Abstract:The protective effects of total saponins from Panax japonicus (TSPJ) on non-alcoholic fatty liver disease (NAFLD) in mice were investigated. A mouse model of NAFLD was established by feeding a high-fat, high-fructose diet, with simultaneous gavage administration of TSPJ (50 mg/kg and 100 mg/kg) to the TSPJ group for 3 weeks. Serum- and liver-related indicators were monitored; histopathologic changes in liver were observed using hematoxylin-eosin (HE) and oil red O staining. Real-time polymerase chain reaction (RT-PCR) and western blotting were utilized for the detection of transcriptional levels of miRNA and related genes in liver tissue and the expression level of peroxisome proliferator-activated receptor (PPAR) α, respectively. The levels of serum alanine aminotransferase (ALT) and liver triglyceride (TG) in the model group were higher than those in the normal group. HE staining and oil red O staining showed fatty degeneration and fat deposition in the liver tissue, suggesting that a successful NAFLD model had been established. The results of RT-PCR and western blot analysis revealed that the expression levels of microRNA (miR)-34a, sterol regulatory element binding protein (SREBP)-1c, and fatty acid synthase (FASN) were significantly increased. Compared with the fatty liver group, the TSPJ treatment group showed significantly improved histopathologic changes in liver, reduced fat deposition, and reduced ALT levels. Therefore, intervention of the total saponins of Panax japonicus on fatty liver in mice was realized by blocking miR-34a, targeting PPARα signaling pathways.

Abstract:The mouse model was used to study the protective effect of water extracts of Orychophragmus violaceus seeds on alcohol-induced acute liver damage. Male ICR (Institute for Cancer Research) mice were randomly divided into six groups: normal group, model group, low-dose water extract group (125 mg/kg), medium-dose water extract group (250 mg/kg), high-dose water extract group (500 mg/kg), and bifendate (150 mg/kg) positive control group. All groups were administered the respective extracts or drug continuously for four days, except for the normal and model groups. Then, alcohol-induced acute liver injury was established in the model and experimental groups by giving each mouse 12 mL/kg 56° Red Star Erguotou at 1 h after the last extract/drug administration. The animals in the normal group were given an equal volume of distilled water instead. The mice were sacrificed after 16 h, and the activities of several key enzymes (the alanine transaminase (ALT), aspartate transaminase (AST), triglyceride (TG) and those in the liver tissue (superoxide dismutase (SOD), alcohol dehydrogenase (ADH), glutathione peroxidase (GSH-Px), and glutathione (GSH) ), were determined. The liver organ index was calculated, and hematoxylin and eosin staining was used to observe the pathological changes in the liver tissue. The seed water extracts could significantly reduce the serum ALT and AST activities and TG level (p<0.05 or p<0.01), and suppress liver steatosis in the mice with alcoholic liver injury, relative to the results in the model mice. Meanwhile, the activities of SOD, ADH, GSH-Px, and GSH in the liver tissue homogenate supernatant were significantly increased in the low- and medium-dose groups (p<0.05, p<0.01). In conclusion, the water extract of Orychophragmus violaceus seeds had a significant protective effect on acute alcoholic liver injury in mice.

Abstract:This study aimed to investigate the effect of mulberry leaf and balsam spear mixed powder on blood lipid metabolism in diabetic mice, and provide a reference for the development and utilization of healthy food with hypoglycemic and antidiabetic activities. A mouse model of diabetes mellitus was established, and the animals were fed a basal or high-fat diet along with different doses of mulberry leaf and balsam spear mixed powder. Blood samples were collected 30 d later to measure changes in the serum biochemical indices related to lipid metabolism in the mice. The results showed that when the mice were fed 0.5 ml of 0.20 g/mL mulberry leaf and balsam spear mixed powder solution, the levels of total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) in the diabetic mice fed with basal or high-fat diets were significantly lower than those in the control group (p<0.05). In addition, the high-density lipoprotein cholesterol (HDL-C) levels were significantly higher than that of the control group. For female and male mice fed the basal diet, LDL-C values decreased by 57.14% and 57.41%, respectively; HDL-C values increased by 96.97% and 95.45%, respectively; TC values decreased by 14.58% and 18.45%, respectively; and TG values decreased by 20.57% and 21.98%, respectively. All values of blood lipid indicators tended to be close to normal values. Therefore, the intake of mulberry leaves-bitter gourd mixed powder with diet control can have a beneficial hypolipidemic effect in diabetic mice.

Abstract:Sprague–Dawley (SD) rats were used as the experimental model in this paper whereby an SD rat model of inflammation was established by implanting cotton ball. Further, the effects of extract M of plant combinations on the body weight, food intake, and water intake of rats with cotton-ball-induced inflammation were studied. Enzyme-linked immunosorbent assay (ELISA) was employed to study the effects of extract M of plant combinations on the secretion of inflammatory mediators and synthetic pathways of prostaglandin E2 and leukotriene in rats with cotton-ball-induced inflammation. The results showed that extract M had no significant effects on the body weight, food intake, and water intake of normal SD rats, however had a certain impact on the food intake of rats after the model of inflammation was established. Extract M could significantly alleviate the excessive secretions of C-reactive protein, nitric oxide, arachidonate 5-lipoxygenase, and leukotriene C4 in the inflammation reaction, and had no significant inhibitory effects on the secretions of interleukin-1β, tumor necrosis factor-α, prostaglandin E2, and cyclooxygenase 2. The above findings indicated that extract M of plant combinations exerted anti-inflammatory effects by inhibiting the synthesis of leukotriene C4 by arachidonate 5-lipoxygenase and therefore can contribute to anti-inflammatory applications.

Abstract:An immunosuppressed mouse model, established through intraperitoneal injection of specific pathogen-free mice with cyclophosphamide (CTX), was used to study the immunomodulatory effect of walnut kernel pellicle polyphenols (WKPs). The mice were randomly divided into five groups: normal group, model group, and low-dose (50 mg/kg), medium-dose (100 mg/kg), and high-dose (200 mg/kg) WKP groups. The effect of different doses of WKPs on the thymus and spleen indexes, phagocytic index, blood-related indicators, immunoglobulin (Ig) G, IgA, and IgM levels, and lactic dehydrogenase (LDH) and acid phosphatase (ACP) activities were investigated. Consequently, in the immunosuppressed mice, the WKPs had a definite effect on improving and enhancing immune functions, by improving the organ index, increasing the carbon clearance index, increasing the rate of lymphocyte proliferation, maintaining the balance of blood cell distribution to some extent, increasing the immunoglobulin content, enhancing the activities of LDH and ACP, and maintaining the stability of physiological indexes.

