In this study, Mesona chinensis Benth. essential oil (M.EO) was extracted by hydrodistillation and its chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS). According to their peak areas, alloaromadendrene (25.53%), β-caryophyllene (19.31%), isocaryophyllene (11.30%), α-humulene (8.30%), and eremophilene (7.62%) were found to be the major components of M.EO. Based on pseudo-ternary phase diagram, M.EO microemulsion (M.EO-ME) was fabricated using Tween-60 as the surfactant, ethanol as the cosurfactant, surfactant-to-cosurfactant mass ratio (Km) of 2:1 and mixed surfactant-to-oil phase mass ratio (Smix) of 8:2, and it remained stable after 100- and 200-dilution. The antioxidant activities of M.EO were improved by encapsulation in microemulsion to different degrees; the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity was only slightly increased, while the oxygen radical absorbance capacity (ORAC) and peroxyl radical scavenging capacity (PSC) were increased by 2.6 and 8.4 times, respectively. Besides, microemulsion encapsulation also improved the antiproliferative activity of M.EO against human malignant melanoma cells A375, and the median effective concentration (EC50) of M.EO-ME was approximately one-fifth of that of M.EO. These results indicated that microemulsion encapsulation improved the antioxidant and anti-proliferative activity of M.EO against A375 cells, which could provide a theoretical basis for the high-value development and utilization of Mesona chinensis Benth.

In this study, the inhibitory effects of lactic acid (LA) and peracetic acid (PAA) on Escherichia coli O157:H7 biofilm formation were investigated, and the underlying mechanisms were explored with regard to the metabolic activity, the contents of extracellular polymeric substances (EPS), the microstructure of biofilm, and the expression of related functional genes. Results showed that the minimum inhibitory concentrations (MIC) of LA and PAA were 0.25% and 0.002 5%. The inhibitory effects of LA and PAA at sub-MIC on E. coli O157:H7 biofilm formation were weaker, as determined by the viable count method. Both organic acids at MIC showed significantly inhibitory effect (P < 0.05), and completely inhibited biofilm formation by E. coli O157:H7 at 2 MIC. After treatment with LA and PAA at MIC, the metabolic activity was reduced by 84.25% and 43.49%, and the contents of extracellular polymeric substances were also reduced significantly (P < 0.05). Both LA and PAA effectively inhibited the expression of E. coli O157:H7 biofilm adhesion-related genes (csgA and flhC), quorum sensing-related genes (luxS and sdiA), polysaccharide synthesis-related genes (csrA, adrB and adrA), and two-component regulatory system-related genes (phoQ, phoP, envZ and ompR). Therefore, LA and PAA can be used as potent disinfectants to reduce the risk of microbial contamination associated with food production and processing in the food industry.

The purpose of this study was to investigate the preparation of citrus low-methoxyl pectin (CLP) and caffeic acid (CaA) conjugate by a green and safe method using laccase. The conjugate was examined for its key composition, ultraviolet (UV)-visible, Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR) spectroscopic characteristics and in vitro antioxidant activity, in order to clarify its formation mechanism and intermolecular bonding mode, and summarize the structural factors contributing to its antioxidant activity. The results of chemical composition and anion-exchange chromatograms showed that CLP contained 51.99% (mol%) galacturonic acid (GalA), 30.95% galactose (Gal), 7.44% rhamnose (Rha) and 9.02% glucose (Glc) as well as a trace amount of total phenolics (1.20 mg/g), with a methoxylation (DE) degree of 38.33%, suggesting that the major molecular fragments of CLP were homogalacturonan (HG) and rhamnogalacturonan type I (RG-I), whose neutral saccharide side chain was galactan. The weight-averaged molecular mass (mw) of CLP was 226.1 kDa. In contrast to CLP, CLP-CaA conjugate showed significantly increased DE and total phenolic content of 46.93% and 9.64 mg/g (P < 0.05), respectively, and an increased mw of 271.4 kDa. Moreover, CLP exhibited UV and FTIR absorption peaks characteristic of CaA at 288 nm and 1 519 cm-1, respectively. The 700 MHz 1H and 176 MHz 13C NMR spectra indicated evidently resonant peaks for α-D-GalA and β-D-Gal moieties, and partial α-L-Rha moieties of CLP, which confirmed its major structure. New resonant peaks were observed for all glucosyl carbons of CLP in CLP-CaA conjugate. The largest chemical shift occurred on the C1 and C4 atoms of the α-D-GalA moieties, the C6 (carboxyl carbon) peak was shifted to δC 175.12, and peaks characteristic of CaA appeared at δH 6–8 in the 1H spectra. To sum up, the conjugation mechanism of CLP with CaA could be laccase-mediated binding of CaA to the C6 carboxyl group of the α-D-GalA moieties in CLP at a 1:1 molar ratio, resulting in the formation of ester groups. As a result, the conjugate had excellent, multiple in vitro antioxidant activities, whose half maximal inhibitory concentration (IC50) was 0.82, 2.47, 0.92, and 0.72 mg/mL for scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation, hydroxyl radial, and superoxide anion radical, respectively. The results of this study provide a theoretical basis for applying CLP-CaA conjugate in the food industry.

The static and dynamic rheological properties of doughs made from six rice and high-gluten wheat flour blends were studied. In the dynamic rheological frequency sweep test, the storage modulus (G’) and loss modulus (G’’) of mixed doughs showed an overall upward trend with increasing amount of rice flour added, and the opposite trend was observed for tan δ. In the creep relaxation test, the maximum creep strain, maximum creep compliance and instantaneous recovery compliance gradually decreased, and the zero shear viscosity and instantaneous recovery ratio gradually increased. These observations indicated that the gluten in wheat flour was diluted after adding rice flour, but the starch granules in rice flour swelled and adhered to each other after absorbing water, and interacted with rice flour proteins, imparting higher elastic modulus and more internal structure to dough. In the dynamic rheological temperature sweep test, the viscoelasticity of mixed doughs was changed significantly before and after the gelatinization temperature, and the G’ and G’’ curves were similar to the starch gelatinization curve, indicating that starch was the major component affecting the rheological properties of raw dough during heating. The G’ and G’’ increased regularly in the high temperature zone, but decreased regularly in the low temperature zone below 60 ℃ during cooling. The samples had solid-like properties during the whole cooling process.

