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Wu J.,Shanghai JiaoTong University | Du B.,SGS CSTC Standards Technical Services Co. | Li J.,Bright Dairy and Food Co. | Zhang H.,Shanghai JiaoTong University
LWT - Food Science and Technology | Year: 2014

The present work deals with the influences of both homogenisation and the degradation of carboxymethylcellulose (CMC) on the stability of two kinds of acidified milk drinks (AMDs), directly acidified milk drinks and yoghurt drinks. The effect of homogenisation pressure for direct acidification process was investigated and evaluated. The experimental results showed that homogenisation was required to achieve a significantly small particle size (0.7μm in the present work) and to prevent sedimentation and serum separation. However, homogenisation at too high pressures was not beneficial for the stability of the colloidal systems. The occurrence of degradation of CMC during homogenisation weakened the stabilisation effect of CMC. A qualified homogenisation pressure of 20MPa should be chosen to achieve a good stability when a usually practical pressure range of 0-30MPa was applied. In addition, the stability of directly acidified milk and yoghurt drinks prepared under the same homogenisation pressure was also investigated. While their stability increased with increasing CMC concentration, the degradation of CMC at low pH during storage gave rise to instability of the final products. © 2013 Elsevier Ltd.


Yang N.,Jiangnan University | Jin Y.,Jiangnan University | Wang H.,SGS CSTC Standards Technical Services Company Ltd | Duan X.,Jiangnan University | And 3 more authors.
Journal of Food Engineering | Year: 2015

This study was aimed to establish a detecting system based on transformer method to evaluate moisture content and conductivity of egg albumen and yolks during storage. Results showed that the decrease in impedance of albumen and yolk resulted in the increase in the secondary terminal voltage during the eggs' storage. Terminal voltage positively correlated with electric conductivity, regardless of frequency. The highest linear coefficient of determination (0.9955) between moisture content of yolk and terminal voltage at 50 Hz was observed. Exponential correlations emerged between the eggs' conductivity and terminal voltage, with highest coefficient of determination (R2 = 0.8311 for albumen, R2 = 0.9772 for yolk) at 200 Hz and 400 Hz, respectively. The correlations obtained in frequencies ranging from 50 to 400 Hz at 10 V laid the foundation for a method of evaluating moisture content and conductivity in albumen and yolks. Results facilitate an alternative application of the technique for rapid evaluation of the quality indices of liquid food products. © 2015 Elsevier Ltd.


Zhou Y.-Y.,Chinese Research Academy of Environmental Sciences | Zhang C.-Y.,Chinese Research Academy of Environmental Sciences | Yan Z.-G.,Chinese Research Academy of Environmental Sciences | Li K.-J.,Chinese Research Academy of Environmental Sciences | And 6 more authors.
Analytica Chimica Acta | Year: 2012

A micro-solid-phase extraction (μ-SPE) device was developed by filling copper(II) isonicotinate coordination polymer (Cu(4-C 5H 4N-COO) 2(H 2O) 4) into a porous polypropylene envelope, and the μ-SPE, coupling with gas chromatography (GC) with a micro-cell electron capture detector (μ-ECD), was used for extraction and determination of PBDEs in soils. Variables affecting extraction procedures, including temperature, water volume, extraction time, and desorption time, were investigated in a spiked soil, and the parameters were optimized. Under the optimal experimental conditions, the method detection limits for seven PBDEs (BDE-28, 47, 99, 100, 153, 154, and 183) were in the range of 0.026-0.066ngg -1, and the reproducibility was satisfactory with the relative standard deviation in range of 1.3-10.1%. Good linear relationship between PBDEs concentrations and GC signals (defined as peak area) was obtained in the range between 0.1 and 200ngg -1. The recovery of the seven PBDEs by μ-SPE varied from 70 to 90%, which was comparable to that determined by accelerated solvent extraction method. Finally, the proposed method was used to determine PBDEs in several field-contaminated soils, and it was suggested that the μ-SPE is a promising alternative microextraction technique for the detection of PBDEs in soils. © 2012 Elsevier B.V.


Ouyang C.,Kingfa Science and Technology Co. | Luo J.,SGS CSTC Standards Technical Services Co. | Wang Y.,Nankai University | Zhang Z.,Nankai University
Lizi Jiaohuan Yu Xifu/Ion Exchange and Adsorption | Year: 2012

The composites between poly(lactic acid) (PLA) and Modified Multiwalled Carbon Nanotubes (MWCNTs) were prepared by solution mixing with CHCl 3. The acidification and esterification of MWCNTs were confirmed by Raman spectroscopy and thermogravimetric (TG) analysis, respectively. Scanning electron microscopy (SEM) results demonstrated the compatibility of the composites. With increasing the content of the modified MWCNTs in the composites, the dispersion of the system became well, and the compatibility was also improved. The further experimental results showed that the mechanical properties of the composites were improved because of good dispersity of modified MWCNTs in the PLA matrix, and the tensile strength reached up to 120.4MPa when the content of the modified MWCNTs was added to 1.5%.


Zhu D.,Chinese Academy of Agricultural Sciences | Mu Y.,SGS CSTC Standards Technical Services Co. | Li Q.,Chinese Academy of Agricultural Sciences | Pang X.,Chinese Academy of Agricultural Sciences | And 4 more authors.
Analytical Methods | Year: 2016

A novel method for leucomalachite green (LMG) hapten synthesis was presented. This method could introduce a pure alkyl chain at the para-position of LMG to form a spacer arm for hapten preparation. It also could be expanded to prepare a series of haptens with different lengths of spacer arms by increasing the lengths of alkyl chains. This synthesis is easy to operate with high yield. In order to find out the best match coating antigens, three other haptens were synthesized. Polyclonal antibodies against LMG were developed by using the above synthesized antigens. The sensitivity and specificity were examined by indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) by optimizing the types of coating antigens and the concentrations of the antigens and antiserum. We demonstrate that the antibody developed from the hapten with a pure alkyl chain gives the best performance. We also reported that heterogenous coating antigen gives better sensitivity in this ELISA method development. The ELISA assay was further used to analyze the LMG residue in fish tissue with an IC50 value of 2.2 ng mL-1 and a limit of detection (LOD) of around 0.06 ng mL-1. Recoveries ranged from 79.8-92.4%, indicating that the IC-ELISA could be used for effective and low-cost analysis of LMG in fish samples. © The Royal Society of Chemistry 2016.


Zhu H.,Fudan University | Wang W.,SGS CSTC Standards Technical Services Co. | Liu T.,Fudan University
Journal of Applied Polymer Science | Year: 2011

Thermal and smoke properties of poly(vinyl chloride)/copper-containing layered double hydroxide (MgCuAl-LDH) composites were studied in this article. Highly crystallized LDH with platelet size at micrometer scale was prepared via urea hydrolysis and further intercalated with a variety of anions. X-ray diffraction results indicated an enlargement of basal spacing to 2.54 nm for dodecylsulfonate-intercalated LDH. The effects of LDHs on thermal stability and degradation behavior of PVC were investigated by Congo Red tests and thermogravimetric analysis (TGA). By incorporating 3 wt % LDHs, the thermal stability times of carbonated MgAl-LDH and MgCuAl-LDH/PVC composites were even three and five times of that of neat PVC. The TGA showed an increase of polyene sequences and char residues formed during PVC pyrolysis. MgCuAl-LDH/PVC composites gave the best reduction in maximum density of smoke, i.e., 25% lower than that of MgAl-LDH/PVC composites. However, the organomodification of LDH by anion exchange gave no contribution to improvement of thermal stability of PVC. © 2011 Wiley Periodicals, Inc.

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