedron head and an irreducible long tail. Pu29 had a wide host spectrum with an adsorption rate of 88.67% on host cells in 15 min, a latent period of 30 min, a rise period of 180 min, and a burst size of 115.74 PFU/cell. Meanwhile, Pu29 had good heat resistance (30–60 ℃) and pH tolerance (pH 4–11). Its genome was composed of 45 715 bp (GC content 46.08%) and 81 open reading frames (ORFs), including 18 ORFs with known functions that did not carry genes encoding toxicity or resistance factors. PhagePu29-MBs were prepared as a probe by coupling the phage with carboxylated nano-magnetic beads (MBs) through amide reaction. When 25 μg of the probe was incubated with Salmonella at 37 ℃ for 20 min, the highest capture rate of Salmonella of 83.93% and the lowest captured bacterial concentration of 45 CFU/mL were obtained. Transmission electron microscopy (TEM) was used to observe that PhagePu29-MBs could specifically capture Salmonella. In spiked samples, the highest capture rate of Salmonella separated and enriched by the probe reached 92.92%. The separation and enrichment process took approximately 30 min. Therefore, this study established a fast and highly specific magnetic separation method for Salmonella based on phage Pu29, which may lay the foundation for the development of a phage-based method for the rapid separation and enrichment of foodborne pathogens in food samples.

To improve the growth and sporulation efficiency of Bacillus subtilis, the effect of malate on the cell growth and metabolism of B. subtilis DF was investigated in a 30 L bioreactor. At 22 h of fermentation, a biomass of 3.68 × 1010 CFU/mL was obtained by malate addition to a final concentration of 1.5% during 16–27 h after the pH reached 8.0 at 16 h, which was 71.9% higher than that of the control group. Meanwhile, the number of spores was 3.63 × 1010 CFU/mL, which was 92.1% higher than that of the control group. Differential transcriptomic analysis showed that malate increased the metabolic efficiency of the gluconeogenesis and pentose phosphate pathways with 1.38 to 2.51-fold up-regulation of the zwf, pckA and fbaA genes, respectively and the metabolic efficiency of the tricarboxylic acid (TCA) cycle with 3.10-fold up-regulation of the citZ gene, reduced cellular oxidative stress with a 72.9% down-regulation of the poxL gene, a 3.88-fold up-regulation of the trxA gene, and thus a 45.9%–51.3% reduction in H2O2 concentration during 19–24 h, and enhanced the phosphorylation efficiency of Spo0A with down-regulation of the kipL, rapAD and abrB genes by 57.5%–75.9%, and up-regulation of the clpX, phrCF, spo0B and sigA genes by 1.73–13.76 folds, significantly improving the growth and sporulation efficiency of B. subtilis DF. These findings provide theoretical supports for the industrial application of B. subtilis.

The fungal community structure, the relationship between fungal flora and physicochemical factors, and the prediction of fungal function in pit muds from different spatial positions of 10- and 50-year-old cellars at Jinhui liquor Co. Ltd. were studied by using Illumina NovaSeq high-throughput sequencing, redundancy analysis and Fungi Functional Guild (FUNGuild). The results showed that the fungal diversity and richness of the 10-year-old pit mud decreased with increasing depth; the fungal diversity of the 50-year-old pit mud showed an overall increasing trend, while the fungal richness initially decrease and then increased. Moreover, for the 10-year-old pit, the fungal diversity and richness of the upper layer of the pit wall were significantly higher than those of the other positions (P < 0.05), while for the 50-year-old cellar, the fungal diversity and richness of the bottom layer were significantly higher than those of the other locations (P < 0.05). The fungal diversity and richness were significantly higher in the wall of the 10-year-old cellar than the 50-year-old cellar (P < 0.05), but were significantly higher in the bottom of the 50-year-old cellar than the 10-year-old cellar (P < 0.05). A total of 21 fungal phyla and 520 genera were detected in all pit mud samples, the relative abundance of four dominant phyla (Ascomycota, Basidiomycota, Mortierellomycota and Rozellomycota) and most dominant genera such as Aspergillus and Kazachstania showed significant changes among pit ages and spatial locations (P < 0.05). Fusarium, Aspergillus, Saccharomyces and Monascus were positively correlated with the contents of water, humus, K+ and Ca2+, while Cladosporium and Vishniacozyma were positively correlated with pH. Seven nutritional modes of fungi were observed, mainly including saprophytic and pathological-saprophytic-symbiotic nutritional modes, and four single and seven mixed functional groups were determined. This study provides a theoretical basis for clarifying the structure and spatial distribution of fungal community in Jinhui Baijiu pit mud.

