The basis for the formation of protein-polysaccharide complexes is intermolecular interactions, including covalent and non-covalent interactions. Under specific processing conditions, proteins and polysaccharides can be assembled together to form multi-scale complexes at the molecular, microscopic and macroscopic levels, driven by intermolecular forces. Regulating the formation of the multi-scale structure of protein-polysaccharide complexes for the synergistic effect of various components is of great significance for designing protein-polysaccharide complexes with specific or new functions. Beginning with an overview of the interactions between protein and polysaccharide molecules, this paper summarizes the formation of the multi-scale structure of protein-polysaccharide complexes and their influence on functional characteristics, and discusses future prospects for the application of protein-polysaccharide multi-scale complex systems, in order to provide references for the design and development of protein-polysaccharide complex products with excellent functions.

In this study, neutral protease enzymatic hydrolysates of wheat germ albumin were separated step by step using ultrafiltration and chromatography techniques. Oxygen radical absorbance capacity (ORAC) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonicacid (ABTS) cation radical scavenging capacity were used as antioxidant activity evaluation indicators for selecting hydrolysate components with high antioxidant activity. The selected component was served as the initial material to further screen small peptides with high antioxidant activity by liquid chromatography-tandem mass spectrometry (LC-MS/MS) combined with PeptideRanker database activity prediction technology. High glucose-induced vascular smooth muscle cells (VSMCs) and H2O2-induced HepG2 and VSMCs were served as oxidative stress injury models to explore the protective effect of obtained small peptides. Results: Component V with small molecular weight obtained by ultrafiltration and chromatography had the highest antioxidant activity. Twenty small peptides were identified with LC/MS-MS analysis from this fraction. PeptideRanker prediction and antioxidant experiment validation showed that the peptide sequence LNYPPY (765.3 Da) had the highest antioxidant activity (ORAC was 3.01 μmol TE/μmol), and ABTS cation radical clearance rate was 95.58%). This peptide had a good protective effect on the H2O2-induced oxidative damage in HepG2 cells and vascular smooth muscle cells (VSMCs), but had no significant effect on the abnormal proliferation and the increase of reactive oxygen species (ROS) levels in VSMCs induced by high glucose. In conclusion, the peptide LNYPPY has good antioxidant properties in vitro and has protective effect against cellular oxidative damage induced by H2O2, which provides an important theoretical reference for the development and utilization of wheat germ albumin.

In this paper, crude glycoprotein from black soybeans (designated HDJ) prepared by alkaline extraction and then alcohol precipitation was fractionated by column chromatography on DEAE-52 cellulose and Sephadex G-100 into two fractions, designated HDJS2 and HDJS5-2. Their chemical compositions were determined and their structures were characterized by spectroscopic methods. Their antioxidant activities were analyzed by reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging rate and total antioxidant capacity assays. Immunoregulatory activities were determined by the methyl thiazolyl tetrazolium (MTT) colorimetric method. The results showed that HDJS2 (3.20 × 104 Da) and HDJS5-2 (3.89 × 104 Da) were mainly composed of neutral carbohydrate and protein. The glycopeptide bond types were O-type. HDJS2 was mainly composed of mannose, glucose, galactose, arabinose and fucose together with 96.1% amino acids. HDJS5-2 was mainly composed of mannose, glucose, galactose and arabinose as well as 71.3% amino acids. HDJS2 and HDJS5-2 had antioxidant activity in a dose-dependent. In addition, both glycoproteins could promote splenocyte proliferation, suggesting that they had immunoregulatory effects.

In this research, the anti-quorum sensing activity of ethyl maltol was evaluated using the quorum sensing reporter strain Chromobacterium violaceum 026 (CV026). The effect of ethyl maltol on the secretion of signal molecules in Aeromonas salmonioida was detected by gas chromatography-mass spectrometry (GC-MS). The inhibitory effect of ethyl maltol on the quorum sensing and spoilage capacity of Aeromonas salmonida in the presence of exogenous signaling molecules was determined by measuring the biofilm formation ability, extracellular protease activity and swarming and swimming motilities. The results showed that the minimum inhibitory concentration of ethyl maltol against CV026 and Aeromonas salmonioida was 0.1 mg/mL, and ethyl maltol could reduce the violacein-producing ability of CV026 at the sub-minimum inhibitory concentration (sub-MIC). According to GC-MS analysis, ethyl maltol significantly reduced the production of the quorum sensing signal molecule C12-HSL by Aeromonas salmonida. The biofilm formation, extracellular protease activity and swarming and swimming motilities of Aeromonas salmonida were inhibited by 71.2%, 69.1%, 80.4% and 82.1% by 0.08 mg/mL ethyl mathol, respectively, and the inhibitory effect was dose-dependent. Therefore, ethyl maltol has an obvious inhibitory effect on the quorum sensing of Aeromonas salmonida and can be developed as a quorum sensing inhibitor for the preservation of aquatic products.

The production process of red raspberry leaf tea from the ‘Autumn Bless’ cultivar was optimized based on the contents of soluble sugar, total phenol, and free amino acids. The bioactive substances, antioxidant activity and bacteriostatic activity of red raspberry leaves, red raspberry leaf tea and commercial green tea were compared, and gas chromatography-mass spectrometry (GC-MS) was used to compare the differences in their aroma profiles. The results showed that the optimum preparation conditions were as follows: spread-drying time 1 h, steam fixation for 45 min at 100 ℃ with spreading density of 5 g/dm2, rolling time 25 min, and hot air drying for 12 h at 50 ℃ with spreading density of 5 g/dm2. All three materials contained polyphenols, flavonoids and proanthocyanidins, and showed different antioxidant capacities. Among them, commercial green tea exhibited the strongest ferric reducing antioxidant power (FRAP). Besides, all of them showed good antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. Totally 8, 14 and 18 aroma substances were identified from red raspberry leaf, red raspberry leaf tea and commercial green tea by GC-MS, respectively. Only 2-heptanol was shared by red raspberry leaves and red raspberry leaf tea; in the former, 2-heptanol and myrylene aldehyde were the major aroma substances, while the latter contained hexaldehyde and 2-n-pentylfuran as the major aroma substances as well as some unique aroma components such as butyraldehyde and 2-ethylfuran. Commercial green tea contained more aroma substances, mainly alcohols and esters. These results provide not only theoretical references for further development and utilization of raspberry leaf resources, but also theoretical support for the entry of red raspberry leaf tea into the market.