In the present study, the digestion characteristics of the common soy products soy protein isolate (SPI), microwaved soybean, boiled soybean, soy milk, calcium chloride-coagulated tofu, and magnesium chloride-coagulated tofu were evaluated using the standardized INFOGEST static (INFOGEST 2.0) in vitro digestion system. The gastrointestinal digests were taken at different time points to determine the intact proteins, molecular mass distribution, free amino group concentration and particle size distribution. The different processing methods promoted the digestion of soy protein. Proteins in the five soy products were partly digested by simulated gastric fluid. During intestinal digestion, soybean proteins are all thoroughly digested into short peptides. Compared with SPI, the free amino group concentration of microwaved soybean and boiled soybean significantly increased, while the digestion of microwaved soy protein was more complete; the digestibility of soy protein was lower in soy milk than in calcium chloride-coagulated tofu and magnesium chloride-coagulated tofu, but there was no significant difference between the two types of tofu. In summary, the results of this study are helpful for better understanding the digestibility of proteins in soy products obtained by different processing methods, which will provide a reference for the consumption of dietary plant proteins.

Zein nanofibers loaded with sea buckthorn oil (SBO) were prepared by electrospinning technology with the addition of sea buckthorn leaf extract (SBE) to improve oil stability and oxidation resistance. The physical properties of nanofibers were characterized, and the changes in the color parameters, peroxide value (PV) and antioxidant activity of encapsulated SBO were tested during accelerated oxidative storage. In addition, the changes in the release rate of SBO and antioxidant activity were also investigated during simulated digestion. The results showed that the encapsulation efficiency of zein + SBO and zein + SBO + SBE were both greater than 90%. Scanning electron microscopy (SEM) showed that the prepared nanofibers were uniform in shape, and Fourier transform infrared (FTIR) spectroscopy confirmed the successful encapsulation and uniform dispersion of SBO in the fiber. Thermogravimetric analysis (TGA) showed that SBO nanometer fibers began to degrade at around 300 ℃ and had high heat resistance. The addition of SBE greatly improved the oxidation resistance of nanofibers and inhibited the oxidation process of SBO, and significantly improved the storage stability of SBO in synergism with nanoencapsulation. Nano-encapsulated SBO was released slowly under gastrointestinal conditions, and the antioxidant activity of zein + SBO + SBE was still high after digestion. In conclusion, the addition of SBE and physical encapsulation are both effective in improving the stability and antioxidant activity of SBO.

Objective: To explore the effect of low-temperature plasma treatment on postharvest ripening, senescence, storage quality and antioxidant enzyme activities in Xinjiang ‘Xiaobai’ apricot fruit. Methods: The fruit were treated for 40 s with cold plasma generated at 80, 90 or 100 kV using a dielectric barrier discharge generator and subsequently stored at 4 ℃ and 95% relative humidity (RH) for up to 42 days. Decay index, quality indicators and antioxidant enzyme activities were measured every seven days throughout the storage period. Results: All cold plasma treatments preserved apricot fruit quality better than the control group, with the most pronounced effect being observed with cold plasma generated at 90 kV. On the 42nd day of storage, the decay index of the treatment group was only 24% as compared to the control group, the hardness was nearly 1.5 times higher, the contents of VC and polyphenols were 1.4 and 1.2 times higher, and the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were increased by 18%, 28% and 23%, respectively. Conclusion: Low-temperature plasma treatment can reduce the decay index, improve the storage quality, and induce the increase of antioxidant enzyme activities in apricot fruit .

Raw and cooked chestnut powders were prepared from fresh and cooked Chinese chestnuts, respectively, by four drying methods: hot air drying (HAD), vacuum freeze drying (VFD), radio frequency-vacuum drying (RFVD) and air-impingement jet drying (AJID). The aim of this study was to investigate the effects of cooking treatment and different drying methods on the quality characteristics and microstructure of chestnut powder. The results showed that the raw and cooked chestnut powders prepared by HAD had higher fat contents, but possessed poorer color and quality and uneven particle size distribution. The raw and cooked chestnut powders dried by VFD had the lowest moisture content (3.01% and 4.29%, respectively) and better storability, and their starch and free phenol contents were the highest. Moreover, they had the highest brightness and whiter color, while the raw powder particles showed an irregular large-scale lamellar structure. The raw and cooked powders prepared by RFVD and AJID had higher reducing sugar contents, and the content of free phenol was significantly higher in them than in the counterparts prepared by HAD. Furthermore, their microstructure was maintained well, but their color was poor. After cooking, the water-holding capacity and bulk density of chestnut powders prepared by different drying methods were increased, while the free phenol content and brightness (L*) were decreased, and the powder particles became swollen with a surface rougher, which was folded and wrinkled. In summary, cooking treatment and different drying methods had significant effects on the quality characteristics and microstructure of chestnut powder. Therefore, the production cost and the requirements for industrial need to be considered in selecting the best method to prepare chestnut powder.

Ultraviolet-C light-emitting diode (UVC-LED) is a new non-thermal sterilization technology. In this study, the inactivation effect of UVC-LED on A. acidoterrestris, a common juice spoilage bacterium, was investigated and the underlying mechanism was explored by measuring intracellular nucleic acid and protein leakage, membrane permeability, intracellular reactive oxygen (ROS) accumulation, and intracellular protein and DNA damage. The results showed that increasing the irradiation dose of UVC-LED enhanced its inactivation effect on A. acidoterrestris, and when the irradiation dose was increased to 50 mJ/cm2, the number of viable cells in normal saline decreased by 4.6 (lg(CFU/mL)). By modeling of survival curves, it was observed that the inactivation effect of UVC-LED on A. acidoterrestris in normal saline was fitted to both the log-linear and Weibull models. The bacterium in different growth stages had different sensitivities to UVC-LED, in the logarithmic phase being more sensitive to UVC-LED. The irradiation treatment led to change in the membrane permeability and leakage of intracellular contents, indicating cell membrane damage, while intracellular ROS levels were not increased significantly (P > 0.05). Raman spectroscopic analysis and fluorescence microscopic analysis with acridine orange (AO) staining showed that the structures of intracellular proteins and DNA were changed. Overall, it was concluded that UVC-LED could inactivate A. acidoterrestris by causing DNA damage, structural change of intracellular proteins and the impairment of cell membrane permeability. According to the different degrees of damage, DNA damage may be the major reason for cell death.

Soluble dietary fiber (SDF), insoluble dietary fiber (IDF) and total dietary fiber (TDF) were prepared from Rosa roxburghii Tratt. pomace by enzymatic hydrolysis using α-amlyase. Dynamic high pressure microfluidization (DHPM) was used to modify SDF, yielding DHPM-SDF. The physicochemical properties of IDF, SDF and DHPM-SDF, as well as their inhibitory effects on glucose diffusion and α-amylase activity were studied. It was shown that both IDF and SDF slowed down the glucose flow process by absorbing glucose and inhibiting its diffusion, and reduced starch digestibility by altering the secondary structure of pancreatic amylase. The ability of IDF to adsorb glucose and inhibit glucose diffusion was 1.28 and 1.99 times higher than that of SDF, respectively. However, the inhibitory effect of SDF against pancreatic amylase was 1.73 times higher than that of IDF, and SDF exerted its inhibitory effect mainly through changing the α-helix and random coil conformations of pancreatic amylase. The ability of TDF to adsorb glucose and inhibit amylase activity were similar to those of IDF. The average particle size of DHPM-SDF was 2.08-fold higher than that of SDF, so that the ability to adsorb glucose and inhibit glucose diffusion were increased by 28.13% and 62.09%, respectively. In addition, DHPM-SDF significantly reduced the α-helix and random coil conformations of pancreatic amylase (P < 0.05), its amylase inhibitory activity is 1.44 times higher than that of SDF. In conclusion, dietary fibers from Rosa roxburghii Tratt. pomace, especially soluble dietary fiber, can be used as a good resource for the development of hypoglycemic products, and DHPM is an effective modification method to improve the hypoglycemic activity of SDF from Rosa roxburghii Tratt. pomace.