In this study, peptide fractions (F1-F4) with different molecular masses were obtained from Bangia fusco-purpurea through enzymatic hydrolysis and ultrafiltration. F2, with molecular masses of 800–2 000 Da, exhibited the highest in vitro angiotensin-converting enzyme (ACE) inhibitory activity as determined by high performance liquid chromatography (HPLC). The amino acid sequence of F2 was identified through liquid chromatography-tandem mass spectrometry (LC-MS/MS) and de novo sequencing using PEAKS Studio software. Six ACE inhibitory peptides that stably bind to ACE were selected through molecular docking. The predicted peptides were synthesized by solid-phase synthesis and their in vitro ACE inhibitory activity was verified. Among them, L1 (LVLLFLFGE) showed the highest ACE inhibitory activity with a half maximal inhibitory concentration (IC50) value of 14.22 μg/mL. Molecular docking results indicated that the inhibition of ACE by L1 was mainly attributed to its ability to form hydrogen bond interactions with the active site of ACE. Finally, the effects of temperature, pH, metal ions, light exposure, and simulated gastrointestinal digestion on the stability of L1 were investigated. The results revealed that L1 was highly stable to heat and ionic strength. However, its activity gradually decreased at pH > 2, and was affected by ultraviolet treatment. The ACE inhibitory activity of L1 decreased after simulated gastric and intestinal digestion, but was still significant.

In this study, a combination of an improved mucin enriched medium with real-time polymerase chain reaction (real-time PCR) was used to test 48 samples of maternal and infant feces for Akkermansia muciniphila (Akk). Under optimized conditions, 24 Akk strains were isolated from eight positive samples. All these strains were confirmed as Akk by 16S rRNA gene sequencing and PCR with Akk-specific primers. Repetitive extragenic palindrome-polymerase chain reaction (rep-PCR) fingerprinting classified the 24 strains into four genotypic groups. Subsequently, these strains were tested in vitro for simulated gastrointestinal fluid tolerance, hydrophobicity, antibiotic susceptibility, and glycan utilization capacity. The results showed that strains HN18D-1, HN18D-3, and WW48D1-13 had the highest tolerance to simulated gastric and intestinal fluids. All Akk strains were resistant to vancomycin, clindamycin, kanamycin and erythromycin. Xylooligosaccharides and soybean oligosaccharides had prebiotic effects on the Akk strains. Collectively, Akk isolates HN18D-1, HN18D-3 and WW48D1-13 can be used as potential probiotic candidates for subsequent in-depth studies.

In this study, the effects of Pediococcus pentosaceus inoculation on the quality characteristics of snakehead surimi during fermentation were analyzed in comparison with natural fermentation. The quality of fermented surimi was evaluated in terms of pH, total acid, total volatile basic nitrogen (TVB-N), fatty acids, color difference, texture, amino acids and sensory scores. The results showed that pH declined and total acid content gradually increased during fermentation. After fermentation for 48 h, total acid content in the inoculated fermentation group increased by 52.29% when compared with that in the natural fermentation group. Compared with the natural fermentation group, the increase in TVB-N content was significantly inhibited in the inoculated fermentation group. The content of saturated fatty acids increased during natural fermentation, but decreased during inoculated fermentation. The content of monounsaturated fatty acids was lower while the content of polyunsaturated fatty acids was higher in the inoculated fermentation group than in the natural fermentation group at the end of fermentation. The inoculated fermentation group showed an increase in L* value and the absolute values of hardness and adhesiveness, and increased the contents of total essential amino acids and umami amino acids in surimi samples and the essential amino acid index from 73.9 to 74.8. After fermentation for 48 h, the scores for odor, color and overall acceptability in the inoculated fermentation group were higher than those in the natural fermentation group, which were significantly correlated with quality characteristics. Therefore, the quality of snakehead surimi can be better improved by fermentation with P. pentosaceus.