In this study, the effect of CO2 deastringency treatment on the physicochemical properties of ‘Hiratanenashi’ persimmon fruit was analyzed. The results revealed that after treatment with CO2, soluble solid content and fruit firmness were maintained at a high level despite a slight decrease, soluble tannin content was decreased to an acceptable level for consumption, the contents of malonodialdehyde (MDA) and polyphenols and the activity of polyphenol oxidase (PPO) were significantly reduced (P < 0.05), and total flavonoid and ascorbic acid contents and the activity of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were increased significantly (P < 0.05). This suggests that reactive oxygen species (ROS)-scavenging enzymes and non-enzymatic antioxidants can effectively scavenge the oxidative stress induced by high-CO2/hypoxic atmosphere and maintain redox balance. In addition, 9 957 and 8 984 characteristic ions were identified using metabolomics in the positive and negative ion modes, respectively, with 6 817 and 4 726 of them being annotated, respectively. In the comparison with the untreated control group, a total of 55 and 11 metabolites were found to be up- and down-regulated, respectively, including 6 down-regulated flavonoids metabolites and 14 up-regulated amino acids metabolites. Together, these results study provide valuable information on the effects of CO2-deastringency treatment on persimmon fruit and will contribute to the ongoing popularization of ‘Hiratanenashi’.

Abscisic acid (ABA) accumulates in citrus peel in quite high amounts after harvest. ABA biosynthesis is through the carotenoid metabolic pathway. In order to study the changes in ABA content and the expression levels of the genes involved in ABA metabolism in mandarins after peel puffing, puffed ‘Clementine’ and ‘ponkan’ fruits stored at 18–20 ℃ for 30 days and normal ones as a control group were used as research subjects in this study. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and quantitative real-time polymerase chain reaction (qPCR) were used to analyze ABA contents, carotenoid composition and gene expression levels involved in ABA metabolism in the peel. The results showed that after storage, peel puffing indexes in ‘Clementine’ and ‘Ponkan’ were increased by 177% and 186% respectively, and peel water contents were increased by 5.9% and 14.4%, respectively. ABA contents in the puffed peel of ‘Clementine’ and ‘Ponkan’ were 795.1 and 230.5 ng/g, respectively, significantly lower than those (1 659.2 and 464.6 ng/g) in the normal peel (P < 0.05). Pearson’s correlation analysis showed that ABA contents in the peel of puffed ‘Clementine’ and ‘Ponkan’ were significantly correlated with the content of β-carotene and the expression levels of LCYB1, LCYE and AB1 (P < 0.05). After peel puffing, the expression levels of LCYB1 and LCYE, both involved in ABA synthesis, were decreased and increased, respectively, inhibiting the synthesis of β-carotene and consequently ABA; AB1 expression level, involved in ABA decomposition, was significantly increased (P < 0.05), inhibiting ABA accumulation. Taken together, the decrease in ABA content after peel puffing is related to the down-regulation of β-carotene synthesis and the acceleration of ABA decomposition, co-regulated by LCYB1, LCYE and AB1. In addition, the occurrence of peel puffing in mandarins may result from relatively delayed senescence of the peel.

The effects of four cooking methods, namely boiling, steaming, stir-frying and microwaving, on the texture, structure and pasting properties of Chinese yam tubers were investigated. The results showed that the hardness of Chinese yam tubers was decreased significantly after cooking (P < 0.05). Microwave cooking resulted in significantly high chewiness (P < 0.05), whereas the chewiness was significantly lowered by boiling and steaming (P < 0.05). After cooking, starch in yam tubers showed varying degrees of gelatinization, the crystal structure was damaged to varying degrees. Among the cooking methods, microwaving led to the lowest gelatinization degree, while steaming resulted in the lowest orderliness and crystallinity of starch granules. Different cooking methods had a significant effect on the pasting properties of yam tubers. The pasting temperature was significantly increased by microwaving (P < 0.05), but was significantly decreased by the other cooking methods (P < 0.05). In conclusion, different cooking treatments have different effects on the structure and gelatinization properties of Chinese yam tubers , which can provide a theoretical basis for Chinese yam scientific cooking.

Pre-slaughter shackling is essential for meat ducks because it can improve the slaughter efficiency. However, pre-slaughter shackling can often aggravate stress in meat ducks and affect post-harvest blood quality, which has become an urgent problem to be solved in slaughterhouses. Herein, the effect of pre-slaughter shackling stress on the gel characteristics of duck blood was investigated by measuring hematological and blood coagulation indicators. Before slaughter, 40 Cherry Valley ducks were randomly divided into two groups: one group was the control group not receiving pre-slaughter shackling, and the other was the experimental group receiving pre-slaughter shackling for 2.5 min. After slaughter, blood samples were collected and used to prepare curds for determination of stress, hematological and blood coagulation indicators as well as gel properties. The results showed that the plasma levels of corticosterone and adrenocorticotropic hormone in the experimental group were higher than those in the control group C, indicating that pre-slaughter shackling induced stress in ducks. This was accompanied by an increase in the numbers of red blood cells and platelets, the concentration of hemoglobin, hematocrit, mean corpuscular volume (MCV) and mean platelet volume (MPV), and a significant increase in the levels of prothrombin (P < 0.01) and tissue factor (P < 0.05). Pre-slaughter shackling eventually accelerated the gelation of duck blood, increased the mobility of water in the gel system, reduced the percentages of bound and free water, increased the percentage of immobilized water, and weakened the texture properties and water-holding capacity of duck blood curds. This research revealed that pre-slaughter shackling stress could affect duck blood hematology and coagulation, thereby changing its gel behavior and gel properties. This finding will provide a theoretical basis for improving the gel quality of duck blood.

This study aimed to explore the effect of different drying methods: sun drying, hot air drying, short- and medium-wave infrared drying, freeze drying and pulsed vacuum drying on the drying characteristics, color, phenolic acid contents, and antioxidant activity in vitro of rape bee pollen. The relationship between microstructure and quality changes was investigated as well. The results showed that the fastest drying rate was observed with infrared radiation drying. Sun drying took the longest time, and resulted in the severest color deterioration. Among the five drying methods, rape bee pollen subjected to pulsed vacuum drying had the highest ferric ion reducing antioxidant power (FRAP) ((1 961.11 ± 4.42) mmol/g), which was 24.78% higher than that of fresh rape bee pollen, and it also had the lowest ΔE value (0.98 ± 0.04). Besides, FRAP and the contents of chlorogenic acid, vanillic acid and sinapic acid in rape bee pollen were significantly after drying (P < 0.05), while no significant change was observed in the content of p-coumalic acid. Correlation analysis showed that the content of p-coumalic acid was significantly negatively correlated with ΔE (P < 0.05) but positively correlated with L* value (P < 0.05). Clustering analysis showed that the similarity between sun drying and four other drying methods was 0. The similarity between hot air drying and infrared radiation drying was 84.11%. The differences between these five drying methods were clearly determined by clustering analysis (CA) and principal component analysis (PCA). Collectively, pulsed vacuum drying can protect the microstructure and color of rape bee pollen at low drying temperature (45 ℃) while significantly increasing the contents of chlorogenic acid, vanillic acid and sinapic acid and antioxidant activity (P < 0.05), suggesting its great potential in drying bee pollen.