Abstract:Using Yunnan truffle as the raw material, black truffle polysaccharides (TPs) were obtained by water extraction and alcohol precipitation. The extracted black TPs were separated by DEAE Sepharose Fast Flow ion exchange chromatography to obtain two truffle polysaccharide fractions: TP1 and TP2. The inhibitory effects of TP1 and TP2 on the proliferation of mouse macrophages (RAW264.7) and the capacities of TP1 and TP2 for the phagocytosis of neutral red pigment were investigated. TP1 was further purified by Sephadex chromatography column to yield TP1-1, which was used for structural characterization. The results showed that TP1 and TP2 had no toxic effects on RAW264.7 cells; they could significantly increase the phagocytic capacity of RAW264.7 cells, and the effect of TP1 was greater than that of TP2. The average molecular weight of TP1 was 757910 u, and its monosaccharide composition was D-glucose and D-mannose, in proportions of 88.94% and 1.19%, respectively. Ultraviolet (UV) spectra revealed that TP1-1 did not contain protein or nucleic acid. The results of infrared spectrum analysis showed that TP1-1 had a pyran ring structure and contained alpha-glycosidic bonds and mannose.

Abstract:A eukaryotic expression vector containing a vitamin D receptor (VDR) fusion protein was constructed, enabling the creation of a cell system that could stably express VDR fusion protein, and a mature cell model for the identification of food and drugs containing active vitamin D was established. Specific primers were designed and synthesized to amplify the VDR gene, the gene amplification products were cloned into a pcDNA 3.1/His eukaryotic expression vector, and the vector was then transfected into HEK293 cells. Immunoprecipitation (IP) was used to identify the expression efficiency of the fusion protein. Using the successfully constructed pcDNA 3.1/VDR-His vector, the transfected HEK293 cells were treated with an active form of vitamin D, 1,25-dihydroxyvitamin D3, and then total protein and mRNA were quantified. Western blot (WB) analysis and quantitative real-time PCR (qRT-PCR) were used to detect the expression of the VDR fusion protein and its target gene, CYP24A1, respectively. The IP results showed that the VDR fusion protein had transcription activity. WB and qRT-PCR results showed that 1 nmol/L 1,25-dihydroxyvitamin D3 could effectively activate VDR fusion protein expression in the transfected cell system and significantly increase CYP24A1 mRNA expression (p < 0.01). This cell model was used to determine the activity of vitamin D drugs, and the results suggested that the vitamin D activity of different drugs was related to drug type. The pcDNA 3.1/VDR-His fusion-protein expression vector system was successfully constructed, and a cell model to identify active vitamin D in food and drugs was successfully established using the working vector.

Abstract:As a rational drug design approach, the three-dimensional quantitative structure-activity relationship (3D-QSAR) is one of the methods that is currently used most often for drug design and development. Based on the relationship between the structure and tyrosinase inhibitory activity of 28 curcumin analogues, a 3D-QSAR model with statistical significance was established, with a cross-validation correlation coefficient q2 of 0.609, a correlation coefficient R2 of 0.997, and an F statistic of 77.070. The reliability and predictive ability of the model were analyzed. Six curcumin analogues (A1, A2, B1, B2, B3, and B4) with a symmetrical structure were designed based on the model. These compounds were then synthesized, separated, and purified, and their structures were characterized. Among them, compounds A2 and B3 were new compounds that have not previously been reported. Using levodopa (L-DOPA) as substrate, the tyrosinase inhibitory activities of the six compounds were measured. Among them, B1 exhibited the strongest activity, and the activities of all compounds were higher than that of curcumin. Additionally, the experimental values were very close to the predicted values, suggesting that the 3D-QSAR model has good external predictive capabilities.

Abstract:A novel long-short-long (LSL) type structured lipid was studied in this paper. The physicochemical properties of the LSL lipids were evaluated, and the results indicated that the appearance, acid value, saponification value, refractive index, and other indicators were very similar to those of soybean oil that served as the acyl donor for long-chain fatty acids of the structured lipid. However, compared to soybean oil, the structured lipid had a lower smoke point and melting point, and smaller molecular weight. Therefore, the ordinary edible oil could be completely replaced by the structured lipid. Subsequently, the functional properties of the new structured lipid were evaluated by postprandial blood lipid test and animal growth experiment. It was found that the novel structured lipid could reduce the postprandial blood triglyceride levels in mice. During the animal growth experiment, after feeding for six weeks, the group that received high fat diet containing high dosage of structured lipids had lower body weight, compared with the control group fed high fat diet containing high dosage of lard. The blood lipid levels, corresponding to the total cholesterol (TC) content of blood, in the group that received high fat diet containing medium and high dosages of structured lipid showed a decreasing trend compared with that of the control group. The observation of pathological liver slices showed that the number and size of fat droplets in the liver of medium- and high-dose groups were relatively reduced. In summary, our results showed that the novel low-calorie structured lipid could suppress the increase in the blood lipid level, prevent the accumulation of body fat, and have the potential to completely replace the ordinary edible oil.

Abstract:The purpose of this paper is to study the effects of dietary supplement containing eucalyptus polyphenols (EPE) on the antioxidant activity and meat quality of beard chicken muscles. A total of 324 90-day-old beard chickens were randomly divided into six groups (six replicates/group and nine chickens/group). The animals were fed for 40 days, and breast and thigh muscles were collected after slaughter to analyze the antioxidant activity, meat color, drip loss, nutrients, etc. of beard chicken muscles. In terms of the indicators of antioxidant activity, the results showed that EPE could significantly enhance the activity of glutathione peroxidase (GSH-PX) and significantly reduce the malondialdehyde (MDA) content of beard chicken muscle. In the case of meat quality, EPE could obviously improve the meat color and increase the content of intramuscular fat. Simultaneously, EPE could obviously improve the composition of fatty acids, enhance the contents of oleic and linolenic acid, and reduce the content of saturated fatty acids, in order to improve the meat quality. In summary, EPE could obviously improve the antioxidant activity of beard chicken muscle and enhance the meat quality.

Abstract:Microbial esterases play an important role in food, pharmaceutical, and fine chemicals industries. In order to enrich available esterase resources, metagenomic DNA was extracted from traditional food fermentation environment, and the metagenomic library was constructed. An esterase gene (est_115) was obtained after screening of the library; it contained 948 bp and encoded a protein of 316 amino acids (AA). Sequence homology analysis showed that its protein had the highest homology (38%) with the carboxylic-ester hydrolase from Pseudomonas lutea, indicating that esterase Est_115 was a new type of esterase. Subsequently, a recombinant expression vector containing the est_115 gene was constructed and expressed in Escherichia coli BL21 (DE3), and the recombinant esterase Est_115 was obtained after purification. Analysis of its enzymatic properties indicated that recombinant esterase Est_115 showed a relatively high catalytic activity on p-nitrophenyl esters with a short carbon chain on their acyl group, and the optimal temperature and pH value were 35°C and 7.0, respectively. Under conditions of 10~18% sodium chloride, the esterase could maintain a high catalytic activity, and showed good salt resistance, which suggested that this new type of esterase enzyme could be used in food processing using high osmotic pressure.

