In order to further analyze the taste characteristics and processing stability of umami peptides from Tetragenococcus halophilus, 41 suspected umami peptides from T. halophilus were tested in this study, and three synthetic peptides (EEEEEE, HAAGMVE, and ESVYAST) with the highest umami values were selected using an electronic tongue. Their taste characteristics were analyzed by sensory evaluation, and the effects of temperature and pH on the stability of the umami peptides were analyzed. The results showed that all three peptides showed umami taste, with perceptual threshold ranging from 0.108 to 0.362 mmol/L. Among them, HAAGMVE demonstrated a particularly potent umami-enhancing effect. The stability analysis results showed that the umami values of EEEEEE, HAAGMVE and ESVYAST increased with increasing pH from 4.0 to 8.0, but remained stable in the temperature range of 25–100 ℃. EEEEEE exhibited the best stability. The results of this study provide a theoretical basis for the development and utilization of umami peptides derived from T. halophilus, and lay a foundation for improving the flavor quality of fermented products and promoting their industrial production.

To determine the appropriate pre-slaughter treatment, the effects of four different pre-slaughter treatments: stunning (CK), tail artery bloodletting (TS), neck artery bloodletting (NS), and cold stress (CS) on the flavor quality of silver carp fillets were studied using gas chromatography-mass spectrometry (GC-MS), ultra-high performance liquid chromatography (UPLC), a taste analyzer, and an odor analyzer. The results indicated that the pre-slaughter treatments had a significant effect on the taste and odor qualities of silver carp fillets, which were significantly improved by both bloodletting and cold stress treatments. Compared with the CK group, the contents of bitter amino acids, adenosine monophosphate, and guanosine monophosphate in the TS, NS and CS groups significantly decreased (P < 0.05), while the content of hypoxanthine nucleoside significantly increased (P < 0.05). The content of adenosine diphosphate in the TS and CS groups, the betaine content in the TS and NS groups, and the carnosine content in the CS group decreased markedly. Bloodletting and cold stress treatments raised the proportion of umami and sweet amino acids in silver carp fillets while decreasing the contents of bitter and sour amino acids, thereby resulting in enhanced umami and sweet taste. The relative contents of heptanal, (E)-2-heptenal, nonanal, decanal, (E,E)-2,4-decadienal, and 2,3-octanedione, contributing to fishy, oily, and overcooked flavors, significantly decreased in the TS, NS, and CS groups, while the relative contents of (E,E)-2,4-heptadienal and 2,3-pentanedione, contributing to nutty and buttery flavors, significantly increased. In conclusion, bloodletting and cold stress treatments before slaughter could significantly reduce the earthy smell of fresh silver carp fillets, thus improving its odor quality.

In this study, the effects of the extracts from mulberry leaves, rosemary, cinnamon, grape seeds, green apples and cloves on the color, oxidative stability and flavor characteristics of oil-fried shiitake mushroom were investigated. It was found that these natural extracts improved the brightness of oil-fried shiitake mushroom and significantly inhibited its browning. The content of melanoid, the Maillard reaction product, was decreased by treatment with each of the extracts, which shared a similar trend with the change in the degree of browning. The natural extracts also significantly improved the antioxidant capacity and inhibited the oxidation reaction of oil-fried shiitake mushroom. Clove extract resulted in the largest decrease in peroxide value (74.36%), while green apple extract resulted in the greatest decrease in thiobarbituric acid reactive substances (TBARS) value (17.54%). Clove, rosemary and grape seed extracts significantly inhibited protein oxidation. Treatment with green apple extract minimized the free radical content. The umami and saltiness were significantly increased by treatment with clove, rosemary or mulberry leaf extract. All six natural extracts increased the levels of nitrogen and oxygen compounds, hydrocarbons, alcohols, aldehydes, and ketone. Seventeen differential volatile compounds, such as methyl 2-methoxybenzoate and isoamyl 2-methylbutyrate, were identified among the six treatment groups and the control group. These results provide a theoretical basis for the application of natural extracts in oil-fried edible mushrooms.

In this study, a method for the simultaneous determination of 20 pyrazines in baijiu was established by direct injection (DI) combined with gas chromatography-tandem mass spectrometry (GC-MS/MS), and the pyrazines in 10 brands of baijiu with different flavors were determined by the method. The developed method showed good linearity in the concentration range of 0.01–10.00 mg/L with determination coefficients (R2) in the range of 0.998 3–0.999 7, the limits of detection (LOD) were in the range of 0.16 × 10-3–3.25 × 10-3 mg/L, the recovery rates at different spiked concentrations ranged from 81.26% to 113.13%, and the intra-day and inter-day relative standard deviations (RSDs) varied between 1.42% and 4.98%. Among the ten types, pyrazines were the most abundant in jiang-flavor baijiu with concentrations ranging from 2.63 to 16.88 mg/L, followed by zhima-flavor and nong jiang-flavor baijiu. This method has higher accuracy and sensitivity than GC-MS, and is suitable for the analysis of pyrazines in different aroma types of baijiu.

In this study, liquid-liquid microextraction coupled with gas chromatography with hydrogen flame ionization detection (LLME-GC-FID) and orthogonal partial least squares-discriminant analysis (OPLS-DA) were integrated to track and monitor the contents of furfural and furfuryl alcohol in the raw materials, Daqu, stacking fermented grains, pit fermented grains, upper and lower steamer fermented grains, and distillates, which were collected at the key steps of the brewing process of sauce-flavor Baijiu. The results showed that the spatial and temporal distribution of furfural and furfuryl alcohol during the brewing process of sauce-flavor Baijiu varied significantly. The contents of furfural and furfuryl alcohol increased at first and then decreased at the Daqu-making stage. The contents of furfural and furfuryl alcohol showed an upward trend at the stacking fermentation stage. During the pit fermentation stage, the content of furfural decreased while the content of furfuryl alcohol increased. During the distillation process, the content of furfural increased, while the content of furfuryl alcohol decreased from the upper steamer to the lower steamer. The contents of furfural and furfuryl alcohol showed an increasing trend at the alcohol extraction stage. The distribution of furfural during the brewing process was generally lower layer > middle layer > upper layer. The distribution of furfuryl alcohol was middle layer > lower layer > upper layer at the stacking fermentation stage, and lower layer > middle layer > upper layer at the cellar fermentation stage and the distillation stage. Traceability analyses showed that furfural and furfuryl alcohol were mainly derived from Daqu powder, rice husk, and the late distillation stage. The formation mechanism of furfural during the brewing process of sauce-flavor Baijiu was attributed to microbial action, sugar degradation, and Maillard reaction under high temperature and acidic conditions. This study provides theoretical guidance for the reduction and control of furfural and furfuryl alcohol during the brewing of Baijiu, and provides a scientific basis for regulating the quality and safety of Baijiu.