In this study, the flavor characteristics and volatile compounds of cold-pressed flaxseed oil were analyzed using quantitative descriptive analysis, headspace solid phase microextraction and simultaneous distillation extraction coupled with gas chromatography-mass spectrometry-olfactometry (GC-MS-O) and chemometrics. The results showed that cold-pressed flaxseed oil had a unique flavor, mainly presenting fresh grassy and fishy flavors. Totally 34 characteristic volatile components were detected, including 12 aldehydes, 7 alcohols, 5 acids, 3 terpenes, 3 alkanes, 2 ketones and 2 aromatic compounds. Based on GC-O analysis, detection frequency (DF ≥ 6) and odor activity value (OAV ≥ 1), 2-ethyl hexanol, hexanol, (E)-2-hexenal, hexanal, and (E,E)-2,4-heptadienal were found to be the major contributors to the grassy flavor, and (Z)-4-heptenal the major contributor to fishy flavor. Principal component analysis (PCA) validated the correlation between the characteristic flavor intensity and the sensory flavor attributes of cold-pressed flaxseed oil from different regions. The results of this study can provide a theoretical basis for improving the aroma, processing and quality of cold-pressed flaxseed oil.

The differences in the proteomes of camel meat from different age groups were analyzed by tandem mass tag (TMT)-based quantitative proteomics and liquid chromatography tandem mass spectrometry (LC-MS/MS) to identify the key quality-related proteins of camel meat. The results showed that differentially expressed proteins (DEPs) had an important effect on the quality of camel meat. A total of 311 DEPs were identified in the longissimus dorsi muscle of camels from three age groups, 3–4 (I), 6–7 (II), and 9–10 (III) years old. Altogether 245 DEPs were identified in groups I versus II, 16 in groups II versus III, and 139 in groups I versus III. In addition, 194, 1, and 110 DEPs were up-regulated, and 51, 15, and 29 DEPs were down-regulated in the three comparison groups, respectively. Gene Ontology (GO) functional annotation analysis indicated that structural proteins, metabolic proteins, and heat stress proteins could be used as biomarkers for discrimination among camel meat from different ages. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the DEPs were mainly involved in fatty acid metabolism, glycolysis/glucose production, amino acid biosynthesis, and the hypoxia inducible factor-1 (HIF-1) signaling pathway. Protein-protein interaction (PPI) analysis showed that metabolic enzyme proteins were key network-connecting proteins that affect camel meat from different ages. Correlation analysis showed that 16 DEPs were correlated closely with meat tenderness. The tenderness of camel meat from the three age groups was mainly influenced by actin, histone and protein kinases. The results of this study can provide a scientific basis for the grading and evaluation of camel meat, the selection of optimal slaughter age, and the study of camel meat quality characteristics.

In order to investigate the differences in flavor quality between white tea made from Oolong tea cultivars and traditional white tea, white teas made from eight Oolong tea cultivars such as Zimeigui and Fuding Dahao white tea as a control were analyzed by sensory evaluation, biochemical assays and multivariate statistical analysis. The results showed that the appearance and infusion color of Oolong white tea were darker, while the taste and aroma were better than those of traditional white tea. The biochemical analysis revealed that the differences in conductivity, pH, and the contents of soluble sugars, free amino acids, gallocatechin gallate (GCG) and epigallocatechin gallate (EGCG) were important factors causing the differences in taste between traditional white tea and white tea made from Oolong tea cultivars. Volatile composition analysis showed that trans-2-nonenal, cis-3-nonen-1-ol, methyl palmitate, linalool, methyl linoleate, cedrol, geranyl formate, phenethyl alcohol, nerolidol, methyl salicylate, dibutyl phthalate and phytone were the key differential aroma components contributing to the difference in aroma between Oolong and traditional white tea. Findings from this study will provide a theoretical reference for flavor diversification of white tea.

To explore the quality characteristics of Gaoyou duck eggs, metabolomics was used to analyze the quality indexes, basic nutritional indexes and small molecule metabolites. The results showed that the mass, egg shape index, egg yolk color, Haugh unit, egg white height, egg yolk index and crude protein content of Gaoyou duck eggs were higher than those of the other studied breeds. The contents of total amino acids, umami amino acids, branched-chain amino acids, total fatty acids and unsaturated fatty acids were higher, and the content of saturated fatty acids was lower, indicating that sensory quality parameters, amino acids and fatty acids can characterize the quality of Gaoyou duck eggs. The characteristic components of Gaoyou duck eggs were uncovered by metabolomic fingerprinting, principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and hierarchical cluster analysis (HCA). Totally 252 compounds and 22 differential compounds were identified in egg yolk, and 184 compounds and 40 differential compounds in egg white. Among them, uridine 5’-monophosphate, guanosine 5’-monophosphate, and N-acetyl-D-glucosamine were the main differential nutrients, and arachidonic acid in egg yolk was the unique nutrient of Gaoyou duck eggs, while indole was not detected in the egg white of Gaoyou duck eggs.