The effect of different durations (15, 20, 25 and 30 min) of ultrasound treatment at a frequency of 20 kHz and a power of 800 W on the particles size, zeta potential, surface hydrophobicity and secondary structures of goat milk proteins was evaluated. Furthermore, the effect on rheological properties and microstructure of rennet-induced goat milk gel was studied by rheological measurement and scanning electron microscopy (SEM). The results showed that ultrasonic treatments reduced the particles size and altered the secondary structures of milk proteins significantly, increasing the percentages of β-sheet and random coil and decreasing the percentages of α-helix and β-turn. The β-sheet structure showed a positive correlation (r = 0.74) with the surface hydrophobicity. Prolonged (more than 20 min) sonication resulted in a significant (P < 0.05) increase in the maximum storage modulus (G’max) when compared to unsonicated raw goat milk and pasteurized goat milk, and the rennet coagulation time decreased after 25, 30 min of ultrasonic treatment. SEM observation revealed that the gel microstructure of the sonicated samples was more interconnected. To sum up, ultrasonic treatment could effectively improve the quality of rennet-induced goat milk gel and have potential application value in industrial production.

The present investigation was performed to evaluate the effect of 1.0 kGy 60Co gamma irradiation on physicochemical characteristics (color, texture and microstructure), water migration and sensory characteristics of shiitake mushrooms (Lentinus edodes) during storage at (4 ± 1) ℃ and (80 ± 5)% relative humidity. The results indicated the L* values of irradiated and non-irradiated mushrooms were 90.06 and 90.54, respectively, which decreased to 87.77 and 80.71 after 21 days of storage, indicating that the irradiation treatment delayed browning and prevented color deterioration of fresh shiitake mushrooms. The firmness of irradiated shiitake mushrooms was significantly higher than that of the non-irradiated one. Moreover, the irradiation treatment slowed down the decomposition of the reticular hyphal structure of mushrooms. Low-field nuclear magnetic resonance (LF-NMR) analysis showed that the states of water in the non-irradiated control were very unstable and the peak area for each of the three states fluctuated greatly. The T23 peak area of free water transverse relaxation time increased slightly in the early stage of storage, then decreased sharply, the T21 peak area of bound water increased first and then decreased, and the T21 peak shifted to the right in the later stage of storage, while the peak area of transverse relaxation time T21 for bound water did not change greatly. The peak area of transverse relaxation time T22 for immobile water increased initially and decreased later for both treated and untreated samples. In conclusion, the 1.0 kGy 60Co gamma irradiation treatment improved the stability of the states of water in fresh shiitake mushrooms and delayed sensory quality deterioration, maintaining the physiological characteristics well, reducing water loss and extending the shelf life.

Previous studies have confirmed that heat treatments can reduce the viscosity of konjac glucomannan (KGM), and significantly affect the physical and chemical properties. This study aimed to investigate the effect of infrared baking temperature and time on the viscosity and microstructure of KGM. The viscosity and rheological properties of KGM hydrosols and the molecular mass of KGM were measured and KGM was analyzed by ultraviolet spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The microstructure was observed by scanning electron microscopy (SEM). The results showed that the apparent viscosity of KGM hydrosols exhibited a typical shear-thinning behavior with the increase in baking temperature and time, and the elastic modulus (G’) and loss modulus (G”) increased markedly. The apparent viscosity at a shear rate of 10 s-1 decreased by 97.18% after 30 min of baking at 150 ℃, and by 99.51% after 10 min of baking at 180 ℃. Scanning electron microscopy (SEM) confirmed that the microstructure was disrupted by baking in a time-dependent and temperature-dependent manner. However, FTIR spectroscopy showed that baking treatment did not destroy the repeating unit structure or characteristic functional groups of KGM, retaining the basic structure in spite of some glycosidic and hydrogen bonds. Baking treatment at 150 ℃ for 30 min or 180 ℃ for 10 min greatly decreased the molecular mass of KGM. Therefore, infrared baking could be an effective way to decrease the viscosity of KGM, altering its physicochemical properties to extend its application in the food and medical fields.

Recently, there has been widespread concern about peanut allergy because of the high sensitization rate to peanut and peanut-induced anaphylaxis. Ara h 1 is a major allergen in peanut that belongs to the Cupin superfamily and can trigger peanut allergies through recognizing and binding to immunoglobulin E (IgE). In this study, bioinformatics was used to analyze the amino acid composition of the linear B cell epitope on peanut allergen Ara h 1 and its correlation with the secondary and tertiary structures of the allergen. The digestion resistant peptides in the Ara h 1 sequence were analyzed by mass spectrometry (MS), and the relationship between the peptides and the predicted linear B cell epitopes was analyzed. The results showed that the linear B cell epitope on Ara h 1 was rich in hydrophilic and charged amino acids. In the secondary structure, the epitope showed no regular distribution pattern but with tuning and folding conformations. In the tertiary structure, it was mainly located in the hydrophobic interaction area between the monomers, partly buried in the trimer conformation. There was a partial overlap between the digestion resistant peptide sequence and the predicted epitope. Detecting peptides from simulated gastrointestinal digestion in vitro by MS combined with bioinformatics analysis can be used as a new method to identify the linear B cell epitope on the Cupin superfamily.

Objective: The protective effect of Bangia fusco-purpurea polysaccharide (BFP) on H2O2-induced oxidative damage in human clone colon cancer cells (Caco-2 cells) was investigated in this study. Methods: The morphology of the oxidatively damaged cells was observed and antioxidant compound contents and antioxidant enzyme activities in the cell lysates were measured. Results: BFP significantly increased the viability of Caco-2 cells damaged by H2O2 in a concentration-dependent manner, reduced the generation of intracellular reactive oxygen species (ROS), increased the activity of superoxide dismutase (SOD) and catalase (CAT) and glutathione level, inhibited the production of malondialdehyde (MDA), and repressed caspase-3 and caspase-9 activity to mitigate cell apoptosis induced by oxidative stress. Conclusion: BFP has a protective effect on H2O2-induced oxidative damage in Caco-2 cells in vitro. It can ameliorate H2O2-induced oxidative stress damage in Caco-2 cells by enhancing the activities of endogenous antioxidant enzymes, increasing the levels of non-enzymatic antioxidants, and inhibiting cell apoptosis.

Objective: To investigate the protective effects of fibrinolytic enzyme from Lyophyllum ulmarium (LUFE) on alcohol-induced liver injury in rats. Methods: Rats were randomly divided into four groups: normal control group, model group, and low- and high-dose LUFE groups. All rats except those in the normal control group were administered orally with 40% alcohol at a dose of 10 mL/kg mb body mass daily to induce liver injury. The animals in the low and high-dose LUFE groups were respectively treated with LUFE at doses of 100 and 400 mg/kg mb body mass, and those in the normal control group and the model group were given the same volume of normal saline by gavage for 28 days. The rats were sacrificed on the next day after the last administration, and the liver was dissected out to observe pathological morphological changes by hematoxylin-eosin staining and blood was withdrawn for detection of the levels of alanine transaminase (ALT) activity, aspartate aminotransferase (AST) activity, albumin (Alb) concentration, γ-glutamyltranspeptidase (γ-GT) activity, alkaline phosphatase (ALP) activity, total bilirubin (T-BIL) concentration, triglyceride (TG) concentration, total cholesterol (T-CHO) concentration, low density lipoprotein cholesterol (LDL-C) concentration and high density lipoprotein cholesterol (HDL-C) concentration. The expression level of inhibitory kappa B-alpha (I-κBα) protein and the phosphorylation level of nuclear factor (NF)-κB p65 were determined using Western blot assay. Results: LUFE alleviated liver the pathological damage, and inhibited the alcohol-induced increase in AST, ALT, γ-GT and ALP activities as well as TG, T-CHO, LDL-C and T-BIL levels and the alcohol-induced decrease in Alb level in the serum, with a significant inhibitory effect being observed at the high dose (P < 0.05 or 0.01). The Western blot results showed that LUFE increased the expression level of I-κBα protein and decreased the phosphorylation level of NF-κB p65 protein significantly at the dose (P < 0.05 or 0.01). Conclusion: LUFE has a protective effect on alcohol-induced liver injury in rats, and the underlying mechanism may be related to its antioxidant and anti-inflammatory effects.

