To investigate the mechanism of action of umami-enhancing peptides, molecular simulation and sensory evaluation were employed to analyze the umami-enhancing effects of three peptides derived from chicken: LPLQD, DGGRYY, and DEAGPSIVH, the molecular mechanism of umami-enhancing peptide-glutamic acid-taste receptor interaction and the dynamic binding process. The results indicated that all three umami-enhancing peptides exhibited good water solubility and non-toxicity and had an additive effect on the umami taste of 0.35% glutamic acid solution. Molecular docking results revealed that the presence of umami-enhancing peptides greatly enhanced the interactions between the ligand system and the taste receptor type 1 (T1R1) including electrostatic interaction, hydrophobic interaction, and hydrogen bonding interaction, thereby leading to enhanced binding stability. Furthermore, molecular dynamic simulations disclosed that the venus flytrap (VFT) domain in the T1R1 receptors was relatively stable, while the cysteine-rich domain exhibited significant spatial fluctuations. Statistics of hydrogen bonds indicated that the addition of umami-enhancing peptides to the ligand system enhanced the hydrogen bonding interaction and consequently binding intensity between ligands and receptors. By analyzing the frontier molecular orbitals, serine, tyrosine, glutamine, arginine, and histidine residues were identified as active sites in the peptides that contributed to the binding with T1R1. The above results provide theoretical support for understanding the umami-enhancing mechanism of peptides and for the development of new umami enhancers.

This study was performed in order to investigate water clustering and its contribution to water diffusion in wheat flour. Based on the water adsorption and desorption isotherms of wheat flour at 20, 30 and 40 ℃, the water clustering properties were explored using the Park isotherm model, the Zimm-Lundberg method and the Brown method. Consistently, the results of the three methods suggested that water clustering occurred at high water activity (aw) levels, while the critical aw for clustering obtained from the three methods were only slightly different, ranging from 0.70 to 0.75, from 0.73 to 0.79 and from 0.56 to 0.68, respectively, which varied with temperature and the water sorption process. The predicted mean cluster size at aw of 0.95 was approximately 3.5, 4.5 and 6.5 from the three approaches, respectively. The number of water clusters kept almost unchanged at aw not lower than 0.90. Water diffusivity sharply decreased when aw was over 0.62–0.70. Furthermore, based on thermodynamic factor and self-diffusivity, it was found that water molecules were more likely to interact with themselves, leading to water clustering, which could be the major contributor to the sharp decrease of water diffusivity. When aw was equal to or more than 0.90, the strong self-diffusion capacity brought about by high water content could counteract the negative effect of water clustering, resulting in an almost constant water diffusivity.

Decolorization of remelt syrup is the most critical step in sugar refining. Currently, benzene-based anion-adsorption resins are commonly used in remelt syrup decolorization, but their slow release of monomers may endanger food safety. In this study, a green and environmentally friendly rosin-derived macroporous anion-adsorbing resin was synthesized and used to efficiently capture the caramels in remelt syrup. The results showed that the equilibrium adsorption capacity of the resin for caramels was 86 mg/g, and the corresponding decolorization efficiency was as high as 90%. Following five cycles of repeated use, the decolorization efficiency decreased by only 5%, indicating excellent reusability. The focus was on the multidimensional visualization of the micro-mechanism of the interaction in the adsorption of caramels by the rosin-based resin at the molecular, atomic, and electronic levels on the basis of quantum chemical theoretical calculations (including electrostatic potential, electrostatic potential interaction, average local ionization energy, frontier molecular orbitals, independent gradient model, and Hirshfeld surface analyses). The results indicated that the adsorption occurred with positive-negative potential neutralization and interpenetration. The interaction mechanism was primarily mediated by the electrophilic reaction between carboxylate and protonated tertiary amine groups, followed by weak hydrogen bonding, with the resin acting as a hydrogen bond donor. The combined use of multiple quantum chemical theory calculations to visualize the micro-mechanism of the adsorption interaction can provide novel insights into exploring the adsorption behavior and mechanism at a deeper level, which has a theoretical contribution and practical value.

In this study, the effects of pea resistant starch type 3 (RS3) at different mass fractions (0%, 2%, 4% and 6%) on the emulsion stability, emulsion gel properties and in vitro digestibility of chicken breast myofibrillar proteins (MP) were analyzed. Fourier transform infrared spectroscopy (FTIR) showed no covalent interaction between MP and pea RS3. The addition of pea RS3 significantly decreased the surface hydrophobicity (P < 0.05) while increasing the fluorescence intensity of MP, indicating enhanced protein-protein interactions. The addition of pea RS3 resulted in improved stability of MP emulsions, as manifested by higher absolute values of zeta potential, smaller droplet sizes and reduced creaming index. These changes promoted the formation of gel networks with improved texture and increased storage modulus (G’), gel strength and water holding capacity (WHC), especially at a pea RS3 concentration of 6%. The chemical force results showed that the addition of pea RS3 led to enhanced hydrophobic interaction and disulfide bonding between MP molecules. Low field-nuclear magnetic resonance (LF-NMR) confirmed that pea RS3 addition facilitated the migration of free water to immobilized water. Furthermore, the incorporation of pea RS3 caused a lower pepsin digestibility without changing the overall in vitro digestibility of MP gels. These results indicated that pea RS3 addition can contribute to the production of high-quality meat products with a low glycemic index without reducing protein digestibility.

The aim of this study is to apply a modification strategy based on covalently grafting acetyl groups onto polysaccharide chains to improve the emulsifying properties of chitosan. A second aim is to explore the optimal degree of acetylation (DA). Infrared spectroscopy (IR) confirmed that acetic anhydride reacetylation could regulate the DA of chitosan, and substitution only occurred on the amino group at the C2 position. The contact angle results showed that acetylation could effectively improve the non-polar part of chitosan, resulting in enhanced emulsifying properties. The droplet size of the Pickering emulsion stabilized by the modified chitosan significantly decreased compared with that observed with untreated chitosan. The emulsifying activity index (EAI) and emulsion stability index (ESI) of acetylated chitosan with 32% DH were the highest (39.56 m2/g and 65.54 min, respectively), and the average droplet size of the emulsion was the smallest (12.71 µm). In addition, the creaming index (CI) decreased significantly to 11.3% compared with that using untreated chitosan. It is proved that changing the molar proportion of N-acetyl-D-glucosamino units in chitosan can effectively improve the emulsifying properties of chitosan and the storage stability of emulsions.