Objective: To investigate the effect of apiin on intestinal health in mice with colitis induced by dextran sodium sulfate (DSS). Methods: Thrity male C57BL/6J mice were randomly divided into normal, model and apiin groups. The normal and model group were given the AIN93G diet alone, and the apiin group was given the same diet supplemented with apiin (0.016 7%) throughout the whole course. After feeding for seven days, the drinking water of the model and apiin groups was switched to sterile water containing 3% DSS to induce colitis. After six days of treatment, DSS was stopped, and the mice were sacrificed 24 hours later. Food intake and body mass of the mice were observed and recorded every day, and disease activity index (DAI) and spleen index were calculated at the end of the experiment. The levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in serum and the activities of myeloperoxidase (MPO) and inducable nitric oxide synthase (iNOS) in colonic tissues were determined. The colonic pathology and the number of goblet cells were observed. Results: Apiin significantly alleviated body mass loss (P < 0.05), decreased DAI (P < 0.001) and spleen index (P < 0.001), and reduced the contents of the inflammatory cytokines TNF-α (P < 0.001) and IL-6 (P < 0.01) in the serum of mice with colitis. In addition, apiin significantly improved colon shortening (P < 0.01), and amelioratesd colonic tissue injury and inflammatory infiltration in mice with colitis. Apiin also significantly decreased the activity of MPO (P < 0.001) and iNOS (P < 0.001), significantly increased the number of goblet cells (P < 0.05), promoted mucus secretion, and maintained the integrity of intestinal barrier function. Conclusion: A dose of 25 mg/kg mb of apiin could alleviate DSS-induced colitis in mice.

The antioxidant activity and cellular immunomodulatory activity of polysaccharide fractions obtained from Lycopi Herba were evaluated in vitro. Two homogenous polysaccharides, designated LHPS1 and LHPS5, were isolated from the crude polysaccharide extract of Lycopi Herba by DEAE-52 and SephadexG-100 column chromatography. The structures and biological activities of LHPS1 and LHPS5 were studied by physicochemical and immunological methods. The results showed that LHPS1 (1.13 × 105 Da) and LHPS5 (7.40 × 104 Da) were acidic polysaccharides, composed of many monosaccharides and galacturonic acid. In terms of total reducing power and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, both polysaccharides had significant antioxidant activity in vitro. Immunoassays indicated that they could activate RAW264.7 cells to produce tumor necrosis factor-α (TNF-α), and promote the proliferation of splenic lymphocytes. Fluorescence immuno-activated transport assay showed that they could regulate immune responses by activating the transcription factor nuclear factor-kappa B (NF-κB) in RAW264.7 cells. In addition, inhibitor neutralization test results showed that the two polysaccharides could activate macrophages by binding to cell surface mannose receptors. Overall, we concluded that LHPS1 and LHPS5 had antioxidant activity and cellular immunomodulatory activity in vitro, and could be used as antioxidant supplements or immunomodulatory agents.

The absorption and metabolism of a 1-deoxynojirimycin and hydroxychalcone heterocomplex (DC-5) as a novel potent α-glucosidase inhibitor was investigated in rats. A total of four metabolites derived from DC-5 were identified in the blood of rats gavaged with DC-5 using ultra-performance liquid chromatography quadrupole time-of-flight tandem mass micrometry (UPLC-Q-TOF-MS/MS), including hydrogenated, methylated, sulfonated, and glucuronidated metabolites of DC-5. The concentration of DC-5 in the blood, heart, liver, lung, stomach and small intestine all peaked at 0.5 h after oral administration, while the peak concentration appeared at 1 h in the spleen and kidney. The peak concentration of DC-5 in the blood was 162.76 ng/mL, with a half-life in the terminal phase (T1/2) of 30.66 h and mean residence time (MRT) of 11.41 h. DC-5 was mainly excreted via feces, and a total of 2.26% of the intragastrical DC-5 was found in feces, which was significantly higher than that in urine (0.015 6%). The results of pharmacokinetics test showed that the bioavailability of DC-5 in rats was 1.47%.

Objective: To study the anti-aging effect and underlying mechanism of partially hydrolyzed fenugreek gum (PHFG) on naturally aging mice. Methods: PHFG, prepared with β-mannanase, was used to dietary intervention in naturally aging mice for 12 months, and then the pathological changes of brain, liver, kidney and colon tissues were observed. Furthermore, the contents of aging markers, total antioxidant capacity (T-AOC), catalase (CAT) activity, glutathione peroxidase (GSH-Px) activity and malondialdehyde (MDA) level in serum were measured. The total number of neurons, and the expression levels of brain-derived neurotrophic factor (BDNF) and p53/p21/p16 pathway associated genes and proteins were detected. Results: PHFG effectively increased the survival rate of aging mice (approximately 25.0%), and significantly improved their reactivity and depilation. The levels of T-AOC, CAT and GSH-Px in PHFG-treated mice increased by 78.1% (P < 0.05), 122.9% (P < 0.05) and 2.7%, respectively, compared with the naturally aging ones, while the MDA content decreased by 40.3% (P < 0.01). Moreover, PHFG increased the numbers of neurons and BDNF positive cells in the hippocampus CA1 area and inhibited the expression levels of the p53, p21 and p16 genes and p53 and p16 proteins in the liver. Conclusion: PHFG can prevent aging, and inhibit oxidative stress and brain damage induced by aging, which provides a scientific basis for PHFG as an anti-aging functional food ingredient.

