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Liu G.,Beijing Technology and Business University | Liu G.,Beijing Advanced Innovation Center for Food Nutrition and Human Health | Song Z.,Beijing Technology and Business University | Yang X.,Beijing Technology and Business University | And 6 more authors.
Food Control | Year: 2016

Bifidocin A, a novel broad-spectrum bacteriocin produced by Bifidobacterium animalis BB04, was isolated from the feces of a healthy centenarian. To understand the mechanism of the antibacterial action of bifidocin A against gram-negative bacteria, its effects at a minimum inhibitory concentration on cell morphology, intracellular organization, membrane permeability, membrane integrity, and membrane proton motive force (PMF) of Escherichia coli 1.90 were investigated. Scanning and transmission electron microscopy analyses showed that bifidocin A induced alterations in the morphology and intracellular organization of E. coli cells. The intracellular organization was more susceptible to changes induced by bifidocin A than the morphology. Bifidocin A treatment caused the leakage of K+ and inorganic phosphate, the release of ATP and UV-absorbing materials, and a collapse of the transmembrane electrical potential and pH gradient in E. coli cells. Confocal laser scanning microscopy images showed that E. coli cells treated with bifidocin A took up propidium iodide. These results suggested that the mechanism of action bifidocin A against E. coli involved dissipation of the PMF of the cytoplasmic membrane, an increase in membrane permeability, pore formation in the cell membrane, a change in membrane integrity, and complete cell disintegration. © 2015 Elsevier Ltd.


Ge S.,Beijing Advanced Innovation Center for Food Nutrition and Human Health | Zhang M.,Beijing Technology and Business University | Zhang M.,China Agricultural University | Hou C.,China Agricultural University | And 6 more authors.
Journal of Chinese Institute of Food Science and Technology | Year: 2016

Quinoline compounds had become common environmental pollutants, various kind of quinolone compounds were genotoxic and have the potential to induce cancer. In this study, a HPLC method was used to determine the degradation of 4HAQO, a powerful carcinogenicquinoline compound, induced by the secretion of L. Salivarius Ren and helped in degenotoxic activity. By means of molecular weight cutting off and enzyme treatment, we indicated that, it was the H2O2 in the secretion of L. Salivarius Ren that played the essential role during 4HAQO degradation. © 2016, Chinese Institute of Food Science and Technology. All right reserved.


Zhang N.,China Agricultural University | Chen H.,Beijing Technology and Business University | Sun B.,Beijing Advanced Innovation Center for Food Nutrition and Human Health | Mao X.,China Agricultural University | And 2 more authors.
International Journal of Molecular Sciences | Year: 2016

To compare the volatile compounds of Chinese black truffle and white truffle from Yunnan province, this study presents the application of a direct solvent extraction/solvent-assisted flavor evaporation (DSE-SAFE) coupled with a comprehensive two-dimensional gas chromatography (GC × GC) high resolution time-of-flight mass spectrometry (HR-TOF/MS) and an electronic nose. Both of the analytical methods could distinguish the aroma profile of the two samples. In terms of the overall profile of truffle samples in this research, more kinds of acids were detected via the method of DSE-SAFE. Besides, compounds identified in black truffle (BT), but not in white truffle (WT), or vice versa, and those detected in both samples at different levels were considered to play an important role in differentiating the two samples. According to the analysis of electronic nose, the two samples could be separated, as well. © 2016 by the authors; licensee MDPI, Basel, Switzerland.


PubMed | Yunnan ZhuoYi Food Company LTD, Beijing Technology and Business University, Beijing Advanced Innovation Center for Food Nutrition and Human Health and China Agricultural University
Type: Comparative Study | Journal: International journal of molecular sciences | Year: 2016

To compare the volatile compounds of Chinese black truffle and white truffle from Yunnan province, this study presents the application of a direct solvent extraction/solvent-assisted flavor evaporation (DSE-SAFE) coupled with a comprehensive two-dimensional gas chromatography (GC GC) high resolution time-of-flight mass spectrometry (HR-TOF/MS) and an electronic nose. Both of the analytical methods could distinguish the aroma profile of the two samples. In terms of the overall profile of truffle samples in this research, more kinds of acids were detected via the method of DSE-SAFE. Besides, compounds identified in black truffle (BT), but not in white truffle (WT), or vice versa, and those detected in both samples at different levels were considered to play an important role in differentiating the two samples. According to the analysis of electronic nose, the two samples could be separated, as well.