An ω-3 and ω-6 fatty acid balanced pumpkin-flaxseed oil was prepared by mixing the seeds of seed purpose pumpkin in Xinjiang as raw material and flaxseed, a specialty oilseed crop in Xinjiang, as auxiliary material and then pressing them or the reverse sequence as a control and was refined. Changes in the physicochemical properties, nutritional composition, fatty acid composition, and oxidative stability of the two blended oils were studied before and after refining. The results showed that the physicochemical properties of the refined oils were significantly improved when compared with those of the crude oils (P < 0.05), and all quality indexes met the requirements of the national standards for edible oil. There were no differences in physicochemical indexes between the crude oils and between the refined oils (P > 0.05). The composition and content of fatty acids did not significantly change before and after refining (P > 0.05), while the contents of total tocopherol and total phenol and oxidative stability significantly decreased (P < 0.05). Compared with the control, the crude and refined oils prepared by mixing and then pressing had higher contents of total tocopherols and total phenols and better oxidative stability (P < 0.05), thus being more advantageous. The results of this study provide a theoretical basis for the market development of pumpkin seed oil.

In this study, soybean meal was hydrolyzed with alkaline protease. The effect of hydrolysis time on the structure, physicochemical properties and emulsifying properties of soybean meal peptides was investigated. Furthermore, a highly stabile oil-in-water (O/W) emulsion was prepared by using soybean meal peptides with the best emulsification properties. The results showed that as enzymatic hydrolysis progressed, the degree of hydrolysis (DH) gradually increased, and the emulsifying properties of soybean meal hydrolysate first increased and then decreased, reaching the maximum value at 2 h. The emulsion stability gradually decreased. With increasing of DH, the structure of soybean meal peptides gradually unfolded. The content of free amino groups in soybean meal hydrolysate increased, the content of total sulfhydryl groups changed, the surface hydrophobicity decreased, and the secondary structure changed from α-helix to random coil. The optimal process conditions were determined as 40 mg/mL, 0.1 and 8.0 for addition level of soybean meal hydrolysate, oil/water ratio and pH, respectively. The soybean meal hydrolysate adsorbed on the surface of oil droplets could act as a “protective layer”, resulting in good emulsion stability. This study provides new ideas for improving the emulsifying properties of soybean meal protein and also provides a theoretical basis for the development and application of soybean meal peptides in emulsion.

In this study, amyloid protein fibrils (APFs) were prepared from whey protein isolate (WPI). The microstructure of APFs was characterized by transmission electron microscopy (TEM), which confirmed the formation of non-branching nanofibers. The differences in secondary structures between WPI and APFs were investigated by circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR). Compared with WPI, APFs had less α-helices and more β-sheets. The free radical scavenging activity of APFs was higher than that of WPI. The ice recrystallization inhibition (IRI) activity of APFs, as evaluated by the splat assay, was significantly stronger than that of WPI, and the higher the incubation temperature, the greater the difference in IRI activity. The color, water-holding capacity (WHC), disulfide bond content, thermal gelation characteristics, and water distribution of minced pork added with APFs at 0%, 1.0%, 3.0%, or 5.0% were measured after freeze-thaw treatment. The results showed that APFs could significantly increase the WHC, improve the thermal gelation characteristics, and reduce protein oxidation without significantly changing the color of frozen minced meat. Therefore, APFs are a potential excellent cryoprotectant for minced meat.

In order to investigate the impact of ozone pretreatment and lipid modification on the structure and properties of starch, ozone-pretreated banana starch-lauric acid complexes were prepared and their physicochemical properties and digestibility were evaluated. Results showed that in comparison with the native starch, the complexation index (CI) of the pretreated starch with lauric acid increased by 12.67%; the resulting complexes exhibited a significant increase in water solubility, swelling power and syneresis, an elevation in gelatinization temperature from 104.24–135.23 ℃ to 155.60–161.68 ℃, and a 6.71% increase in resistant starch, but a decrease in iodine binding capacity. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrated that lauric acid was bound to the surface of starch granules to form a complex, thereby increasing the surface height of starch granules. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) revealed that banana starch and lauric acid formed non-V-type and V-type complexes through hydrogen bonding and hydrophobic interactions. The results of contact angle and thermogravimetric (TG) analysis demonstrated that the hydrophobic properties and thermal stability of the complexes were improved. Consequently, the combination of ozone pretreatment and lauric acid modification could enhance the water solubility, swelling capacity, and thermal stability of banana starch, further improving its digestibility resistance. These findings will expand the application potential of starch in the food field.

In this study, low-salt fermented large yellow croaker was prepared by inoculating low-salt cured yellow croaker with Pediococcus pentosaceus and fermenting it, its flavor profile and volatile flavor compounds were characterized using flavor metabolomics and molecular sensory science, and its key odor-active compounds were identified. The differential metabolism of fatty acid flavor precursors was investigated and the correlation between the key odor-active compounds and free fatty acids was analyzed. Moreover, the metabolic pathways of P. pentosaceus for promoting the production of the key odor-active compounds from fatty acids were explored. The results showed that fermentation with P. pentosaceus reduced the grassy and fishy smell while enhancing the fatty and meaty aroma, thereby improving the acceptability of large yellow croaker. Eight compounds, including heptanal, 1-octen-3-ol, nonanal, (E,Z)-2,6-nonadienal, (E)-2-nonenal, decanal, undecanal, and (E,E)-2,4-decadienal, were identified as the key odor-active compounds. The study also elucidated the potential metabolic pathways for the oxidation and degradation of four differential fatty acids, including (Z,Z)-9,12-octadecadienoic acid and (Z,Z,Z)-9,12,15-octadecatrienoic acid, by P. pentosaceus to produce the key odor-active compounds 1-octen-3-ol, (E,Z)-2,6-nonadienal, (E)-2-nonenal, decanal, and (E,E)-2,4-decadienal.