To explore the effects of Empoasca onukii puncturing on metabolites in beauty tea produced from the cultivar Qingxindamao, sensory evaluation, ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and gas chromatography-mass spectrometry (GC-MS) were used to compare the sensory quality and metabolites of beauty tea processed from fresh tea leaves punctured or not punctured by E. onukii. The results showed that the quality of beauty tea with E. onukii puncturing was better. The contents of flavones, flavanols and their glycosides, phenolic acids, theaflavins, glycoside derivatives and tannins increased compared with beauty tea without E. onukii puncturing, while the contents of amino acids, saccharides and lipids decreased. Based on odor activity value (OAV) and partial least squares discriminant analysis (PLS-DA), a total of five characteristic volatile components, including geraniol, linalool, β-myrcene, methyl salicylate and D-limonene, were identified.

To explore the effect of room temperature storage on the flavor quality and biochemical composition of flower and fruit scented black tea, this study compared the sensory flavor quality of flower and fruit scented black tea produced in the years 2019, 2020, 2021 and 2022 and stored at room temperature, and it detected volatile and non-volatile compounds in the tea by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and ultra-performance liquid chromatography coupled to orbitrap high resolution mass spectrometry (UPLC-Orbitrap-MS). The results showed that the sensory quality of flower and fruit scented black tea was significantly affected by storage at room temperature, and the tea lost its floral and fruity aroma characteristics after three years of storage at room temperature; its quality characteristic was mature sour taste. The tea samples were divided into four groups of age by principal component analysis (PCA) and hierarchical cluster analysis (HCA). Totally 15 volatile differential compounds such as linalool, cis-β-ocimene, and hexanoic acid (VIP > 1 and P < 0.05), and 154 non-volatile differential compounds such as theanine, epicatechin, and gluconic acid (VIP > 2 and P < 0.05) were selected by partial least squares discriminant analysis (PLS-DA) and one-way analysis of variance (ANOVA). The content of volatile compounds such as linalool, hexanal, cis-β-ocimene, and 2-pentylfuran decreased with increasing storage time, while the contents of hexanoic acid, dihydroactinidolide 1-ethyl-2-formyl-1H-pyrrole, and β-ionone increased. The contents of non-volatile compounds such as most amino acids, nucleotides, sugars, tea polyphenols tended to decrease with increasing storage time, while the contents of organic acids and lipids showed an increasing trend. The results obtained from this study can provide a scientific basis for elucidating the quality changes of flower and fruit scented black tea during storage and help guide its rational storage and scientific consumption.

To investigate the characteristics of quality formation of Simian tea, the non-volatile components, mineral elements and filamentary structure of fresh leaves from different positions of ‘Simian Tucha’ tea plants, endemic to Zigui, were analyzed using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS), inductively coupled plasma optical emission spectrometry (ICP-OES), and scanning electron microscopy (SEM). The results showed that the non-volatile components were more abundant in the leaves with higher tenderness, with amino acids, alkaloids, catechins, and aroma glycosides being mainly concentrated in the first (L1) and second leaves (L2). Theanine, organic acids, and flavonoids were mainly concentrated in the third leaf (L3), while the content of non-volatile components in the older leaves was relatively lower. The accumulation of mineral elements greatly varied among tea leaves with different tenderness. The contents of nitrogen, phosphorus, potassium, zinc, and copper in L1 (32.41 mg/g, 4.53 mg/g, 15.65 mg/g, 45.45 μg/g, and 10.75 μg/g, respectively) and L2 (30.60 mg/g, 3.70 mg/g, 14.12 mg/g, 35.82 μg/g, 9.02 μg/g, respectively) were higher than those in older leaves. The contents of iron, manganese, and calcium were higher in mature leaves. Through SEM observation, it was found that the filamentary structure of Simian tea leaves consisted of two forms, triple-stranded coil and single-stranded coil, and was distributed in the internal thread or ringed vessels of the xylem in the vascular bundles in the midvein and lateral veins, and the number of filamentary structures was higher in the second, third and fourth leaves than that in buds and L1.

