石英砂吸附AOT和蛋白质主要影响因素研究

石英砂通过Ca2 的桥连作用对AOT(丁二酸二异辛酯磺酸钠)和蛋白质有吸附作用,研究了不同吸附温度和溶液pH值对AOT吸附率和蛋白质吸附率的影响。结果表明温度、pH对AOT和蛋白质的吸附表现出一定的规律性,最佳吸附温度为45℃,最佳溶液pH值为8.00。     

冷冻高速离心影响蛋白质和AOT分离及相互作用的因素研究

在高速离心作用下,分离反萃液(AOT/蛋白质溶液体系)中的蛋白质.考察了反萃液pH、离心速度和离心时间对AOT和蛋白质的分离程度及蛋白质和AOT相互作用的影响,并确定了最佳分离参数为:离心速度9 000 r/min,离心时间15 min,溶液pH 4.5.     

反胶束法提取红芸豆蛋白的前萃工艺优化

采用二-（2-乙基已基）琥珀酸酯磺酸钠（AOT）-异辛烷-氯化钾组成的反胶束体系萃取红芸豆蛋白（RKBP）。采用电导法考察AOT浓度对AOT-异辛烷-水反胶束体系含水量和临界增溶水量的影响,确定反胶束体系稳定的AOT浓度范围。采用单因素实验分别研究了AOT浓度、缓冲液pH、KCI浓度和萃取时间等因素对RKBP前萃率的影响,通过正交实验优化前萃条件。结果表明,不同AOT浓度对应的反胶束体系的临界含水量值（Wc）基本一致,反胶束体系能够增溶的水的体积随AOT浓度的增加而明显增大,反胶束体系稳定的AOT浓度上限值为2mol／L。正交优化获得反胶束法萃取RKBP的最佳前萃条件为：AOT浓度1．25mol／L,缓冲溶液pH7．5,KCl浓度0．05mol／L,萃取时间90min。在该最优工艺条件下,RKBP前萃率达到43．57％。     

AOT-异辛烷反胶束萃取技术分离牛初乳IgG的研究

在一个琥珀酸二(2-乙基己基)酯磺酸钠(AOT)-异辛烷反胶束体系中，研究了水相pH值、离子强度和有机相表面活性剂AOT浓度等因素对牛初乳乳清蛋白中IgG分离效果的影响。结果表明，在以下两组优化条件：①pH值为7．668，[Na^ ]浓度为0．270mol／L，[AOT]浓度为0．088mol／L；②pH值为6524，[Na^ ]浓度为0．205mol／L，[AOT]浓度为0．175mol／L，水相IgG的残留率或纯度分别达到最大值，分别为90．23％和98．35％．RID分析表明，反胶束萃取过程对原牛初乳乳清IgG的免疫反应活性基本无影响。     

反胶束溶液萃取大豆蛋白前萃工艺的研究

本文研究了AOT/异辛烷反胶束溶液萃取大豆蛋白的前萃机理和工艺,研究了pH、 W0、表面活性剂AOT的浓度、KCl的浓度、萃取时间和萃取温度对蛋白前萃取率的影响,得到了以AOT/异辛烷体系萃取低温脱脂豆粕中蛋白质的最佳前萃工艺条件。     

二次通用旋转组合设计法优化AOT反胶束体系萃取大豆蛋白质的研究

表面活性剂浓度、pH、温度、W0、电解质浓度、乙醇浓度与时间是影响AOT反胶束萃取大豆蛋白质的主要因素,采用二次通用组合旋转对AOT反胶束前萃取大豆蛋白质的工艺进行了研究,建立前萃工艺回归方程,得出前萃工艺优化条件分别为:W014、AOT浓度0.08 g/mL、pH值7.0、KCl浓度0.05 mol/L、萃取时间30 min、萃取温度40 ℃、乙醇浓度0.5%.在此条件下,蛋白质含量为24.14%,蛋白前萃率为65.82%.     