In order to improve the thermal stability of nicotinamide riboside kinase 1 from Saccharomyces cerevisiae (ScNRK1), six single-point mutants of ScNRK1 were virtually designed using computer-aided technology, and their expression using site-directed mutagenesis and enzymatic characterization were carried out. Out of these, three superior mutants were selected for a second round of combined mutagenesis. The results showed that after two rounds of mutagenesis, a mutant named T136P/S209A with significantly improved thermal stability and catalytic activity was obtained. Its optimal reaction temperature was increased to 45 ℃, and its half-life at 45 ℃ was 48.98 min, which was 4.2 times as high as that of the wild-type ScNRK1. The specific enzyme activity of the purified mutant enzyme was 146.63 U/mg, which was 1.98 times as high as that of the wild type. This study is expected to provide new ideas for improving the thermal stability of enzymes through rational design, and provide a new enzyme source for efficient and low-cost production of nicotinamide mononucleotide.

The purpose of this study was to screen potential anti-inflammatory peptides from Channa argus. Toll-like receptor (TLR)2 and TLR4 were chosen as the target proteins. Virtual hydrolysis was used to select the best enzyme for obtaining bioactive peptides from C. argus proteins. Anti-inflammatory peptides were selected by the combined use of physicochemical prediction, molecular docking, and a cell model, and their mechanisms of action were elucidated. The results showed that 109 bioactive peptides obtained with papain were not toxic, from which 34 highly water-soluble peptides were selected for analysis of adsorption, distribution, metabolism, excretion and toxicity (ADMET) properties. Peptides KF, PR, NC, YR, WEL, QWWR and DEECWF exhibited high-affinity binding to TRL2 and TRL4 mainly through hydrogen bonding. These peptides were found to increase cell viability and inhibit the overproduction of nitric oxide (NO) and inflammatory factors (tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6) in lipopolysaccharide (LPS)-induced RAW264.7 cells, indicating their anti-inflammatory activity. This study revealed the interaction mechanism between the anti-inflammatory peptides and TLR2 or TLR4 targets and provides theoretical support for understanding the mechanism underlying the immunoregulatory effect of bioactive peptides from C. argus.

Objective: To isolate bacteriophages with strong lytic activity against multi-drug resistant Vibrio parahaemolyticus. Methods: Using V. parahaemolyticus as host bacteria, bacteriophages were isolated and purified from seafood, and their biological characteristics and whole genome were analyzed. Results: Phage vB_VpP_3, which was isolated from crab, had a narrow host range and high host specificity with an optimal multiplicity of infection 0.1 and a maximum adsorption rate of 93%. The one-step growth curve showed that the latent period of the phage was 15 min, the average burst size was 110 PFU, and it was highly tolerant to the environment. Phage vB_VpP_3 belonged to the order Caudovirales of the family Podoviridae with a regular icosahedral head about 60 nm in diameter and a non-contractile tail about 20 nm in length. Its genome was double-stranded linear DNA with a total length of 42 459 bp and a total GC content of 46.87% without any virulence or drug resistance genes. Conclusion: Bacteriophage vB_VpP_3 was highly safe and could be used for biological control of multi-drug resistant V. parahaemolyticus.

Protein-polysaccharide complexes of Agaricus bisporus, Stropharia rugosa and Morchella esculenta were prepared and their protein and polysaccharide contents as well as amino acid and monosaccharide composition were evaluated. The in vitro and in vivo lipid-lowering effects of the complexes on oleic acid-induced liver LO-2 cells and high-fat diet fed mice were investigated. The results showed that the protein contents of the three complexes were (55.56 ± 0.51)%, (52.41 ± 0.31)%, and (54.96 ± 0.47)%, respectively, and the polysaccharide contents were (21.98 ± 1.17)%, (31.95 ± 0.52)%, and (15.55 ± 0.78)%, respectively. In vitro cell experiments showed that all the complexes significantly inhibited the accumulation of lipid droplets in hepatocytes. Animal experiments showed that they significantly inhibited the increase in body mass, triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) levels, blocked the swelling of the swelling of hepatocytes, and inhibited hepatic lipid deposition in mice fed a high-fat diet. In the high-dose group, the hepatic lipid content of mice with hyperlipidemia was reduced from (30.59 ± 0.38)% to (13.74 ± 1.57)%, (9.68 ± 0.73)%, and (7.15 ± 0.39)%, respectively, by the complexes from A. bisporus, S. rugosa and M. esculenta, and the inhibition rates of hepatic lipid droplets by these complexes were (55.09 ± 5.12)%, (68.34 ± 2.37)% and (76.64 ± 1.28)%, respectively. In addition, the protein-polysaccharide complexes alleviated liver function damage caused by long-term high-fat diet. In summary, it can be concluded that A. bisporus, S. rugosa and M. esculenta protein-polysaccharide complexes can regulate lipid metabolism, alleviate liver injury and hyperlipidemia, which provides a reference for the development of functional products based on edible fungi.