This study was conducted in order to evaluate the ameliorative effect of polysaccharides from Chinese yam treated with the fermentation broth of Bacillus sp. to inhibit browning on acute colitis induced by 3% dextran sulfate sodium (DSS) in mice. The results showed that the polysaccharides significantly reduced the disease activity index (DAI) of mice with colitis (P < 0.01), alleviate colon atrophy (P < 0.05), decreased the secretion of tumor necrosis factor-α (TNF-α) (P < 0.01) and colonic histopathological score (P < 0.05), and increased the diversity of intestinal flora by increasing the abundance ratio of Firmicutes to Bacteroidetes and the relative abundance of beneficial bacteria such as Roseburia and reducing the relative abundance of harmful bacteria such as Alistipes. Similar effects were observed with those from Chinese yam treated with water. Likewise, the polysaccharides from Chinese yam treated with the fermentation broth of Bacillus sp. ameliorated DSS-induced colitis in mice, and the underlying mechanism may be related to the regulation of the intestinal flora and the secretion of pro-inflammatory factors. These results provide theoretical reference for the processing of Chinese yam and the research and development of functional foods containing Chinese yam polysaccharides.

Objective: This study investigated the effect and mechanism of oral administration of diallyl trisulfide (DATS) on ovalbumin (OVA)- and Al(OH)3-induced food allergy in mice. Methods: Female Balb/c mice (about 5 weeks old) were randomly divided into three groups: control, food allergy (FA) and FA + DATS. The experimental groups were injected intraperitoneally with 0.2 mL sterile physiological saline containing 50 μg of OVA and 1 mg of Al(OH)3 on day 0 and day 14, and 50 mg of OVA (dissolved in 250 μL of sterile physiological saline) was intragastrically administered at one-day intervals for six consecutive times starting from the 28th day. Fluorescein-labeled dextran (fluorescein isothiocyanate-dextran) was used to detect the permeability of the small intestine in mice; reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression levels of Th2 type (T helper 2) cytokine interleukin-4 (IL-4), IL-5 and IL-13 in mouse jejunum tissue; enzyme-linked immunosorbent assay (ELISA) was used to measure serum OVA-specific immunoglobulin E (OVA-sIgE) and mast cell protease 1 (mMCP-1) levels. Results: The FA + DATS group had a significantly lower incidence of diarrhea and a smaller decrease in body temperature than the FA group. Moreover, serum OVA-sIgE and mMCP-1 levels and Th2 type cytokine levels in jejunum were significantly reduced (P < 0.01 or 0.001), and food allergy symptoms and intestinal barrier were alleviated. Conclusion: Supplementation of DATS can enhance intestinal barrier function and effectively reduce the immune response of food allergy, thereby alleviating the symptoms of food allergy.

The purpose of this study is to explore the mechanism of action of Fuzhuan brick tea water extract (FTE) in preventing obesity and hypercholesterolemia. Specific pathogen-free Sprague Dawley (SPF SD) rats were selected and divided equally into six groups: normal diet, high-fat diet, positive control (Xuezhikang, a hypolipidemic agent), and low-, medium- and high-dose FTE intervention. A comparative analysis was performed to evaluate the effect of Fuzhuan brick tea in preventing obese dyslipidemia. The results showed that FTE affected the intestinal and hepatic bile acid (BA) metabolism cycle by regulating the structure and function of the intestinal microbiota, enhanced antioxidant capacity and systemic lipid consumption in rats, had a significant protective effect on the structure and function of the liver and intestines, improved the lipid profile and inflammatory response, and inhibited excessive body mass gain induced by a high-fat diet in rats. Collectively, we concluded that FTE has a significant preventive effect on nutritional obesity and hypercholesterolemia, and it is advantageous over Xuezhikang in preventing body mass gain and lipid accumulation, increasing lipid consumption, inhibiting liver functional enzymes and regulating bile acid metabolism.

Objective: The present study aimed to investigate the protective effect of oat polysaccharides on 70% ethanol-induced acute gastric mucosal injury in mice. Methods: Sixty Kunming male mice were randomly divided into normal, model, cimetidine (positive control), and low-, medium- and high-dose oat polysaccharide groups. The positive control group was gavaged with 100 mg/kg mb of cimetidine, and the low-, medium- and high-dose oat polysaccharide groups were intragastrically administered with 100, 200, 400 mg/kg mb of oat polysaccharides, respectively. The administration lasted for 14 consecutive days. On the 15th day, acute gastric mucosal injury was successfully by oral administration of 70% ethanol to all animals except those in the normal group. Afterwards, visceral organ indexes and the degree of gastric mucosal injury were examined and gastric pH, serum nitric oxide (NO) levels, and the levels of interleukin (IL)-10, lipopolysaccharide (LPS), vascular endothelial growth factor (VEGF), malondialdehyde (MDA), glutathione (GSH), pepsin activity and superoxide dismutase (SOD) activity in gastric tissues were measured. Results: Compared with the model group, gastric mucosal injury in the mice treated with oat polysaccharides was significantly reduced, and the most pronounced effect was observed at the high-dose level with an inhibition rate of 76.04%. Furthermore, oat polysaccharides increased the pH of gastric juice, serum NO levels, the activity of SOD and the contents of GSH and VEGF in gastric tissue, and reduced the activity of pepsin and the content of LPS in gastric tissue, especially at the high dose. Conclusion: Oat polysaccharides significantly protect against ethanol-induced acute gastric mucosal injury in mice with the most pronounced effect being observed at the high dose. The mechanism may be related to the increase in the pH of gastric juice, serum NO levels and the content of VEGF in gastric tissue, the decrease in LPS content and pepsin activity, and the enhancement of antioxidant capacity in the gastric mucosa.

This work aimed to explore the effects of different colored quinoas from the same habitat on lipid metabolism in high-fat diet-fed mice. Totally, 50 specific pathogen-free (SPF) male mice were fed adaptively for seven days and then randomly divided into five groups: blank control, model, white quinoa, black quinoa and red quinoa according to their body mass. After eight weeks of dietary intervention, physiological and biochemical indicators including Lee’s index, waist circumference, abdominal fat mass, and total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) levels in serum and liver tissue were determined. The mRNA and protein expression levels of key genes related to cholesterol and lipid metabolism in liver were detected by quantitative real-time polymerase chain reaction (q-PCR) and Western blotting. The results indicated that compared with the model group, quinoa reduced the Lee’s index, waistline and abdominal fat mass, significantly lowered TC and TG levels in serum and liver (P < 0.05), increased HDL-C level in liver (P < 0.05), and down-regulated the mRNA and protein expression levels of 3-hydroxy-3-methylglutaryl CoA reductase (HMG-CoAr) and sterol regulatory element binding protein (SREBP)-1c (P < 0.05). The mRNA expression level of HMG-CoAr was decreased by 56.22%, 72.55% and 27.77% by white, black and red quinoas, respectively, and the protein expression level was decreased by 53.02%, 29.72% and 29.80%, respectively. The mRNA expression of SREBP-1c was decreased by 62.96%, 45.50% and 21.27%, respectively, and the protein expression was decreased by 20.79%, 23.97% and 20.26%, respectively. The mRNA expression levels of AMP-activated protein kinase (AMPK)-α, low density lipoprotein receptor (LDL-R), liver X receptor (LXR), peroxisome proliferators-activated receptor-α (PPARα) and cytochrome P450 family 7 subfamily A member 1 (CYP7A1) and the protein expression levels of LDL-R and PPARα were significantly increased by dietary supplementation of quinoa. LDL-R mRNA expression was increased by 243.86%, 273.04% and 121.93% by white, black and red quinoas, respectively, and protein expression was up-regulated by 18.02%, 17.16% and 22.45%, respectively. The mRNA expression of PPARα was increased by 62.45%, 87.54% and 126.91%, and protein expression was up-regulated by 54.26%, 51.10% and 33.82%, respectively. Collectively, the different colored quinoas can improve lipid metabolism disorders in high-fat diet-fed mice, white quinoa and black quinoa being more effective than the red one. The underlying mechanism may be related to the reduction of cholesterol synthesis and de novo synthesis of fatty acids.

