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ABSTRACT: Peanut shell, a byproduct in oil production, is rich in natural antioxidants. Here, a rapid and efficient method using DPPH-HPLC-DAD-TOF/MS was used for the first time to screen antioxidants in peanut shell. The method is based on the hypothesis that upon reaction with 1, 1-diphenyl-2-picrylhydrazyl (DPPH), the peak areas of compounds with potential antioxidant activities in the HPLC chromatogram will be significantly reduced or disappeared, and the identity confirmation could be achieved by HPLC-DAD-TOF/MS technique. With this method, three compounds possessing potential antioxidant activities were found abundantly in the methanolic extract of peanut shell. They were identified as 5,7-dihydroxychromone, eriodictyol, and luteolin. The contents of these compounds were 0.59, 0.92, and 2.36mg/g, respectively, and luteolin possessed the strongest radical scavenging capacity. DPPH-HPLC-DAD-TOF/MS assay facilitated rapid identification and determination of natural antioxidants in peanut shell, which may be helpful for value-added utilization of peanut processing byproducts.
Food Chemistry 12/2012; 135(4):2366-71. · 3.65 Impact Factor
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ABSTRACT: Far-UV circular dichroism (CD) spectroscopy was used to study the conformation of protein from soybean flour under the influence
of various reverse micelle environments and salt treatments, as compared with the protein using aqueous buffer extraction.
These proteins exhibited characteristic CD spectra that reflected a considerable amount of residual secondary structures.
The CD analysis showed that the protein modification by reverse micellar system was related to loss of α-helix and β-structure
and increase of random coil. The ellipticity of protein in bis (2-ethylhexyl) sodium sulfosuccinate (AOT) and sodium dodecyl
sulfate (SDS) reverse micelles was higher than in hexadecyl trimethyl ammonium bromide (CTAB) and TrionX-100. The CD spectra
in reverse micelles except for SDS at 210nm had lower intensity than in aqueous solution. Salts could influence the ellipticity
of protein at near 194nm in an order of NaCl > KNO3> > KCl > NaNO3 > Na2SO4 in monovalent salts and in MgCl2 > BaCl2 > CaCl2 divalent ones. Besides, the ellipticity was totally higher in monovalent salts than in divalent ones.
KeywordsSoybean flour–Reverse micelles–Salts–Soybean protein–CD spectra–Protein secondary structure
Food Analytical Methods 04/2012; 4(3):268-275. · 1.94 Impact Factor
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ABSTRACT: In this study the surface composition of 7S and 11S globulin powders from soybean proteins by aqueous buffer and reverse micelle extractions had been examined using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Analysis by XPS revealed that the O and N atomic percentage of 7S and 11S globulin surfaces from bis(2-ethylhexyl) sodium sulfosuccinate (AOT) reverse micelle was higher than from aqueous buffer, but the C atomic percentage was lower. The O/C ratio of the 7S globulin powder from aqueous buffer and reverse micelle was similar while significant differences were obtained in the O/C ratio of the 11S globulin powder, N/C atom ratios of the 7S and 11S globulin powders and high-resolution XPS C 1s, N 1s, O 1s spectra. Powder microstructure after reverse micelle treatment showed the presence of small pores, indicating the effect of reverse micelle on the 7S and 11S globulin structure. The obtained results indicated that the reverse micelle could affect the C, O and N components on the surface of soybean proteins.
Colloids and surfaces. B, Biointerfaces 09/2011; 86(2):260-6. · 2.60 Impact Factor
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ABSTRACT: The 7S and 11S globulins from soybean proteins using reverse micelle and aqueous buffer extraction methods were characterized by using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and scanning electron microscope (SEM), and their amino acid compositions were also evaluated. SDS-PAGE did not show electrophoretic differences between 7S and 11S globulin subunits with two extraction methods. SEM analysis showed that the AOT reverse micelle processing of 7S and 11S globulins induced a reduction of droplet size. Some individual amino acid contents of 7S and 11S globulins using two extraction methods were different, some were similar. In all the samples, the glutamic acid, aspartic acid, and leucine were the dominant amino acids while the cystine and methionine were the first-limiting amino acids. The proportion of essential amino acids to the total amino acids (E/T) of the 7S globulin from aqueous buffer and reverse micelles was similar. While significant differences were obtained in the proportion of E/T of the 11S globulin.
Applied biochemistry and biotechnology 06/2011; 165(3-4):802-13. · 1.94 Impact Factor
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ABSTRACT: Bacterial polysaccharides play important roles both in medicine and industry. Due to the development of bacterial genome sequencing, many gene clusters related to the biosynthesis of bacterial polysaccharide have been found, aligned and analyzed. Despite of their complex composition and structures, different bacterial polysaccharides are biosynthesized via similar pathways. This review discussed the research development of the biosynthetic mechanism of different bacterial polysaccharides, with emphasis on the glycosyltransferases and polymerases involved in the biosynthetic pathway.
ACTA MICROBIOLOGICA SINICA 12/2010; 50(12):1583-9.