Objective: To explore the in vitro anti-inflammatory activity and action mechanism of a polysaccharide extracted from Polygonum divaricatum L. (PSPDL). Methods: The structure of PSPDL was characterized using high-performance gel permeation chromatography (HPGPC), high-performance liquid chromatography (HPLC), Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and nuclear magnetic resonance spectroscopy (NMR). The in vitro anti-inflammatory activity and action mechanism of PSPDL were investigated in lipopolysaccharide (LPS)-induced RAW264.7 cells. Results: PSPDL had a relative molecular mass of 59.475 kDa and consisted mainly of mannose (Man), rhamnose (Rha), glucuronic acid (GlcA), galacturonic acid (GalA), glucose (Glc), galactose (Gal), and arabinose (Ara), with a molar ratio of 1.69:4.95:1.04:21.79:19.01:31.68:19.84. PSPDL was an α-pyran polysaccharide containing (1→4)-α-D-Glcp linkage. PSPDL inhibited the release of inflammatory factors and related gene mRNA expression, ameliorated oxidative stress, down-regulated the protein expression levels of p38, p-p38, IκB-α, p65, and p-p65. Conclusion: PSPDL exhibited anti-inflammatory activity, perhaps by regulating inflammatory mRNA expression and modulating the mitogen-activated protein kinases/nuclear factor kappa B (MAPK/NF-κB) signaling pathway. This finding provides a scientific basis for the development and utilization of PSPDL resources.

In this study, sauced beef was prepared by three different cooking processes: ultrasonic-assisted stepwise cooking (CF), stepwise cooking (F) and traditional cooking (CT). In order to investigate changes in the flavor substances of sauced beef during different cooking processes, the effect of the three cooking processes on the flavor of sauced beef were analyzed from the perspective of the Maillard reaction. Absorbance at 294 nm (A294 nm) and 420 nm (A294 nm), which can reflect the amount of Maillard reaction products (MRPs) formed in the middle and late stages, respectively, were measured. The results showed significant differences in A294 nm between the CF and CT groups at 0.5 h of cooking (P < 0.05), but no significant differences between the CF and CT groups at 2 and 4 h (P > 0.05). A294 nm and A420 nm were significantly higher in the F group than in the CT and CF groups at 0.5 and 4 h. The CF group had the highest fluorescence intensity. Protein secondary structure analysis indicated an increase in the relative content of β-sheet and a decrease in the relative content of α-helix in the CF and F groups compared with the CT group; α-helix unfolding led to the exposure of intramolecular hydrophobic groups, thereby increasing the surface hydrophobicity and fluorescence intensity. Ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) identified 103, 167, and 200 differential metabolites in the CT, F, and CF groups, respectively, and a large number of amino acids, dipeptides, nucleosides, and heterocyclic compounds were produced in the CF group; gas chromatography-mass spectrometry (GC-MS) results showed that CF and F promoted the production of volatile flavor substances in sauced beef. The above results indicated that both cooking processes could promote the Maillard reaction and consequently improve the flavor of sauced beef.

This study examined the differences in the extracellular metabolites and in vitro antioxidant activity of 8 strains of Wolfiporia hoelen (Fr.) Y.C. Dai & V. Papp and conducted their comprehensive evaluation using principal component analysis (PCA). To investigate the major antioxidant components of W. hoelen, widely targeted metabolomics was used to analyze the composition of extracellular flavonoids and phenolic compounds. The results showed that the contents of extracellular polysaccharides, total triterpenes and sterols were the highest in strain GTR1. The contents of extracellular flavonoids and phenolics were the highest in strain GTR2. The results of in vitro antioxidant tests showed that strains F5.78, GTR2 and XJ28 had the highest capacity to scavenge 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals, respectively. The results of correlation analysis showed that the contents of extracellular flavonoids was highly significantly positively correlated with the DPPH radical scavenging capacity and the contents of extracellular total phenols in W. hoelen (P < 0.01). Totally 55 flavonoids and 33 phenolic compounds were qualitatively detected using ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS). The relative content of each component varied among different W. hoelen strains; the most abundant flavonoid was malonyldaidzin and the most abundant phenolic component was 3-formylsalicylic acid in W. hoelen strains FLA, FGD, FGZ, FHB, GTR1, XJ28 and F5.78. The most abundant flavonoid component in strain GTR2 was kaempferol-3-O-(6-galloyl)glucoside, which was highly significantly positively correlated with the DPPH radical scavenging capacity (P < 0.01). In this strain, the most abundant phenolic component was α-cyano-4-hydroxycinnamic acid, which was significantly positively correlated with the DPPH radical scavenging capacity (P < 0.05). PCA showed that GTR2 scored highest among the eight strains. In conclusion, this strain has a high content of extracellular bioactive ingredients and good antioxidant activity, making it a potential candidate for the development of antioxidant products.

To investigate the effects of tea varieties on the quality of Enshi Yulu tea, 10 main tea cultivars (Fuyun 6, Echa 1, Chunbolü, Zhenong 117, Longjing 43, Wuniuzao, Zhongcha 108, Echa 10, Zhuyeqi, and Fuding Dabai) grown in Enshi were processed into Yulu tea, which was then evaluated for sensory quality, major physicochemical quality components (tea polyphenols, free amino acids, water extracts, and chlorophylls), dry tea color parameters (L*, a*, and b*), and volatile components. The results showed that Yulu teas made from different cultivars had their own characteristics. Among the 10 teas, Fuyun 6 had the highest sensory score for appearance with a tight and straight shape and a green color. Echa 1 and Chunbolü had the best mellow and fresh taste. Zhenong 117 had a high and long-lasting chestnut-like aroma with the highest sensory score for aroma. Chemical composition analysis showed that the phenolic/ammonia ratio of each tea was lower than 5, with Fuyun 6 having the lowest value, but not significantly different from Longjing 43. Wuniuzao had the highest soluble sugar content, while Fuyun 6 had the lowest value. Echa 1 had the highest total amount of catechins, followed by Echa 10 and Zhenong 117, while Zhongcha 108 and Wuniuzao had the lowest value. Chunbolü and Echa 1 had the highest ratio of lutein to chlorophyll a plus b, while Longjing 43 had the lowest level. Overall, Longjing 43, Chunbolü and Wuniuzao Yulu teas had better sensory and physicochemical qualities. A total of 98 aroma components were detected in the 10 Yulu teas using headspace solid-phase microextraction (HS-SPME), including 22 alcohols, 13 hydrocarbons, 15 aldehydes, 14 olefins, 16 esters, 6 ketones, 3 halogenated hydrocarbons, 2 phenolic compounds, 1 ether compound, and 6 heterocyclic compounds. Among them, alcohols were the most abundant. Analysis of relative odor activity values (rOAV) revealed that linalool, phenylethanol, geraniol, jasmine, trans-β-ionone and nonanal were the major contributors to the characteristic aroma of the 10 Yulu teas. Totally 17 key differential aroma components among these teas were identified, including benzyl alcohol, linalool, phenylethanol, geraniol, benzaldehyde and nonanal.