This study aimed to explore the improvement effect of xylooligosaccharides (XOS) on chronic diarrhea. According to the principle of randomized parallel controlled experiments, patients with clinical chronic diarrhea were recruited and randomly divided into three groups, a placebo group (CK, taking 3 g of maltodextrin per day), a low-dose XOS group (3X, taking 3 g of XOS per day) and a high-dose XOS group (6X, taking 6 g of XOS per day). The diarrhea symptom scores, serum biochemical indexes, fecal short-chain fatty acids and gut microbiota were analyzed after four weeks of intervention. Then, the fecal bacterial supernatant of the patients in each intervention group was administered by gavage to mice for 24 consecutive days, and the intestinal permeability and the levels of inflammatory factors were measured after 12 h fasting on the 25th day. The results showed that diarrhea symptoms and lipid metabolism tended to be improved in the intervention groups compared to the placebo group, and fecal butyric acid levels increased. The relative abundance of Blautia, Bifidobacterium, and Lachnospiraceae_unclassified were increased, while the relative abundance of Prevotella was decreased. Compared to the placebo group, the intestinal barrier tended to be stable in the mice gavaged with the fecal bacterial supernatant of the XOS intervention groups, colonic inflammation was significantly alleviated, the level of serum D-lactic acid (D-LA) was significantly decreased (P < 0.05 or 0.01), and the expression of tight junction protein (zonula occludens-1 (ZO-1) and occludin) was up-regulated. These results indicate that XOS are effective in improving chronic diarrhea, and are expected to alleviate chronic diarrhea.

The fresh melon fruit were cut into trapezoids, cubes and slices and then stored at 10 ℃ for up to 72 h. The effects of different cutting methods on the quality, and total phenol and γ-aminobutyric acid (GABA) contents of fresh-cut Hami melon were investigated. The results indicated that fresh-cut processing promoted the decrease in the color parameters L, a and b values, firmness, total soluble solid (TSS) and ascorbic acid contents, and the increase in total bacterial count and transparency, and higher wounding intensity resulted in greater changes in these indicators. Meanwhile, fresh-cut processing significantly induced the increase in L-phenylalanine ammonialyase (PAL) and glutamate decarboxylase (GAD) activity, total phenolic and GABA contents and 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) radical scavenging capacity (P < 0.05), and slicing, casuing the greatest wounding intensity, resulted in the highest PAL and GAD activity, DPPH radical scavenging capacity and total phenolic and GABA contents. These results implied that although fresh-cut processing accelerated deterioration in the quality of fresh-cut cantaloupe, it could also promote the accumulation of bioactive compounds including phenolic compounds and GABA, thus improving antioxidant capacity.

Hami melon is vulnerable to chilling stress during postharvest storage. Phytohormones play an important role in regulating crop responses to chilling stress. In order to explore the molecular mechanism of endogenous phytohormone metabolism in Hami melon under chilling stress, the effects of different storage temperatures (3 and 21 ℃) on storage quality, endogenous phytohormone metabolism and gene expression levels in Hami melon were investigated by targeted metabolomics and transcriptomics. The results showed that low-temperature storage kept fruit mass and hardness at higher levels, delayed decay, and inhibited the increase of malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents, but also caused chilling injury to a certain extent. In addition, metabolomics analysis showed that low-temperature storage inhibited the accumulation of abscisic acid (ABA) in Hami melon fruit, but promoted the accumulation of indole-3-acetic acid (IAA) and salicylic acid (SA). Transcriptome analysis showed that low temperature significantly affected the expression levels of key genes (such as PYR/PYLs, IAAs, TIRs, GH3, NPRs, and TGAs) involved in the phytohormone signal transduction pathway, and the expression levels of some of the key genes (bHLH13, IAA9-like, IAA27, MYC2-like, and PYL4) were validated by real-time quantitative polymerase chain reaction (qPCR). These findings provide a theoretical basis for understanding the molecular mechanism of phytohormone metabolism during low-temperature storage of Hami melon.

To investigate the effect of postharvest NO treatment on the metabolism of reactive oxygen species (ROS) and physiological quality of litchi fruit, harvested fruit were soaked in different concentrations (10, 50 and 100 μmol/L) of sodium nitroprusside or water as a control. The changes in physiological indexes were measured regularly during storage at 4 ℃. The results showed that sodium nitroprusside treatment could significantly reduce the mass loss rate, inhibit the generation and accumulation of hydrogen peroxide (H2O2) and superoxide anion (O2-·), reduce the production of malondialdehyde (MDA) as a cell membrane lipid peroxide product and membrane permeability, improve the activity of antioxidant enzymes such as superoxide dismutase (SOD), and slow down the senescence and browning of litchi fruit. Treatment with sodium nitroprusside at 10 μmol/L could significantly delay the increase in browning index and decrease the permeability of the cell membrane, and at 100 μmol/L effectively reduce the mass loss rate and increase the activity of SOD at the middle and late stages of storage. The results from principal component analysis showed that the key factors affecting the quality of postharvest litchi fruit were browning index, membrane permeability, mass loss rate and SOD activity, and the comprehensive score of litchi fruit treated with 100 μmol/L sodium nitroprusside were higher at the late stage of storage (after six days), and its storage quality was the best. These results indicated that sodium nitroprusside treatment could effectively delay the senescence and browning of litchi and prolong its shelf life by regulating ROS metabolism.

