Prevention of peroxynitrite-induced oxidation and nitration reactions by ellagic acid

Four benzoic acid derivatives and three phenylpropanoids were tested for their ability to suppress oxidation of dichlorodihydrofluorescein (DCDHF) induced by 3-morpholinosydnonimine (SIN-1, a peroxynitrite donor). Ellagic acid was found to potently inhibit this oxidation and to inhibit oxidation of DCDHF induced by peroxynitrite itself. Moreover, this compound prevented peroxynitrite-induced oxidative single strand breaks in pTZ 18U plasmid DNA and nitration of tyrosyl residues in bovine serum albumin. These results show that ellagic acid protects biomolecules against oxidative and nitrative damage induced by peroxynitrite in vitro.     

Transformation of bisphenol A and alkylphenols by ammonia-oxidizing bacteria through nitration

Transformation of bisphenol A (BPA) by ammonia-oxidizing bacteria (AOB) Nitrosomonas europaea ATCC 19718 was investigated. On the basis of the ultraperformance liquid chromatography (UPLC) coupled to quadrupole time-of-flight mass spectrometry (Q-TOF MS) and nuclear magnetic resonance analysis, we found N. europaea could transform BPA into nitro- and dinitro-BPA, suggesting that abiotic nitration between the biogenic nitrite and BPA played a major role in the transformation of BPA in the batch AOB system. Nitrite concentrations, temperature, and pH values were the major factors to influence the reaction rate. Furthermore, the yeast estrogenic screening assay showed that the formed nitro- and dinitro-BPA had much less estrogenic activity as compared with its parent compound BPA. Similar reactions of abiotic nitration were considered for 4-n-nonylphenol (nNP) and 4-n-octylphenol (nOP) since nitro-nNP and nitro-nOP were detected by UPLC-Q-TOF MS. In addition, results from the local wastewater treatment plant (WWTP) showed the occurrence of nitro-BPA and dinitro-BPA during the biological treatment process and in the effluent, indicating that nitration of BPA is also a pathway for removal of BPA. Results of this study provided implication that AOB in the WWTPs might contribute to removal of selected endocrine-disrupting compounds (EDCs) through abiotic nitritation.     

Multiphase chemical kinetics of the nitration of aerosolized protein by ozone and nitrogen dioxide

Proteins contained in pollen and other biological particles are nitrated by ozone and nitrogen dioxide in polluted air. The nitration can enhance the allergenic potential of proteins, which may contribute to the increasing prevalence of allergic diseases. The reactive uptake of NO(2) by aerosolized protein (bovine serum albumin) was investigated in an aerosol flow tube using the short-lived radioactive tracer (13)N. In the absence of O(3), the NO(2) uptake coefficient was below detection limit (γ(NO2) < 10(-6)), but with 20-160 ppb O(3) γ(NO2) increased from ~10(-6) to ~10(-4). Using the kinetic multilayer model of surface and bulk chemistry (KM-SUB), the observed time and concentration dependence can be well reproduced by a multiphase chemical mechanism involving ozone-generated reactive oxygen intermediates (ROIs), but not by NO(3) radicals formed in the gas phase. Product studies show the formation of protein dimers, suggesting that the ROIs are phenoxy radical derivatives of the amino acid tyrosine (tyrosyl radicals) which are also involved in physiological protein nitration processes. Our results imply that proteins on the surface of aerosol particles undergo rapid nitration in polluted air, while the rate of nitration in bulk material may be low depending on phase state and surface-to-volume ratio.     

Copper stabilization by zeolite synthesis in polluted soils treated with coal fly ash

This study deals with the process of zeolite formation in an agricultural soil artificially polluted by high amounts of Cu (15 mg of Cu/g of soil dry weight) and treated with fused coal fly ash at 30 and 60 degrees C and how this process affects the mobility and availability of the metal. As a consequence of the treatment, the amount of dissolved Cu, and thus its mobility, was strongly reduced, and the percentage of the metal stabilized in the solid phase increased over time, reaching values of 30% at 30 degrees C and 40% at 60 degrees C. The physicochemical phenomena responsible for Cu stabilization in the solid phase have been evaluated by EDTA sequential extractions and synchrotron radiation based X-ray microanalytical techniques. These techniques were used for the visualization of the spatial distribution and the speciation of Cu in and/or on the neo-formed zeolite particles. In particular, micro XRF (X-ray fluorescence) tomography showed direct evidence that Cu can be entrapped as clusters inside the porous zeolitic structures while mu-XANES (X-ray absorption near edge structure) spectroscopy determinations revealed Cu to be present mainly as Cu(ll) hydroxide and Cu(ll) oxide. The reported results could be useful as a basic knowledge for planning new technologies for the on site physicochemical stabilization of heavy metals in heavily polluted soils.     

