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Shanghai, China

Wang S.,Fuzhou University | Zhao J.,Fuzhou University | Xu Z.,Fudan University | Wu J.,Bor Luh Food Safety Center
Applied Mechanics and Materials | Year: 2012

Antifreeze proteins have characteristics of inhibiting the growth of crystals, decreasing the injury of cells and can retain the structure, texture and quality of productions. The purpose of this study is to obtain natural antifreeze peptides, and to investigate the hypothermia protection activity on bacteria. Gelatin derived from shark skin was hydrolysed to obtain antifreeze peptides. The most appropriate protease and hydrolysis time was selected with the index of the hypothermia protection activity on bacteria. The hydrolysate was subsequently added on to Sephadex G-50 gel filtration column and SP-Sephadex C-25 column to acquire high activity fractions. The fraction of cationic peptides termed P2 shows higher antifreeze activity. The hypothermia protection assay shows that the survival rate of E.COLI was 80.8 % when the concentration of peptides complexes was up to 500 μg/mL. Source

Wu J.,Bor Luh Food Safety Center | Wang S.,Fuzhou University | Wu Y.,Bor Luh Food Safety Center | Wang Z.,Bor Luh Food Safety Center
Applied Mechanics and Materials | Year: 2012

In this study, cryoprotective effects of sericin enzymatic peptides (SEP) on the freeze-induced denaturation of grass carp surimi were evaluated on the basis of sulfhydryl content and surface hydrophobicity of actomyosin, as well as the SDS-PAGE pattern of myosin heavy chain (MHC) of myofibrillar proteins. Results: show that SEP, containing a high polar amino acid content and abundant in amino acids with hydroxyl-containing side chain (Ser and Thr), was effective in preventing the decrease of SH content, slowing down the exposure of buried hydrophobic residues on the protein surface, and retarding the degradation of MHC in a non-linear dosage-dependent way. These findings suggest that SEP obtained in our study appear to be a promising cryoprotectant applied in the frozon storage of surimi. Source

Hu G.,Bright Dairy and Food Co. | Hu G.,Bor Luh Food Safety Center | Hu G.,Shanghai JiaoTong University | Zheng Y.,Bright Dairy and Food Co. | And 8 more authors.
High Pressure Research | Year: 2015

The effects of ultraviolet-C radiation (UV-C, 11.8W/m2), single-cycle and multiple-cycle high hydrostatic pressure (HHP at 200, 400 or 600MPa) on microbial load and physicochemical quality of raw milk were evaluated. Reductions of aerobic plate count (APC) and coliform count (CC) by HHP were more than 99.9% and 98.7%, respectively. Inactivation efficiency of microorganisms increased with pressure level. At the same pressure level, two-cycle treatments caused lower APC, but did not show CC differences compared with single-cycle treatments. Reductions of APC and CC by UV-C were somewhere between 200MPa and 400/600MPa. Both HHP and UV-C significantly decreased lightness and increased pH, but did not change soluble solids content and thiobarbituric acid-reactive substances values. Two 2.5min cycles of HHP at 600MPa caused minimum APC and CC, and maximum conductivity. Compared with HHP, UV-C markedly increased protein oxidation and reduced darkening. © 2015 Taylor & Francis. Source

Li X.,Bor Luh Food Safety Center | Li X.,GMO Detection Laboratory | Shen K.,Bor Luh Food Safety Center | Yang L.,Bor Luh Food Safety Center | And 3 more authors.
Food Control | Year: 2010

Plasmid molecule based reference material (RM) has been shown to be a good alternative as the calibrator for genetically modified organisms (GMOs) identification and quantification, while most of the currently developed plasmid RM can only be used for one specific target detection. In this study, a flexible plasmid RM pNK containing three DNA fragments, i.e. 5′ and 3′ event-specific sequences of maize NK603 and endogenous gene zSSIIb, was developed. We have proved that pNK is suitable for using as a calibrator in both 5′ and 3′ event-specific detection of maize NK603, compared with that of genuine genomic DNA. The limit of detection (LOD) was 10 copies of pNK DNA in conventional PCR assays. The absolute LOD and limit of quantification (LOQ) in quantitative PCR assays were 5 and 25 copies. The standard curves targeting to zSSIIb, 5′ and 3′ event-specific sequences based on pNK DNA showed high reaction efficiency and good linearity. Also, low bias and variations were obtained in practical samples quantification using pNK as the calibrator. These results demonstrated that the developed pNK is flexible and suitable for identification and quantification of maize NK603, as a preferable substitute of RM from the plant raw material. © 2009 Elsevier Ltd. All rights reserved. Source

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