To study the anticoagulant effect of garlic oil, garlic oil was extracted from garlic bulbs in this study and its major chemical components were allyl sulfide (DAS), diallyl disulfide (DADS) and diallyl trisulfide (DATS) as identified by gas chromatography-mass spectrometry (GC-MS). Experiments in vitro showed that garlic oil, DAS, DADS and DATS partially inhibited thrombin activity, and the inhibitory effect followed the decreasing order: DATS > garlic oil > DADS > DAS. Enzymatic kinetic analysis was carried out using the Lineweaver-Burk double reciprocal plotting method, which showed that garlic oil and its three components inhibited thrombin activity in both competitive and non-competitive mode. Molecular fluorescence analysis revealed that each inhibitor could interact with chromophores in thrombin, resulting in fluorescence quenching. Two-dimensional molecular docking results revealed that DATS could form hydrogen bonds with Asp189, Gly219 and Ala190 in the active site of thrombin and form hydrophobic interactions with Gly216, Ser195 and Trp215 for competitive inhibition; and also form hydrophobic interactions with Gly226, Asp221A, Tyr225, Glu217, Cys191 and Val213 in non-active sites for non-competitive inhibition. Garlic oil and its components exerted their anticoagulant effect by positively four blood coagulation parameters in rats, which decreased in the order of DATS > DADS > DAS > garlic oil. However, they could only weakly enhance antioxidant capacity in rats. Hence, their anticoagulant effect was not correlated with their antioxidant potential.

Prebiotics can be used in fermented dairy products for improved sensory and textural properties, as well as enhanced health beneficial effects. In this study, the immunomodulatory effects of yogurt fortified with konjac mannanoligosaccharides (KMOS), a new type of functional oligosaccharides, were investigated in immunosuppressed BALB/C mice induced by cyclophosphamide (CTX). The results suggested that addition of KMOS enhanced the ability of yogurt to attenuate CTX-induced immunosuppression. Yogurt added with 0.5% (based on the weight of fresh milk) KMOS significantly improved the basic physiological state, the phagocytic activity of peritoneal macrophages, the proliferation rate of splenic lymphocytes, serum immunoglobulin concentration, and the release of inflammatory cytokines from peritoneal macrophages. Moreover, KMOS-fortified yogurt increased the relative abundance of non-dominant flora and the quantity of intestinal probiotics, and simultaneously suppressed the proliferation of Clostridium in the colon of immunosuppressed mice, thereby modulating the composition and structure of intestinal microbiota. These findings will provide useful information for the development of novel fermented milk products fortified with prebiotic oligosaccharides.

The aim of this study was to investigate the effect of microencapsulated cinnamon oil on antioxidant capacity and gut microbiota in mice. Six-week-old male C57 BL/6 mice were randomly divided into control, free cinnamon oil, and microcapsuled cinnamon oil groups (100 mg/(kg mb·d)). Antioxidant capacity in liver, duodenum, and colon tissues were measured after 4 weeks of continuous gavage. The 16S rDNA gene in mouse feces was detected by Illumina MiSeq high-throughput sequencing to explore the changes of gut microbiota, and the contents of short chain fatty acids in mouse feces were detected by gas chromatography-mass spectrometry. The results showed that compared with free cinnamon oil, the microcapsules could significantly increase the total antioxidant capacity in the liver, and significantly decrease the MDA content in the duodenum (P < 0.05). At the phylum level, the increase in the abundance of Bacteroidetes and the decrease in the abundance of Fimicutes in mouse feces after supplementation of cinnamon oil microcapsules were more pronounced than after supplement of cinnamon oil. At the genus level, microcapsulated cinnamon oil supplementation significantly increased the abundance of beneficial bacteria such as Bacteroides, Lactobacillus, Family_XIII_AD3011_group, unclassified_f__Lachnospiraceae, Blautia, and Ruminiclostridium, and significantly inhibited the abundance of opportunistic pathogenic bacteria including norank_f__Muribaculacea, Ruminococcaceae_UCG-014, and Gordonibacter (P < 0.05). The contents of propionic acid, butyric acid, and total acid in the feces of mice given the microcapsules were significantly increased (P < 0.05). To sum up, cinnamon oil microcapsules can continuously release bioactive ingredients in a sustained manner to inhibit opportunistic pathogenic bacteria and promote the proliferation of beneficial microflora and the production of short-chain fatty acids in the gut, thereby having a more obvious regulatory effect on the gut microbiota structure and redox state.

Sucralose is currently one of the most widely used sugar substitutes. Its safety assessment is still limited at the toxic level, so it is impossible to determine the effect of sucralose on human health. In this study, potential changes in the intestinal microecology of BALB/C mice after the ingestion of sucralose were investigated as well as its impact on the diversity and composition of intestinal flora. Further, we inferred whether the intestinal microecological changes can cause damage to the immune barrier and consequently chronic diseases. In this experiment, BALB/C male mice at the age of 4 weeks were randomly divided into blank control, low-, medium- and high-dose sucralose groups (15, 25 and 50 mg/(kg mb·d), respectively). After administration for 6 weeks, blood samples were collected from the eyeballs and all mice were sacrificed to measure the structure of intestinal flora in mice (by 16S rDNA high-throughput sequencing), spleen index, thymus index, contents of the inflammatory cytokine interleukin (IL)-1β, tumor necrosis factor (TNF)-α, secretory immunoglobulin A (SIgA) and intestinal tissue pathological changes. The results showed that compared with the blank group, the intestinal flora diversity of mice was significantly reduced after ingestion of sucralose (P < 0.05). At the phylum level, the abundance of Actinomycetes and Proteobacteria increased significantly (P < 0.05). At the family level, the abundance of Clostridiaceae and Ritiaceae was significantly reduced (P < 0.05). At the level of genus, the abundance of Bacteroidetes was significantly increased (P < 0.05). The immune organ index and SIgA level in mice were significantly reduced (P < 0.05), and intestinal epithelial lesions were observed. These results showed that sucralose could lead to structural changes of intestinal flora in mice, reduced intestinal flora diversity, and an imbalance in intestinal homeostasis, thus reducing both local and systemic immune response and increasing the risk of various diseases.