In order to determine good jujube varieties for the production of vinegar, databases of soluble solids, total acid, transmittance, color, total phenols, total flavonoids, antioxidant properties and volatile flavor components were constructed for jujube vinegars made from four different varieties, Ruoqiang grey jujube from Xinjiang, Zanhuang jujube from Hebei, Tanzao jujube from Shanxi, and Tongxin round jujube from Ningxia. By comparing quality indexes and combining the results of principal component analysis (PCA) and sensory evaluation, it was concluded that Tanzao jujube vinegar was significantly superior to the other three jujube vinegars in terms of total acid content, total flavonoid content, 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging capacity, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cationic radical scavenging capacity, hydroxyl radical scavenging capacity, and volatile flavor components, and scored highest in both PCA and sensory evaluation. Therefore, Tanzao jujube was the most suitable raw material for jujube vinegar production. The results of this research provide a reference for raw material selection for and nutritional quality optimization of jujube vinegar.

This study investigated the effects of different ozone treatment times (0, 10, 20, 30, 40, and 50 min) on off-flavor removal from egg white powder (EWP) and the underlying mechanism. Results showed that compared with the untreated group (0 min), ozone treatment reduced the contents of the characteristic off-flavor substances (geranyl acetone, 1-octen-3-ol, octanal, and nonanal) in EWP by more than 40.94%. The sensory off-flavor score reached its lowest point (which decreased by 75% compared with the untreated group) after 20 min of ozone treatment, when egg white protein was slightly oxidized, leading to protein unfolding and structural disordering, increased carbonyl content and particle size, and decreased endogenous fluorescence intensity. In addition, fluorescence quenching and molecular docking showed that the major binding force between egg white protein and off-flavor substances was hydrophobic interaction, and their main binding sites were in a hydrophobic cavity composed of amino acids such as Leu66, Lys69, Glu87E, Ala87F, Cys87H, Glu129, Tyr130, Cys133, and Gly320. Ozone treatment for 20 min reduced the hydrophobic interaction between egg white protein and off-flavor substances by 45.98% compared with the untreated group, releasing off-flavor substances and reducing sensory off-flavor score, thereby ultimately deodorizing EWP. In conclusion, ozone treatment can reduce the off-flavor of EWP, the most pronounced effect being observed after 20 min treatment.

In this study, marinated beef tendon was subjected to sous-vide cooking under different combinations of temperature and time. Traditional high-temperature stewing was used as a control. The cooked meat was digested in vitro and the digest was added to an in vitro absorption model based on Caco-2 cells to simulate the absorption process. The effects of different temperature-time combinations on the protein absorption of sous-vide cooked beef tendon were determined by measuring the protein absorption products. The results showed that sous-vide processing increased the absorption of free amino acids and peptides especially those with small molecular mass of 300-500 Da. Sous-vide cooking at 60 ℃ favored the absorption of myosin and actin, while sous-vide cooking at 80 ℃ favored the absorption of collagen. Compared with the other treatment groups, sous-vide cooking at 60 ℃ for 8 h resulted in the occurrence of significantly more essential amino acids and antioxidant amino acids as well as more small-molecular-mass peptides and specific bioactive peptides in the absorbed products, showing higher nutritional levels.

In this study, we investigated the changes of physicochemical properties and structure of defatted camel’s milk proteins with four different heat treatments (65 ℃/30 min (T1), 85 ℃/15 s (T2), 120 ℃/15 s (T3), and 135 ℃/5 s (T4)) by measuring particle size, potential, turbidity, secondary structure, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) pattern, tertiary structure, surface hydrophobicity, free sulfhydryl group and disulfide bond content. The results showed that the particle size of camel’s milk proteins increased, the absolute value of the zeta potential decreased, and the turbidity increased with increasing temperature. Heat treatment had a significant effect on the secondary and tertiary structures, resulting in a decrease in the relative contents of α-helix and β-turn and an increase in the relative contents of β-fold and random coil in camel’s milk proteins. T3 had the greatest effect on the particle size, zeta potential, secondary structure and tertiary structure compared with the unheated control. SDS-PAGE profiles showed that the intensities of the soluble whey protein bands gradually decreased as the heating temperature increased. Observations by laser scanning confocal microscopy (LSCM) showed that the heat treatment caused protein aggregation, and T3 and T4 resulted in the production of large protein polymers. Under the T1 and T2 conditions, protein polymers were formed mainly through disulfide bonding. However, with the increase in heating temperature, the disulfide bonds of camel’s milk proteins were broken under the T3 and T4 conditions, resulting in the formation of free sulfhydryl groups and the exposure of the hydrophobic groups of camel’s milk proteins. The above results indicated that the structural and physicochemical properties of camel’s milk proteins can be changed to different degrees by different heat treatments, which in turn can affect the stability of camel milk. The results of this study provide a theoretical reference for the development of liquid camel’s milk products.

