The binding of orally dosed hydrophobic active pharmaceutical ingredients to casein micelles in milk

Casein proteins (α_S1-, α_S2-, β- and κ-casein) account for 80% of the total protein content in bovine milk and form casein micelles (average diameter = 130 nm, approximately 10¹⁵ micelles/mL). The affinity of native casein micelles with the 3 hydrophobic active pharmaceutical ingredients (API), meloxicam [351.4 g/mol; log P = 3.43; acid dissociation constant (pK_a) = 4.08], flunixin (296.2 g/mol; log P = 4.1; pK_a = 5.82), and thiabendazole (201.2 g/mol; log P = 2.92; pK_a = 4.64), was evaluated in bovine milk collected from dosed Holstein cows. Native casein micelles were separated from raw bovine milk by mild techniques such as ultracentrifugation, diafiltration, isoelectric point precipitation (pH 4.6), and size exclusion chromatography. Acetonitrile extraction of hydrophobic API was then done, followed by quantification using HPLC-UV. For the API or metabolites meloxicam, 5-hyroxy flunixin and 5-hydroxy thiabendazole, 31 ± 3.90, 31 ± 1.3, and 28 ± 0.5% of the content in milk was associated with casein micelles, respectively. Less than ～5.0% of the recovered hydrophobic API were found in the milk fat fraction, and the remaining ～65% were associated with the whey/serum fraction. A separate in vitro study showed that 66 ± 6.4% of meloxicam, 29 ± 0.58% of flunixin, 34 ± 0.21% of the metabolite 5-hyroxy flunixin, 50 ± 4.5% of thiabendazole, and 33 ± 3.8% of metabolite 5-hydroxy thiabendazole was found partitioned into casein micelles. Our study supports the hypothesis that casein micelles are native carriers for hydrophobic compounds in bovine milk.     

UHT milk contains multiple forms of αS1-casein that undergo degradative changes during storage

Milk proteins are susceptible to chemical changes during processing and storage. We used proteomic tools to analyse bovine α_S1-casein in UHT milk. 2-D gels of freshly processed milk α_S1-casein was presented as five or more spots due to genetic polymorphism and variable phosphorylation. MS analysis after phosphopeptide enrichment allowed discrimination between phosphorylation states and genetic variants. We identified a new alternatively-spliced isoform with a deletion of exon 17, producing a new C-terminal sequence, K¹⁶⁴SQVNSEGLHSYGL¹⁷⁷, with a novel phosphorylation site at S¹⁷⁴. Storage of UHT milk at elevated temperatures produced additional, more acidic α_S1-casein spots on the gels and decreased the resolution of minor forms. MS analysis indicated that non-enzymatic deamidation and loss of the N-terminal dipeptide were the major contributors to the changing spot pattern. These results highlight the important role of storage temperature in the stability of milk proteins and the utility of proteomic techniques for analysis of proteins in food.     

甘二酯对油脂中抗氧化剂活性的影响

研究sn-1,3-棕榈酸甘二酯对纯净菜籽油氧化稳定性的影响,以期探明其作用机理,为油脂加工和储存提供科学的依据。通过柱层析的方法制备仅含甘三酯成分的纯净菜籽油,测定DAG在菜籽油中形成反相胶束的临界浓度,并在反相胶束体系中,研究DAG及与天然抗氧化剂γ-生育酚及合成抗氧化剂(TBHQ、BHA、BHT)联合作用对纯净菜籽油氧化稳定性的影响。结果表明:DAG在菜籽油中的临界胶束浓度为0.5%;在反相胶束体系中,DAG的添加促进了纯净菜籽油的氧化,DAG对不同种类的抗氧化剂活性的影响存在差异,DAG增强了弱极性抗氧化剂γ-生育酚、BHT的活性,但是减弱了极性较强的抗氧化剂TBHQ、BHA的活性。     

The production of volatile compounds in model casein systems with varying fat levels as affected by low-frequency ultrasound

The effects of low-frequency ultrasound on the production of volatile compounds in model casein protein systems containing various fat concentrations of 2%, 4% and 6% (w/w) were investigated. Ultrasound application was performed at 20 kHz for up to 10 min which corresponded to energy densities ranging from 9.54 to 190.8 J mL⁻¹. Similar volatile compounds were detected both in pure fat and mixtures of casein and fat (CF) systems. These volatiles belonged to the groups of aldehydes, ketones, esters, alcohols and hydrocarbons, which were the products of oxidation of lipids or protein degradation due to acoustic cavitation. The amount of fat in the casein systems had minor effects on the production of volatiles, whereas the production of volatile compounds was significantly affected by the ultrasound treatment. Short sonication times <5 min generated similar volatile profiles to the untreated samples. In contrast, prolonged sonication for 5 and 10 min considerably increased the production of volatile compounds and the amounts of fatty acids. Thus, the application of low–frequency ultrasound for short periods should be considered to minimise the production of volatile compounds which can ultimately affect the taste.     