Objective: To study the anti-alcoholic and hepatoprotective effects of polyphenols from the fruit of Rosa roxburghii Tratt. (RRTP) in rats with acute alcoholism (AAH). Methods: Rats were randomly assigned to six groups: normal, model, positive control (Haiwangjinzun, a commercial dietary supplement with hepatoprotective potency; 100 mg/(kg mb·d)), and low-, medium- and high-dose RRTP (50, 100 and 200 mg/(kg mb·d)). After oral administration for 30 days, all rats except those in the normal group were administered by gavage with Chinese Baijiu with 56% (V/V) alcohol at a dose of 15 mL/kg mb to establish an AAH model. Instead, physiological saline was given to the normal group. At 30, 60, 90 and 120 min after administration of Baijiu, blood was collected from the tail vein to detect its alcohol concentration. At 12 h post-administration, blood and liver samples were collected for the detection of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and triglyceride (TG) levels in serum as well as the activities of ethanol metabolism-related enzymes and antioxidant enzymes in liver. Hematoxylin-eosin staining was performed to observe pathological changes of liver tissues. The?relative?mRNA?expression?levels?of?nuclear factor erythroid-2 related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were?measured by?real-time fluorescent quantitative polymerase chain reaction (PCR). Results: The levels of alcohol, ALT, AST and TG in serum and the level of malondialdehyde (MDA) in liver were decreased in the RRTP treatment groups when compared with the model group, while the activities of alcohol dehydrogenase, acetaldehyde dehydrogenase, superoxide dismutase, catalase and glutathione peroxidase and the content of glutathione were increased. Moreover, RRTP upregulated the relative mRNA expression levels of Nrf2 and HO-1 and ameliorated?hepatic pathological changes. Conclusion: In AAH rats, RRTP exhibits anti-alcoholic and hepatoprotective effects, and the underlying mechanism may be related to accelerating alcohol metabolism and enhancing antioxidant function.

Objective: To investigate the effect of a polysaccharide isolated from sweet corncob (designated SCP-80-I) on glucose metabolism in insulin resistant (IR) HepG2 cells. Methods: The optimal conditions for inducing IR in HepG2 cells were established and applied. The IR cells were incubated for 24 h in the presence of different concentrations of SCP-80-I (50, 100, 200 and 400 μg/mL) to evaluate the effect of the polysaccharide on glucose uptake as well as assess the cytotoxicity by methyl thiazolyl tetrazolium (MTT) assay. Biomarkers of oxidative stress, including superoxide dismutase (SOD) activity, malondialdehyde (MDA) and reactive oxygen species (ROS) levels, were measured. In addition, intracellular glycogen accumulation and the activities of rate-limiting enzymes for glycolysis (hexokinase, HK; pyruvate kinase, PK) were determined. Results: Treatment with 1 × 10-6 mol/L insulin for 24 hours was the optimal condition for the formation of IR HepG2 cells. SCP-80-I significantly increased glucose uptake in IR HepG2 cells (P < 0.01), and the cell viability increased first and then decreased with increasing SCP-80-I concentration. The contents of MDA and ROS decreased, and the activities of SOD, HK and PK and intracellular glycogen contents increased in the SCP-80-I intervention group (200 μg/mL) compared with the model control group (P < 0.01). Conclusion: The hypoglycemic effect of SCP-80-I may be related to the alleviation of oxidative stress-induced liver injury and the improvement of glucose metabolism in IR liver cells.

Objective: The effect of the natural antioxidant astaxanthin on the function of the human body was studied by using nuclear magnetic resonance (NMR)-based metabonomics from the aspects of metabolites and metabolic network regulation. Methods: Totally 16 adult males were selected and equally and randomly divided into a control group and an experimental group. The experimental group took astaxanthin at a moderate dose of 12 mg/d for 28 days and the control group took the same dose of a placebo (starch capsule) for 28 days. On the morning of the first day, fasting fingertip blood samples were collected from all the subjects to determine antioxidant capacity and blood lactate values. Blood samples were taken again on the morning of the 29th day, and 5 mL of blood was taken from the elbow vein, followed by three cycles of bicycling for 30 s each at 3 min intervals with a load of 0.075 kg/kg mb. Blood samples were taken for the third time immediately after exercise. A free oxygen radical analyzer was used to determine blood lactate values and antioxidant capacity and nuclear magnetic resonance (NMR) spectroscopy was used to fingerprint vein blood samples. The data extracted from the spectra were processed and analyzed with MestReNova, SIMCA-P, and SPSS software. Results: In the quiet state, 15 potential differential metabolites (DMs) were identified between the two groups, and a total of three metabolic pathways were found to have a great influence on the DMs. The DMs creatine, betaine (Bet), and glycine were involved in the glycine, serine and threonine metabolism pathways, acetoacetic acid and β-hydroxybutyric acid were involved in the ketone body anabolism and catabolism pathways, and alanine, glutamic acid and glutamine were involved in the alanine, aspartic acid and glutamic acid metabolism pathways. Antioxidant capacity was significantly higher in the experimental group than in the control group (P < 0.05), while the opposite was observed for blood lactate values (P < 0.05). Immediately after exercise, three potential DMs were found, and only the alanine, aspartate and glutamic acid metabolic pathways, in which glutamine was involved, were observed to have a great influence on them. After exercise, antioxidant capacity significantly decreased in both groups (P < 0.05), but it was significantly higher in the experimental group than in the control group (P < 0.05); blood lactate values rose significantly after exercise (P < 0.01), and significantly dropped in the experimental group compared with the control group (P < 0.05). Conclusion: Astaxanthin supplementation can cause marked changes in blood metabolites both before and after acute high-intensity exercise, which are involved in amino acid metabolism and lipid metabolism pathways in the body, thereby improving the body’s antioxidant capacity and exercise capacity.

To explore the mechanism by which hawthorn proanthocyanidins (HPC) combined with vitamin C (VC) alleviates liver oxidative stress in insulin resistance (IR) rats through the Wnt/β-catenin signaling pathway. To create an animal model of IR, 80 Wistar male rats were given a high-fat diet. The changes in body mass, fasting blood glucose and serum insulin concentration were measured before and after the establishment of the model. Colorimetry was used to test the activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline?phosphatase (ALP). A total of 50 IR rats were randomly selected and divided into model, HPC (56 μg/mL), VC (180 μg/mL), HPC (56 μg/mL) + VC (180 μg/mL) and metformin (2 μg/mL)?groups, each consisting of 10 animals. Blood glucose and insulin levels, as well as the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione (GSH) and the content of malondialdehyde (MDA) in liver homogenate were determined after 12 weeks of continuous administration. The mRNA expression of Wnt1, Axin, glycogen synthasc kinase-3β (GSK-3β), adenomatous polyposis coli protein (APC), β-catenin and peroxisome proliferators-activated receptors γ (PPARγ) were tested by real-time polymerase chain reaction (PCR). The expression of Wnt1, β-catenin and PPARγ proteins was tested by Western blotting. The binding capacity of Wnt1 to dishevelled (Dsh) proteins was evaluated by fluorescence resonance energy transfer (FRET) assay. IR was successfully induced in 54 (67.5%) of the 80 rats. The body mass, fasting blood glucose, serum insulin, and ALT, AST and ALP activities of the model group were significantly higher than those of the control group (P < 0.01). Compared with the model group, the three intervention groups exhibited significant differences in all the studied parameters in the liver homogenate (P < 0.01), and the effect of HPC + VC was better than that of HPC alone (P < 0.05). In the HPC + VC group, the relative mRNA expression of Wnt1 and β-catenin was decreased significantly (P < 0.01), while the relative mRNA expression of Axin, GSK-3β, APC and PPARγ were significantly increased (P < 0.01). Moreover, the expression of Wnt1 and β-catenin proteins were decreased significantly (P < 0.01), whilst the protein expression of PPARγ was increased significantly (P < 0.01). The FRET signal for the HPC + VC group was obviously weakened, indicating that the binding force between Wnt1 and Dsh was significantly weakened over time, and the formation of heterodimers was reduced significantly (P < 0.05). The results from this study showed that the combined application of HPC with VC could ameliorate liver oxidative stress in rats with insulin resistance through the Wnt/β-catenin signaling pathway.