This study investigated the preservation of tender ginger using a combination of ginger essential oil (GEO) nano-emulsion coating and vacuum packaging. The nano-emulsion was prepared with konjac glucomannan (KGM), lysozyme (Ly), and Tween 80 as wall materials, and its optimal concentration was determined based on its stability. The effect of wall material composition on the preservation of tender ginger was evaluated by physiochemical and biochemical analyses. The results indicated that the emulsion with 2% GEO was the most stable. Vacuum packaging combined with the KGM + Ly + GEO (KLE) nano-emulsion coating containing 0.5 g of KGM, 0.1 g of Ly, 0.8 g of Tween 80, and 2 g of GEO per 100 mL of emulsion significantly reduced mass loss rate, and prevented enzymatic browning and texture changes of tender ginger. During storage, the levels of total phenols, total flavonoids, and 6-gingerol were increased, which inhibited the activities of peroxidase, catalase, polyphenol oxidase, and phenylalanine ammonia-lyase in tender ginger. Microbiome analysis indicated that the combined treatment effectively reduced the diversity and richness of bacteria and fungi. The dominant microorganisms in tender ginger coated with the KLE nano-emulsion were Latilactobacillus and Rahnella, and the common spoilage microorganism Mucor in tender ginger was effectively inhibited.

In this study, three varieties of fresh bamboo shoots (Dendrocalamus brandisii, Dendrocalamopsis oldhami, and Phyllostachys edulis) were frozen by immersion quick-freezing (IF), liquid nitrogen spray quick-freezing (LNF), or pressure transfer quick-freezing (PSF). The effects of the three quick-freezing techniques on the freezing characteristics and quality of bamboo shoots were investigated. Among these quick-freezing techniques, LNF showed the best freezing efficiency with the fastest freezing rate. The freezing rates of D. brandisii, D. oldhami and P. edulis shoots were 12.43, 3.92 and 7.5 times higher than those of the slow freezing (SF) group, respectively. For all three bamboo shoots, the thawing loss was less than 2%; the hardness of quick-frozen samples increased by 47.26%–65.02%, and the total amino acid loss decreased by 7.88%–38.91% compared with the SF group. In addition, the proportion of free water in the LNF group was significantly lower than those in the other three groups, water was most tightly bound to the tissue, and the microstructure was most similar to that of fresh samples. IF had the second highest freezing efficiency. Although PSF performed best in maintaining the color and inhibiting the enzymatic browning of bamboo shoots, peroxidase (POD) and phenylalanine ammonialyase (PAL) activities were 27.76%–45.24% and 27.05%–80.86% lower in the PSF group than in fresh samples, respectively. In addition, the structure of vascular bundles was seriously damaged by PSF, resulting in 6.12%-10.47% thawing loss and more serious water migration. In conclusion, LNF performed best in terms of freezing rate and quality maintenance, and could be the most suitable method for the quick freezing of bamboo shoots among the three quick-freeze technique.

To investigate the effects of three circulation methods including normal temperature, cold chain, and broken cold chain on the flavor substances of fresh Lentinula edodes before and after storage and transportation, the changing trends of volatile flavor compounds and taste components of L. edodes during simulated transportation under the three temperature conditions were analyzed using an electronic nose, gas chromatography-ion mobility spectrometry (GC-IMS), an electronic tongue, high performance liquid chromatography (HPLC), and an automatic amino acid analyzer. The results showed that electronic nose was able to quickly distinguish between the aroma characteristics of L. edodes under different simulated temperature conditions. In total, 55 volatile compounds were detected by GC-IMS, including 16 alcohols, 10 aldehydes, 8 terpenes, 6 ketones, 4 esters, and 11 other compounds. The electronic tongue revealed differences in the sourness, bitterness, astringency, umami, richness, and saltiness among early storage and transportation (control), simulated normal temperature logistics (NTL), simulated cold chain logistics (CCL), and simulated broken chain logistics (BCL), with the CCL group being characterized by moderate sourness and prominent umami. In the NTL, CCL, and BCL groups, the total amounts of free umami amino acids were 90.82, 81.83, and 84.31 mg/g, respectively, and the 5’-nucleotide contents were 122.99, 107.42, and 118.27 μg/g, respectively. Among them, the volatile flavor compounds and taste components in the CCL group were most similar to those in the control group, indicating that consistent low-temperature conditions are helpful for preserving the flavor quality of L. edodes during storage and transportation. In contrast, the BCL group, which experienced temperature fluctuations during both storage and transportation, exhibited slightly lower flavor quality than did the CCL group due to the negative impact on the flavor compounds before entering the shelf life. In conclusion, in the post-harvest circulation process of L. edodes, cold-chain transportation is needed to minimize quality deterioration caused by temperature fluctuations during storage and transportation. The results provide valuable insights for improving the cold chain distribution system for L. edodes.

A colorimetric/fluorescent dual-sensing assay for the detection of glucose was established based on the peroxidase-like activity of fluorescent carbon quantum dots derived from corncob. In the system, glucose oxidase was added to specifically catalyze the oxidation of glucose to produce H2O2, which was then reacted with 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) under the catalysis of carbon quantum dots. Under optimized conditions, good linearity was observed between the absorbance (y) of the reaction system and glucose concentration (x) in the range of 0.001–0.5 mmol/L, which was fitted as follows: y = 10.907x + 0.659 5, R2 = 0.993 8, with a detection limit of 1.305 5 μmol/L. Moreover, good linearity was observed between the difference in fluorescence intensity (y) and glucose concentration (x) in the range of 0.001–0.1 mmol/L, which was fitted as follows: y = 9 172x + 4 438, R2 = 0.994 4, with a detection limit of 9.249 7 nmol/L. The method was applied to the detection of glucose in four real samples, with good spiked recovery rates and precision, which indicated that corncob fluorescent carbon quantum dots have the potential for application as an enzyme mimic in the detection of glucose.