Soy Protein Concentrates by Ultrafiltration

ABSTRACT: Soybean protein concentrates were produced by ultrafiltration with a commercial 4-in spiral wound module with a polyvinylidene difluoride membrane. With soy flour suspensions of 2% total solids (TS), protein content could be increased from 50% (dry basis) to 67% by ultrafiltration and/or diafiltration. Soluble sugars could be removed almost completely, but ash content of retentate solids did not decrease significantly. Higher protein contents would require removal of some of the fiber and/or manipulation of the feed environment to reduce solute-solute interactions. Protein yields were 90%. Flux decreased from 78 L/m²/h (LMH) with 2% TS soy flour suspension to 22 LMH at 17% TS.     

Protein encapsulation by humic substances

Protein encapsulation by natural organic matter is hypothesized to preserve the activity of proteins in terrestrial and aquatic environments. Direct molecular-level evidence for encapsulation of net positively charged proteins lysozyme, trypsin, and ribonuclease A by a diverse set of humic substances (HS) in nanostructured films was collected using a combination of optical waveguide lightmode spectroscopy and quartz crystal microbalance measurements. The results suggest that protein-HS electrostatic attraction drives encapsulation of positively charged lysozyme by a soil humic acid at pH 5 to 8 and by six additional humic and fulvic acids from terrestrial and mixed terrestrial aquatic sources at pH 5 and 6. Encapsulation of trypsin and ribonuclease A, which had negatively charged surface patches under the studied conditions, suggested that localized protein-HS electrostatic repulsion is overcompensated by attractive forces, likely including contributions from the hydrophobic effect. Evidence is provided showing that encapsulation of lysozyme at pH 8 and of ribonuclease A at pH 5 and 6 involved partial disassembly of HA supramolecular associations. This work advances a molecular-level picture of protein encapsulation by HS and presents a novel approach to study the effects of encapsulation on protein enzymatic activity and susceptibility to abiotic and biotic transformations.     

超滤法生产大豆浓缩蛋白

采用商业聚砜平板膜生产大豆浓缩蛋白。脱脂豆粕和水按一定比例混合 ,pH8 0室温下搅拌 40min ,离心 ,上清液经超滤、冷冻干燥 ,得到大豆浓缩蛋白。蛋白质含量由 5 2 % (干基 )提高到 72 % (干基 )。蛋白质的回收率达到 90 %以上。根据浓差极化模型得到间歇式超滤浓缩蛋白质时的理论极限蛋白质含量。     

高效液相色谱法测定骨髓蛋白粉的蛋白质系数

建立了高效液相色谱法测定骨髓蛋白粉总蛋白质系数。采用酸水解法分解骨髓蛋白粉中的蛋白质,以保留时间定性,氨基酸面积百分比定量,求得骨髓蛋白粉中的蛋白质系数为5.65。     

新疆番茄热风干燥工艺实验研究

对新疆番茄进行一系列烘干实验,确立了新疆番茄较佳的脱水加工工艺。      

Soy Protein Hydrolysate Debittering by Lysine-Acetylation

To reduce bitterness of soy protein hydrolyates, chemical modification of lysine was investigated. Isolated soy protein (ISP) was treated with N-acetylimidazole for acetylation of lysine and tyrosine. 0-acetyI tyrosine was deacetylated at pH 11. The lysine-acetylated soy protein and control protein were hydrolyzed by bromelain to the same degree of hydrolysis (10%), and then bitterness of each protein hydrolysate was evaluated. Sensory analyses indicated that bitterness of hydrolysates of lysine-acetylated ISP decreased in comparison with hydrolysates of control ISP (p<0.005). Surface hydrophobicity of hydrolysates of lysine-acetylated ISP slightly increased, and they had fewer lysine residues at the C-terminal region than hydrolysates of control ISP.     

双酶分步水解制备菜籽蛋白肽

实验选取Alcalase 2.4 L碱性蛋白酶和复合风味蛋白酶分步水解菜籽蛋白。结果表明双酶分步水解制备菜籽肽的最佳工艺为Alcalase碱性蛋白酶在pH值9.5,温度55℃,底物质量分数3%,酶活性5 500 u/g条件下酶解5.5 h,水解度为21.14%,再用复合风味酶在pH值6,温度50℃,酶活性900 u/g条件下继续酶解3 h。单因素试验和正交实验研究粗肽液用活性炭脱色的优化条件为:在活性炭质量分数1.5%,pH值4.5,温度55℃条件下脱色50 min,脱色率达32.15%,氨基酸损失率为25.15%。     

Searching ingredients polluted by polycyclic aromatic hydrocarbons in feeds due to atmospheric or pyrolytic sources