Abstract:Hyperuricemia is a metabolic disease caused by purine metabolic disorders that lead to the overproduction and (or) reduced excretion of uric acid, and is an important biochemical basis for gout. In the present study, a cell model of hyperuricemia was established and the anti-hyperuricemic activity of whey protein-derived peptides was studied. Thehepatic (LO2) cells were seeded into a 24-well plate and divided into two groups–normal control and model groups. After 48 h of incubation, the model group was incubated with adenosine-containing medium, while the control group was incubated with fresh basal medium. After further incubation for 36 h, xanthine oxidase was added and the incubation was continued for another 12 h. Finally, the cell culture supernatants were collected and analyzed by high performance liquid chromatography (HPLC) assays. The results demonstrated that the uric acid level of model group was significantly higher than the normal control group, and the optimal adenosine concentration for incubation, cell plating density, and optimal incubation time were 2.5 mmol/L, 105 cell/mL, and 36 h, respectively. Under the best conditions for model construction, febuxostat and whey protein hydrolysate were used to evaluate the anti-hyperuricemic activity of the model, and the results showed that the uric acid content of febuxostat group was markedly decreased in a dose-dependent manner, further suggesting that the hyperuricemia model was successfully established. After hepatic cells were incubated with whey protein hydrolysate, when whey protein-derived proteins reached a certain concentration, the level of uric acid decreased significantly compared with that of model group, indicating that whey protein hydrolysates exhibited anti-hyperuricemic activity.

Abstract:In order to investigate the microbial diversity in a papaya enzyme preparation during the natural fermentation process, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was used to analyze the diversity and the pattern of changes of bacteria and yeast during natural fermentation. The results indicated that the main bacterial species were Lactobacillus plantarum, Leuconostoc pseudomesenteroides, Weissella paramesenteroides, and uncultured Propionibacterium sp.; the dominant bacterium was Lactobacillus plantarum. The main yeast species were Saccharomyces cerevisiae, Candida xestobii, Candida intermedia, Pichia guilliermondii, Komagataella phaffii, Pichia punctispora, Pichia galeiformis, Clavispora sp., and Cyberlindnera fabianii. The dominant yeast species were Saccharomyces cerevisiae and Pichia guilliermondii. Moreover, Lactobacillus plantarum and Pichia galeiformis shared a high affinity with uncultured Propionibacterium sp. and Cyberlindnera fabianii, respectively, and a low affinity with other microorganisms. During natural fermentation, the microflora populations exhibited alternating growth patterns and showed a certain affinity; the colony structure changed slightly with uniform distribution.

Abstract:Changes in the concentration of the main phenolic compounds and their antioxidant capacities in raw and aged Liubao tea during gastrointestinal digestion were evaluated in this study. Ethyl acetate, an extract of the aged Liubao tea, was used as a control. The results indicated that differences in the composition of Liubao tea during the production process led to changes in antioxidant activity. Before digestion, the amount of gallic acid (GA) in raw tea was relatively high, whereas high caffeine content was observed in aged tea. After digestion, the concentrations of the main phenolic compounds (GA, protocatechuic acid, procyanidins, epigallocatechin 3-gallate (EGCG), gallocatechin 3-gallate (GCG), and epicatechin 3-gallate (ECG) decreased by 80~90%, and their antioxidant activities also decreased accordingly. The concentrations of GA, procyanidins, EGCG, ECG, and GCG in the aqueous extract of Liubao tea significantly correlated with their antioxidant activity. In addition, the amounts of procyanidins (0.994) and EGCG (0.997) showed a significant correlation. The percentage of phenols in raw and aged tea were 28.41% and 17.87%, respectively, and their corresponding antioxidative capacities were 16.73 mg/L and 15.37 mg/L, respectively. After digestion, the amount of polyphenols decreased by 68.85% and 69.72%, respectively, and the corresponding antioxidant activities decreased by 88% and 82%, respectively. The aged tea demonstrated better antioxidant activity and a higher ability to maintain antioxidant activity. The substances that most likely affected the antioxidant activities were GA, procyanidins, EGCG, and ECG.

Abstract:Black-bone silky fowl oligopeptides (BSFOP) were prepared by enzymatic hydrolysis of muscle from black-bone silky fowls and then reacted with iron (II) to yield iron (II)-chelated black-bone silky fowl oligopeptides (BSFOP-Fe). The iron-chelating capacity of BSFOP was 84.76±0.12%. BSFOP-Fe had a high protein content (54.64 ± 1.03%) and low molecular weight; 85.50% of peptides were less than 1000 u. Scanning electron microscopy, ultraviolet (UV) wavelength scanning, and infrared spectra were used to analyze the structure of BSFOP-Fe, and the results showed that BSFOP-Fe was a new type of iron-chelated compound. An in vitro stability study indicated that BSFOP-Fe maintained certain stability against temperature, pH, and in vitro gastric protease digestion. BSFOP-Fe was separated and purified by reverse-phase high performance liquid chromatography. One main fraction was collected and analyzed by mass spectrometry. One pentapeptide was identified from the main fraction of BSFOP-FE, and its amino acid sequence was Thr-Ser-Gly-Met-Pro. BSFOP-Fe could be applied as a food additive, to dietary nutrients, and to pharmaceutical products as an iron supplement.

Abstract:Yoghurts were fermented using different starter cultures (187, 495, or 885) for examination of the influence of soy protein hydrolysates (SPHs) on the fermentation pH and whey precipitation, as well as rheological and textural properties of the fermented products during storage. SPHs had a definite effect on the stimulation of fermentation of the three yoghurts, especially on those fermented by cultures 187 and 495 that had a lower pH reduction rate during fermentation. In storage, SPHs could effectively slow whey precipitation in the three yoghurts, where the most significant effect (reduction rate: 49.35%) was found in the yoghurt fermented by culture 885, which had the highest whey precipitation rate among the three control groups. Moreover, SPHs could greatly increase the apparent viscosity and hysteresis area of the three yoghurt samples, contributing to their structure recovery. Through further investigation of the yoghurts on the 7th day of storage, the SPH was found to have significantly improved the consistency and zero-shear viscosity of the three yoghurts, and reduced their flow behavior index, compliance value, and viscous index, thus improving their rheological and textural properties, increasing their stability under low stress, and reducing the degree of damage caused by deformation under high stress.

Abstract:The arachin/conarachin-rich fractions were isolated from defatted peanut flour by cryoprecipitation in this study. The peanut protein-rich fractions were mixed with maltodextrin in a 1:1 weight ratio. At a temperature of 60 ℃ and a relative humidity of 79%, arachin-rich and conarachin-rich fractions underwent glycosylation reactions for one to seven days and 8 to 24 h, respectively. The extent of glycosylation between peanut protein-rich fractions and polysaccharides was characterized using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and the changes in the conformational properties of the glycosylation products of peanut protein isolates and polysaccharides were investigated using thermal properties and fluorescence spectra. The SDS-PAGE analysis indicated arachin/conarachin-rich fractions underwent cross-linking reaction with maltodextrin to generate macromolecular grafted products under dry-heating conditions. The subunits of conarachin-rich fraction readily underwent Maillard reaction with maltodextrin than those of the arachin-rich fraction. The thermal stability of peanut protein fractions was remarkably improved by mixing or conjugation of peanut protein-rich fractions with maltodextrin. The conformational structure of peanut protein-rich fraction became loose and subsequently compact with increasing extent of glycosylation.