In this study, using mixed solutions of sucrose (SUC) and fructo-oligosaccharides (FOS), isomalto-oligosaccharides (IMO), or xylo-oligosaccharides (XOS) as the medium, pulsed ultrasound (US)-assisted osmotic dehydration (OD) of kiwifruit chunks was carried out. Changes in the properties of mixed sugar solutions were systematically analyzed during the dehydration process, the quality formation of kiwifruit chunks was examined, and the process of mass transfer during OD was evaluated from a multidimensional perspective. Results showed that US accelerated the mass transfer. Specifically, the content of total soluble solids (TSS), osmotic pressure and conductivity of the mixed sugar solutions significantly decreased and the turbidity increased. US-SUC-XOS group showed the highest TSS content (23.65 °Brix), osmotic pressure (1 439.00 mOsm/L), conductivity (13 316.87 μS/cm) and turbidity (12.50 NTU). During the OD process, the TSS content and osmotic pressure of the mixed sugar solutions decreased, the turbidity increased, and the conductivity decreased first and then increased, indicating that mass transfer took place. Analysis of the quality changes of kiwifruit chunks demonstrated that the TSS content continued to increase. The highest TSS content (15.35 °Brix) was observed in the 12 h US-SUC-XOS group. Additionally, the infiltration of sugars could support cells, resulting in obvious plasmolysis, which in turn contributed to decreased texture properties. Analysis of electrical characteristics demonstrated that US-assisted OD facilitated the movement of charged particles, which was reflected in a decrease in the impedance and reactance values of kiwifruit chunks. Notably, in the US-SUC-XOS group, the adhesion effect slowed down the particle movement, leading to the highest impedance and reactance values. X-ray spectroscopy analysis confirmed the mass transfer of elements. The highest proportion of K (67.08%) and the lowest proportion of Ca (28.61%) were obtained in the 12 h US-SUC-XOS group. Additionally, 1H nuclear magnetic resonance (NMR) spectroscopy confirmed the mass transfer of sugar molecules between the mixed sugar solution and kiwifruit chunks. The moisture distribution results highlighted that the infiltration of sugar molecules could induce a large amount of free water to escape from kiwifruit chunks and reduce the mobility of water molecules. The 12 h US-SUC-XOS group showed the lowest peak area of free water and the highest peak area of immobile water and bound water. In summary, different mixed sugar solutions mediate different degrees of mass transfer. In particular, SUC-XOS solution can retard the degradation of kiwifruit tissues, in turn contributing to the formation of good quality in kiwifruit chunks.

This study investigated the effects of the intrinsic properties of sorghum for Baijiu production on its hydration process in order to enable prediction of the moisture content of different varieties of sorghum during soaking. The physicochemical properties of 23 cultivars of Baijiu sorghum were measured, and the kinetic process of their hydration was analyzed upon soaking at a constant temperature of 40 ℃. Besides, the correlation between the hydration kinetics characteristics (initial hydration rate and equilibrium moisture content) and physicochemical properties of sorghum (seed coat thickness, hardness, specific surface area, protein, fat, tannin, starch, amylose, amylopectin) was analyzed. It was found that the hydration kinetics characteristics of sorghum were correlated with the specific surface area, hardness, fat, tannin, amylose and amylopectin. A backward propagation (BP) neural network model with 10 nodes in the hidden layer was established using the hardness, specific surface area, fat, tannin, amylose, soaking time and initial moisture content as the input layer, and the moisture content of sorghum as the output layer. Using the Levenberg-Marquardt (L-M) algorithm as the training function and tansig-purelin as the network transfer function, the BP neural network model was obtained after finite training. The correlation coefficient (r) between the predicted and the experimental values of the moisture content was 0.99, and the mean square error (MSE) was 0.02. This BP neural network model was capable of predicting the moisture content in different varieties of Baijiu sorghum during the soaking process. This research provides a theoretical foundation and technical support for the further development and precise control of the soaking process.

To overcome the problems associated with maize yellow pigment (MYP) such as poor water solubility, instability, and low bioavailability, MYP was microencapsulated with different plant-based proteins, pea protein isolate (PPI), hemp protein (HP), or soybean protein isolate (SPI) combined with sodium alginate (SA) as a mixed wall materials or maltodextrin as a single wall material. The encapsulation efficiency, physicochemical properties, particle size, thermal stability, microstructure, in vitro digestion characteristics, and antioxidant capacity of the microcapsules were evaluated, and their protective effect on H2O2-induced oxidative damage in ARPE-19 cells was investigated. The results showed that microencapsulation of MYP improved its solubility, bioavailability and antioxidant activity. Microcapsules with MYP concentrations in the range of 375–1 125 μg/mL did not affect the viability of ARPE-19 cells, and showed superior cellular antioxidant effect in the H2O2-induced oxidative damage model. The three mixed wall materials exhibited different functional characteristics. Compared with those prepared with the other wall materials, PPI-SA microcapsules showed higher encapsulation efficiency, lower water content, smaller particle size, and better fluidity and stability.

