Food Safety Key Laboratory of Liaoning Province

Jinzhou, China

Food Safety Key Laboratory of Liaoning Province

Jinzhou, China
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Li Y.C.,Bohai University | Zhang X.,Food Safety Key Laboratory of Liaoning Province
Advanced Materials Research | Year: 2014

Polyphenols from Porphyra are important biological active substances. The effects of temperature, times, ethanol concentration and liquid to solid ratio were studied for the extraction yield of polyphenols from Porphyra through a single-factor exploration.Then, through an orthogonal experiment, it was investigated to get the best extraction conditions. The content of polyphenols was determined by Folin-Ciocalteu method. Scavenging ability to oxygen free radicals was also assessed. The results show that extraction temperature is 75° C, the extraction time is 2.5 h, ethanol concentration is 70% and the ratio of liquid to solid is 25:1(mL/g).The proportion of the extraction of the polyphenols from Porphyra under these industrial process conditions is 6.263mg/g. Polyphenols from Porphyra have strong scavenging hydroxyl radical and superoxide anion radical. IC50 of polyphenols from Porphyra on hydroxyl radical and superoxide anion radical is 0.405 mg/mL, 0.539mg/mL, respectively. © (2014) Trans Tech Publications, Switzerland.


Meng H.-C.,South China University of Technology | Bi S.-L.,Guangdong Pharmaceutical University | Yan H.,South China University of Technology | Yan H.,Food Safety Key Laboratory of Liaoning Province | Shi L.,South China University of Technology
Huanan Ligong Daxue Xuebao/Journal of South China University of Technology (Natural Science) | Year: 2012

Eight poultry samples including chicken and duck were collected in a certain fresh market and were enriched in Bolton and Preston broths, followed by the inoculation on selective agar media (Skirrow and mCCDA) and by the membrane filtration. Then, the molecular types of the isolated Campylobacter strains were analyzed by means of pulse field gel electrophoresis (PFGE) and denaturing gradient gel electrophoresis (DGGE), and C. jejuni or C. coli were isolated from six samples. The results show that the combination of Preston broth and mCCDA media is the optimal isolation method, that there are four samples contaminated by the same C. coli isolate and two samples contaminated respectively by 2 species of C. jejuni and 3 species of C. coli, and that, though DGGE genotyping is not as sensitive as PFGE genotyping, it is more suitable for the rapid genotyping of Campylobacter in food borne because it is of high speed, low cost as well as stable and accurate operation.


Li Y.C.,Bohai University | Li Y.C.,Food Safety Key Laboratory of Liaoning Province | Wang Y.L.,Bohai University | Wang Y.L.,Food Safety Key Laboratory of Liaoning Province | And 2 more authors.
Advanced Materials Research | Year: 2014

Polysaccharide from Porphyra is a kind of important biological active substance. Therefore, it is significant to effectively develop and utilize the polysaccharide from porphyra and improve the economic and social benefits of porphyra. In this paper, polysaccharide was extracted by the method of hot water immersed extraction and ethanol precipitation. Extraction process of water-soluble polysaccharides from Porphyra was optimized by response surface methodology. The content of polysaccharide was determined by sulfuric acid to phenol method. The results show that the extraction time is 4.4 h, extraction temperature is 88°Cand the ratio of material to liquid is1:42(g/mL). Polysaccharide is precipitated with 5 folds volume of ethanol for 6 h. The proportion of the extraction of the porphyra polysaccharide under this industrial process conditions is 10.012%. © (2014) Trans Tech Publications, Switzerland.


Chen J.,Zhejiang Ocean University | Huang Y.T.,Zhejiang Ocean University | Deng S.G.,Zhejiang Ocean University | Li J.R.,Food Safety Key Laboratory of Liaoning Province
Advanced Materials Research | Year: 2013

Resting cells of Pseudomonas sp. SY031 were used for the direct transformation of adiponitrile to 5-cyanovaleramide (5-CVAM), which is an important intermediate of azafenidin, a new kind of herbicide with high efficiency, low toxicity and non-pollution. In this study, reaction conditions for this nitrile hydratase mediated conversion were optimized. It was observed that the maximum conversion of adiponitrile to 5-CVAM was in a solution containing 50 mM phosphate buffer (pH 6.4), 10 mM adiponitrile at 35°C. 10 mM adiponitrile was completely converted into 5-CVAM and adipamide in shaking flasks with 5-CVAM as the main product (9.004 mM) and adipamide as a low yield (0.896 mM), indicating high regio-selectivity of the nitrile hydratase in Pseudomonas sp. SY031. © (2013) Trans Tech Publications, Switzerland.