反胶束溶液同时萃取植物油料中的油和蛋白质——反萃工艺研究

研究了AOT／异辛烷反胶束体系萃取植物油和蛋白质的反萃工艺。结果表明：影响蛋白质反萃率的主要因素是：萃取时间、水的pH值和KCl浓度。反萃条件为：萃取时间90min,水的pH值7.7,KCl浓度1.2mol/l,与传统制油工艺比较,油的萃取效果基本相同。     

利用反胶束萃取大豆蛋白同时酶水解的研究

本文利用丁二酸二异辛酯磺酸钠（AOT）／异辛烷反胶束体系萃取低温脱脂豆粕中的蛋白质。同时加入蛋白酶对大豆蛋白进行酶解，研究了酶的种类、pH值、W0、萃取温度、萃取时间对蛋白前萃率的影响。研究确定了最佳工艺和参数，为今后研究奠定了理论基础。     

响应面法优化反胶束提取花生粕蛋白前萃工艺

采用二-(2-乙基已基)琥珀酸酯磺酸钠(AOT)-异辛烷-氯化钾组成的反胶束体系萃取花生粕蛋白质。研究了AOT浓度、KCl溶液pH、KCl溶液浓度、萃取时间、料液浓度、温度等因素对提取率的影响关系,在单因素基础上,通过响应面分析法确定前萃最佳工艺条件为AOT浓度0.06 mol/L、KCl溶液p H 8.15、KCl溶液浓度0.1 mol/L、萃取时间60 min、料液浓度10 g/L和温度37.40℃,在此最佳工艺条件下,花生粕蛋白前萃率为61.2%。     

反胶团提取大豆中的蛋白质和豆油

本文进行了由丁二酸-（二）-2-乙基乙基酯磺酸钠（AOT）-正乙烷-氯化钾组成的反胶团体系从大豆中萃取蛋白质和豆油的研究，考查了大豆和反胶团质量体积比、萃取时间、温度、pH值和盐浓度等因素对蛋白质的萃取及反萃取的影响。结果表明：大豆蛋白质的萃取率最高达96.9%，豆油的萃取率为90.5%。     

The study of beta-lactoglobulin adsorption on polyethersulfone thin film surface using QCM-D and AFM

The adsorption process of beta-lactoglobulin on the polyethersulfone-coated surface has been investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D), which allowed simultaneous measurements of frequency and energy dissipation changes caused by the formation of a beta-lactoglobulin layer during the protein adsorption process. The results showed that the protein adsorption on the spin-coated polyethersulfone surface consisted of reversible and irreversible adsorption processes, and the irreversible adsorption was the principal factor to cause the permanent protein adsorption onto the polymer surface. The amount of irreversible adsorption of beta-lactoglobulin increased significantly, from 380.5 +/- 23.2 to 745.5 +/- 29.7 ng/cm2, when the concentration of beta-lactoglobulin solution varied from 0.1% to 2.0% (w/v). The pH also played an important role in the protein adsorption. When the pH of the solution varied from 7.0 to 3.0, the amount of irreversible adsorption of beta-lactoglobulin increased from 427.1 +/- 80.7 to 741.2 +/- 135.1 ng/cm2.     

Adsorption of transgenic insecticidal Cry1Ab protein to SiO2. 1. Forces driving adsorption