To ascertain the interactions between the major acids and esters in nongxiangxing Baijiu and the underlying mechanisms, the effects of different types and concentrations of acids on the aroma release of Baijiu model systems containing ethanol (52%, V/V), four acids (acetic acid, lactic acid, butyric acid, an hexanoic acid) and four esters (ethyl hexanoate, ethyl lactate, ethyl acetate, and ethyl butyrate). Electronic nose and sensory evaluation showed that the response intensity and aroma profile of Baijiu model systems varied with different concentrations of acetic acid, lactic acid, butyric acid and hexanoic acid, being most pronouncedly affected by lactic acid. Furthermore, we studied the effect of lactic acid concentration on the volatility and ultraviolet (UV) absorption of Baijiu model systems. The results showed that the volatility was reduced by adding lactic acid. UV spectra demonstrated that there was an interaction between lactic acid and other substances in Baijiu model systems. The volatilization curves of binary systems of lactic acid and esters showed that lactic acid could promote the release of ethyl acetate and ethyl lactate but inhibited the release of ethyl hexanoate and ethyl butyrate. UV spectroscopy showed that the characteristic absorption peaks of the binary system varied with increasing concentration of lactic acid. The thermodynamic parameters showed that the interactions between lactic acid and four esters were spontaneous; the primary interaction force with ethyl hexanoate was hydrophobic interaction, while the interaction forces with the other three esters were hydrogen bond and van der Waals force. This study provides a theoretical basis for the flavor regulation of nongxiangxing Baijiu.

To improve the solubility, stability and bioactivity of rice bran protein (RBP) and its hydrolysates and to enhance their utilization as biological carriers, this study prepared binary nanoparticles composed of rice bran protein hydrolysates and gum arabic (GA) by taking advantage of the interaction between proteins and polysaccharides. Trypsin hydrolysate (R-t) and alkaline protease hydrolysate (R-a) of RBP were prepared and their physicochemical and structural properties were determined. Subsequently, each hydrolysate was combined with GA to prepare binary nanoparticles, which were characterized using intermolecular interaction analysis, transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The results showed that the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity of R-t and R-a were (72.82 ± 1.95)% and (66.83 ± 2.34)%, respectively, which were significantly higher than that of RBP. R-t-G nanoparticles with good stability were obtained at pH 1.4, R-t/GA ratio of 1:1 (m/m), and total polymer concentration of 4 mg/mL. R-a-G nanoparticles with good stability were obtained at pH 1.4, R-a/GA ratio of 1:2.5 (m/m), and total polymer concentration of 4 mg/mL. Electrostatic interaction played a significant role in the binding of R-t and R-a to GA, thereby stabilizing the structure of nanoparticles, and R-t-G exhibited a more stable system compared with R-a-G, with superior dispersion, thermal stability and a stronger crystal structure.

In order to investigate the effect of caspase-3 on the water retention and tenderness of Tan sheep meat during postmortem aging, the right hind leg meat of Tan sheep was injected with Ac-DEVD-CHO, a caspase-3 inhibitor, or 0.8% NaCl (control group), and aged at 4 ℃. After 0, 6, 12, 24, 48, 96 and 192 h, the activity of caspase-3 and caspase-9, water distribution, degradation of myofibrillar proteins, microstructure and water retention and tenderness indicators were determined. The results showed that with increasing postmortem aging time, the activity of caspase-3 and caspase-9 in the DEVD group was inhibited, and the myofibril fragmentation index (MFI) showed a significantly lower upward trend than the control group (P < 0.05). The pH initially decreased and then increases, and the ultimate pH was lower while the pH at 192 h was higher in the DEVD group than in the control group (P < 0.05). At 24–192 h postmortem, the cooking loss, centrifugal loss, T23 transverse relaxation time and shear force of the DEVD group were distinctly higher than those of the control group. Moreover, during the early postmortem period, the microstructural integrity of muscle in the DEVD group was better than that of the control group. In summary, during the early post-slaughter period (0–24 h), DEVD preserved the integrity of myofibrils and slowed down the process of apoptosis by inhibiting the activity of caspase-3, which resulted in the deterioration of the water retention and tenderness of Tan sheep meat. In the late post-slaughter period (48–192 h), the rise in pH weakened the effect of DEVD, and the consequent rapid activation of caspase-3 accelerated the degradation of myofibrils, thereby improving meat tenderness. Furthermore, the rise in MFI aggravated the collapse of muscle structure, resulting in poor water retention of Tan sheep meat. Overall, the DEVD treatment had a stage-specific effect on the quality of Tan sheep meat during postmortem aging.

In this study, fermented mung bean milk was prepared from 12 commonly cultivated Chinese mung bean varieties, and the effects of these varieties on the textural properties and sensory quality of fermented mung bean milk were investigated. It was found that fermented mung bean milk prepared from the cultivar B9 exhibited the highest water-holding capacity of 53.23%, the highest hardness of 70.66 g, the highest apparent viscosity, an average particle size of 3.65 μm, and the highest absolute value of zeta potential of 16.23 mV. The gel structure of the fermented mung bean milk was dense with small pore size, and it scored high in sensory evaluation, demonstrating that B9 was the most suitable variety for the preparation of fermented mung bean milk. In this study, we explored the raw material characteristics affecting the quality of fermented mung bean milk, and found that mung bean with a high protein content and a high content of vicilin-like subunit (55 kDa) is suitable for the preparation of fermented mung bean milk with excellent textural and organoleptic qualities. The above indexes can serve as criteria for the selection of suitable varieties for the processing of fermented mung bean milk.

This study aimed to comparatively analyze the common and unique glycoside hydrolase (GH) family genes in Bifidobacterium. On this basis, a rapid method for isolating target Bifidobacterium strains from infant fecal samples was developed. The GH family genes of four bifidobacterial taxa, including B. breve, B. longum subsp. longum, B. bifidum and B. longum subsp. infantis, were compared, revealing that there were common and unique patterns in the GH family genes among these species, which could serve as molecular markers for the isolation and identification of Bifidobacterium strains. Based on colony polymerase chain reaction (PCR) and nucleic acid electrophoresis, a rapid method for the isolation and identification of the aforementioned bifidobacterial strains were successfully developed and applied to the isolation of B. bifidum. This method is characterized by not only high efficiency of isolation but also low costs. The results of this study contribute to a better understanding of the diversity of Bifidobacterium, thereby laying a foundation for future probiotic research and development.