Zhao F.,China Agricultural University | Zhao F.,Key Laboratory of Fruit and Vegetable Processing | Wang Y.,China Agricultural University | Wang Y.,Key Laboratory of Fruit and Vegetable Processing | And 8 more authors.
mBio | Year: 2016

The formation of viable but nonculturable (VBNC) Escherichia coli O157:H7 induced by high-pressure CO2(HPCD) was investigated using RNA sequencing (RNA-Seq) transcriptomics and isobaric tag for relative and absolute quantitation (iTRAQ) proteomic methods. The analyses revealed that 97 genes and 56 proteins were significantly changed upon VBNC state entry. Genes and proteins related to membrane transport, central metabolisms, DNA replication, and cell division were mainly downregulated in the VBNC cells. This caused low metabolic activity concurrently with a division arrest in cells, which may be related to VBNC state formation. Cell division repression and outer membrane overexpression were confirmed to be involved in VBNC state formation by homologous expression of z2046 coding for transcriptional repressor and ompF encoding outer membrane protein F. Upon VBNC state entry, pyruvate catabolism in the cells shifted from the tricarboxylic acid (TCA) cycle toward the fermentative route; this led to a low level of ATP. Combating the low energy supply, ATP production in the VBNC cells was compensated by the degradation of L-serine and L-threonine, the increased AMP generation, and the enhanced electron transfer. Furthermore, tolerance of the cells with respect to HPCD-induced acid, oxidation, and high CO2stresses was enhanced by promoting the production of ammonia and NADPH and by reducing CO2production during VBNC state formation. Most genes and proteins related to pathogenicity were downregulated in the VBNC cells. This would decrease the cell pathogenicity, which was confirmed by adhesion assays. In conclusion, the decreased metabolic activity, repressed cell division, and enhanced survival ability in E. coli O157:H7 might cause HPCD-induced VBNC state formation. IMPORTANCE Escherichia coli O157:H7 has been implicated in large foodborne outbreaks worldwide. It has been reported that the presence of as few as 10 cells in food could cause illness. However, the presence of only 0.73 to 1.5 culturable E. coli O157:H7 cells in salted salmon roe caused infection in Japan. Investigators found that E. coli O157:H7 in the viable but nonculturable (VBNC) state was the source of the outbreak. So far, formation mechanisms of VBNC state are not well known. In a previous study, we demonstrated that high-pressure CO2(HPCD) could induce the transition of E. coli O157:H7 into the VBNC state. In this study, we used RNA-Seq transcriptomic analysis combined with the iTRAQ proteomic method to investigate the formation of VBNC E. coli O157:H7 induced by HPCD treatment. Finally, we proposed a putative formation mechanism of the VBNC cells induced by HPCD, which may provide a theoretical foundation for controlling the VBNC state entry induced by HPCD treatment. © 2016 Zhao et al.


Gao G.,Beijing Advanced Innovation Center for Food Nutrition and Human Health | Gao G.,China Agricultural University | Gao G.,National Engineering Research Center for Fruit & Vegetable Processing | Gao G.,Key Laboratory of Fruit & Vegetable Processing | And 24 more authors.
Food and Bioproducts Processing | Year: 2016

High hydrostatic pressure (HHP) and thermal processing of strawberry in ethylene vinyl alcohol copolymer cups were evaluated by examining their impacts on microorganism survival and growth, texture, nutritional properties (total phenols, total anthocyanins and antioxidant capacity) and color during 45 days of storage at 4 and 25 °C. During storage, total aerobic bacteria and yeasts and molds were not detected in all treated samples except for those HHP-treated and stored at 25 °C (3.08 and 2.58 log10 CFU/g at day 45, respectively). There was a reduction in hardness, total phenols, total anthocyanins and antioxidant capacity of flesh, being more striking in samples stored at 25 °C and thermal processing treated samples, and an increase in viscosity, total phenols, total anthocyanins and antioxidant capacity of syrup during storage. Moreover, a significant decrease in the total level of nutritional properties in cupped strawberry (combined flesh and syrup) was observed during storage. All samples showed noticeable color changes, and ΔE values significantly increased during storage. Samples treated by HHP and stored at 4 °C showed higher hardness, total phenols, total anthocyanins and antioxidant capacity and better color than samples treated by thermal processing and stored at 25 °C, indicating that HHP processing and lower storage temperature were very useful tool in preserving the quality of cupped strawberry. © 2016 Institution of Chemical Engineers


Wang X.,Beijing Advanced Innovation Center for Food Nutrition and Human Health | Wang X.,China Agricultural University | Wang D.,Beijing Advanced Innovation Center for Food Nutrition and Human Health | Wang D.,China Agricultural University | And 8 more authors.
Environmental Pollution | Year: 2016

Understanding of xenobiotic metabolism is necessary for risk assessment as well as toxicological research. In the present study, nanoLC/LTQ-Orbitrap mass based non-targeted metabolomics method coupled with ultra-performance liquid chromatography (UPLC)/triple quadrupole mass based targeted metabolomics method was carried out to investigate the stereoselective metabolism of benalaxyl in mouse hepatic microsomes. As a result, 7 metabolites of benalaxyl were identified, including 5 previously reported and 2 newly identified metabolites in present work. Hydroxylation, oxidation and esterolysis were major biotransformation reactions of benalaxyl in mouse hepatic microsomes. For stereoselective metabolism study, (-)-R-benalaxyl degraded much faster than its antipode with the t1/2 of 81.24 and 190.38 min for (-)-R- and (+)-S-benalaxyl, respectively. More importantly, stereoselectivity was also observed in the formation of the identified metabolites. In conclusion, the combined use of the mass spectrometry based targeted and non-targeted metabolomics provided a new approach to investigate stereoselective metabolism and identify novel metabolites of chiral pesticides. This study highlights the stereoselective metabolic profile of benalaxyl enantiomers and provides reliable data for benalaxyl toxicological risk assessment in mammal. © 2016 Elsevier Ltd. All rights reserved.