Genetically modified Bt crops express insecticidal Cry proteins (Bt toxins) that may enter agricultural soils. A mechanistic understanding of Cry protein adsorption to soils is critical for risk assessment, as this process governs Cry protein fate and bioavailability. We used quartz crystal microbalance and optical waveguide lightmode spectroscopy to elucidate the driving forces of the adsorption of monomeric Cry1Ab to negatively charged quartz (SiO(2)) and positively charged poly-L-lysine (PLL) at pH 5-8 and constant ionic strength of 50 mM (NaCl). Bovine serum albumin and hen egg white lysozyme were used as reference proteins because of their known adsorption behavior. Electrostatics governed Cry1Ab adsorption; as pH increased above the isoelectric point of Cry1Ab, the initial rate and the extent of adsorption decreased on SiO(2) and increased on PLL. Reversible adsorption to SiO(2) suggested weak Cry1Ab-SiO(2) electrostatic interactions and no irreversible conformational changes of Cry1Ab at the surface. High conformational stability of Cry1Ab was further supported by supply rate-independent extent of adsorption of Cry1Ab to apolar gold. Some evidence is presented that the nonuniform surface charge distribution of Cry1Ab resulted in patch-controlled electrostatic attraction with sorbents that carried the same net charge as Cry1Ab. A more detailed discussion of this mechanism is given in a companion paper.     

Adsorption of transgenic insecticidal Cry1Ab protein to SiO2. 2. Patch-controlled electrostatic attraction

Adsorption governs the fate of Cry proteins from genetically modified Bt crops in soils. The effect of ionic strength (I) on the adsorption of Cry1Ab (isoelectric point IEP(Cry1Ab) ≈ 6) to negatively charged quartz (SiO(2)) and positively charged poly-L-lysine (PLL) was investigated at pH 5 to 8, using quartz crystal microbalance with dissipation monitoring and optical waveguide lightmode spectroscopy. Cry1Ab adsorbed via positively and negatively charged surface patches to SiO(2) and PLL, respectively. This patch controlled electrostatic attraction (PCEA) explains the observed increase in Cry1Ab adsorption to sorbents that carried the same net charge as the protein (SiO(2) at pH > IEP(Cry1Ab) and PLL at pH < IEP(Cry1Ab)) with decreasing I. In contrast, the adsorption of two reference proteins, BSA and HEWL, with different adsorption mechanism, were little affected by similar changes of I. Consistent with PCEA, Cry1Ab desorption from SiO(2) at pH > IEP(Cry1Ab) increased with increasing I and pH. Weak Cry1Ab-SiO(2) PCEA above pH 7 resulted in reversible, concentration dependent adsorption. Solution depletion experiments showed that PCEA also governed Cry1Ab adsorption to SiO(2) particles at environmentally relevant concentrations (a few ng mL(-1)). These results imply that models describing Cry1Ab adsorption to charged surfaces in soils need to account for the nonuniform surface charge distribution of the protein.     

Surface properties of walnut protein from AOT reverse micelles

The surface chemical composition and microstructure of walnut protein obtained through aqueous buffer and bis(2‐ethylhexyl) sodium sulfosuccinate (AOT) reverse micelles were determined by X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The surfaces were characterised by XPS to monitor surface composition. The different components of C 1s, N 1s and O 1s peaks were provided precisely. By comparison with walnut protein surface from aqueous buffer, XPS analysis revealed that the O atomic percentage of walnut protein powder surface from AOT reverse micelles was higher, but the C and N atomic percentages were lower. The N/C ratio of the walnut protein powders using two extraction methods was similar, while significant difference was obtained in the O/N. The obtained results indicated that the reverse micelles could affect the C, O and N components on the surface of walnut protein powder. Protein microstructure after reverse micelle treatment showed many crystals.     

Highly dense protein layers confirmed by atomic force microscopy and quartz crystal microbalance

Protein adsorption on a gold surface is investigated by comparing the results of quartz crystal microbalance method and atomic force microscopy. The adsorption of streptavidin on functional gold surfaces is directly monitored by a quartz crystal microbalance, and confirmed by atomic force microscopy. For this investigation, a modified gold substrate is fabricated to obtain a topographic image of streptavidin molecules. Both methods show a correlation in terms of the highly dense protein single-layer formation, and the modified gold electrode shows a slightly denser protein layer formation because of the difference in substrate geometry as compared with that of a mica surface.     