In this study, Debaryomyces hansenii PETY002, isolated from Pu-erh tea, was used for enhanced fermentation (EF) of Pu-erh tea. The total number of yeast colonies was significantly higher in the EF group than in the natural fermentation (NF) group. Sensory evaluation revealed that the tea infusion from the EF group was darker in color, mellower in taste, and had a mushroom-like aroma. Compared with NF, EF showed an increase in the contents of theabrownins and water extracts and a decrease in the contents of tea polyphenols, catechins including catechin (C), epigallocatechin (EGC), gallocatechin (GC) and epigallocahechin-3-gallate (EGCG), and caffeine. On the other hand, there was little difference in the contents of flavonoids or amino acids. Microbial community analysis revealed that Debaryomyces was the dominant fungus in EF. Furthermore, there was a competitive interaction between Debaryomyces and Thermomyces. Correlation analysis revealed that Debaryomyces were positively correlated with theabrownins, but negatively correlated with soluble sugars and theaflavins. In conclusion, inoculation with D. hansenii PETY002 changed the diversity and composition of the microbial community during Pu-erh tea fermentation, which improved the quality of Pu-erh tea through interactions with other dominant microorganisms.

This study was conducted in order to investigate the effect of Lactobacillus helveticus LH43, which has the ability to produce high-molecular-mass extracellular polysaccharides, as an auxiliary starter on the gel properties and protein conformation as determined using a texture analyzer, a rheometer, scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), fluorescence spectrophotometry and circular dichroism (CD) spectroscopy. The results showed that the application of L. helveticus LH43 as an auxiliary starter significantly enhanced the textural properties, water-holding capacity (WHC) and rheological characteristics of yoghurt and improved its microstructure and flavor characteristics. Additionally, the strain reduced the surface hydrophobicity, free sulfhydryl content and relative content of random coil of yoghurt proteins, and increased the relative content of α-helical structures, confirming α-helix and random coil to be intrinsic factors leading to differences in the gel properties of fermented milk. In conclusion, L. helveticus LH43 can be used to improve the gel properties of dairy products, and this study provides a new reference for improving the fermentation process of yoghurt.

To achieve high value-added utilization of tea residue, we carried out an in-depth study on the activity and mechanism of action of tea residue proteins and peptides derived from their enzymatic hydrolysis using a protease mixture. Antioxidant activity-guided fractionation of the hydrolysate was performed, and the structure of the purified peptides was identified using liquid chromatography-mass spectrometry (LC-MS). Molecular docking was utilized for simulated analysis of the matched peptides to select peptides with high antioxidant activity. The synthesized peptides were used for in vitro activity validation. The results showed that the purity of the purified antioxidant peptide was (90.06 ± 0.23)%. Totally 25 matched peptides were identified from fraction I, which exhibited high antioxidant activity. Two potent antioxidant peptides, CsTP4 SFDPLG and CsTP10 PLYPGG, were selected from the 25 peptides. The molecular docking results showed that the peptides bound to their target proteins with antioxidant activity mainly through hydrogen bonds and hydrophobic interactions, with binding energy of −3.92 and −7.12 kcal/mol for CsTP4 SFDPLG and CsTP10 PLYPGG, respectively. The synthesized peptides were confirmed to have high in vitro antioxidant activity. This study contributes to understanding the mechanism underlying the interaction between active peptides from tea residues and their target proteins, which will promote the development and utilization of these active peptides in the pharmaceutical and health food fields.

In order to reduce the content of ethyl carbamate (EC), a harmful by-product in the fermentation process of Baijiu, this study isolated bacteria and yeasts with EC-degrading ability and excellent fermentation performance from Daqu, and the co-fermentation conditions for the two microbial species were optimized by response surface methodology and applied to the fermentation of Baijiu. The results showed that 5 strains of yeast and 4 strains of bacteria with high EC-degrading activity were obtained from Baijiu Daqu and screened for ester production ability and protease activity. Bacillus amyloliquefaciens (JX2-10) and Wickerhamomyces anomalus (QX-2) with excellent fermentation performance were obtained. The degradation rates of 200 μg/L EC by JX2-10 and QX-2 were 85% and 35% after 24 h culture, respectively. Using single factor experiments and response surface methodology (RSM) with protease activity and total ester concentration as response variables, the optimal co-fermentation conditions were determined to be 5.6, 30.1 ℃ and 3.9% for initial pH, culture temperature, and ethanol concentration, respectively. Under these conditions, the activity of protease was 41.59 U/mL, and the total ester concentration was 5.85 g/L. EC contents in fermented grains and Baijiu produced using the co-culture decreased by 12.7% and 10.8%, respectively, compared with those of the control group, and the content of volatile flavor substances in Baijiu increased. This study provides a data basis for the degradation of EC during the fermentation of Baijiu.

Objective: To investigate the neuroprotective effect and mechanism of procyanidin B2 on high glucose-induced ferroptosis in differentiated SH-SY5Y cells. Methods: An in vitro cell injury model was created by treating differentiated SH-SY5Y cells with 45 mmol/L glucose, and the cells were randomly divided into normal control, high-glucose model, high-concentration procyanidin B2 treatment, low-concentration procyanidin B2 treatment, and positive control drug lipvastatin-1 groups. The CCK8 method was used to observe cell viability. Flow cytometry was used to detect Fe2+ and lipid peroxide (LPO) levels, immunofluorescence was used to detect lipid reactive oxygen species (ROS) levels, JC-1 staining was used to detect mitochondrial membrane potential, transmission electron microscopy (TEM) was used to observe morphological changes characteristic of mitochondrial ferroptosis, and Western blot was used to detect the expression levels of ferroptosis-related proteins including solute carrier family 7 member 11 (SLC7A11) and transferrin receptor (TFRC). Results: Compared with the normal control group, the high glucose model group showed a significant decrease in cell viability and mitochondrial membrane potential, reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio, and SLC7A11 protein expression level, while the intracellular levels of Fe2+, LPO, lipid ROS, and TFRC increased obviously. Compared with the high glucose group, a certain concentration of procyanidin B2 significantly increased cell viability, mitochondrial membrane potential, GSH/GSSG ratio, and SLC7A11 protein expression and simultaneously down-regulated LPO and lipid ROS levels. The TEM results showed that procyanidin B2 significantly alleviated mitochondrial shrinkage, cristae rupture and disappearance, and other distortions caused by high glucose. Conclusion: Procyanidin B2 can inhibit lipid peroxidation damage induced by high glucose in differentiated SH-SY5Y cells, and its action mechanism is related to the inhibition of ferroptosis by regulating the glutathione pathway.