According to the results of sensory evaluation performed by experts, 14 black tea samples were divided into two groups based on their aroma quality: high-quality and quality-deficient black tea. Using fast gas chromatography-electronic-nose (GC-E-Nose) and gas chromatography-mass spectrometry (GC-MS) combined with multivariate statistical analysis, discriminant analysis of the two groups were carried out, and the key differential components between these groups were selected. The results showed that 117-dimensional dataset was obtained by the fusion of the GC-E-Nose (44-dimensional) and GC-MS (73-dimensional) data and used to establish a model for accurate classification of the two types of black tea employing orthogonal partial least squares-discriminant analysis (OPLS-DA). The model’s explanatory and predictive capacity (R2Y = 0.976, Q2 = 0.959) were better than those of the model established based on the GC-E-Nose or GC-MS data. Based on variable important in projection (VIP) scores > 1.6 and P < 0.05, eight key aroma components including dimethyl sulfide (B3 and B25), β-ionone (A59), (3E)-4,8-dimethylnon-1,3,7-triene (A20), dihydroactinidiolide (A64), linalool (A17), phenylethyl alcohol (A19), δ-octyl lactone (A41) and γ-nonalatone (A45) were selected, which played an important role in the classification. These results showed that GC-E-Nose combined with GC-MS allows rapid and accurate discrimination between quality-deficient and high-quality black tea, which can be used as a supplement to traditional sensory evaluation, providing technical support for quality control and improvement of black tea.

Objective: To simultaneously detect acetamiprid and thiram in juice by surface-enhanced Raman spectroscopy (SERS) based on optimized Au-Ag alloy nanoparticles as substrate. Methods: Raman spectra of acetamiprid and thiram standard solutions and their mixtures at different concentrations were collected, and the Raman peaks were assigned. Apple juice was selected as a representative sample to detect and analyze mixed pesticide residues at different concentration gradients. Calibration curves between the Raman characteristic peak intensities and the concentrations of the two pesticides were established. Finally, the accuracy and precision of the method were evaluated by recovery experiments. Results: Acetamiprid was identified based on its Raman characteristic peak at 631 cm-1, and thiram based on its Raman characteristic peak at 1 380 cm-1. The limits of detection (LOD) of acetamiprid and thiram in apple juice were 0.422 31 and 0.035 56 mg/L, respectively, which were lower than the national maximum residue limits (MRL) for acetamiprid (0.8 mg/L) and thiram (5 mg/L) in apples. The average recoveries of acetamiprid and thiram were 81.67%–101.25% and 98.70%–119.36% with relative standard deviations (RSDs) of 2.72­%–7.68% and 5.44%–15.15%, respectively. Conclusion: SERS, characterized by sharp peak and narrow peak width, combined with Au-Ag alloy nanoparticles allows the simultaneous quantitative detection of acetamiprid and thiram in apple juice, and thus can be further applied to the on-site simultaneous detection of a variety of other pollutants.

Two new types of elastic porous silanized melamine sponges (MeS) were prepared by silylation reaction using octadecyltrichlorosilane (OTS) and N-[3-(trimethoxysilyl)propyl]ethylenediamine (ATS), which were respectively designated as OTS@MeS and ATS@MeS. The silanized sponges were used to develop a modified quick, easy, check, effective, rugged, and safe (QuEChERS) method that can quickly and efficiently separate interfering matrices from the extract through spontaneous solution infiltration and physical extrusion. In this study, an analytical method using the modified QuEChERS procedure combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established for the simultaneous determination of 49 antibiotic residues in pork. Samples were extracted with 10 mL of acetonitrile containing 0.1% acetic acid, and then salted out with 2.0 g of Na2SO4 and 0.5 g of NaCl. After centrifugation, a 1 mL aliquot of the supernatant was cleaned up with a mixture of OTS@MeS and ATS@MeS. The chromatographic separation was conducted on an Agilent ZORBAX Eclipse Plus C18 column with gradient elution using a mobile phase comprised of methanol and aqueous solution (methanol/water, 5:95, V/V) containing 0.1% formic acid and 5 mmol/L ammonium acetate. The qualitative and quantitative detection were performed by multiple-reaction monitoring (MRM) using an electrospray ionization source in the positive ion mode. The results showed that the correlation coefficients for all analytes were greater than 0.999. The matrix effects (ME) were in the range of −13.5%−10.9%. The limits of detection (LOQ) and quantitation (LOQ) were 0.1–10.0 and 0.3–33.3 μg/kg, respectively. The recoveries at three spiked levels ranged from 65.0% to 112.7%, with intra- and interday relative standard deviations (RSDs) of 0.3%–11.8% and 2.4%–18.4%, respectively. The developed method was simple, rapid, highly sensitive and accurate, and could be used for the efficient and rapid determination of the 49 antibiotics residues in pork.