Abstract:The effect of lactic acid bacteria fermentation on the sugars, phenolics, flavonoids, and mono-phenols of longan pulp was investigated in this study. The results showed that after lactic acid bacteria fermentation, the amounts of total and reduced sugar in longan pulp decreased markedly by 48.59% and 38.42%, respectively (p<0.05). The concentrations of total phenolics and flavonoids in longan pulp showed an upward trend after an initial decrease during fermentation. The concentration of total phenolics after fermentation was 47.8 mg GAE/100 g, which showed no significant difference compared with that before fermentation (p>0.05). The amount of total flavonoids after fermentation was 13.7 mg CE/100 g, which significantly increased by 28.0% compared to that before fermentation (p<0.05). In addition, lactic acid bacteria fermentation could increase the concentrations of free gallic acid, ferulic acid, and quercetin, as well as reduce the amounts of bound gallic acid, ferulic acid, and quercetin. The concentrations of protocatechuic acid and rutin, which only existed in free forms, markedly increased in the process of fermentation, and the amount of bound vanillic acid decreased dramatically. These results suggest that lactic acid bacteria fermentation can significantly reduce the amounts of total sugars and sugars, increase the total flavonoid content, and increase the amounts of gallic acid, ferulic acid, quercetin, protocatechuic acid, rutin, and free mono-phenols. This study could provide guidance for the development of longan pulp products fermented by lactic acid bacteria.

Abstract:Broccoli was used as the raw material for fermentation, and yeast, lactic acid bacteria, and acetic acid bacteria were added to carry out mixed fermentation to study the changes of biochemical indicators and antioxidant activity in broccoli Jiaosu during fermentation. In this study, the changes of biochemical indicators were investigated by monitoring the changes in the pH value, total number of colonies, total amounts of carbohydrate, ethanol, lactic acid, and acetic acid. Further, the antioxidant activity was studied by measuring the total phenol, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging rate, superoxide dismutase (SOD) activity, and oxygen radical absorbance capacity (ORAC). The results showed that during fermentation, the pH value decreased constantly from the original 4.49±0.02 to 3.51±0.03. The highest total number of colonies was observed on the third day, which was 9.03(±0.45)×107 CFU/mL. Carbohydrate present in the medium was consumed by the microbes resulting in the reduction of its total concentration from 213.20±0.12 mg/mL to 79.24±0.07 mg/mL. Finally, the contents of ethanol, lactic acid, and acetic acid were 28.23±0.06 mg/mL, 7.89±0.05 mg/mL, and 11.66±0.05 mg/mL, respectively. The total phenolic content, DPPH radical scavenging ability, SOD activity, and ORAC showed an increasing trend during the first seven days and tended to remain stable after day seven. The total phenolic content showed positive correlations with DPPH radical scavenging rate and ORAC (p<0.01). Compared with the mulberry enzyme prepared by the laboratory, broccoli enzyme had a higher DPPH radical scavenging rate and better antioxidant activity.

Abstract:The optimal reaction time and the antioxidant activity of different types of polyphenols isolated from red wine were determined using a micro-model of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,20-Azino-bis (3-ethylben zothiazoline-6-sulfonic acid) diammonium salt (ABTS), and ferric reduction ability plasma (FRAP) assays. Using Trolox and vitamin C as controls, the reaction processes of different types of red wine polyphenols in DPPH, ABTS, and FRAP systems were dynamically monitored, and the antioxidant activity of red wine polyphenols at different concentrations were calculated. The results showed that the optimal reaction times of DPPH, ABTS, and FRAP were 100 min, 240 min, and 370 min, respectively. Different types of red wine polyphenols were similar to the antioxidants, and their antioxidant activity showed a dose-dependent relationship with concentration. The correlation analysis suggested that epicatechin, polymers, oligomers, and anthocyanins were the main components affecting the antioxidant activity of red wine and could be determined as indicators for red wine quality control. The micro-model of DPPH, ABTS, and FRAP established in this study was simple and reproducible, and demonstrated low sample consumption.

Abstract:Brewer’s yeast, as the main byproduct of the beer industry, has a high value for development and utilization. Here, brewer’s yeast was used as the raw material from which an odorless extract was prepared by autolysis and ethyl acetate extraction. Ultraviolet (UV) protection, tyrosinase inhibitory effect, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability, hygroscopicity, moisture retention, and other skin care benefits of the extract were studied. The results showed that when the protein mass concentration of the odorless extract of brewer’s yeast was 4.77 g/L, the average UV, UVA, UVB, and UVC absorbance, the tyrosinase inhibition rate and DPPH scavenging rate were 85.08%, 64.25%, 93.42%, 100%, 97.90%, and 31.12%, respectively. The hygroscopicity of this extract was significantly higher than that of glycerin, and the moisture-retention capacity of this extract was equivalent to that of glycerin. The results indicate that the odorless yeast extract could serve as a good UVB absorber and tyrosinase inhibitor. It could also prevent sunburn caused by UV absorption, skin cancer, and other associated health problems. It also shows sun screening and whitening effects, antioxidant activity, moisture retention capacity, and other skin care benefits.

Abstract:Procyanidins of Xinjiang white grape seeds were extracted by microwave and enzyme-assisted treatments for study of their antibacterial activity. Response surface analysis was conducted, using the Box-Behnken design experiment based on the single-factor test, to investigate the influence of four main factors (solid-liquid ratio, microwave time, microwave temperature, and cellulose dosage) on the procyanidin extraction rate. The extracted procyanidin sample was purified (purity 95.6%) using AB-8 macroporous resins. The optimal extraction conditions were as follows: temperature, 60 ℃; solid-liquid ratio, 1:14.6 (g:mL); microwave time, 9 min; and cellulose dosage, 0.56 mg/mL. Under these conditions, the procyanidin extraction yield was 5.72%. The purified procyanidins could effectively inhibit the growth of Staphylococcus aureus, with an inhibition zone diameter of 19.2 mm, a minimal inhibitory concentration (MIC) of 2.5 mg/mL, and a minimum bactericidal concentration (MBC) of 5 mg/mL. After treatment with the procyanidins, the permeability of the bacterial cell membrane was increased and the cell wall was destroyed. Scanning electron microscope images of the procyanidin-treated S. aureus showed wrinked bacterial surfaces and different cell sizes .

Abstract:The bioavailability enhancement of bioactive compounds is an interesting research topic. Sodium tripolyphosphate (STPP) was used as a cross-linking agent to study the structural properties of crosslinked chitosan film and the controlled release property of a crosslinked chitosan-based hydrogel matrix tablet. Chitosan has an abundant source and good biocompatibility. Fourier transform infrared spectroscopy-attenuated total reflectance (FT-IR-ATR) analysis showed that some chemical groups were introduced to chitosan film via crosslinking reactions, which improved the strength of the three-dimensional network structure, and endowed the film with certain swelling and water absorption properties. Meanwhile, the acid resistance of the chitosan film was significantly improved after crosslinking; scanning electron microscopy showed that after transport in simulated gastric fluid (SGF), the surface of the crosslinked chitosan film was still compact with no damage, and it had the potential to be a carrier material for bioactive substances. Moreover, 5-aminosalicylic acid (5-ASA) was used as a model bioactive compound, and a crosslinked chitosan-based hydrogel matrix tablet was prepared by compression. In the simulated release experiment, the release rate of 5-ASA in SGF was dramatically reduced. These results suggest that chitosan crosslinked with STPP could have a wide range of applications in the transport of bioactive substances and the controlled release of drugs.