Li Y.,Bohai University | Li Y.,Food Safety Key Laboratory of Liaoning Province | Li Y.,Fresh Technology | Wang Y.,Bohai University | And 5 more authors.
Journal of Chinese Institute of Food Science and Technology | Year: 2016

The effects of natural preservative agents: chitosan, polyphenol from blueberry leaves and the compound fresh-keeping agent on the preservation of Peru squid fish balls during storage at 4℃ were investigated. Microbiology indictor (total bacterial count), chemical indictors (pH value, TVB-N value, formaldehyde content) and sensory evaluation were analyzed every 4 days. The results showed that chitosan, polyphenol from blueberry leaves and the compound fresh-keeping agent can inhibit microbial growth, decrease TVB-N value, which can enhance the hardness of fish-ball, but the effects on springiness are not obvious. Meanwhile, Formaldehyde content can be inhibited by polyphenol from blueberry leaves and the compound fresh-keeping agent at storage time. Chitosan, polyphenol from blueberry leaves have the effect of preservation on Peru squid fish balls during refrigerate. And the effect of compound fresh-keeping agent on Peru squid fish balls during refrigerate is the best. © 2016, Chinese Institute of Food Science and Technology. All right reserved.


Chen H.,Bohai University | Chen H.,Food Safety Key Laboratory of Liaoning Province | Zhang Y.-Y.,Bohai University | Zhang Y.-Y.,Food Safety Key Laboratory of Liaoning Province | And 11 more authors.
Journal of Hazardous Materials | Year: 2014

A diffusive gradients in thin films (DGT) device with polyquaternary ammonium salt (PQAS) as a novel binding agent (PQAS DGT) combined with graphite furnace atomic absorption spectrometry (GFAAS) was developed for the selective sampling and measurement of Cr (VI) in water. The performance of PQAS DGT was independent of pH 3-12 and ionic strength from 1×10-3 to 1molL-1. DGT validation experiments showed that Cr (VI) was measured accurately as well as selectively by PQAS DGT, whereas Cr (III) was not determined quantitatively. Compared with diphenylcarbazide spectrophotometric method (DPC), the measurement of Cr (VI) with PQAS DGT was agreement with that of DPC method in the industrial wastewater. PQAS-DGT device had been successfully deployed in local freshwater. The concentrations of Cr (VI) determined by PQAS DGT coupled with GFAAS in Nuer River, Ling River and North Lake were 0.73±0.09μgL-1, 0.50±0.07μgL-1 and 0.61±0.07μgL-1, respectively. The results indicate that PQAS DGT device can be used for the selective sampling and measurement Cr (VI) in water and its detection limit is lower than that of DPC method. © 2014 Elsevier B.V.


Xu Y.,Bohai University | Xu Y.,Food Safety Key Laboratory of Liaoning Province | Liu Y.,Bohai University | Liu Y.,Food Safety Key Laboratory of Liaoning Province | And 8 more authors.
International Journal of Food Properties | Year: 2016

The sensory, physicochemical, microbiological, and volatiles changes of postmortem turbot during 20 days of chilled storage at 4°C were studied. No significant changes were found in pH value and whiteness during the storage, while total viable counts, total volatile base nitrogen, and K-values increased significantly with storage time. The textures profile, springiness and resilience, and sensory attributes changed significantly during storage. A total of 50 volatile compounds including aldehydes, ketones, esters, alcohols, alkenes, alkanes, aromatics, amines, and others were identified in turbot muscle during storage by the solid-phase microextraction and gas chromatography-mass spectrometry methods. Among these volatile components, the relative content of some decreased significantly with time, while others increased significantly. The results suggested that hardness, springiness, resilience, sensory attributes, total volatile base nitrogen, K-value, and total viable counts combined with some volatile compounds could more perfectly reflect the quality changes of turbot during storage. The study indicated that turbot fillets stored at 4°C maintain better quality for 16 days during storage. © 2015 Taylor and Francis Group, LLC.