A method based on gas chromatography-mass spectrometry (GC-MS) was developed for the determination of the residues of 2,4-di-tert-butylphenol (2,4-DTBP), butylated hydroxytoluene (BHT) and its derivatives 2,6-di-tert-butyl-p-benzoquinone (BHT-Q) and 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHT-CHO) and their migration to isooctane from wheat straw-based plastic lunchboxes. The effects of food handling practices such as microwaving, steaming, and refrigeration on the migration of these four substances were explored. The experimental results showed that the migration behaviors of 2,4-DTBP, BHT, BHT-Q and BHT-CHO from plant fiber-based plastic products to food simulants were mainly related to the types of food simulants, residue amounts and actual application scenarios. Repeated microwaving, cooking and freezing of straw-based plastic lunch boxes might affect (or even slightly increase) the release of some compounds, but their concentrations remained relatively low and tended to decrease with increasing number of repeated cycles, and even the migration of the compounds became negligible after several consecutive applications. BHT-Q, BHT, 2,4-DTBP, and BHT-CHO migrating from wheat straw-based plastic lunch boxes were found to be relatively safe for consumers.

In this study, cerium dioxide-modified cobalt oxyhydroxide (CeO2/CoOOH) nanomaterial was synthesized by a liquid-phase precipitation method. CeO2/CoOOH showed good oxidase-like activity toward 3,3’,5,5’-tetramethylbenzidine (TMB), and could directly oxidize TMB to ox-TMB, which presented a clear blue color. Reversely, ascorbic acid (AA) could reduce ox-TMB to TMB, leading to a decrease in the absorbance of ox-TMB at 652 nm and a fading of the blue color. Based on this phenomenon, a new colorimetric sensor for AA detection was developed. The sensor exhibited a highly sensitive response to AA with a limit of detection (LOD) of 2.73 μg/mL and a wide detection range of 5-100 μg/mL and could be successfully applied for rapid detection of AA in oranges and apples.

A biosensor for the determination of phosphatidylcholine (PC) in artificial crude soybean oil was fabricated by immobilizing horseradish peroxidase (HRP) and choline oxidase (ChOx) onto on a glassy carbon electrode (GCE) modified with multi-walled carbon nanotube (MWCNTs), SnO2 and chitosan (CS). Under the conditions of ChOx and HRP addition each at 2.5 U and pH 7.5, the sensor showed significant electrochemical response to PC. PC concentrations in the range of 10–300 mg/L were linearly correlated with the peak current, and the detection limit was 2 mg/L. Recoveries for spiked samples ranged from 90% to 110% with relative standard deviations (RSDs) less than 4.68%. Good correlation was observed between the results of the biosensor and those of high performance liquid chromatography (HPLC) with a correlation coefficient (r) of 0.992 9. After 14 days of storage, the sensor still retained 98% of its initial current value, indicating its good stability. This study can provide theoretical support for the rapid inspection and control of vegetable oil refining.

A method was developed for the simultaneous determination of 26 pyrrolizidine alkaloids (PAs) in milk powder and liquid milk by solid phase extraction (SPE) combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were extracted with 5% trichloroacetic acid solution, cleaned up on a polymer cation exchange-solid phase extraction (PCX-SPE) column, separated on an ACQUITY HSS T3 column with gradient elution using a mobile phase consisting of methanol and 0.1% formic acid in water, detected using an electrospray ionization (ESI) in the positive ion mode with multiple reaction monitoring (MRM), and finally quantified by the external standard method. The method validation was performed under optimal conditions. The calibration curves for the 26 PA compounds showed good linearity in the range of 1.0–40 ng/mL with determination coefficients (R2) greater than 0.992. The limits of detection (LOD) and quantification (LOQ) of the developed method were in the range of 0.01-0.33 μg/kg (RS/N = 3) and 0.03–1.0 μg/kg (RS/N = 10), respectively. Recoveries for blank milk powder and liquid milk spiked at 1 ×, 2 ×, and 10 × LOQ levels ranged from 73.1% to 111.6% with relative standard deviations (RSDs, n = 6) of 0.6%-9.8%. In conclusion, this method is simple, efficient, sensitive, accurate, and suitable for the determination of the 26 PAs in milk powder and liquid milk.

In this study, a method for the simultaneous determination of neonicotinoid insecticides and their metabolites in meat was established by the QuEChERS (quick, easy, cheap, effective, rugged, safe) pretreatment method followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Samples were extracted with acetonitrile containing 1% acetic acid. After salting-out with 1 g of NaCl and 4 g of anhydrous MgSO4, the supernatant was cleaned-up using C18. The separation of the analytes was carried out on a XSelect HSS T3 (150 mm × 3.0 mm, 2.5 μm) column by gradient elution with a mobile phase composed of 0.1% formic acid and acetonitrile. The analytes were detected by multiple reaction monitoring (MRM) in the positive ion mode and quantified by the matrix-matched external standard method. The results showed that the calibration curves for all analytes had a good linearity with correlation coefficients (r) more than 0.995. The limit of quantitation (LOQ) was 2 μg/kg for 12 target compounds and 20 μg/kg for the two compounds. The recovery rates of the proposed method were in the range of 61.0%–116.7% with relative standard deviations (RSDs) below 14.81%. This method has the merits of simple pretreatment steps and satisfying recovery rates and enables fast and accurate detection of neonicotinoid insecticides and their metabolites in meat.

The intestinal barrier plays a key role in preventing harmful substance invasions and maintaining intestinal homeostasis, with tight junction proteins being essential for maintaining the integrity of the intestinal barrier. This review summarizes the structural composition of the intestinal barrier, the role of tight junction in maintaining intestinal physiological functions, with an emphasis on the potential application value of the major phenolic components in ginger, 6-gingerol and 6-shogaol, for alleviating tight junction damage. Through comprehensive analysis of clinical research and experimental results in recent years, it is found that 6-gingerol and 6-shogaol can improve the expression levels of tight junction-related proteins and maintain the integrity and biofunction of the intestinal barrier by inhibiting inflammation, oxidative stress and apoptosis as well as regulating the composition of intestinal microbiota. This paper provides a theoretical basis and insights for understanding the mechanisms of action of ginger phenolic compounds in regulating health and for expanding their application scopes.