To establish a model based on near-infrared (NIR) spectra for quickly detecting the freshness of frozen crayfish, NIR spectra of thawed crayfish (tail, meat, and mince) were collected, and data were pretreated by first derivative, multiple scattering correction, wavelet transform (WT), or standard normal transform. The original and pretreated spectral data were correlated to total volatile basic nitrogen (TVB-N) contents using partial least squares (PLS) or convolutional neural network (CNN), and different quantitative prediction models were established and compared. The best model was selected to investigate its accuracy and applicability. The results showed that pretreatment methods had a significant influence on the accuracy of the model, and the CNN model established after spectral preprocessing had a better ability to predict the TVB-N content of crayfish compared with the PLS model. The CNN model based on the WT pretreated spectra of crayfish meat had the highest prediction accuracy for the validation set with correlation coefficients of 0.97 and 0.96, and root mean square errors of 1.26 and 0.93 mg/100 g for the calibration set and validation set, respectively. Moreover, the accuracy, precision, and sensitivity of the NIR method were within reasonable limits, and it had good figures of merit. According to the requirements of fast operation, accurate results, and low damage in practice, the WT-CNN-crayfish meat model was determined as the optimal model for predicting the TVB-N content in frozen crayfish. These results suggested that the WT-CNN-crayfish meat model have a great potential for predicting the TVB-N content and rapidly evaluating the freshness of frozen crayfish.

A dual-signal fluorescent aptasensor based on gold nanoflower (AuFL) was constructed for the simultaneous detection of ochratoxin A (OTA) and zearalenone (ZEN). Single-stranded DNA containing OTA and ZEN aptamers were covalently cross-linked on the surface of AuFL as a nanocarrier and hybridized with complementary DNA labeled with two fluorescent dyes (FAM and Cy3) to prepare a DNA functionalized nanoprobe. Because of fluorescence resonance energy transfer (FRET) between the fluorescent dyes and AuFL, the nanoprobe itself had no fluorescence. When OTA and ZEN were added, FAM and Cy3 were shed from the probe’s surface, disturbing the FRET process and consequently restoring the fluorescence of both fluorescent dyes. Under optimized conditions, the linear range was from 0.05 to 500 ng/mL, and the detection limit was 0.017 ng/mL for OTA; the linear range was from 0.1 to 500 ng/mL, and the detection limit was 0.033 ng/mL for ZEN. The dual-signal fluorescent aptasensor had good selectivity and reproducibility and was successfully applied to the detection of OTA and ZEN in real wine samples.

Alzheimer’s disease (AD) is one of the most common neurodegenerative diseases with a complex pathological mechanism, and as the incidence of AD has increased recently, there is an urgent need to develop more effective prevention and treatment methods. Many studies have shown that plant polyphenols have great potential in the prevention and treatment of neurodegenerative diseases, but their bioavailability is poor, limiting their practical applications. The application of nanotechnology can be helpful for the delivery of plant polyphenols. This article aims to elaborate recent progress and challenges in the development of nano-delivery systems for plant polyphenols, and review the common plant polyphenols used for AD treatment and their action mechanisms.

The survival rate and storage period of lactic acid bacteria (LAB) are affected by numerous factors in the vacuum freeze-drying process. Hence, optimizing the freeze-drying process and storage conditions is an effective method to improve the survival rate and prolong the storage period of LAB. This paper reviews the factors that influence the survival rate of LAB during the vacuum freeze-drying process and explores how to optimize the freeze-drying process and storage conditions to improve the survival rate and extend the storage period of LAB. We expect that this review will provide a basis and reference for the preparation of lyophilized LAB formulations with high activity and good storage stability.