Zhu D.S.,Bohai University | Zhu D.S.,Food Safety Key Laboratory of Liaoning Province | Wang L.N.,Bohai University | Wang L.N.,Food Safety Key Laboratory of Liaoning Province | And 6 more authors.
Advanced Materials Research | Year: 2014

Three different plastic packaging (CPP, LDPE and HDPE) were researched on preservation of carp in this study, and the indicatiors of color difference and sensory evaluation were tracked. Color difference of carp block muscle was analyzed by CR-400 chroma meter, and the value of L*, a* and b* were measured at different stage of storage. At the same time, sensory evaluation was conducted. The results showed that the value of L* a* and b* all increased along with storage days, which indicated that the color of the carp block skin turning lighter, redder and yellower. The material of High Density Polyethylene (HDPE) could be better for keeping muscle color of carp during storage. However, the results of sensory evaluation showed that Cast Polypropylene (CPP) was better for keeping shelf quality of carp block. There was negative correlation between color difference and sensory evaluation. The value of b* could better represent sensory score in MAP, for it was correlate significantly with sensory evaluation in all three types of packaging. © (2014) Trans Tech Publications, Switzerland.


Di H.-L.,South China University of Technology | Yan H.,South China University of Technology | Yan H.,Food Safety Key Laboratory of Liaoning Province | Shi L.,South China University of Technology
Modern Food Science and Technology | Year: 2014

In order to find out CRISPRs in 18 lineage I (serotype1/2b, 4b) strains of food-borne Listeria monocytogens isolated from 2177 retail food samples in Hebei province, the CRISPR sequences were obtained by PCR amplification, and homology analysis was predicted using bioinformatic methods, then cluster typed by using a CRISPR-based approach. We detected three CRISPR loci in all studied strains. Loucus1 was most popular (13/18); locus2 and locus3, as two activity loci, were only detected at least one in 5 serotype 1/2b strains. Locus1, a putative remnant of a functional CRISPR ancestor, was beared unconserved repeats (DR1) and a few of spacers; locus2 and locus3, relative new functional structures, were beared conserved repeats (DR2, DR3) and fast growing number of spacers. In all, 2 strains containerd all three loci, 3 strains contained the first 2 of the three loci, as well as 8 strains only contained the first one locus, and 5 strains did not find any CRISPR structure. As the diversity of CRISPR arrays, 18 strains typed to 5 clusters (A~F), and 4 subset clusters (A1and A2, B1 and B2). CRISPR typing can be good used in differentiating serotype 1/2b strains. In other hands, the CRISPR structures, especially that beared more spacers, enhance the host's environmental adaptability, enlarged the clear difficulty in food processing, alarm the food safety. The government should reinforce the control of these kinds of L. monocytogenes.


Di H.-L.,South China University of Technology | Zhang Y.-Q.,South China University of Technology | Shan X.-X.,South China University of Technology | Yan H.,South China University of Technology | And 2 more authors.
Modern Food Science and Technology | Year: 2014

In this study, the usefulness of fatty acid typing to identify and evaluate strain similarity among Listeria monocytogenes (LM) strains was evaluated. Ninety LM strains isolated from six types of food in Hebei area from 2005 to 2007 were selected for this study. The fatty acids were extracted, and their components were analyzed using the MIDI Sherlock system. SPSS 19.0 statistical software was used for data and cluster analyses. The fatty acid typing was compared with traditional serotyping and pulsed-field gel electrophoresis (PFGE), which is the gold standard for typing. The results showed that the fatty acid analysis method successfully identified 96.67% of LM strains, 20 fatty acid components were detected from all of the tested strains, and the three main fatty acid components were 15:0 anteiso, 17:0 anteiso, and 15:0 iso. The fatty acid components differed among the different serotypes, and the differences in two main fatty acid components between serotype 1/2c isolates and serotype 1/2a, 1/2b, and 4b isolates were statistically significant (P〈0.01). Compared with PFGE typing, fatty acid typing was a more efficient method for identifying genetic relationships between strains in small samples with simple structures. The combination of fatty acid typing along with serotyping and PFGE typing could better identify correlations among LM strains. ©, 2014, South China University of Technology. All right reserved.

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