The objective of this study was to evaluate the effect of Bacillus amyloliquefaciens NCPSJ7 against green molds on postharvest navel oranges and the underlying mechanism. The antifungal effect of cultures of NCPSJ7 was determined by the Oxford cup method and disease incidence, disease resistance-related enzymes activities and antioxidant capacity in oranges artificially inoculated, treated with the fermentation broth and inoculated with Penicillium digitatum were determined. The results indicated that a high NCPSJ7 concentration significantly inhibited the growth of P. digitatum on navel oranges in vitro (P < 0.05). The diameter of inhibition zone of 1 × 108 CFU/mL NCPSJ7 was 3.50 cm, which was twice higher than that observed at 1 × 105 CFU/mL (1.75 cm). In vivo tests showed that the antagonist NCPSJ7 could colonize rapidly the wounds in oranges within 24 h after inoculation for space and nutrient competition to inhibit the growth of P. digitatum. Moreover, compared with single P. digitatum and the control group, NCPSJ7 combined with P. digitatum significantly decreased disease incidence and lesion diameter, increased the activities of polyphenol oxidase (PPO), peroxidase (POD), chitinase (CHI) and β-1,3 glucanase (GLU), and promoted the increase in reducing power and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity as well as total phenol and total flavonoid contents. These observations indicated that B. amyloliquefaciens NCPSJ7 could be used as a biocontrol agent against P. digitatum on postharvest oranges.

In order to explore the mechanism of postmortem energy metabolism in Qinchuan cattle muscle during cold storage and its effect on meat quality, this study investigated the proteomic changes in the Longissimus dorsi muscle of Qinchuan cattle during different storage periods (0, 4 and 8 days) using 4D label-free quantitative (4D-LFQ) proteomics, and high performance liquid chromatography (HPLC) was used to detect the changes of energy substances. The results showed that ATP synthase subunit δ and ATP synthase subunit γ, both related to energy metabolism, were up-regulated by 1.516 (P = 0.017), and 1.579 times (P = 0.037), respectively on day 8 compared with those on day 0, NADH dehydrogenase [ubiquinone] 1β subunit 5 was down-regulated by 0.497 times (P = 0.023) on day 8 compared with that on day 4 and succinate CoA linker [ADP formation] subunit β was down-regulated by 0.762 times (P = 0.000 7) on day 8 compared with that on day 0, NADH dehydrogenase [ubiquinone] 1 α subunit 6 was up-regulated by 1.467 times (P = 0.026) on day 4 compared with that on day 0, and cytochrome c oxidase subunit 7A1 was down-regulated by 0.692 times (P = 0.024) on day 8 compared with that on day 4. The changes in the expression abundance of the above six proteins could affect the synthesis and transportation of ATP and other energy substances through mitochondrial electron transport, respiratory chain complex I assembly, ATP biosynthesis and other processes, thereby resulting in insufficient supply of energy materials in muscle cells during cold storage, and consequently affecting the change of meat quality. ATP content was reduced by 95.07% after 8 days of storage, affecting myoglobin transformation, leading to the occurrence of browning, promoting anaerobic glycolysis to produce energy and lactic acid, causing muscle acidification, and leading to cell apoptosis and finally myofibrillar protein hydrolysis to promote muscle tenderness changes.

In order to study the effects of different temperatures on the quality characteristics of prepared chicken steak during low-temperature storage, chicken samples were stored at 4, ?2 or ?18 ℃ and evaluated for total viable count, color, water-holding capacity and texture characteristics as well as observed by scanning electron microscopy (SEM). The shelf-life of prepared chicken steak stored at ?2 ℃ was about 12 days compared to only about four days at 4 ℃. The water-holding capacity and textural properties were best maintained at ?2 ℃. Moreover, the results from SEM suggested that the microstructure was less damaged at ?2 ℃ compared to the other two storage temperatures. Although the shelf-life of frozen chicken steak was much longer (over 90 days), the water-holding capacity, texture and microstructure deteriorated faster. In contrast, storage at ?2 ℃ could prolong the shelf life while maintaining the quality characteristics of prepared chicken steak well. This study provides strong evidence that prepared meat products should be stored at ?2 ℃.

In order to explore the change in the microenvironment around kiwifruits subjected to three different typical E-commerce packaging treatments during transportation and its influence on subsequent storage quality, kiwifruits were packaged in cartons or cartons lined with polystyrene foam boxes or polyethylene foam cotton material (placed singly) and transported after precooling. The changes in the temperature and humidity in packaging boxes and in vibration intensity were recorded during transportation. After the completion of transportation, the fruit were transferred into perforated plastic boxes and stored at (4.0 ± 0.5) ℃, and the quality changes were measured on a regular basis during storage. The results showed that both lining materials could effectively delay the temperature rise and keep the humidity in the cartons. The vibration of kiwifruits during transportation mainly resulted from the acceleration, deceleration and turbulence of the vehicle. Generally, the carton lined with polyethylene foamed cotton material was the most effective in reducing the vibration. The turbulence and temperature change during transportation were important factor influencing the quality of kiwifruits. Kiwifruits packaged in the cartons lined with polyethylene foam cotton material showed the slowest increase in percentage mass loss, maintained the highest hardness and the brightest color as well as high contents of total soluble solids (TSS) and total acid during subsequent storage, generally exhibiting the best storage quality. The storage quality of kiwifruits packaged in cartons lined with polystyrene foam boxes was slightly inferior, and the storage quality of kiwifruits packaged in cartons was the worst. Based on the change in transportation microenvironment and the change in quality during shelf life, cartons lined with polystyrene foam box and those lined with polyethylene foamed cotton material are suitable for E-commerce transportation packaging of kiwifruits.