Objective: To investigate the effect of cyanidin-3-O-glucoside (C3G) on brain damage and gut microbiota in naturally aging mice. Methods: Mice aged 2 and 18 months were divided into four groups: young control, young + C3G, aging model and aged + C3G. The second and fourth groups were administered by gavage with 50 mg/kg C3G consecutively for eight weeks. The following parameters were assessed: serum levels of inflammatory factors and antioxidant indexes, expression levels of neurotrophic factors and brain damage markers in brain tissue; microbial diversity and metabolite changes in intestinal contents. Results: C3G significantly decreased the level of inflammatory factors (P < 0.05), increased the activity of antioxidant enzymes (P < 0.05), and up-regulated the expression of brain-derived neurotrophic factor (BDNF), while inhibiting the production of brain damage markers including beta amyloid 1-42 (Aβ1-42) (P < 0.05). In addition, C3G increased the relative abundance of Faecalibaculum and Bifidobacterium in the gut, while decreasing the level of Enterorhabdus. These changes in gut microbiota contributed to the production of docosahexaenoic acid and eicosapentaenoic acid and decreased linoleic acid levels (P < 0.05). Correlation analysis showed that Faecalibaculum and Bifidobacterium were negatively correlated with inflammatory factors and nerve damage indicators, but positively correlated with antioxidant capacity and neurotrophic factors. Conclusion: C3G can alleviate aging-related neurological damage and improve brain health in naturally aging mice by modulating gut microbiota. This finding may provide a theoretical basis for the development of aging-delaying health foods containing anthocyanins.

This study aimed to investigate the impact of three postbiotics at different doses on cognitive function in a rat model of Alzheimer’s disease (AD) induced by D-galactose combined with AlCl3. Specific pathogen-free (SPF) Wistar rats were randomly divided into nine groups: control (Ctrl), AD model, positive drug (donepezil hydrochloride), low-dose (108 CFU/kg) and high-dose (109 CFU/kg) Bifidobacterium animalis spp. lactis IOBL07, Lactiplantibacillus plantarum IOB602 and L. paracasei IOB413. The Ctrl group was intraperitoneally and orally administered with normal saline, while all other experimental groups were subjected to intraperitoneal injection of D-galactose and oral gavage of AlCl3. The model induction period lasted for 13 consecutive weeks. At 1 h following the last injection and oral gavage, the intervention groups were orally administered with donepezil hydrochloride or postbiotics, whereas the Ctrl and AD groups were given an equivalent volume of normal saline. The Morris water maze was used to assess the learning and memory capacities of the rats in each group. Additionally, the content and immunofluorescence intensity of amyloid β-protein (Aβ) in hippocampal tissues were determined. Histopathological changes in the small intestine were examined along with changes in the intestinal microbiota. The levels of lipopolysaccharide (LPS) in feces, serum, and hippocampal tissues were determined as well as the relative mRNA transcription levels of toll-like receptor 4 (TLR4), NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and myeloid differentiation factor 88 (MyD88) in brain tissues. The results showed that all three postbiotics could significantly improve the learning and memory capacities of AD rats, significantly reduce the content of Aβ in hippocampal tissues, and decrease the LPS levels in feces, serum, and hippocampal tissues and the relative mRNA transcription levels of TLR4, NLRP3 and MyD88 in brain tissues. Intervention with the postbiotics regulated the structure and composition of the intestinal microbiota. In the postbiotic intervention groups, the relative abundance of the predominant intestinal bacteria, Firmicutes, and the beneficial species, Ruminococcaceae increased, the relative abundance of the potential harmful intestinal bacteria, Muribaculaceae, decreased compared with the AD model group. Thus, the postbiotics IOBL07, IOB602, and IOB413 have significant efficacy in ameliorating memory and cognitive deficits in AD rats, the most pronounced effect being observed with high-dose IOB602. The underlying mechanisms might be associated with regulating the structure and composition of the gut microbiota and down-regulating the relative mRNA transcription levels of TLR4, NLRP3 and MyD88 in brain tissues.

In this study, untargeted metabolomics based on ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) and multivariate statistics were combined to analyze the differences in metabolite composition in the peel and pulp of three apple varieties from Northeast China (Saiwaihong, K9, and Longfeng) using Red Fuji apples as a control. Our aim was to explore the metabolomic profile and characteristic components of the three varieties. The results showed that a total of 239 metabolites were detected in the peel and pulp of the four varieties, including phenols (48.95%), sugars (15.06%), terpenoids (13.81%), vitamin and fatty acids (11.72%), amino acids (7.11%), and nucleotides (3.35%). For each fruit part, the number and types of metabolites and metabolic pathways in the varieties from Northeast China were similar to those of Red Fuji apples, indicating comparable quality characteristics among the four varieties. Differences were observed in the relative contents of metabolites among the four varieties. Principal component analysis and hierarchical clustering analysis indicated that the peel and pulp were grouped into distinct clusters, with clear separation being found among the different varieties for each fruit part, highlighting compositional differences in the metabolites of the peel and pulp. The number of characteristic differential metabolites (CDMs) in the peel and pulp was follows: 19 and 10 for Saiwaihong vs. Red Fuji, 22 and 16 for K9 vs. Red Fuji, and 31 and 20 for Longfeng vs. Red Fuji, respectively, indicating greater differences in metabolite composition between Longfeng and Red fuji for both fruit parts. When comparing the three Northeast apple varieties, the number of differential metabolites in the peel and pulp was as follows: 22 and 22 for Saiwaihong vs. K9, 21 and 21 for Saiwaihong vs. Longfeng, 31 and 15 for K9 vs. Longfeng, respectively. Phenolic compounds were the major class of CDMs in the peel and pulp of apples among the four varieties. Flavanols such as epicatechin and its oligomer exhibited the highest abundance in Saiwaihong, flavonols such as quercetin glycoside showed the highest abundance in K9, and phenolic acids such as chlorogenic acid and neochlorogenic acid presented the highest abundance in Longfeng. The results of this study provide a scientific reference for the precise development of the three apple varieties from Northeast China and for the cultivation and improvement of apple germplasm resources in China.