In this study, high-throughput sequencing was used to analyze the changes in the bacterial flora of salmon during cold storage, and a dominant spoilage bacterium in salmon stored at 4 ℃ was isolated, purified and identified as Pseudomonas fragi MS 02. Then, the antibacterial activity and mechanism of action of linalool against P. fragi MS 02 were investigated. The results showed that the bacteria flora composition of salmon stored at 4 ℃ changed with storage time. Photobacterium, Pseudomonas, Ralstonia and Acinetobacter were the dominant bacteria in salmon during storage. The relative abundance of Pseudomonas gradually increased with storage time, while P. fragi was the fastest growing strain during the storage period. It was found that linalool had a good antibacterial effect on P. fragi MS 02. Scanning electron microscopic (SEM) results showed that the bacterial cell membrane became wrinkled and sunken after treatment with linalool. By measuring electric conductivity, optical density at 260 nm (OD260 nm), fluorescence intensity using fluorescein diacetate as a dye, and alkaline phosphatase (AKP) and Na+/K+-ATPase activities, it was confirmed that linalool could destroy the permeability and integrity of the cell membrane and cell wall of P. fragi, and affect energy metabolism, eventually resulting in cell death.

This work was undertaken in order to study the combined treatment effects of ultrasound and caffeic acid on the quality of sea bass (Lateolabrax japonicas) during refrigerated storage. Fresh sea bass fillets were arbitrarily allocated into five groups: ultrasonic treatment at 20 kHz and 600 W for 10 min (US), dipping in 2.0 g/L caffeic acid for 10 min (CA), ultrasonic treatment at 20 kHz and 600 W for 5 min followed by dipping in 2.0 g/L caffeic acid for 5 min (US + CA), dipping in sterile water for 10 min (blank control, CK), and dipping in 1% acetic acid for 10 min (AA). After draining off the soaking solution, the samples were packed separately with polyethylene (PE) pouches, and then stored in a refrigerator at 4 ℃. Total viable count (TVC), physicochemical properties such as pH, total volatile basic nitrogen (TVB-N) content, thiobarbituric acid (TBA) value, texture profile analysis (TPA) parameters, and water-holding capacity (WHC), intrinsic fluorescence intensity (IFI) and sensory quality were measured every two days. The results showed that the US and CA treatments retarded the growth of TVC. On the fifth day, the TVC values in the CA and US groups were 18.49% and 15.53% lower than that in the control group, respectively. The increase of pH and TVB-N values in the treatment groups was obviously slower than that in the control group. On the 10th day of storage, the TVB-N content of the control group exceeded the spoilage limit, reaching (33.88 ± 0.56) mg/100 g compared to (16.71 ± 0.41) mg/100 g for the US + CA group. Both the US and CA treatments improved the WHC of fish greatly, while the CA treatment also had a stronger inhibitory effect on lipid oxidation in fish. Among the five groups, the US + CA group had the best overall quality. Compared with the CK group, the US + CA treatment maintained the quality better and extended the shelf-life of sea bass by four days at least.

This study addressed the effect of treatment with 2.0 mmol/L salicylic acid (SA) for 6 min and/or modified atmosphere packaging (MAP) consisting of 21.0% O2, 0.0% CO2 and 79.0% N2 on the storage quality of goji berries. The treated fruit were stored at (7.0 ± 0.5) ℃ and (93.0 ± 3.0)% relative humidity for 28 days. Quality indicators were monitored every four days. Results showed that the mass loss (ML), decay index (DI) and firmness were mainly affected by MAP, while the color, total soluble solid (TSS), malondialdehyde (MDA) and ascorbic acid (AsA) contents, and alternative oxidase (AOX) activity were mainly affected by SA. SA combined with MAP could activate AOX activity, inhibit respiration rate (RR), reduce AsA loss and MDA production, and maintain lower ML and DI, higher firmness and better color, showing quality more similar to the fresh fruits.

This work was carried out in order to study the effect of light emitting diode (LED) blue light and/or medium-wave (UV-B) and short-wave ultraviolet (UV-C) on the storage quality of fresh-cut Pleurotus eryngii. Results showed that light irradiation treatments effectively maintained the color of fresh-cut P. eryngii, delayed the decrease of total phenols, flavonoids and vitamin C contents, and inhibited the growth of microorganisms. After the combined treatment, the vitamin D2 content of fresh-cut P. eryngii was increased to 0.77 μg/100 g mw, the soluble protein content was increased by 20.85% compared with the initial value on the second day of storage, and the reducing sugar content was 2.06 folds higher than that of the control group on the 10th day. The combined treatment significantly enhanced the activity of enzymes associated with reactive oxygen species (ROS) metabolism and secondary metabolism, and delayed the production of superoxide anion radicals. Transmission electron micrographs showed that both lights could delay cell wall and mitochondrial degradation of fresh-cut P. eryngii. In summary, LED blue light combined with UV-C/B treatment could effectively maintain the storage quality and nutritional value of fresh-cut P. eryngii and prolong its storage period.

Fresh walnut kernels are prone to browning, making it difficult to produce and market it as a finished product. In this study, fresh walnut kernels (cv. ‘Xiangling’) were subjected to four browning inhibition methods and browned kernels were decolorized by two methods. According to the changes of color parameters and sensory quality during storage at 20 ℃, dipping in 1.0% ascorbic acid (AsA) + 0.05% citric acid (CA) for 5 min and dipping in 1.0% AsA at 20 ℃ for 1 h were found to be the best browning inhibition and decolorization conditions, respectively. To evaluate their effect on the quality maintenance of walnut kernels, the two treatments were performed individually or in combination with 1 kJ/m2 ultraviolet radiation C (UVC), and the treated samples were subsequently packed in polythene (PE) bags (30 μm thick) and stored at 5 ℃. Those treated with deionized water under the same conditions served as a control group. Results showed that both individual and combined treatments inhibited the increase in the activities of polyphenol oxidase (PPO) and peroxidase (POD) during storage. The activity of phenylalanine ammonia-lyase (PAL) was significantly enhanced during 14-21 d in comparison to controls (P < 0.05). On 56 d, acid value (AV) of both individual and combined treatments in browning inhibition group as well as the combined treatment in decolorization group were significantly lower than their controls (P < 0.05). Combined treatments in two experiments simultaneously delayed the breeding of bacteria and mould, partially promoted the ferric reducing antioxidant power (FRAP), and the peroxide value (POV) was increased, while the oil content was little changed. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging capacity was not significantly different from that of the control group. AsA competitively inhibited PPO activity in walnut kernel skins and skinless walnut kernels. After 56 days of storage at 5 ℃, the brightness (L*) value of decolorized walnut kernels was similar to that of the browning inhibition group, and no mildew was observed. The results from this study could provide a theoretical and technical basis for the commercial production of fresh walnut kernel.

Teichoic acid is one of the most important surface molecules of probiotics, which plays an active role in immune regulation and treatment of colitis. A large number of studies have proved that teichoic acids with different structures can cause different immune responses, which is considered to be an important reason for the different immune responses caused by teichoic acids from probiotics and pathogenic bacteria. The immune responses induced by teichoic acid are summarized at the cellular and molecular levels. On this basis, the role of teichoic acid-deficient mutants of probiotic bacteria in alleviating immune response-related diseases and preventing and treating colitis is analyzed. The purpose of this review is to provide new regulatory targets and research ideas for probiotics in the treatment of immune-related diseases.