Abstract:The conditions of the process used to prepare a nanoemulsion consisting of cinnamon essential oil and medium-chain triglycerides (MCTs) as the oil phase and modified starch (e.g., octenyl succinic acid modified starch) as the emulsifier were investigated. An orthogonal design method was adopted, where the parameters and conditions of high pressure homogenization were optimized according to emulsion particle size, and the Turbiscan dispersion stability analyzer was used to analyze the particle size and the stability of the nanoemulsion. Consequently, an oil-in-water nanoemulsion with a particle size of 90~120 nm was prepared with the following conditions: weight percentage of emulsifier, 20%; weight percentage of oil, 10%; mass ratio of cinnamon oil to MCT, 1:3; homogenization cycles, six; and homogenization pressure, 100 MPa. Moreover, the particle size was uniform, and no floatation and sedimentation occurred during storage of the nanoemulsion. Gas chromatography-mass spectrometry analysis identified 99.64% of the components from the cinnamon essential oil, and the relative contents (percentage) of all components were calculated using the peak area normalization method. The main compounds in the essential oil were cinnamaldehyde, cinnamic acid, α-pinene, 2-methoxycinnamaldehyde, α-ylangene, and α-cadinol, all of which did not change apparently throughout the process. The addition of 83% MCT to the oil phase helped to slow Ostwald ripening of the emulsion, and the retention rate of cinnamon essential oil was above 85% after 15 d of cold storage.

Abstract:In order to provide a theoretical basis for the large-scale processing of air-dried sausages and establishment of anthropogenic climate and safety controls, the influence of wind speed on the quality of dried sausages was investigated. By simulating the day and night conditions (temperature and humidity) in Guangdong, differences in the changes of the physicochemical indexes, lipid oxidation, and flavor compound composition and contents of sausage samples processed under different wind speeds (0.5 m/s, 1.0 m/s, or natural wind) were compared. The results showed that wind speed was an important factor that affected the sausage quality. The changes in the drying rate and pH value of the sausage samples prepared by the artificial processes were significantly higher than those prepared by natural air drying. Lipid oxidation occurred throughout the entire drying and maturation stages of the sausages, and enhancement of the wind speed delayed the rancidity of the products and strengthened the accumulation of flavor amino acids. Furthermore, anthropogenic control of the drying speed could extend the shelf life of the sausage, where its acid, peroxide, and thiobarbituric acid values at the end stage of the drying process were lower than those of the naturally dried sausage.

Abstract:The effects of different concentrations of iron (II) (Fe2+) and iron (III) (Fe3+) on the activity of bromelain and the thermostability of bromelain at 60 ℃ were studied, and circular dichroism (CD) spectra were used to determine conformational changes of bromelain caused by Fe2+ and Fe3+. In addition, the iron ion removal effect of a method combining ethylenediaminetetraacetic acid disodium salt and ultrafiltration during the preparation of bromelain was preliminarily explored. The results showed that Fe2+ at a concentration range from 0 to 0.75 mmol/L improved the activity of bromelain, and the best Fe2+ concentration was found as 0.5 mmol/L. When the concentration of Fe2+ was higher than 0.75 mmol/L, the activity of the enzyme was inhibited, and the extent of inhibition was increased with increasing Fe2+ concentration. Fe3+ had an inhibitory effect on enzyme activity, and the extent of inhibition was proportional to the concentration of Fe3+. The inhibitory effect of Fe3+ on the enzyme was stronger than that of Fe2+. At 0.5 mmol/L, Fe2+ had a promoting effect on the thermostability of bromelain at 60 ℃ and extended the half-life of the enzyme. However, Fe3+ had an inhibitory effect on the thermostability of bromelain. When the concentrations of Fe2+ and Fe3+ were higher than 0.5 mmol/L, their inhibitory effects on the thermostability of bromelain increased with increasing ion concentration. According to CD spectra, the inhibitory effects of Fe2+ and Fe3+ on bromelain were reflected in a decrease in the contents of α-helices, a slight decrease in the contents of β-sheets and β-turns, and a significant increase in random coil contents. The method combining ethylenediaminetetraacetic acid disodium salt and ultrafiltration was effective for iron ion removal, with a reduction of iron content from 291.63 mg/kg to 142.99 mg/kg (dry weight), and the elimination rate of iron ion was 50.97%. Moreover, the enzyme activity increased from 597.27 U/mg to 808.52 U/mg, and the growth rate of activity was increased by 26.13%.

Abstract:Frozen silver carp surimi was used as the raw material to study the effects of sodium chloride concentration on its quality characteristics when prepared under vacuum chopping (-0.06 MPa). Compared with samples prepared under atmospheric chopping, the surimi protein prepared under vacuum chopping had a significantly increased surface hydrophobicity (p<0.05), a decreased disulfide bond content (p<0.05), and decreased number and diameter of bubbles; the breaking force, penetration distance, and water-holding capacity of surimi gel increased (p<0.05), while whiteness decreased (p<0.05). Under atmospheric chopping and vacuum chopping, as sodium chloride concentration increased, the surface hydrophobicity, disulfide bond content, and foamability of surimi protein increased significantly (p<0.05). The breaking force and penetration distance of surimi gel increased with increasing sodium chloride concentration and then decreased significantly when the sodium chloride concentration was higher than 1% (p<0.05). The water-holding capacity increased significantly with increasing sodium chloride concentration (p<0.05). With increasing sodium chloride concentration, the whiteness values of surimi gel increased significantly and decreased gradually under atmospheric chopping (p<0.05) and vacuum chopping (p<0.05), respectively.

Abstract:The effects of different ratios of raw materials on the quality characteristics of twin-screw extruded potato rice cakes were determined by adding different proportions of potato granules to japonica rice flour, glutinous rice flour, and indica rice flour under specific twin-screw extruding conditions. The results showed that with increasing ratio of potato granules, the L* value of potato rice cakes decreased and the b* value increased. After the addition of potato granules, the highest cooking loss from potato rice cakes was found in the glutinous rice group, followed by the indica rice group, and the lowest cooking loss was found in the japonica rice group. Increasing the proportion of potato granules increased the cooking loss in all groups. With the addition of potato granules, the hardness and the chewiness of the potato rice cakes increased; for the japonica rice group, the stickiness first increased and then decreased, and the stickiness reached a maximum when the proportion of added potato granules was 40%. The stickiness of the glutinous rice group increased with the addition of potato granules, but the elasticity did not change significantly. Scanning electron microscopy results indicated that the structure of glutinous rice cakes was relatively loose, that of indica rice cakes was relatively firm, and the addition of potato granules made the structure of the rice cakes more compact. Considering all of the above results, the quality of potato rice cakes made by twin-screw extrusion was better when japonica flour was used as the raw material and the amount of added potato granules was 40%.