Polyethylene/Polycaprolactone Nanocomposite Films for Food Packaging Modified with Magnetite and Casein: Oxygen Barrier,Mechanical, and Thermal Properties

Polyethylene (PE) was modified and prepared as double-layer polyethylene/polycaprolactone (PE/PCL) film. Magnetite and casein were added to the PCL-coating film to improve barrier properties and prevent destruction of basic structure of primary polymer PE. Significant improvements were observed with regards to mechanical (tensile strength, elongation at break) and thermal properties, while barrier (O₂ permeability) properties were slightly improved. Overall migration values into acetic acid were lower (from 1 to 4.6 mg/dm²) than the upper limit set by the legislation. Specific migration of iron in PE/PCL-Fe samples is also below (µg/L) specific migration limit value set by the legislation (mg/kg).     

Reversed micelle synergistic extraction from phosphonium ionic liquid extractants in diluent for rare earth

The first synergistic extraction between quaternary phosphonium type ionic liquid extractants in toluene for rare earth was reported in this article. There were two different ion‐association mechanisms in the synergistic extraction system. The formed reversed micelles contributed to increase extractability of the synergistic extraction system to a considerable extent. On the one hand, million tons of saponification wastewater from acidic extractants may be avoided by developing the extraction system using bifunctional ionic liquid extractants. On the other hand, the novel synergistic extraction offers an effective strategy to increase the extractabilities of industrial extractants. This article reveals sustainable and efficient potentials for industrial rare earth separation. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2163–2169, 2016     

P2缓蚀剂处理铝合金的耐腐蚀性能研究

目的：通过加入一种合成缓蚀剂提高锆化液防锈性能。方法将P2缓蚀剂磷酸三乙醇胺加入到锆化液中处理铝合金,使其表面形成一层新型锆化膜。用扫描电镜(SEM)分析处理后样品放大20000倍的表面,并与原液处理的样品进行对比,通过能谱(EDS)及XRD分析微团成分,辅助使用硫酸铜点滴试验判断耐腐蚀能力的增强程度,并用百格试验测试处理后表面对漆膜的附着力变化,通过酸性盐雾试验(CASS)分析新型锆化膜处理后的附着力变化程度。结果使用加入P2缓蚀剂的锆化液的辅助硫酸铜点滴实验,较原样颜色变化所用的时间提高了48 s,用加入缓蚀剂的锆化液处理的样品中,氧元素较原样品中氧元素减少了一半,判断微团为氧化微团且在加入缓蚀剂的锆化液处理后大量减少,百格实验效果相当,能通过480 h的CASS。结论使用添加P2缓蚀剂的锆化液处理铝合金,能增强其耐腐蚀性能。     

Structural and Physicochemical Properties of a Polymerizable Surfactant Synthesized from <Emphasis Type="Italic">N</Emphasis>-Methylol Acrylamide

A new polymerizable nonionic surfactant with reactive vinyl groups has been synthesized from N‐methylol acrylamide using a two‐step procedure. The structure of the surfactant molecule was characterized by Fourier transform infrared, ¹H nuclear magnetic resonance and mass spectroscopy. The surface active properties alongside its self‐assembly properties were investigated by surface tension, electrical conductivity, and fluorescence spectroscopy measurements. As compared with other nonionic surfactants, this study showed that this polymerizable surfactant possesses slightly a higher critical micelle concentration (CMC) value and the surface tension value at CMC. The obtained CMC values were compatible among measurements, ca. 0.02–0.038 M. The evidence of micelle formation also provided by the zeta potential measurements and the obtained zeta potential values showed that the polymerizable surfactant solutions had limited stability. The hydrolysis stability and solubility of the polymerizable surfactant were also investigated. The solubility results have shown that it was soluble in polar solvents while insoluble in nonpolar solvents both at room temperature and 40 °C. The acidic and basic hydrolysis of the surfactant increased as the temperature increased and the hydrolysis stability was 180 min (basic medium) and 55 min (acidic medium) at 80 °C.