Excessive exposure to blue light caused by the wide use of smart phones, tablet computers and other electronic devices can induce retinal photooxidative damage, causing a public health problem that cannot be overlooked. Anthocyanins, edible plant pigments, are widely distributed in dark-colored vegetables, berries and cereals. The individual daily intake of anthocyanins has been estimated to be tens of milligrams per person. Previous studies have reported that anthocyanins exert protective effects on retinal cells and are beneficial for vision health, but the specific mechanism of action is not yet clear. In this paper, we review the current status of research on the absorption and metabolism of anthocyanins, the mechanism of light-induced retinal oxidative damage and the mechanism by which anthocyanins protect the retina from light-induced damage, focusing on the fact that anthocyanins protect against photo-oxidation and photo-degradation of bisretinoids, reduce damage caused by lipid peroxidation products, activate antioxidant pathways, reduce inflammation, suppress endoplasmic reticulum stress, and inhibit cells apoptosis. Furthermore, we systematically elucidate the key targets for the protective effect of anthocyanins on retinal cells, which provide scientific evidence for anthocyanins as functional food factors to maintain vision health.

Pectin methylesterase (PME) exists naturally in plant tissues and can catalyze the demethyl esterification of high-ester pectin into low-ester pectin, which affects the hardness, juice yield and other texture and processing quality of fruits and vegetables. During the processing of fruits and vegetables, PME needs to be inhibited in order to avoid undesirable quality attributes such as excessive turbidity in fruit and vegetable juices, softening of canned fruits and vegetables, and separation between fruit skin and flesh in seasoning sauce such as chili sauce. One the other hand, in order to improve the juice yield of fruits and vegetables and produce low-ester pectin, exogenous PME needs to be added into products. Currently, there are few studies on activating endogenous PME to improve food processing. Therefore, this article focuses on the factors that promote the catalysis of plant endogenous PME on pectin demethylesterification, the underlying mechanism and its applications in fruit and vegetable storage and processing, which hopefully will provide a reference for the application of plant endogenous PME in fruit and vegetable processing.

Yeast and lactic acid bacteria (LAB) are widely used for the production of fermented foods and play a pivotal role in the production of fermented foods, and their modes of action in the fermentation system directly determines the quality of the final product. Studying the interaction mode between yeast and LAB in the fermentation system is helpful to reveal the relationship between microorganisms and food functions, and is of great significance to the positive regulation of the fermentation process. The interaction modes between yeast and LAB during food fermentation are reviewed herein, including synergy/antagonism, nutrient and metabolite exchange, quorum sensing, and biofilm coating. Besides, we discuss the positive role of yeast-LAB interaction in improving the flavor and texture of fermented foods, shortening the fermentation cycle, and enhancing the probiotic characteristics of the product. Finally, future prospects for the application of yeast and LAB as a mixed starter culture for enhancing fermentation are discussed.

Ellagic acid (EA), a natural antioxidant, is a polyphenolic compound found in fruits, nuts, and vegetables. EA can be metabolized by gut bacteria to urolithins. EA has very poor intestinal bioavailability, while urolithins can be more easily absorbed than EA and hence can be considered as the material basis for the antioxidant activity of EA. Various animal and clinical studies indicate that EA and urolithins can improve the intestinal microbial flora, promote intestinal health, and prevent the occurrence and development of intestinal diseases. The bioactivities of EA and urolithins mainly include antioxidation, anti-inflammation, and regulating the intestinal flora. The present paper reviews the chemical structures, metabolic pathways and bioactivities of EA and urolithins and their applications in research on intestinal diseases.

Pyrethroid pesticides are widely used in agricultural production due to their stability and high effectivity. The problem of pyrethroid residues in agricultural products has become increasingly prominent, posing a threat to food safety. The problem of pesticide residues has attracted growing attention from consumers and researchers. Therefore, it is urgent to understand the pollution status of pyrethroid pesticides in agricultural products and seek effective measures to control it. This article introduces the characteristics of pyrethroid pesticides and describes the current status of pyrethroid pesticide residues in agricultural products globally. Besides, it summarizes the technologies for the removal of pyrethroid pesticides and outlines future prospects for the development of new technologies in this field. We expect that this article will provide a reference for reducing pyrethroid pesticide residues in agricultural products and ensuring the safety of agricultural products.

Enrofloxacin is the first fluoroquinolone compound to be used in food animals in China, and plays an important role in the prevention and control of livestock and aquaculture diseases. However, enrofloxacin residues in foods resulting from its irregular or excessive use can damage seriously consumer health. In this review, the sample pretreatment techniques and the latest detection methods of enrofloxacin residues in foods are described, highlighting the advantages and disadvantages of the new sample pretreatment techniques and those from the national standards. This review focuses on the achievements and trends in the development of fluorescence methods, surface enhanced Raman scattering spectroscopy, microbial methods, electrochemical analysis, immunoassay and quartz crystal microbalance for the detection of enrofloxacin in foods, in an effort to offer new technical support for the monitoring of enrofloxacin residues in foods.

Because of its high sensitivity and far-reaching influence, infant food safety is a major concern to governments and the society. Although China and some international organizations, including the Codex Alimentarius Commission (CAC) and the European Union (EU), have set limits on risk factors such as pollutants, mycotoxins, and microorganisms in infant foods, there are still some problems such as the discrepancy in the range and value of limit indicators, and unbalanced development. Great progress has been made in the development and improvement of food safety standards for infants and young children in China in recent years. Based on a systematic review of the current situation of risk factor limits in Chinese and international food safety standards for infants and young children, this paper gives an in-depth analysis of the differences in the risk factor limit indicators and limit values, and puts forward some suggestions for improving the risk factor limits of food safety for infants and young children in China, which hopefully will provide a scientific basis for the upgrading of infant food safety standards in China.

In recent years, numerous studies have demonstrated that grain proteins and peptides derived from their enzymatic hydrolysis such as dipeptidyl peptidase-4 (DPP-IV), glucagon-like peptide-1 (GLP-1), peptide YY (PYY) and related enzymes can act on the therapeutic targets for type 2 diabetes mellitus (T2DM) and thereby improve T2DM. This article gives a summary of recent research on the beneficial effect of grain proteins and peptides on T2DM, and discusses future prospects for the application of grain proteins and peptides in T2DM treatment.