Tea origin traceability is an important means to ensure the quality and safety of tea. Currently, China’s tea traceability system is under rapid development. Incidents of tea origin and product counterfeiting are not uncommon. Fortunately, the application of elemental fingerprinting technology provides a new solution for tracing the origin of tea. This article summarizes the progress on elemental fingerprinting in tracing the origin of tea and influencing factors thereof, introduces the domestic and international progress that has been made over the past decade in the application of stable isotopes and mineral elemental fingerprinting in tea origin tracing, discusses the impacts of geographical environment, tea tree varieties and processing techniques on tea elemental fingerprints, and proposes future research directions for tea traceability technology, aiming to provide references for achieving more accurate traceability of tea origin.

Human milk oligosaccharides (HMOs), as the third largest solid component of breast milk, have been widely emphasized in recent years due to their important physiological functions. Bovine milk oligosaccharides (BMOs) have similar structures and functions to HMOs and similar complexity in composition, which make them high-quality ingredients in infant formula milk powder and functional foods. In this article, the structural compositions, quantitative distributions, physiological functions and industrial applications of HMOs and BMOs are reviewed to provide references for the research and development of HMOs and BMOs.

Raw starch degrading enzymes (RSDE) refer to amylases that can directly degrade starch granules below the gelatinization temperature of starch. The enzymes have broad application prospects because they can degrade starch without gelatinization, which reduces the energy consumption of starch processing and the production cost of starch-based products. However, not all amylases can directly act on starch granules, and not all ungelatinized starch can be hydrolyzed by amylases. It is of great significance to review what is currently known about the action mechanism of RSDE on starch granules. This review systematically summarizes the mechanism underlying the hydrolysis of starch granules by RSDE from the perspectives of starch type and RSDE type and elaborates on the action mode of RSDE on starch. Thereafter, this review outlines the sources of RSDE and analyzes the factors affecting RSDE activity, such as amylase action conditions, metal ions, and starch granule-associate protein. Finally, it summarizes the application of RSDE in the starch industry. This review provides a basis and new ideas for the further development and application of RSDE.

Animal-derived processing by-products are a treasure house of bioactive compounds with huge output and low price. Their efficient exploitation is of great significance. Deep eutectic solvents are a new type of designable “green solvents” and are formed by mixing hydrogen bond donors with hydrogen bond acceptors in appropriate proportions. They possess great advantages, such as easy availability of raw materials, simple preparation, designable structure, and biodegradability and are therefore extensively used in the fields of chemistry, food and medicine. This paper briefly reviews the application of deep eutectic solvents in the extraction of bioactive components from animal-derived processing by-products and gives an outlook on future prospects, hoping to provide new strategies the extraction of bioactive components from animal-derived processing by-products.

Soy protein, as one of the major plant proteins, has good functional properties such as solubility, emulsification and gelation properties. Freezing, as one of the effective ways to extend the storage period of products, is widely used in the food and medicine industries. However, freezing can cause changes in the secondary and tertiary structures of soy protein and further affect the functional properties of soy protein such as emulsification and gelation properties, limiting the application of soy protein in frozen foods. At present, understanding the effect of freezing on soy protein and improving its freezing stability has become a research focus, and several methods such as ultrasound, glycosylation and enzymatic crosslinking have been adopted to improve the freezing stability of soy protein. In order to gain a better understanding of the effect of freezing on functional properties of soy protein, this article focuses on the effect of freezing on the emulsification and gelation properties and structure of soy protein, and it summarizes and analyzes the methods used to improve the freezing stability of soy protein products and their mechanisms in order to provide a theoretical basis for the application of soy protein in frozen foods and the improvement of food quality.

Lactic acid bacteria (LAB) play a crucial role in improving the flavor and enhancing the nutritional value food, which have found wide application in the field of food fermentation. Genome-scale metabolic models (GSMMs) serve as essential tools for studying microbial metabolism, which simulate the metabolic networks of microorganisms and accurately describe the genotype-phenotype relationships. Several GSMMs have already been successfully applied to the metabolic regulation of LAB. This article systematically summarizes LAB GSMMs constructed over the past two decades, emphasizing their application in food systems. Moreover, it analyzes the primary challenges and limitations of the GSMMs and gives an outlook on future directions in by combining emerging technologies and innovative ideas. The final goal is to provide valuable insights for the effective and precise application of LAB GSMMs to the intelligent design of microbial communities in the food industry.

Mycotoxins are toxic small-molecular-mass compounds produced naturally by toxigenic fungi. Ingestion of mycotoxin-contaminated products has a high potential to cause carcinogenic, teratogenic, and mutagenic effects in the human body. As mycotoxin residues have been detected in both foods and Chinese herbal medicine, the development of effective methods for rapid and highly sensitive detection as well as green detoxification of mycotoxins has become a research priority. Magnetic nanoparticles have high specific surface area, high surface energy and high magnetic response and hence have great potential for application as magnetic adsorbent carriers in mycotoxin detection and detoxification. This paper summarizes the methods used for the preparation and functionalized modification of common magnetic nanomaterials and their applications in mycotoxin detection and detoxification, and discusses future trends in mycotoxin control.

With the exacerbation of relevant issues such as population growth and environmental deterioration, the adverse impact of traditional livestock farming is gradually becoming prominent, while the market for plant-based meat products is expanding. Numerous studies have focused on improving the quality of plant-based meat products in terms of appearance, texture, taste and flavor to make them more similar to real meat. However, plant-based meat products on the market generally contain high sodium levels, which contradicts the concept of healthy diet and seriously affects the nutritional value and promotion of plant-based meat products. Therefore, this article starts with an overview of the development of plant-based meat products, analyzes the current status and causes of high sodium levels in related products, and focuses on the salt and sodium reduction strategies used in the production of plant-based meat in the three aspects of texture and flavor shaping, fiber structure construction and raw material preparation, with a view to reducing the sodium content without affecting the sensory quality of plant-based meat products in order to produce and promote healthier low-sodium plant-based meat products.