In order to reveal the primary structural characteristics and chemical composition of theabrownins in Pu-erh tea, the differences in the chemical composition of theabrownin fractions with different molecular masses from the tea were studied using membrane ultrafiltration and mass spectrometry (MS). The contents of proteins, polysaccharides, total polyphenols and active groups and color difference in the theabrownin fractions were analyzed, and their structural characteristics were analyzed by Fourier transform infrared spectroscopy (FTIR), ultraviolet (UV) absorption spectroscopy, gas chromatography-mass spectrometry (GC-MS) and Curie-point pyrolysis combined with gas chromatography-mass spectrometry (CP-Py-GC-MS). The results showed that the smaller the molecular mass of theabrownin fractions, the lighter the color of their aqueous solutions, while no significant difference was observed in the content of active groups. The contents of proteins, polysaccharides and total polyphenols showed a downward trend with decreasing molecular mass. All the fractions contained a large amount of –OH groups, saturated C–H peaks and C=C benzene ring peaks, and exhibited an absorption peak at 200 nm. Ribose, rhamnose, arabinose, xylose, mannose, glucose and galactose were all contained in the fractions with molecular mass > 300 kDa and in the range of 500 Da–10 kDa. The main pyrolysis products derived from the theabrownin fractions with different molecular masses were methyl palmitate, octadecenoic acid methyl ester, methyl octadecadienoate, tetracosane, pentacosane, furfuryl methanol, and tocopherol.

In this study, we investigated the effects of pomace maceration and mixed culture fermentation on the quality of pomegranate wine, made from Tunisian pomegranates. Single factor experiments and an orthogonal array design were jointly employed to optimize the process parameters for pomace maceration, which was conducted before fermentation. Mixed culture fermentation of pomegranate juice prepared under optimized conditions was conducted by co-inoculation of Torulaspora delbrueckii NX-1 or Metschnikowia pulcherrima NX-2 with Saccharomyces cerevisiae ES488 to explore the effects of different mixed starters on the aroma quality of pomegranate wine. The results showed that the optimum conditions for preparing pomegranate juice were maceration at 6 ℃ for 24 h after the addition of 200 g/L pomace. Mixed culture fermentation significantly increased the content of volatile compounds in pomegranate wine. In particular, co-fermentation with T. delbrueckii NX-1 and S. cerevisiae ES488 evidently increased the contents of the characteristic aroma components in pomegranate wine such as ethyl acetate, isoamyl acetate, ethyl caprylate and phenyl ethyl acetate, which imparted rich floral and fruity aromas to pomegranate wine, thereby improving the flavor complexity and richness. Meanwhile, pomace maceration followed by mixed culture fermentation could improve the antioxidant capacity of wine samples. In conclusion, the results of this study hold potential application value for improving aroma quality and antioxidant capacity of pomegranate wine.

High performance liquid chromatography (HPLC) fingerprints and multi-component determination methods were established to investigate the differences in quality among the dried tubers of wild-simulated Gastrodia elata Bl. (Rhizoma Gastrodiae) from different geographical origins by combining fingerprint similarity evaluation, principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA). By comparative analysis of the fingerprints of 15 batches of Rhizoma Gastrodiae samples from major production regions in Guizhou province, a total of 14 shared peaks were identified and assigned to 6 signature components, including gastrodin, p-hydroxybenzyl alcohol, parishin E, parishin B, parishin C and parishin A. PCA showed that the first three principal components cumulatively explained 83.373% of the variance, and gastrodin and parishin A were selected as markers to discriminate between different categories of Rhizoma Gastrodiae. OPLS-DA ascertained that gastrodin, p-hydroxybenzyl alcohol, parishin C, parishin B, and parishin A affected the quality of Rhizoma Gastrodiae. The total content of signature components of Rhizoma Gastrodiae was 12.957–36.738 mg/g, and parishin A accounted for the largest proportion of it. Under the same limiting condition, significant differences in the contents of signature components were observed between wild-simulated and bag-cultivated Rhizoma Gastrodiae. The antioxidant capacity and neuroprotective activity of Rhizoma Gastrodiae were investigated by kits and in vitro cellular experiments, revealing that the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cationic radical and hydroxyl radical scavenging capacity and neuroprotective activities of wild-simulated Rhizoma Gastrodiae on PC12 and HT-22 neurons were superior to those of bag-cultivated Rhizoma Gastrodiae. This study provides data support for the establishment of quality standards for wild-simulated Rhizoma Gastrodiae.

In this study, the effect of Ligilactobacillus salivarius M18-6, with the capability to stably and rapidly ferment soybean protein and strong antioxidant capacity, on the flavor quality and antioxidant activity of fermented soymilk was analyzed. This study found that with increasing fermentation time, soybean protein and fat gradually decomposed, and the particle size of fermented soymilk showed a downward trend, making its texture more delicate and smoother. Additionally, the volatile components of soymilk before and after fermentation were analyzed by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) and gas chromatography-ion mobility spectrometry (GC-IMS). It was found that the concentration of hexanal, which primarily contributed to beany flavor, gradually decreased with fermentation time, and so did the concentration of 1-octen-3-ol. The concentrations of diacetyl, acetoin and 2-heptanone and other flavor substances associated with fruity aroma gradually increased, thereby resulting in good flavor of soymilk. Furthermore, fermented soymilk with L. salivarius M18-6 had potent hydroxyl radical scavenging activity in a Caco-2 cell model of oxidative injury induced by acrylamide. Compared with the oxidative damage model group, the activities of catalase (CAT) and superoxide dismutase (SOD) in Caco-2 cells treated with the fermented soymilk increased by 2.67 and 30.80 times, respectively, and the concentration of glutathione increased by 13.83 times. In summary, soymilk fermented by L. salivarius M18-6 has a significant repairing effect on oxidatively damaged cells.