Studying the role of common membrane surface functionalities on adsorption and cleaning of organic foulants using QCM-D

Adsorption of organic foulants on nanofiltration (NF) and reverse osmosis (RO) membrane surfaces strongly affects subsequent fouling behavior by modifying the membrane surface. In this study, impact on organic foulant adsorption of specific chemistries including those in commercial thin-film composite membranes was investigated using self-assembled monolayers with seven different ending chemical functionalities (-CH(3), -O-phenyl, -NH(2), ethylene-glycol, -COOH, -CONH(2), and -OH). Adsorption and cleaning of protein (bovine serum albumin) and polysaccharide (sodium alginate) model foulants in two solution conditions were measured using quartz crystal microbalance with dissipation monitoring, and were found to strongly depend on surface functionality. Alginate adsorption correlated with surface hydrophobicity as measured by water contact angle in air; however, adsorption of BSA on hydrophilic -COOH, -NH(2), and -CONH(2) surfaces was high and dominated by hydrogen bond formation and electrostatic attraction. Adsorption of both BSA and alginate was the fastest on -COOH, and adsorption on -NH(2) and -CONH(2) was difficult to remove by surfactant cleaning. BSA adsorption kinetics was shown to be markedly faster than that of alginate, suggesting its importance in the formation of the conditioning layer. Surface modification to render -OH or ethylene-glycol functionalities are expected to reduce membrane fouling.     

pH和AOT添加物对大豆分离蛋白基生物可降解膜机械性能的影响

运用响应面分析法分析了pH和AOT(琥珀酸二异辛酯磺酸钠)添加物对大豆分离蛋白(SPI)基生物可降解膜机械性质的影响,确定了影响该种膜机械性能的最优工艺参数。测试的膜的机械性质包括抗拉强度、穿刺强度、断裂伸长率。分析结果表明,在pH为8.795,AOT的添加量为13.00%时,膜的综合机械性能达到最优。     

pH和AOT添加物对大豆分离蛋白基可降解膜机械性能影响

运用响应面分析法分析pH和AOT(琥珀酸二异辛酯磺酸钠)添加物对大豆分离蛋白(SPI)基生物可降解膜机械性质影响,确定影响该种膜机械性能最优工艺参数;测试膜机械性质,包括抗拉强度、穿刺强度、断裂伸长率;分析结果表明,在pH为8.95,AOT添加量为13.00%(w/w)时,膜综合机械性能达到最优。     

Extraction and physicochemical properties of soya bean protein and oil by a new reverse micelle system compared with other extraction methods

Reverse micelle extraction is a novel technology for the separation of plant components such as proteins and oil. In this study, sodium bis(2‐ethylhexyl) sulphosuccinate (AOT) reverse micelle system and AOT/Tween 85 reverse micelle system were used to extract soya bean protein and oil from soya bean flour. The physicochemical properties of the protein and oil extracted were investigated and compared with traditional extraction methods. The results showed that the efficiency of forward extraction of soya bean protein using an AOT/Tween 85 reverse micelle system was superior to that using an AOT reverse micelle system at the optimal extraction conditions. In addition, soya bean proteins extracted using reverse micelle extraction had no unordered structure under Fourier transform infrared spectroscopy. The acid and peroxide values of oil products from two reverse micelle extractions were lower than that from immersion. The results indicated that AOT/Tween 85 reverse micelle system is effective in extracting soya bean protein and oil.     

AOT反胶束体系萃取大豆蛋白质的研究

研究了AOT反胶束萃取大豆蛋白的工艺,针对影响AOT反胶束萃取大豆蛋白质的各种因素如反胶束直径、缓冲溶液pH值、离子强度、温度、萃取时间进行了研究,得出主要的影响因素为反胶束直径、缓冲溶液pH值和离子强度,并得到最佳的萃取条件为:反胶束直径为4.9nm,此时的Wo值为15.8;pH值为6.5;离子强度为0.1mol/L;萃取温度为45℃;萃取时间为20min。在此条件下蛋白质的萃取率为82.57%。