缓慢消化淀粉测定过程中的影响因素分析

研究缓慢消化淀粉测定过程中的影响因素,探讨前处理、底物浓度、热处理时间、酶用量以及消化时间对SDS 的影响。结果表明,最适的测定条件为：200mg 淀粉于50ml 试管中,加入15ml 磷酸缓冲液(0.5mol/L,pH6.9)和4000U 胰淀粉酶,在37℃条件下水浴振荡,水解1h 和10h 时各取0.5ml 水解液,采用DNS 法在波长540nm处测定水解液中麦芽糖含量。     

泡沫分离法纯化十二烷基硫酸钠的研究

用泡沫分离法 ,纯化了十二烷基硫酸钠 (SDS) ,并通过红外光谱、熔点测定、表面张力 -表面活性剂浓度的对数 (γ- lgc)曲线的分析 ,确证了 SDS的纯度。     

SDS—PAGE法分析含乳饮料和乳清粉的蛋白组成和含量

利用SDS-PAGE电泳结合凝胶成像分析测定了乳清粉及含乳饮料中的酷蛋白、α-乳白蛋白（α-LA）和β-乳球蛋白（β-LG）的含量,探讨了两种乳蛋白提取方法对测定结果的影响。     

Metabolic profile and biological activities of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco: Studies on the essential oil and polar extracts

We investigated the metabolic profile and biological activities of the essential oil and polar extracts of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco collected in south Portugal. Gas chromatography–mass spectrometry (GC–MS) analysis revealed that oxygen-containing monoterpenes was the principal group of compounds identified in the essential oil. Camphor (40.6%) and fenchone (38.0%) were found as the major constituents. High-performance liquid chromatography with diode array detection (HPLC–DAD) analysis allowed the identification of hydroxycinnamic acids (3-O-caffeoylquinic, 4-O-caffeoylquinic, 5-O-caffeoylquinic and rosmarinic acids) and flavones (luteolin and apigenin) in the polar extracts, with rosmarinic acid being the main compound in most of them. The bioactive compounds from L. pedunculata polar extracts were the most efficient free-radical scavengers, Fe²⁺ chelators and inhibitors of malondialdehyde production, while the essential oil was the most active against acetylcholinesterase. Our results reveal that the subspecies of L. pedunculata studied is a potential source of active metabolites with a positive effect on human health.     

Wheat-bug damage in New Zealand wheats: Some properties of a glutenin hydrolysing enzyme in bug-damaged wheat

Some properties of a glutenin hydrolysing enzyme present in bug (Nysius huttoni) damaged wheat (Triticum aestivum) were examined using a modified SDS sedimentation test reported previously. The enzyme appears to be a water-soluble alkaline protease with an activity optimum at pH 9.0. It is relatively heat stable, but the temperature optimum for activity is quite low (35–40°C). The enzyme is not inhibited by EDTA or N-ethylmaleimide, but is inhibited by the metal ions Co²⁺, Mn²⁺ and Fe²⁺.     

Insights Into Molecular Interaction of Antitumor Drug Mitoxantrone With Anionic Surfactant Sodium Dodecyl Sulfate at Different Temperatures

A study of the interaction of antitumor drug mitoxantrone with anionic surfactant sodium dodecyl sulfate (SDS) has been carried out by UV–Vis absorption spectroscopy at submicellar and micellar surfactant concentrations, pH 7.4 and 10, and over a temperature range of 293.15–323.15 K. The variation of the monomer drug absorbance as a function of SDS concentration indicates, at pH 7.4 and all investigated temperatures, two definite processes: process I in the submicellar range, attributed to the electrostatic interaction between mitoxantrone and SDS monomers; and process II in the micellar range, when the drug is incorporated into SDS micelles in monomer form. At pH 10, the results have indicated only the process II at micellar SDS concentrations. The monomer absorbance changes occurring as a result of the interactions between mitoxantrone and SDS were rationalized in terms of binding constant, micelle/water partition coefficient, and the corresponding thermodynamic parameters for binding and partitioning processes. Thermodynamic parameters indicate that at pH 7.4 both binding process of mitoxantrone to SDS and partition process of mitoxantrone between micellar and bulk aqueous phases are spontaneous and enthalpy controlled, while at pH 10 both processes are spontaneous and entropy controlled.     