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ABSTRACT: Diacylglycerol (DAG) supplementation has been shown to be associated with the reduction of fasting serum triacylglycerol (TAG) concentration, although the extent of the association is uncertain. We quantitatively examined the effect of dietary DAG on fasting serum TAG concentration by conducting a meta-analysis of randomized controlled trials. Potential papers were searched from electronic databases of Medline, Embase and Cochrane Library. Information was extracted and the net change of fasting serum TAG concentration was used as the primary outcome to examine the effect of DAG in Review Manager 4.2. Six papers with seven independent studies (298 subjects) were included into the statistic pooling. Meta-analysis with random effect model showed that DAG did not reduce the fasting serum TAG concentration (WMD: -0.07 mmol/L; 95% CI: -0.21 to 0.08 mmol/L; P = 0.37). Sensitivity analysis indicated the robustness of overall results. Fail-safe number analysis indicated that 18 studies with positive effect were necessary to reverse the reported non-significant efficacy of DAG. Weight estimation analysis indicated that the effect of DAG was influenced to some extent by the initial fasting serum TAG concentration. In conclusion, DAG supplementation did not reduce the fasting serum TAG concentration significantly compared with TAG, but some effects were suggested in diabetic patients with hypertriglyceridemia.
Lipids 12/2010; 45(12):1139-46. · 2.13 Impact Factor
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ABSTRACT: Suitability of reverse micelles of anionic surfactant sodium bis(2-ethyl hexyl) sulfosuccinate (AOT) and sodium dodecyl sulfate (SDS), cationic surfactant hexadecyl trimethyl ammonium bromide (CTAB) and nonionic surfactant polyoxyethylene p-t-octylphenol (TritonX-100) in organic solvent isooctane for extraction of soy isoflavone-enriching proteins was investigated. The results showed that the order of combined isoflavone contents was SDS>CTAB>Triton X-100>AOT, while the order of protein recovery was SDS>AOT>TritonX-100>CTAB. As compared with ACN-HCl extraction, the total amount of isoflavones was lower than reverse micellar extraction. Ion strength was one of the important conditions to control extraction of isoflavone-enriching proteins with AOT reversed micelles. For the six salt systems, KNO(3), KCl, MgCl(2), CaCl(2), NaCl, and Na(2)SO(4), extracted fraction of isoflavone-enriching proteins was measured. Salt solutions greatly influenced the extraction efficiency of isoflavones in an order of KNO(3)>MgCl(2)>CaCl(2)>KCl>NaCl>Na(2)SO(4), while protein in an order of MgCl(2)>CaCl(2)>NaCl>KNO(3)>Na(2)SO(4)>KCl.
Applied biochemistry and biotechnology 11/2010; 162(7):2087-97. · 1.94 Impact Factor
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ABSTRACT: The surface composition of five types of ginger powders with the particle sizes of 300, 149, 74, 37 and 8.34 microm was investigated by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and various types of physical-chemical characteristics regarding material particle size distributions, discoloration and chemical composition. The results show that the color differences are greater for superfine ground ginger than for conventional comminuted ones; the values of crude fibre, neutral detergent fiber (NDF) and acid detergent fiber (ADF) decrease with decreasing ginger particle size. However, no relationship with the surface fat, crude protein, ash and total solids exists. With superfine grinding the XPS O/C ratios of the five ginger powders were similar since the surfaces were not oxidized. Correlations were observed between the XPS N/C ratios and the high resolution XPS N 1s spectra. SEM observations revealed that the surface of ginger powder with a particle size of 300 microm is rougher, while superfine ground powders with particle sizes of 149, 74, 37 and 8.34 microm are similar to each other. This roughness difference between these surfaces correlates with the differences in their O/C ratios and the surface morphology of five ginger powders.
Colloids and surfaces. B, Biointerfaces 09/2010; 79(2):494-500. · 2.60 Impact Factor
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ABSTRACT: Astragalus membranaceus is a common traditional Chinese medicinal plant widely used as a tonic to enhance the body's natural defense mechanisms. The objective of this study was to investigate the application of the superfine grinding technology in A. membranaceus. The physical-chemical properties of five types of A. membranaceus powders with particle sizes of 300, 149, 74, 37 and 7.56 μm were investigated. The experiments showed that the smaller the A. membranaceus particle dimension was, the greater the surface area (from 0.191 to 1.573 m2/g) and bulk density (from 0.5139 to 0.6139 g/ml) was, the smaller the angles of repose (from 52.30° to 35.63°) and slide (from 47.37° to 29.47°) were. The water holding capacity (WHC) and polysaccharide solubility significantly improved as decreasing the size of A. membranaceus particle (p < 0.05). SEM images revealed the shape and surface morphology of five types of A. membranaceus powders.Graphical abstractThe solubility of polysaccharide with different particle size A. membranaceus powders was studied as shown in Fig. 2. The results indicated that the superfine ground A. membranaceus could increase polysaccharide solubility. The main factor to affect the solubility of polysaccharide was shown to be the particle size and the surface area of the powder.
Powder Technology. 203(3):620-625.