The primary aim of the proposed work is to propose the potential sources of pollution by polycyclic aromatic hydrocarbons (PAHs) in feeds and ingredients. To reach this propose the development of a simple, fast, quantitative and economic method for determining PAHs using liquid-liquid extraction (LLE), clean-up and detection by liquid chromatography with fluorescence detection (LC-FD) in polluting feeds and ingredients was developed. The overall method quantification limits range from 0.020 to 4.0μg/kg and analyte recoveries are between 70% and 105% with relative standard deviations (RSD) lower than 20%. Molecular patterns of PAHs were used to study their distribution in the selected samples by cluster analysis, separating them in two groups: contaminated by atmospheric or pyrolytic sources. In order to find a relationship between the nutritional composition (protein, fibre, ash and fat content), and the hypothetical toxicity of selected feeds, a partial least squared (PLS) analysis was used, showing that fibre was a major contributor. Moreover, the complete data set of 27 feed samples and 25 feed ingredients x 13 PAH concentrations were analysed by PCA to find out what ingredients were controlling PAH pollution.     

大豆压榨厂废气污染治理

采取有效措施限制或减少油厂排放的污染气源和污染量,对锅炉和其他排废气源进行处理。在5000t／d大豆压榨厂调试期间,经环保检测部门跟踪检测,环保排放指标达到或超过有关标准。     

Coagulation and electrocoagulation of wastes polluted with dyes

Dyes are common pollutants in a large variety of industrial wastewaters, and the treatment of these wastes by coagulation has been extensively studied in the literature. This work is focused on the comparison of the efficiencies of the chemical and the electrochemical coagulation processes with hydrolyzing aluminum salts, and it tries to determine the similarities or differences that exist between the two coagulation processes. To do this, Eriochrome Black T solutions were used as a model of dye-polluted wastewater, and experiments of both coagulation technologies were planned to meet the same operation conditions. The pH, the aluminum concentration, the type of electrolyte, and the mode of dosing of aluminum were found to influence the process. Moreover, the speciation of aluminum was found to be the key parameter to explain the results, in terms of the mechanisms previously proposed in the literature for dissolved organic matter coagulation.     

Inhibition of Oxidant-Induced Biochemical Changes of Pork Myofibrillar Protein by Hydrolyzed Potato Protein

ABSTRACT:  The objective of the study was to investigate the role of hydrolyzed potato protein (HPP) in protecting myofibril protein isolate (MPI) from oxidative modification. MPI prepared from pork muscle was suspended (30 mg protein/mL) in 15 mM piperazine- N , N -bis(2-ethane sulfonic acid) buffer (pH 6.0) with 0, 0.3, 0.75, and 1.5 mg/mL of antioxidative HPP (1-h Alcalase hydrolysate). Oxidation was induced by incubating the protein suspensions at 4 °C for 24 h with (1) an iron-catalyzed oxidizing system (IOS: 0.01 mM FeCl₃, 0.1 mM ascorbic acid, and 1.0 mM H₂O₂) and (2) a metmyoglobin-oxidizing system (MOS: 0.1 mM metmyoglobin and 0.1 mM H₂O₂). Changes in oxidized MPI were measured as thiobarbituric acid-reactive substances (TBARS), protein carbonyl content, Ca- and K-ATPase activities, and ultraviolet (UV) spectra. Oxidation increased the production of TBARS and protein carbonyls by 2.9- and 0.24-fold in IOS and 5.6- and 2.2-fold in MOS, respectively. The 2 oxidizing systems altered the Ca- and K-ATPase activities and exposed hydrophobic groups buried in MPI. The presence of HPP reduced the extent of MPI oxidation in all physicochemical categories tested. Therefore, HPP may be used as a potential functional ingredient in meat products to enhance their oxidative stability.     

Preservation of leaf protein preparations by air drying

Air-dried leaf protein has hitherto been dark and gritty, but by drying in two stages, initially to between 20 and 30% moisture, then fine grinding before completion of air drying, a product can be made with as good an appearance and texture as that made by freeze-drying. The keeping quality and digestibility of this material are also similar to freeze-dried protein.     

空气悬浮包衣法制备藻蓝蛋白微胶囊

以钝顶螺旋藻中的藻蓝蛋白为芯材,利用空气悬浮包衣法制备藻蓝蛋白的微胶囊,提高其稳定性。选取了明胶和麦芽糊精为壁材,考察了进风温度、雾化压力、壁材中明胶质量分数、芯壁材比这4个因素,结果表明微胶囊制备的最佳条件是进风温度80℃、芯壁材比1:1.5、雾化压力0.15MPa、壁材中明胶含量20%。在此条件下,其应用稳定性提高了26.21%,贮藏稳定性提高了75.1%。