Abstract:The effects of different culture conditions, including different types and concentrations of nitrogen sources and surfactants, fermentation time, temperature, and rotation speed, on the biomass and hydrolytic activity of Aspergillus niger (A. niger) cells were studied in this paper. The results showed that different nitrogen sources enhanced the production of the induced enzymes with hydrolytic activities in A. niger cells, and the rate of enhancement by the different nitrogen sources were different. Among the tested nitrogen sources, yeast extract showed the best inducing effect on the cells. For yeast extract concentration of 1.5 g/L, the biomass of A. niger corresponds 1.35 g/L. Among the surfactants examined, the optimal hydrolytic activity was found in the A. niger cells cultured using Triton X-100. In the culture media with 0.5% Triton X-100, the hydrolysis efficiency of A. niger reached 58.12%. In addition, the effects of inorganic salts, culture temperature, and rotation speed were also investigated and the optimal conditions to cultivate Aspergillus niger cells with hydrolytic activities were as follows: yeast extract 1.5 g/L, Triton X-100 0.5%, magnesium sulfate heptahydrate 1 g/L, monopotassium phosphate 1 g/L, potassium chloride 0.5 g/L, ammonium sulfate 1.5 g/L, and anhydrous calcium chloride 0.1 g/L. The ideal culture temperature and rotation speed were confirmed as 35℃ and 140 r/min, respectively. Under the optimal culture conditions, biomass and hydrolysis efficiency of A. niger cells were 1.73 g/L and 90.23%, respectively.

Abstract:To evaluate the effect of electron beam dose rate on the ultrastructure, protein quality, and sensory characteristics of chilled beef, Longissimus dorsi muscles obtained from Chinese Yellow Cattle were irradiated at 2.5 kGy with dose rates of 30, 150, 300 kGy/min using a high-energy electron accelerator. The samples were stored at 4 ℃ to determine the effects of dose rate and storage time on the values of color, odor, ultrastructure, protein content, and amino acid component of the chilled beef at each storage period. At the beginning of storage, a comparison of the experimental and control groups demonstrated that the irradiated samples had a darker color, an off-odor, and a lower sensory evaluation score. However, with a prolonged storage time, the overall quality of the control samples decreased, while those of irradiated samples remained relatively stable. The quality of the chilled beef exposed to 150 kGy/min was better than that in the other irradiation groups. Irradiation accelerated aging of the beef meat. The effect of 150 kGy/min irradiation on sarcomere length was similar to the influence of 15 d of storage. The irradiation technique did not affect the protein content and amino acid component of the chilled beef. However, the amounts of lysine, valine, and other essential amino acids were affected by the storage time.

Abstract:Polyphenols were extracted from the needles of different pine species by high-shear mixing emulsification. Shear speed, shear time, ethanol concentration, sample to solvent ratio, and shear temperature were used as the indices. From the results of single factor testing, ethanol concentration, shear time, and extraction temperature were selected as the factors to be considered for the steepest ascent and response surface methodology using a central composite design. The optimum extraction conditions were as follows: shear speed: 18000 r/min, sample to solvent ratio: 1:10, ethanol concentration: 64%, shear time: 140 s, and shear temperature: 44 ℃. The yields of polyphenols from the needles of Pinus koraiensis, Abies nephrolepis, Pinus sylvestris, Pinus tabulaeformis, and Picea koraiensis were 19.7623, 24.6992, 14.0626, 9.4983, and 29.7984 mg/g, respectively. Meanwhile, 2,2-diphenyl-1-picrylhydrazyl (DPPH·) scavenging ability and total reducing power were used as indicators to compare the antioxidant capacities of the extracted polyphenols from the five pine species; these were in the order of Pinus koraiensis > Pinus tabulaeformis > Picea koraiensis > Pinus sylvestris > Abies nephrolepis. When 2,2′-azino-bis(3-ethylbenzothiazoline -6-sulfonic acid ABTS+· was used as the indicator, the antioxidant capacities were in the order of Pinus sylvestris > Pinus koraiensis > Pinus tabulaeformis > Picea koraiensis > Abies nephrolepis.

Abstract:A two-step process for the purification of molasses wastewater from the yeast industry was developed using a combination of active charcoal-based decolorization and mixotrophic cultivation of Chlorella pyrenoidosa in the effluent. The color removal effects of eight types of commercial active charcoal powders were compared, and the optimal color removal effect was obtained using No. 200 active charcoal powder at a concentration of 3.0% (m/V) and pH 3.00. The removal rates of color, chemical oxygen demand (COD), and total nitrogen (TN) were high: up to 98.96%, 54.50%, and 46.75%, respectively. The decolored effluent was then used for mixotrophic cultivation of C. pyrenoidosa. The final biomass concentration (2.29 g/L) and the removal rates of COD and total phosphate (TP) (72.41% and 79.36%) after 8 days’ cultivation were significantly higher (p<0.05) than those of the original wastewater without pretreatment. The total removal rates of COD, TN, and TP of this two-step process reached 87.82%, 68.26%, and 78.57%, respectively. These results indicate that the decolorization of wastewater by active charcoal can dramatically enhance the transparency and reduce the concentration of wastewater, and deep purification was realized by the subsequent mixotrophic cultivation of Chlorella pyrenoidosa. In conclusion, the two-step process developed in the current study is an optimized process combining high-efficiency wastewater purification and Chlorella cultivation.

Abstract:Sweep frequency ultrasound is an important physical processing technique for food that can provide an acoustic field, which improves the cavitation effect and enhances the extraction yield of oils. However, oxidation may occur, and the viscosity is affected as a result of the cavitation effect. Therefore, it is necessary to study the oil oxidation and the rheological properties of this technique. In this study, a piezoelectric polyvinylidene fluoride (PVDF) sensor was used to monitor the sweep frequency ultrasonic fields with the eigenfrequencies of 20 kHz, 40 kHz, and 60 kHz during the entire process of oil extraction. The oxidative properties of the extracted oils were measured according to the national standards. The rheological properties of the samples were determined using a rotational rheometer. The results showed that the resonance frequency of the oil extraction was 40 kHz, and its cavitation effect was the most significant. When the ultrasonic eigenfrequency was less than 40 kHz, the peak voltage amplitude, frequency spectrum coverage range, and oxidative properties increased with the increment of eigenfrequency, and the viscosity decreased. The opposite effect was observed when the ultrasonic eigenfrequency was greater than 40 kHz, such that the voltage amplitude, frequency spectrum coverage range, and oxidative properties decreased with the increment of eigenfrequency, and the viscosity increased. The viscosity of the oils was the lowest at the resonance frequency. The extracted oils were plastic fluid with the flow characteristic of Bingham flow, and demonstrated a shear-thinning trend.