The Effect of Aniline Hydrochloride Hydrotrope on the Phase Behavior of SDS/Water System

The aim of this work was to determine the detailed phase behavior of the sodium dodecyl sulfate/aniline hydrochloride/water system as a function of concentration of sodium dodecyl sulfate (SDS), aniline hydrochloride (AHC) to sodium dodecyl sulfate molar ratio (R = [AHC]/[SDS]) and temperature. Phase behavior information was obtained via polarizing microscopy, differential scanning calorimetry (DSC), cryo-scanning electron microscopy (Cryo-SEM) and oscillatory linear rheological measurements with good agreement among these techniques. It is well known that SDS in water forms spherical micelles at concentrations lower than 40 wt% and temperatures above its Krafft temperature (T _k = 16–21 °C). In this region, the SDS/water system exhibits Newtonian rheological behavior, which is characteristic of spherical micellar solutions. The addition of the hydrotrope, aniline hydrochloride, to SDS aqueous solutions produces a viscosity increase in this system as R augments, and a maximum of about five orders of magnitude was found at R = 0.47 for 5 wt% SDS at 20 °C. Moreover, the system shows a transition from viscous to strong viscoelastic behavior. These changes in the rheological behavior are produced by the transitions from sphere to rodlike micelles, which are induced by the hydrophobicity of AHC causing it to be absorbed into the core and the hydrophilic interface of the micelles, which screens the repulsions between the charged head groups.     

THF-SDS对矿井瓦斯水合分离影响研究

基于瓦斯水合分离实验,研究了3种THF-SDS复配体系(THF,0.50mol/L,SDS,0.20,0.35和0.50mol/L)对3种合成瓦斯气样(Ⅰ型、Ⅱ型和Ⅲ型)水合分离过程影响,并对THF-SDS复配体系的促进机理进行了初步分析.结果表明:在THF-SDS复配溶液中,φ(CH4)分别为24.90%,40.40%和59.80%的气样经过一级水合分离后,φ(CH4)分别提高13.81%,15.63%和20.04%;THF-SDS复配体系可以改善瓦斯水合分离热力学条件,有效缩短瓦斯水合物生成的诱导时间,随着复配体系中SDS浓度的升高,诱导时间逐渐缩短;然而随着THF-SDS复配体系中SDS浓度的增加,水合物中瓦斯气体含量减少,分离效果变差,高浓度的SDS对CH4-N2-O2-THF-H2O体系水合物晶体生长过程有一定抑制作用.     

Influence of sodium dodecyl sulfate on the characteristics of bovine serum albumin solutions and foams

Results from surface tension measurements on mixed solutions of the protein bovine serum alburnin (BSA) and an anionic surfactant (SDS: sodium dodecyl sulfate) suggested that at an air-liquid interface, adsorption was affected by the protein-surfactant interaction and by the relative concentration of each component in solution. Two plateaus corresponding to the critical aggregation concentration (CAC) and the critical micelle concentration (CMC) of SDS, respectively, were observed in the surface tension isotherms of SDS in the presence of BSA. The CAC and CMC depended on the concentration of BSA. Effects of SDS concentration on the conformational changes of BSA were investigated by Fourier transform-Raman spectroscopy. The results showed that the contents of α-helix decreased while the contents of random coil increased. The presence of the anionic surfactant SDS had a negative influence on the way that proteins adsorb at an air-liquid interface, leading to the change of behavior of protein-stabilized film.     

应用吖啶橙- 分光光度法检测重组人白介素- 2制品中SDS含量

目的 用吖啶橙－分光光度法检测重组人白细胞介素－2（rIL－2）制品中Si含量。方法 将被检样品与吖啶橙混合后，加入甲苯进行萃取，然后用紫外分光光度计测　A499吸收峰。结果 在 0-0．o1％SDS浓度范围内，SDS浓度与A400呈线性关系，本法可检测浓度低至 0．001％的 SDS。结论 在一定的 SDS浓度范围内可用吖啶橙-分光光度法检测SDS。