In this study, the changes in total polyphenols, total flavonoids and chlorogenic acid contents during the processing of Lycium barbarum bud tea were compared and analyzed, and the metabolite composition of the tea at different processing stages was systematically analyzed by widely targeted metabolomics to clarify their effects on the chemical composition of L. barbarum bud tea. The results showed that L. barbarum buds had the highest contents of total polyphenols, (43.65 ± 3.15) mg/g, total flavonoids, (10.68 ± 0.25) mg/g, and chlorogenic acid (5.24 ± 0.52) mg/g. The contents of these phenolic substances decreased significantly (P < 0.05) as bleaching, primary fixation, secondary fixation, frying and flavoring progressed. Notably, after the secondary fixation, the contents of total polyphenols, total flavonoids and chlorogenic acid decreased by 19%, 29% and 27%, respectively. Widely targeted metabolomics identified 594 metabolites belonging to 11 categories, including flavonoids, phenolic acids, alkaloids, amino acids and their derivatives, and lipids. In total, 270, 287, 298, 295, and 298 significantly differential metabolites were identified in L. barbarum buds versus bleaching, primary fixation, secondary fixation, frying and flavoring, respectively, with the major ones being flavonoids, nucleotides and their derivatives, phenolic acid, amino acids and their derivatives. These differential metabolites were predominantly enriched in metabolic pathways such as purine metabolism, niacin and nicotinamide metabolism, cysteine and methionine metabolism, and a small proportion of them was enriched in pathways like zeeatin biosynthesis, and ABC transporter. Significant differences were observed in inosine, homocysteine, cinnamic acid, 4-hydroxy-3-methoxycinnamic acid, and isoferulic acid among processing stages, indicating their involvement in the quality formation of L. barbarum bud tea during processing. The findings of this study provide a theoretical basis for understanding the changes in nutritional and functional components and for the quality control of L. barbarum bud tea during processing.

In order to investigate the difference in aroma quality among Osmanthus fragrans absolute oil and the permeate and retenate obtained from its membrane separation, a total of 66 volatile organic compounds (VOCs) were detected in the samples by gas chromatography-mass spectrometry (GC-MS). Statistical analysis revealed significant difference in both the types and concentrations of VOCs among different samples (P < 0.05). The application of orthogonal partial least squares-discriminant analysis (OPLS-DA) successfully discriminated the three samples, with a predictive accuracy of 93.6%. In addition, 10 differential compounds were selected using variable important in the projection (VIP) value > 1 as the cutoff, and clustering heatmap analysis identified 9, 3 and 1 major VOCs in the oil, retenate and permeate, respectively. The permeate exhibited good anti-flocculation properties and a stable rheological tend, containing the lowest contents of palmitic acid and its derivatives. The absolute oil exhibited the most prominent floral, fruity, greasy and cologne-like aromas with odor activity value (OAV) of 1 371 871.65, 41 885.15, 37 199.21 and 3 050.71, respectively, whereas the permeate showed the most intense herbaceous aroma with OAV of 3 241 379.60. The results from the present study will provide a theoretical basis for the application of membrane separation to the purification of O. fragrans absolute oil and for the evaluation of the characteristic aroma of the oil and its fractions.

In this study, sensory evaluation, high performance liquid chromatography (HPLC), high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) were employed to analyze the major flavor components of different aroma types of Anxi Huangjingui tea. The results indicated that Anxi Huangjingui tea had an intense aroma as well as a mellow and sweet aftertaste. Each type of Anxi Huangjingui tea had their own unique sensory characteristics. Specifically, the light-aroma type had a long-lasting refreshing fruity aroma and a fresh, mellow, sweet, and brisk aftertaste, whereas the strong-aroma type had a strong sweet aroma and a heavy, mellow, sweet, and brisk aftertaste. A total of 61 differential aroma compounds were identified between the two aroma types. The light-aroma type showed significantly higher aroma character impact (ACI) values for methyl heptenone, methyl salicylate, hexanal, and isoamyl alcohol than did the strong-aroma type. Combining this finding with their odor activity values (OAV), we inferred that the above four compounds were key contributors to fresh, floral, and fruity aromas. Meanwhile, dehydrolinalool, myrtenol, 2,5-dimethyl-3-ethylpyrazine, 2-acetyl-3-methylpyrazine, limonene, and crocinaldehyde exhibited significantly higher ACI values in the strong-aroma type, indicating that these compounds may contribute to baked, floral, and fruity aroma characteristics. This study provides a scientific basis for understanding the flavor characteristics of Anxi Huangjingui tea with different aroma characteristics.

In this study, the effects of treatment with different doses of electron beam irradiation on physicochemical characteristics and functional components of Aronia melanocarpa juice, being rich in anthocyanins, were investigated. Meanwhile, targeted metabolomics was employed to explored the effect of irradiation treatment on the composition and content of anthocyanin metabolites in the fruit juice, and its sensory quality was evaluated as well. Irradiation treatment at 3-9 kGy increased the browning of A. melanocarpa juice, and significantly reduced the total anthocyanin content (TAC) and total polyphenol content (TPC) by 18.10%–33.72% and 2.47%–12.03%, respectively (P < 0.05). The major monomeric anthocyanins in the fruit juice were cyanidin-3-O-galactoside, cyanidin-3-O-arabinoside, cyanidin-3-O-xyloside and cyanidin-3-O-glucoside, among which cyanidin-3-O-glucoside was more stable under irradiation treatment; the content of cyanidin-3-O-glucoside was not significantly changed after irradiation with 3 kGy dose (P > 0.05), whereas the contents of the other three anthocyanins were reduced significantly (P < 0.05). In term of sensory quality, irradiation treatment increased the redness and yellowness and reduced the contents of volatile sulphides and volatile terpenoids in the fruit juice. This study is expected to provide some technical references for the selection and parameter determination of irradiation processing for anthocyanin-rich foods.

In this study, the effects and underlying mechanisms of storage conditions on the gel properties of soft-boiled egg white prepared from fresh eggs stored at 4 or 25 ℃ for 0–12 days were investigated. The results showed that the texture properties, β-sheet content, and disulfide bond content of egg white gel initially increased and subsequently decreased with storage time, reaching the highest values after 9 days. Disulfide bonds served as the major intermolecular force. Compared with those of fresh samples, the resilience, springiness, β-sheet content, and disulfide bond content of soft-boiled egg white gels from eggs stored for 9 days increased by 16.7%, 29.9%, 16.1% and 22.1% for 4 ℃, and by 34.7%, 32.4%, 30.4% and 25.7% for 25 ℃, respectively, and the microstructure of the samples stored at 25 ℃ for 9 days was more uniform and compact, so it had the best gel properties. Proteomics analysis showed that the abundance of mucin 5B in the 25 ℃/9 days group was 6.4 and 11.4 times higher than that of the 4 ℃/9 days group and the fresh sample, respectively. which may account for its enhanced thermogel properties.