In order to study the effect of postharvest treatment with abscisic acid (ABA) on apple ripening and the expression of genes related to ethylene biosynthesis and ethylene signal transduction, ‘Granny Smith’ apple fruit were treated with ABA or sterile water as a control and stored at 20 ℃. Fruit firmness, titritable acid content, cellulase activity, pectin methylesterase (PME) activity, chlorophyll content, endogenous ABA content, ethylene production rate, and the expression of genes related to ethylene biosynthesis (ACO1, ACO2, ACS1 and ACS3) and ethylene signal transduction (ERS1, ERS2, ETR2, ERF3, ERF4 and ERF5) were measured. It was found that relative to the control group, ABA decreased fruit firmness and titratable acid content, increased cellulase and PME activities, and promoted the decrease in the contents of chlorophyll a, chlorophyll b and total chlorophyll during storage. Quantitative polymerase chain reaction (q-PCR) results showed that ABA treatment significantly increased the expression of ethylene biosynthesis-related genes (P < 0.05). The expression levels of ERS2, ETR2 and ERF3/4/5 significantly increased during apple postharvest ripening, and they were significantly higher in ABA-treated fruit than in the control group (P < 0.05). Taken together, exogenous ABA treatment promoted the biosynthesis of endogenous ABA in apple fruit, and increased the expression of genes involved in ethylene biosynthesis and signal transduction, thus accelerating the postharvest ripening process.

Nanofibers with core-shell structure and fiber membrane based on sacha inchi oil/polyvinyl alcohol (PVA) emulsion were prepared by emulsion electrospinning. The conductivity and viscosity of the emulsion were measured by conductivity meter and viscometer and the morphology and structure of the nanofiber membrane were observed by scanning electron microscopy (SEM) and transmittance electron microscopy (TEM). The emulsion composition and electrospinning parameters were optimized. Thermal analysis and Fourier transform infrared spectroscopy (FTIR) were used to explore the interactions between the components of the fiber membrane. The surface hydrophilicity of the fiber membrane was determined by contact angle measurement and the mechanical strength was measured with a tensile strength tester. The results showed that the optimal emulsion composition was determined as follows: PVA concentration, 14% (m/m); and mass ratio of sacha inchi oil to PVA to Tween-80, 5:14:1, and the optimal spinning conditions were spinning voltage 25 kV, receiving distance 18 cm, and feeding rate 1.0 mL/h. Under these conditions, nanofibers with average diameter of 570 nm were obtained exhibiting good morphology and uniform distribution. The results of FTIR and thermal analysis showed that the fiber film successfully encapsulated sacha inchi oil and showed good thermal stability at temperatures below 330 ℃. The fiber film had good hydrophilicity. The results of mechanical properties showed that the addition of the oil could improve the tensile properties of the nanofiber films.

The effect of 0.05 g/L kojic acid treatment on the browning of the stem cut section of baby cabbages and its mechanism were studied. The stem cut section was dipped in 0.05 g/L kojic acid or ultrapure water as a control for 1 min and stored at 20 ℃ and 90% relative humidity for up to five days. Samples were taken every day to measure the appearance, respiration intensity, ethylene release rate, total phenolic content, flavonoid content and the activity of browning-related enzymes. The results showed that kojic acid treatment could effectively maintain the sensory quality of baby cabbages, inhibit the browning of the stem cut section, reduce the mass loss percentage and the content of malondialdehyde (MDA), and increase the content of flavonoids and total phenols. Moreover, it inhibited the activity of peroxidase (POD) and polyphenol oxidase (PPO) (by 29.7% and 28.5% relative to the untreated control group on day 5, respectively), but enhanced the activity of phenylalanine ammonia lyase (PAL) and catalase (CAT) (by 1.0% and 12.4% in contrast to the control group on day 5, respectively). Consequently, we concluded that kojic acid treatment could effectively inhibit the browning of the stem cut section of baby cabbages, maintaining the commerciality and nutritional quality and extending the shelf life.

2’-Fucosyllactose (2’-FL) is the most abundant human milk oligosaccharides (about 31%), which plays an important role in the growth and development of infants. At the end of 2019, 2’-FL was approved as a new food ingredient for marketing in the European Union. Therefore, how to produce 2’-FL efficiently and safely has become a research hotspot nowadays. Compared with other methods for the synthesis of 2’-FL, using a microbial cell factory has the advantages of low cost, safety and quickness, which is a feasible method for the mass production of 2’-FL. This brief review focuses on the activity of the key enzymes involved in the biosynthesis of 2’-FL, the secretion and accumulation of products, the catabolism of substrates and intermediate metabolites, and the regeneration of cofactors during the process, and it also discussed future trends in this field.

Pyrrolizidine alkaloids (PAs) are a class of plantsecondary metabolites, and unsaturated PAs and most pyrrolizidine alkaloid N-oxides (PANOs) have multiple toxic effects. PAs have been found widely in various kinds of tea samples, and have become one of the major contaminants hindering China’s tea export. This paper reviews the development of sample pretreatment methods for chromatographic-mass spectrometric detection of PAs in tea, and presents an outlook on future trends. Next, it summarizes the levels of PAs pollution in tea from different countries, and analyzes the types of PAs in tea, the occurrance of PAs in different teas, and the differences in PAs between tea and other foods or agricultural products. Finally, discusses the health risk of PAs in tea. Studies to monitor PAs pollution levels in tea and assess the health risk of PAs in tea are currently lacking in China. Therefore, it is urgent to clarify the source of PAs pollution in tea and assess the health risk of PAs in tea.

Mycotoxins are widely distributed, heavily polluting, and difficult to prevent and control. During the whole process from farm to table, agricultural products are easily polluted by mycotoxins, posing serious threats to human and animal health as well as ecological and environmental safety. According to statistics, more than 75% of mycotoxin contamination in agricultural products is caused by a mixture of multiple mycotoxins. Therefore, establishing a highly sensitive and high-throughput mycotoxin detection technology is a major challenge in the field of food safety testing. This article summarizes the progress in the multiple detection of mycotoxins in the past five years, including high performance liquid chromatography-tandem mass spectrometry, immunochromatography, chemical colorimetry, electrochemistry, chemiluminescence and fluorescence spectroscopy. The applications of these methods in the multiple detection of mycotoxins and the problems to be solved are analyzed, and prospects are discussed.

From a physicochemical perspective, the internal factors causing meat quality changes mainly include fat and protein oxidation. Protein oxidation is a research hotspot recently. This review firstly summarizes the mechanism of protein oxidation in meat and protein covalent modification, the characterization of protein oxidation (the types of oxidative modification of proteins including carbonylation, sulfhydrylation and cross-linking). Then, the effect of protein oxidation on the eating quality of meat is deciphered from both microscopic and macroscopic perspectives. Finally, we propose some solutions to the problems in the field of protein oxidation that have not been fully resolved. We hope that this review can provide a reference for exploring the mechanism of muscle protein oxidation and its effect on the eating quality of meat.