Abstract:To investigate the effects of forchlorfenuron treatment on the sensory qualities of different varieties of kiwifruit, Qin Mei, Xu Xiang, Atlantis, Hayward, Qi Hong, and Hong Yang kiwifruits were used as experimental materials, and all fruits were treated with 5 mg/L forchlorfenuron during the full bearing period. Quality indices, including physical and chemical indices, sensory evaluation, and aroma components, of control and forchlorfenuron-processed fruits on the harvest day and during the ripening period were measured. The results showed that on harvest day, the hardness, titratable acidity, and chlorophyll content of control fruits were significantly higher than those of forchlorfenuron-processed fruits, but the soluble solids content (SSC) of control fruits was significantly lower than that of forchlorfenuron-processed fruits. When all fruits were ripened, the shelf life of the fruits treated with forchlorfenuron was shorter than that of control fruits to varying degrees. Control fruits had significantly higher SSC and titratable acidity, and significantly lower chlorophyll contents than forchlorfenuron-processed fruits, and there were no significant changes in water content. The electronic nose was used to better identify and distinguish the differences in aroma substances between controls and forchlorfenuron-processed fruits. Based on the results of comprehensive sensory evaluation and measurements of the shelf life, physicochemical indices, and content of aromatic substances, forchlorfenuron treatment exhibited less impact on Hayward kiwifruit, but had a significant adverse effect on Qin Mei, Xu Xiang, Stuart, and Hong Yang kiwifruits. In agricultural production, forchlorfenuron can be selectively used according to kiwifruit variety to improveoutput and avoid unnecessary economic losses.

Abstract:The apparent viscosity, shear stress, and rheological properties of wheat gluten hydrolysates obtained from the hydrolysis of wheat glutens of different concentrations by an alkaline protease, Alcalase, were investigated. The results showed that a higher concentration of wheat gluten in the hydrolysis system resulted in a smaller decrease in pH value. The first six hours of the reaction showed the most significant change in pH, and samples with a higher solid concentration achieved a steady-state change earlier. With increasing solid concentration and hydrolysis time, the water activity of the wheat hydrolysates showed a downward trend. In addition, a higher solid concentration led to a higher magnitude of reduction in water activity and a faster reduction rate. During the whole hydrolysis process, the viscosity and shear stress of the hydrolysates at different solid concentrations dropped constantly as the hydrolysis time was increased; a higher solid concentration led to a more apparent declining trend, and the viscosity and shear stress values of wheat gluten hydrolysates at different solid concentrations were always in the order of 40%>32%>24%>16%>8%. In addition, it was found that the Ostwald-de Waele model could be used to fit the rheological properties of wheat gluten hydrolysates obtained from the hydrolysis of wheat glutens of different concentrations by an alkaline protease.

Abstract:Using West Lake Longjing tea as the raw material, a total of six treatments combining three different storage temperatures (-20 ℃, -5 ℃, and 4 ℃) with or without temperature compensation were carried out, and samples were collected for analysis after 3, 6, and 12 months of storage, respectively. The contents of moisture, polyphenols, amino acids, chlorophyll, vitamin C, and other components in the samples were measured, and sensory evaluation tests were performed to study the effects of temperature compensation treatment, storage temperature, and time on the preservation of green tea. Consequently, with increasing storage time, the moisture content of tea increased gradually, where that of the sample treated with temperature compensation was significantly lower than that of the sample without this treatment, but the differences among different storage temperatures were not significant. The polyphenol, total chlorophyll, chlorophyll a, and vitamin C contents decreased gradually; the amino acids first increased and then decreased in amount; and the chlorophyll b level was relatively stable. Differences among different storage temperatures were not significant, and the temperature compensation process could significantly reduce the loss of the above quality substances. Without temperature compensation, the sensory scores of green tea decreased gradually with increasing storage time. However, combined with temperature compensation, the three temperatures could effectively retain the original quality of the tea, where the total sensory scores were all above 83.00 points after 12 months of storage. The three low-temperature treatments alone did not affect the preservation of green tea significantly. Therefore, 4 ℃ storage with temperature compensation was concluded to be the most conducive to the preservation of green tea.

Abstract:The effects of the mass ratio of chloroacetic acid to schizophyllan, reaction time, and reaction temperature on the degree of substitution in carboxymethyl schizophyllan were studied using response surface experiments. The in vitro weight method and body surface instrument method were used to study the moisturizing effects of carboxymethyl schizophyllan, which were then compared with the commonly used cosmetic moisturizers glycerol (Gl) and hyaluronic acid (HA). The response surface experiments showed that, under the optimum conditions ( themass ratio of chloroacetic acid to schizophyllan of 2.38, reaction temperature of 61.58 ℃, and reaction time of 2.82 h), the maximum degree of substitution (0.54) was obtained. In vitro test results showed that under relative humidity conditions of 43% and 81%, the moisture absorption rates of the samples were in the order of carboxymethyl schizophyllan > glycerol > hyaluronic acid > schizophyllan. Under dry environment conditions using silica gel, the moisture retention rates of the samples were in the order of glycerol > schizophyllan > carboxymethyl schizophyllan > hyaluronic acid. Under relative humidity of 43%, the moisture retention rates of the samples were in the order of glycerol > carboxymethyl schizophyllan > hyaluronic acid > schizophyllan. The skin moisturizing test showed that the moisturizing effect of carboxymethyl schizophyllan was significantly higher than that of hyaluronic acid and lower than that of glycerol, and the water-locking effect of carboxymethyl schizophyllan was stronger than those of glycerol and hyaluronic acid.

Abstract:A multiresidue method for the determination of twenty-two quinolone residues (garenoxacin, trovafloxacin, moxifloxacin, orbifloxacin, gemifloxacin, gatifloxacin, pefloxacin, ciprofloxacin, etc.) in eggs was developed based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). In this method, the analytes were extracted using acidified (2%) acetonitrile, degreased by n-hexane, and purified through an Oasis HLB SPE column. The twenty-two quinolones were separated on an Acquity UPLC BEH Shield RP18 column (100 mm×2.1 mm, 1.7 μm), using methanol and 0.1% formic acid as the mobile phases for gradient elution. The signals were acquired through the dual-channel multiple reaction monitoring (MRM) mode. All analytes could be well separated by using a gradient program of 11 minutes. The calibration curves of the twenty-two quinolones showed good linearity in the concentration range of 2.0~100.0 μg/L (r>0.99), and the limits of quantitation were all less than 1.0 μg/kg. The recoveries of the 2, 10 and 20 μg/kg spiked samples ranged from 60.1% to 96.2%, with RSDs of 1.44%~11.1%. Compared with the existing national standard, this new method has the advantage of detecting more types of quinolone drugs, especially the new ones. The new method has a certain reference value for a more comprehensive screening and identification of quinolone residues in eggs and prevention of illegal additions.