Intake of whole grains has substantial health benefits, which are attributed to various functional substances in whole grains. When consumed, whole grais are digested and fermented in the gastrointestinal tract, transforming active ingredients into important metabolites regulating human health and having multiple beneficial effects on certain human diseases. Numerous studies have shown that diabetes, obesity, inflammatory bowel disease and intestinal cancer are related to diet and the intestinal microflora. Although the relationship between these diseases and whole grains and the gut microbiota has not been thoroughly studied, the interactions between the gut microbiota and whole grains and the effects on the expression of related regulatory genes have been increasingly studied in recent years, and an increasing number of findings have confirmed the role of whole grains in regulating human diseases. In this paper, we review the role and molecular mechanism of whole grains in the regulation of these diseases, which will provide a biological basis and reference for further research and application of whole grains.

Hypertension is a major threat to health and food-derived angiotensin-converting enzyme inhibitory peptides (ACEIPs) have been recognized as potential alternatives to synthetic angiotensin-converting enzyme (ACE) inhibitors in the treatment of hypertension due to their high safety and non-toxicity. A large number of antihypertensive peptides with in vitro ACE inhibitory activity have been isolated and identified, but only a few of them including Ile-Pro-Pro (IPP), Val-Pro-Pro (VPP), and Leu-Pro-Pro (LPP) have been confirmed to be clinically effective for humans. Originally isolated from fermented milk, the three peptides are collectively called lactotripeptides. Several antihypertensive functional foods based on lactotripeptides have been marketed in many overseas countries and their efficacy has been fully verified, but such products are yet not available in China. In this context, the functions, safety, production methods, and new sources of the lactotripeptides are reviewed and patents concerning them are summarized herein. This review is expected to provide valuable information for the development of third-generation antihypertensive functional foods in China.

The processing of ready-to-eat fermented meat products has a long history, which are popular with consumers because of their plentiful nutrients and unique color and flavor. There is not yet a comprehensive review on the ripening process and mechanism of these products. Beginning with a review of the recent research on ready-to-eat fermented meat products, this paper presents a systematic summary of the physical and chemical changes during the ripening process of ready-to-eat fermented meat products, including the hydrolysis and oxidation of proteins and lipids, the formation of flavor substances, and texture changes. Furthermore, this paper discusses the factors that affect the ripening of ready-to-eat fermented meat products including enzymatic hydrolysis, the antioxidant effect of starter cultures and the flavor and color enhancement mechanism of curing agents. Finally, the shortcomings of the current research and future research directions are discussed. The aim of this review is to provide a theoretical basis for the in-depth research and development of ready-to-eat fermented meat products.

The development and application of sensor detection technology based on molecularly imprinted polymers (MIP) have been a hot topic of research in recent years. Being characterized by convenience, high efficiency, high sensitivity, low cost and good repeatability, this detection technology holds great promise for a wide range of applications in the detection of endogenous harmful substances and prohibited additives in meat products. MIP having a specific adsorption effect, MIP-based sensors allow easy detection and quantification of the presence of endogenous harmful substances and prohibited additives in meat products. This review introduces readers to the mechanism of MIP and the principle and classification of MIP-based sensors, highlighting the current applications of MIP-based sensors to detect veterinary drug residues, banned drugs and biogenic amines in meat products, which may provide a reference for better application of MIP-based sensors in the field of meat safety detection.

Plant terpenoids are natural secondary metabolites derived from the structural units of isoprene with a molecular formula of C5H8. Limonene is a monoterpene compound, which has many functions such as antibacterial, flavor-enhancing, anticancer, and anticough functions, so it has a wide range of applications in food, pharmaceutical, cosmetic, and other fields. At present, limonene is mainly produced by extraction from plants, which is limited by factors such as seasonal raw materials, complicated separation and purification, and low yield of limonene, while chemical synthesis of limonene is hindered by high energy consumption and pollutant emission. With the advent of biosynthetic technology, microbial biosynthesis has been developed as a new method of producing limonene, which has the advantages of low energy consumption, environmental protection, and sustainability. However, microbial biosynthesis of limonene also has some problems such as low yield and low efficiency, which makes it challenging to commercialize microbial limonene production. Therefore, constructing an efficient microbial cell factory for heterologous biosynthesis of limonene to replace traditional plant extraction methods will have great economic and social benefits. Here, we critically review the recent achievements in engineering yeast for limonene biosynthesis, and describe the synthetic strategies for limonene overproduction in microbial chassis by metabolic engineering and synthetic biology. We also discuss the feasible strategies for relieving limonene toxicity to the host cells and enhancing the tolerance of yeast to limonene.

Synbiotics refer to biological agents (probiotics) used in combination with probiotics. In recent years, accumulating studies have reported that synbiotics possess many health benefits. The ef?cacy of symbiotics is affected by the selection of probiotics and prebiotics. Fructooligosaccharides and inulin are commonly used as probiotics, which can be selectively absorbed by probiotics in the intestine and promote the proliferation of probiotics, thereby keeping the host healthy. This paper reviews the differential metabolism and metabolism pathways of fructooligosaccharides (FOS) and inulin by lactic acid bacteria, and summarizes the mechanisms of action of the hydrolases, transport systems, and regulatory proteins at the molecular level in order to provide basis for understanding the regulatory mechanism of the metabolic network of FOS and inulin by lactic acid bacteria. Besides, it summarizes the recent applications of synbiotics containing FOS and/or inulin with a view to providing valuable evidence to extend the combined application of prebiotics and probiotics.

As a very important group of proteins in muscle, myofibrillar proteins can directly affect the quality of meat products. However, myofibrillar proteins are prone to oxidation during processing and storage, which leads to a series of adverse consequences, such as amino acid side chain modification, protein cross-linking, aggregation and functional alterations. Polyphenols, potent natural antioxidants, can effectively inhibit the oxidation of myofibrillar proteins by interacting with them, while affecting their structure, function and nutritional properties. In this article, we summarize the mechanism of the free radical chain reaction involved in myofibrillar protein oxidation, the structure-activity relationship of polyphenols as an antioxidant against myofibrillar protein oxidation, the mechanisms of the covalent and non-covalent interactions between polyphenols and myofibrillar proteins, and the effects of the interactions on the structure and properties of myofibrillar proteins. Through this review, we hope to provide theoretical guidance for the application of polyphenols in meat product preservation.

Phloretin (Pht), a dihydrochalcone compound, is mainly found in apples, pears, strawberries and other plants. Extensive studies have reported that Pht has a wide spectrum of biological activities, such as antibacterial, antiviral, anti-tyrosinase, antioxidant, hypoglycemic, and antitumor activity. It holds great promise for application in the fields of foods, medicine and cosmetics. However, the molecular structure of Pht causes strong intermolecular hydrogen bonding, resulting in its poor water solubility and low bioavailability. These problems restrict the application of Pht. In order to expand the scope of application of Pht, it is urgently necessary to improve its solubility. In this context, this article reviews the physiological functions and major solubilization methods of Pht and discusses the problems currently existing in the research and development of Pht. We hope that this review can provide a reference for the future development and utilization of Pht.