A growing body of research suggests that intestinal flora can affect the occurrence and development of food allergies by modifying food allergens and regulating intestinal mucosal immune balance and barrier function. This article reviews the effects of dietary structures and components on intestinal microflora, discusses the relationships between the changes of intestinal microflora and intestinal epithelial immune response and reveals the mechanism of action by which dietary components affect food allergy by specifically regulating intestinal microorganisms. Understanding the regulatory effect of dietary components on intestinal microorganisms is of great significance to clarify the role of dietary habits and structure in the occurrence and development of food allergies and more broadly to provide scientific dietary guidance for people with food allergies.

Processing properties and nutritional characteristics of maize flour prepared by different techniques and the sensory and texture quality of maize flour-based foods are reviewed herein. With regard to the processing characteristics, this paper focuses on the effects of preparation methods on hydration characteristics (including water-binding capacity and water absorption index) and gelatinization characteristics. In respect of the nutritional characteristics, this paper presents a comprehensive analysis of the correlation between energy substances (starch, fat and protein) of maize flour and preparation techniques, and summarizes the effects of preparation techniques on the antioxidant and digestive properties of maize flour. Moreover, we review the effects of different wheat flour processing techniques on the sensory and texture quality of steamed, boiled or baked maize flour-based foods.

Glycogen is a naturally occurring nanometer-sized dendrimer-like glucan, whose functional derivatives can be obtained through its surface and interior modification by chemical or physical methods. However, the application of glycogen as a functional component or nanocarrier in the food, biological and medical fields is restricted because it is synthesized in a complex environment, raising strict requirements for its in vitro extraction. Glycogen-like α-glucan, enzymatically synthesized in vitro, can be used as an ideal industrial substitute for glycogen due to its similar structure and properties to glycogen. This article reviews four methods for in vitro enzymatic synthesis glycogen-like α-glucan and compares the structures and physicochemical properties of glycogen-like α-glucan obtained by these methods. In addition, the possibility of controlling the fine structure of glycogen-like α-glucan and the future prospects for its application are discussed. This review is expected to provide a reference for the application of glycogen-like α-glucan in foods, medicine and cosmetics.

The biofilm of foodborne microorganisms is a community that is spatially organized and attaches to solid surfaces. Its attachment to biotic or abiotic surfaces in the food industry environment renders resistance to disinfectants and antibacterial agents, making it difficult to control biofilm formation. This phenomenon is considered a cause of food processing equipment damage, increased energy consumption and costs, food quality deterioration and foodborne diseases, bringing great challenges to the food industry. It has been found that quorum sensing plays a paramount role in biofilm formation, which can be controlled by blocking the quorum sensing system. Therefore, quorum sensing inhibitors can be used as a new strategy to control biofilm formation and possess great potential for application in the food industry. In the present article, the biofilm formation of foodborne microorganisms, quorum sensing system and its regulation on the biofilm formation are reviewed. Meanwhile, the regulation mechanism and classification of quorum sensing inhibitors are discussed. We hope that this review can provide useful information for regulating the biofilm formation of foodborne microorganisms through quorum sensing inhibitors.

Listeria monocytogenes (L. monocytogenes) often encounters environmental stresses, such as acid stress, heat stress, cold stress, dryness and osmotic stress, and cross protection during food processing, and can respond to these stresses. The resistance to environmental stress of L. monocytogenes can be significantly enhanced after exposure to sub-lethal environmental stress, which brings great risks to food safety. The acid stress response mechanism of L. monocytogenes involves the F0F1-ATPase, glutamate decarboxylase and arginine deiminase systems and heat shock proteins, cold shock proteins and compatible solutes play important roles in the response of L. monocytogenes to heat stress, cold stress, dryness and osmotic stress. From the above aspects, this review describes the current status of research on the environmental stress response and underlying mechanism in L. monocytogenes and presents potential future research directions. The information gathered in this article will provide support for further research of stress response in L. monocytogenes during food processing and will help prevent and control this pathogenic bacterium.

The determination of foodborne pathogen concentration is an important prerequisite for quantitative microbial risk assessment (QMRA). The existence of censored data readily causes bias in the estimation of the contamination levels of pathogens in foods. The analysis of censored data has gradually become an important part of the quantitative modeling of foodborne pathogens. This article presents a comprehensive review of recent related studies conducted in China and across the world, introduces readers to the classification of censored data in the detection of foodborne pathogen contamination and compares four commonly used methods for censored data analysis, namely substitution, parameter estimation, non-parametric estimation method and multiple imputation. This article gives a brief overview of the application of pathogen contamination datasets with different characteristics and related statistical methods in the estimation of foodborne pathogen contamination levels. Finally, it discusses the problems currently existing in the estimation of foodborne pathogen contamination levels. While great efforts should be made to reduce the uncertainty of estimation results, the variability of detection data should not be ignored either. This review concludes with an outlook on risk monitoring, risk assessment, and risk communication in the future.

Acrylamide (AM) is a toxic by-product produced during the Maillard reaction (MR) in carbohydrate-rich foods. It is neurotoxic, immunotoxic and genotoxic to humans, and also has potential carcinogenicity. Therefore, it is of paramount importance to detect and control the AM content in foods. In view of the current progress in AM research, this article elaborates on a variety of AM inhibition strategies for three major stages of the production of processed foods, namely agricultural production, pretreatment and processing, and systematically summarizes the inhibitory mechanisms, which will provide useful information for inhibiting the formation of AM in foods.

Undenatured type II collagen is a type II collagen that can retain the triple helix structure after extraction, and it has great potential in the prevention and treatment of osteoarthritis and rheumatoid arthritis. Type II collagen is widely present in animal cartilage tissues and is tightly combined with proteoglycans. This article introduces readers to the function and structure of undenatured type II collagen, and reviews the methods for the extraction, and qualitative and quantitative characterization of undenatured type II collagen and the current status of its application in the food industry, with the aim of providing references for further processing and comprehensive utilization of undenatured type II collagen.

Foods rich in carbohydrates, proteins and lipids will undergo an intense Maillard reaction during thermal processing, generating a large amount of Maillard reaction products (MRPs) including low-molecular-mass compounds and melanoids, which have a variety of biological activities, as well as advanced glycation end products and acrylamide as potential health risk factors, which can accelerate the aging process or cause chronic degenerative diseases. This review presents the biological activities of MRPs including antioxidant, antibacterial, and anti-inflammatory activities, discusses the mechanism by which harmful compounds produced during Maillard reaction such as advanced glycation end products and acrylamide damage the human body, and proposes some preventive countermeasures. We expect that this review will provide a scientific reference for further research on Maillard reaction.

With the rapid social and economic development in China, the life style and disease spectra of people are constantly changing, and unhealthy life styles such as smoking, excessive drinking, physical inactivity and unreasonable diet and related chronic diseases are prevalent, leading to growing interest in and demand for dietary supplements. The unique nutritional and physiological functions of functional polypeptides and their important roles in the regulation of biological metabolism have been gradually discovered. More notably, plant-derived polypeptides have attracted significant attention from researchers around the world because of their natural availability and having no toxic or side effects. In view of the recent advances in functional peptides in the fields of food and medicine, this article reviews the preparation methods for plant-derived functional peptides, their physiological functions and prospects for application in functional foods, which will lay a theoretical foundation for the development and application of plant-derived functional polypeptides.