Chen L.,Beijing Advanced Innovation Center for Food Nutrition and Human Health | Chen L.,China Agricultural University | Xu P.,CAS Research Center for Eco Environmental Sciences | Diao J.,China Agricultural University | And 5 more authors.
Journal of Hazardous Materials | Year: 2016

Beta-cypermethrin (BCYP), a synthetic pyrethriod (PYR) pesticide which is a mixture of the alpha- and theta- cypermethrin, have been reported various toxicological profiles to non-target organisms. But little is known about assimilation, accumulation and toxic effects of BCYP in reptiles. The present study firstly elucidated absorption, tissue distribution, excretion of BCYP in Eremias argus Treated group were administered orally with BCYP 20 mg/kg body weight (bw) dissolved in corn oil. Neurotoxicity was observed at 24 h after gavage, and the poisoning symptom ameliorated at 72 h. The changes of BCYP concentration depended on degradation time and tissues. Lizards had a strong capacity to eliminate BCYP with different tissue distribution. The tissues concentration of BCYP from high to low were intestine, stomach, heart, kidney, blood, lung, liver and brain. Bimodal phenomena were observed in lung, liver and kidney. These results may be due to the activities of enzymes, circadian rhythm, and enterohepatic circulation in lizards. Based on the results of organ coefficient and histopathology analysis in liver, the liver was confirmed as the main target organ. © 2015 Elsevier B.V.


Fan H.,Beijing Advanced Innovation Center for Food Nutrition and Human Health | Liu X.,Beijing Advanced Innovation Center for Food Nutrition and Human Health | Hong H.,Beijing Advanced Innovation Center for Food Nutrition and Human Health | Shen S.,Beijing Advanced Innovation Center for Food Nutrition and Human Health | And 4 more authors.
Journal of Food Protection | Year: 2016

Postmortem quality changes of black carp (Mylopharyngodon piceus) fillets stored at 20, 4, and 08C (in ice) were determined in terms of pH value, K value, total volatile basic nitrogen, free amino acids, biogenic amines, drip loss, electrical conductivity (EC), sensory score, and microbial growth. The results showed that black carp fillets could maintain a good quality for 2, 9, and 12 days when stored at 20, 4, and 08C, respectively. Pseudomonads, Aeromonas, and Enterobacteriaceae were the main spoilage bacteria in black carp. Tryptamine, 2-phenylethylamine, putrescine, cadaverine, and tyramine increased significantly (P , 0.05) during storage at the three temperatures, but not spermidine and spermine, among which tyramine and putrescine were the main biogenic amines in black carp fillets. A significantly higher concentration of histamine (132.05 mg/kg on the third day) was detected in the samples stored at 208C (P , 0.01) than at 4 and 08C (0.62 to 3.28 mg/kg) throughout storage, indicating storage of samples at 208C favored the formation of histamine. The accumulations of tyramine, cadaverine, and histamine were highly correlated with the productions of tyrosine, lysine, and histidine, respectively. Correlations between EC and sensory, physical, chemical, and microbial parameters at the three storage temperatures showed that EC could be used as a better quality indicator to assess the overall quality of fish stored at 4 and 08C (low temperature) than at 208C. © Copyright International Association for Food Protection.


Liu F.,Huazhong Agricultural University | Liu F.,China Agricultural University | Liao X.,China Agricultural University | Liao X.,Beijing Advanced Innovation Center for Food Nutrition and Human Health | Wang Y.,China Agricultural University
Food and Bioprocess Technology | Year: 2016

The effects of high-pressure processing (HPP 300 MPa/15 min, 400 MPa/5 min, 500 MPa/2.5 min, and 600 MPa/1 min) and high-temperature/short-time processing (HTST 110 °C/8.6 s), with or without blanching, on mango pulp were comparatively evaluated in terms of the antioxidant compounds, antioxidant capacity, sugars, and color. Blanching treatment significantly increased the total phenol content and the antioxidant capacity of mango pulp, but did not change the levels of L-ascorbic acid, carotenoids, sugars, and visual color (total color difference, △E < 2.00). Both HPP and HTST treatments significantly increased the total phenol content and antioxidant capacity of un-blanched mango pulp, but no significant changes occurred in the blanched mango pulp. HPP did not affect the levels of L-ascorbic acid, carotenoids, and sugars in mango pulp regardless of blanching. However, HTST significantly decreased the fructose and glucose levels, as well as induced the isomerization of β-carotene, with the increase in 13-cis-β-carotene accompanied by the decrease in all-trans-β-carotene. Moreover, HPP-treated mango pulp consistently showed lower △E values than those HTST-treated samples, regardless of blanching. © 2016 Springer Science+Business Media New York

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