Abstract:Alopex lagopus- and Nyctereutes procyonoides-specific primers and TaqMan probes were designed based on the conserved sequences in the mitochondrial genome of the Alopex lagopus and the displacement-loop (D-loop) region of Nyctereutes procyonoides. A real-time polymerase chain reaction (RT-PCR)-based method for the determination of Alopex lagopus- and Nyctereutes procyonoides-derived constituents of commercial meat products was developed in this study. The established RT-PCR method was evaluated for specificity, sensitivity, and linearity; the method showed good specificity and sensitivity, and the limits of detection for Alopex lagopus DNA and Nyctereutes procyonoides DNA were 0.5 pg/μL and 5 pg/μL, respectively. In summary, this RT-PCR method can be used for the identification of Alopex lagopus- and Nyctereutes procyonoides-derived constituents in commercial samples.

Abstract:A method for the determination of seven heavy metal element residues (lead, chromium, nickel, arsenic, antimony, cadmium, and barium) in disposable paper cups was established using microwave digestion and inductively coupled plasma mass spectrometry (ICP-MS). Samples were digested by microwave digestion with nitric acid and hydrogen peroxide as the digestion solutions, and then analyzed with the kinetic energy discrimination model (KED) and an online internal standard solution. The detection signal (counts per second, CPS) showed a good linear relationship with the content of seven heavy metal elements; the correlation coefficient R2 was>0.9997, the recovery was in the range of 85.0%~112.2%, and the relative standard deviation (RSD) was less than 6.46%. This method was used to analyze the seven heavy metal elements in the national standard material GBW10045, and the results were consistent with the standard values. The method developed in this study is sensitive, rapid, and accurate, and it is suitable for the analysis and detection of seven trace heavy metal elements in disposable paper cups.

Abstract:The analysis of trace elements in food is necessary for food safety control and nutrition evaluation. This can provide a reference for the proper evaluation of the edible and medicinal value of Ganoderma lucidum spore oil. Commercial G. lucidum spore oil was digested using a microwave digestion system. Pretreatment with a nitric acid and hydrogen peroxide acid system was carried out for the digestion process. This reduced the use of acid and allowed the digestion to be more complete. The concentrations of 24 trace elements in G. lucidum spore oil were determined by inductively coupled plasma mass spectrometry (ICP-MS) in collision mode. The results indicated that G. lucidum spore oil was rich in calcium, phosphorus, magnesium, iron, potassium, and zinc, followed by sodium, tin, strontium, chromium, copper, boron, and manganese. Furthermore, the concentrations of the toxic trace elements lead, arsenic, and mercury were lower than the limits required for health food pollutants. For all measured elements, the linear range of mercury was 0~1 μg/L, and the linear ranges of other elements were 0~100 μg/L. The limit of detection for the instrument ranged from 0.03~7.0 μg/L. The limit of quantitation for the method was in the range of 0.1–23.33 μg/kg. The recoveries ranged from 84.16% to 107.00%, and the relative standard deviations were between 0.83% and 4.25% (n=6). In conclusion, the method demonstrates high precision and sensitivity, and yields reliable results.

Abstract:Lycium ruthenicum Murray (Black Chinese wolfberry) is a unique plant with both medical and dietary applications and has been an important source of study in both traditional medicine and modern pharmacological research. Currently, L. ruthenicum has been widely used as a health supplement, drawing attention to its quality and safety. As a major production region, Qinghai Province produces better quality L. ruthenicum compared to other regions and the former is very popular among consumers. Our study demonstrated that L. ruthenicum from Nuomuhong and Jinyu Lake, two major production areas in Qinghai Province, contained higher levels of active ingredients, such as anthocyanin and total flavonoids, as compared with L. ruthenicum from the Xinjiang Uygur Autonomous Region. Moreover, no residual carbendazim, imidacloprid, or avermectin was detected in L. ruthenicum from the two production regions, and the bacterial examinations for Salmonella and Staphylococcus aureus showed negative results, meeting the green food standards of Ministry of Agriculture. However, heavy metal measurement indicated that chromium content exceeded the national food limit. Therefore, prevention of heavy metal pollution should be of immense importance for improving L. ruthenicum quality in the future plantation, production, and processing practices.

Abstract:The bacterial contamination of ready-to-eat (RTE) beef products in Shanghai was investigated. Twenty RTE beef samples were randomly collected from five international supermarkets and five street vendors in Shanghai, China. The total number of bacterial colonies was measured using the culture method, and ten colonies from each sample were randomly selected for bacterial classification and identification by 16S rRNA gene sequencing. The average total colony counts of the beef samples collected from the supermarkets and street vendors were 1.08±1.73×108 CFU/g and 2.84±8.49×108 CFU/g, respectively; there was no statistically significant difference (p>0.05) between them, but both were higher than the national standard of China (≤8×104 CFU/g). Pathogens that could cause severe food poisoning were not detected in any sample, but several operational taxonomic units (OTUs) that were closely related to food poisoning, urinary tract infections, pneumonia, mastitis, and bacteremia were detected. The results suggest that RTE foods are an important but often overlooked reservoir for pathogenic microorganisms, and we should strengthen our hygienic practices and management of RTE foods to reduce the risk of food-borne disease caused by them.

Abstract:In the field of food science, protein and polysaccharide glycosylation based on Maillard reaction mechanism is an effective and green method for protein modification, and belongs to the category of chemical modification of protein. In this reaction, protein is covalently grafted with sugar, and the reaction proceeds spontaneously by heating alone and does not require addition of any chemical catalyst. Previous studies have shown that protein glycosylation is one of the effective ways to improve the functional properties and other application features of proteins. In this paper, the structure and reaction mechanism of protein glycosylation, major function of sugar chain in protein glycosylation, method of glycosylation, and research directions of protein glycosylation were introduced and discussed. Due to certain limitations of protein glycosylation methods, it is difficult to achieve controllability, industrialization, and large-scale applications. The areas that receive wide attention include methodologies to utilize interdisciplinary approaches to study the existing glycosylation methods, and controllability and industrialization of the glycosylation process. Moreover, methods to expand the application of glycosylated products will also be a potential hot research topic in the future.

Abstract:The source, chemical components, biological activities, and utilization of pickling liquid from Prunus mume are summarized in this paper, and prospects for the development of future industrialization are also analyzed. Pickling liquid from Prunus mume is a by-product generated from the pickling of Prunus mume with salt. One ton of fresh Prunus mume fruit can produce approximately 0.5 tons of pickling liquid after the pickling process using salt is complete. This liquid contains a large amount of water, salt, and components from Prunus mume, including organic acids, soluble carbohydrates, phenolic compounds, and minerals, and possesses antioxidant activity, antimicrobial activity, and other biological activities. The main organic acids are citric acid and malic acid, while the dominant phenolic compounds are neochlorogenic, chlorogenic, and cryptochlorogenic acids. At present, pickling liquid from Prunus mume has been mainly used in the development of pickled flavored foods, seasoning products, drinks, and functional foods. In the future, the traditional pickling method for Prunus mume will be gradually shifted from pickling with salt to sugar, Prunus mume juice and drinks will be developed, and no more pickling liquid will be produced. Conventional salt pickling liquid from Prunus mume has good industrialization prospects in the production of seasoning products and functional drinks.