To investigate the effect of spermidine (SPD) on postharvest fruit pitting, storage quality and reactive oxygen (ROS) metabolism in sweet cherry, ‘Summit’ sweet cherry fruits were treated with one of SPD and two polyamine synthesis inhibitors: methylglyoxal-bis(guanylylhydrazone) (MGBG) and dicyclohexylamine (DCHA) before storage. Physicochemical indices were determined periodically during storage. The results showed that SPD treatment significantly inhibited the increase in pitting rate, pitting index and decay rate during storage, while maintaining high fruit firmness, soluble solid content and titratable acidity. At the end of storage, the pitting rate, pitting index and decay rate of SPD-treated fruits were 28.69%, 27.28% and 19.97% lower than those of the control group, respectively. The fruit firmness, soluble solid content and titratable acidity were 38.74%, 9.23% and 11.20% higher than those of the control group, respectively. Furthermore, SPD treatment promoted the accumulation of the endogenous SPD, putrescine (PUT) and spermine (SPM), significantly enhanced the activities of superoxide dismutase (SOD), glutathione reductase (GR), catalase (CAT) and peroxidase (POD), promoted the accumulation of total phenolics and reduced glutathione, and maintained high free radical scavenging capacity, thereby effectively inhibiting the accumulation of superoxide anion, hydrogen peroxide and malondialdehyde (MDA). In addition, it slowed down the increase in relative conductivity. On the contrary, MGBG and DCHA treatments inhibited the accumulation of endogenous SPD, PUT, and SPM in sweet cherry fruits, reduced the activity of antioxidant enzymes and the contents of antioxidants, and inhibited free radical scavenging capacity, thereby resulting in the accumulation of large amounts of ROS, causing cell membrane damage, and leading to a significant increase in the rate of fruit pitting and decay and consequently a significant decline in fruit quality. In conclusion, SPD treatment could significantly improve the antioxidant capacity of sweet cherry fruits during cold storage and reduce the damage caused by ROS to the cellular membrane, thereby inhibiting the occurrence of fruit pitting and consequently maintaining high fruit quality during storage.

Heavy metals are highly toxic and can contaminate a wide range of foods. Their pollution and residues can bring about serious harm to food safety. Therefore, it is critical to strengthen efforts to detect heavy metal residues in food products. Immunoassay is promising for the rapid and efficient detection of heavy metals. Heavy metal antibodies are at the heart of immunoassays for the detection of heavy metals. Heavy metal antigens consist of two parts: heavy metal ions and chelating agents. Due to the structural similarity among metal ions and the universality of chelating agents, the resulting antibodies often show inadequate specificity, although antibodies with good specificity have been reported in some literatures. Therefore, it is significant to explore the specific recognition and interaction mechanism between heavy metal antibodies and antigens. In this article, we elaborate three research methods for understanding the recognition mechanism between heavy metal antibodies and antigens and recent progress in this area, and analyze the critical factors for the specific recognition and interaction. We hope that this review will provide a reference for enhancing the performance of heavy metal antibodies, and lay the foundation for establishing efficient, sensitive and specific methods for the detection of heavy metal residues in foods.

Postmortem energy metabolism is a key biochemical pathway that affects meat tenderness, and glycolysis is the dominant process of postmortem energy metabolism, which is regulated by numerous factors. This article reviews the factors that affect the postmortem glycolysis process and the underlying mechanisms. AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1) are important upstream regulatory factors for postmortem glycolysis. This article focuses on summarizing the effect of the AMPK/SIRT1 signaling pathway on glycolysis and postmortem endogenous enzyme systems and clarifying the underlying mechanism, in order to provide new ideas for regulating meat tenderness through the AMPK/SIRT1 signaling pathway.

Linseed cyclic peptides are important active ingredients in flaxseed, exhibiting antioxidant, anti-inflammatory and anti-cancer properties. However, linseed cyclic peptides undergo partial oxidation during processing and storage, leading to structural changes in [1-8-NαC],[1-MetO2]-linusorb B1. As a result, the bitter compound [1-8-NαC],[1-MetO]-linusorb B1 is produced, which reduces the flavor of linseed-related products, thus limiting the use of linseed in the food industry. This article summarizes the structures and encoding genes of linseed cyclic peptides as well as the methods for their detection. Based on related research, the biological activities of cyclic peptides, the mechanism underlying their bitter taste and the de-bittering methods for them are described. Furthermore, this review envisages the application of linseed cyclic peptides in the pharmaceutical and food fields, and proposes that germination may be a new idea for de-bittering linseed cyclic peptides, with a view to providing a theoretical basis for the integrated regulation of the physicochemical properties and biological activities of linseed cyclic peptides.

Food safety is not only important for the nation, but also for its people. Since the founding of the People’s Republic of China, the governance of food safety in our country has undergone comprehensive and profound transformations. This article conducts an in-depth analysis of the evolution of China’s food safety governance system from the perspective of historical institutionalism. Within the structural framework of historical institutionalism, the process of institutional change is influenced by factors such as the macro-social background, meso-level ideas, and micro-level actors. The evolution of China’s food safety governance system can be divided into five stages: the administrative control system led by the food sector (1949-1978), the mixed governance system led by the health department (1979-2002), the multi-departmental parallel segment-wise governance system (2003-2012), the professional governance system led by the food and drug administration (2013-2017), and the comprehensive governance system led by market regulatory authorities (2018 to present). From a historical institutionalist perspective, the evolution of the system reveals a profounder internal logic. Under the constraints of path dependence as well as the joint influence of external key nodes and internal adaptations, China’s food safety governance system exhibits a continuous interaction between institutional balance and institutional transformation, demonstrating strong institutional resilience.