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Zhou J.,China Agricultural University | Wang X.,China Agricultural University | Ai T.,China Agricultural University | Cheng X.,China Agricultural University | And 3 more authors.
Journal of Dairy Science | Year: 2012

The purpose of this study was to determine the best preparation condition of β-lactoglobulin hydrolysate-iron complexes and characterize its structural transformation both before and after binding using the UV-visible absorption spectrum, Fluorescence spectrum, and Fourier transform infrared spectroscopy. Results showed that β-lactoglobulin hydrolysates obtained with alcalase after hydrolysis for 6h possessed the highest iron-binding capacity. The highest yield of complexes was obtained when the mass ratio between β-lactoglobulin hydrolysate and Fe3+ reached 40:1, with the optimal pH value of 7.0. All of the spectra indicated that some sites such as amido bonds transformed during chelation, and nitrogen atoms could chelate with Fe3+ to form coordinate bonds by offering electron pairs. Therefore, β-lactoglobulin hydrolysate-iron complexes may be good carriers for iron and possess great potential to be used as iron supplements. © 2012 American Dairy Science Association.

Yang S.,China Agricultural University | Mao X.-Y.,China Agricultural University | Li F.-F.,China Agricultural University | Zhang D.,China Agricultural University | And 3 more authors.
European Food Research and Technology | Year: 2012

Although whey protein hydrolysate (WPH) possesses good physiological functionality, its bitter taste and hygroscopic property limit its direct utilization as food ingredient. The aim of this work was to encapsulate whey protein hydrolysate by spray drying using maltodextrin or maltodextrin/β-cyclodextrin mixture as wall materials to attenuate the bitter taste and enhance the stability of whey protein hydrolysate. Hygroscopicity, glass transition temperature, bitter taste, and morphology of non-encapsulated WPH and encapsulated WPH were evaluated. Solubility, particle size, bulk density, and moisture content were also measured. Compared with the non-encapsulated WPH, the encapsulated WPH exhibited significantly lower hygroscopicity and higher glass transition temperature. The bitterness of both maltodextrin-encapsulated WPH and maltodextrin/β-cyclodextrin-encapsulated WPH was significantly lower than that of the original non-encapsulated WPH. Morphological analysis by scanning electron microscopy showed that the microcapsules of the spray-dried encapsulated WPH were matrix-type with less link bridge and had a continuous wall with many concavities. In addition, encapsulation process did not exert negative effect on the solubility of whey protein hydrolysate. The results indicated that encapsulation with maltodextrin and β-cyclodextrin as carriers was helpful to attenuate the bitter taste and enhance the stability of whey protein hydrolysate. © 2012 Springer-Verlag.

Chen L.-S.,Harbin Institute of Technology | Ma Y.,Harbin Institute of Technology | Maubois J.-L.,French National Institute for Agricultural Research | Maubois J.-L.,Agrocampus Ouest | And 3 more authors.
Dairy Science and Technology | Year: 2010

Consumption of dairy products containing probiotics with cholesterol-lowering activity has been proposed as a means to lower serum cholesterol. In the present work, 19 yeast strains, isolated from raw milk, were tested to obtain potential probiotic yeasts for assimilating cholesterol. During in vitro tests, 17 yeast strains were capable of growth in bile salt solutions, and most of the yeast strains tolerated low pH, surviving in gastric juice. Among the 19 strains assessed, Geotrichum sp. BY2 and Pichia kudriavzevii BY10 showed highest adhesive ability to HT-29 cells. All yeast strains were able to assimilate cholesterol in the range of 3.6-44.4% over a 72 h incubation, and seven of the yeast strains were significantly higher at assimilating cholesterol (P < 0.05). According to these results, the yeast strains P. fermentans BY5, P. kudriavzevii BY10, P. kudriavzevii BY15 and Yarrowia lipolytica HY4 may serve as potential probiotics to assimilate cholesterol in the human intestine. © INRA, EDP Sciences, 2010.

Li X.,Dalian Polytechnic University | Mu G.,Dalian Polytechnic University | Chen L.,Dalian Polytechnic University | Jiang T.,Beijing Sanyuan Foods Co.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui | Year: 2013

An analytical method was developed for the determination of the residues of five environmental estrogens, including estriol, estradiol, estrone, bisphenol A and diethylstilbestrol, in the cow feed and soil by solid phase extraction (SPE) and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The important parameters which affect the determination efficiency such as the mobile phase, the condition of mass spectrometry and solid phase extraction column were optimized. The optimal determination conditions were as follows: the sample was extracted with acetonitrile at first, then cleaned-up with an NH2-SPE column, and an Acquity UPLC HSS T3 column was selected to separate the analytes. Acetonitrile-methanol (4: 1, v/v) and 0.01% ammonia aqueous solution were used as the mobile phase by gradient elution in the negative mode. The limits of detection (LOD, S/N = 3) were 0.06 - 0.22 microg/kg. The overall recoveries varied from 81.70% to 102.20%, and the relative standard deviations (RSDs) were all less than 10.00%. This method is simple, sensitive and accurate, and suitable for the determination of environmental estrogens in cow feed and soil.

Chen L.-S.,Harbin Institute of Technology | Ma Y.,Harbin Institute of Technology | Maubois J.-L.,French National Institute for Agricultural Research | Chen L.-J.,Beijing Sanyuan Foods Co. | And 2 more authors.
International Journal of Dairy Technology | Year: 2010

Eleven different species of yeasts isolated from raw milk, such as Issatchenkia orientalis, Pichia fermentans, Rhodotorula mucilaginosa and Yarrowia lipolytica were identified using an integrated approach, including phenotypic and genotypic methods and the API 20C AUX system. Eleven selected strains which tolerated low pH levels, gastric juice and bile salt were further analysed for the presence of functional traits useful for probiotic application as antioxidants. The ability to scavenge DPPH (2, 2-diphenyl-1-picrylhydrazyl) and inhibit linoleic acid peroxidation indicated that P. fermentans BY5 and HJ15 may be promising candidate strains for use as probiotics with antioxidant activity. © 2009 Society of Dairy Technology.

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