l-Arginine-Catalyzed Synthesis of Nanometric Organosilica Particles through a Waterborne Sol-Gel Process and Their Porous Structure Analysis.

We report an efficient and easy-to-implement waterborne sol-gel process for the synthesis of nanometric organosilica particles. In this process, tetraethyl orthosilicate (TEOS) and 3-(methacryloxy)propyl trimethoxy silane (γ-MPS), employed as silica sources, were heterogeneously delivered in an aqueous solution of l-arginine, a basic amino acid used as a catalyst, from a top organic layer. Co-condensation of TEOS with γ-MPS led to the formation of organosilica particles with diameters between 30 and 230 nm when increasing the γ-MPS content from 0 to 10.1 mol % in the silica source. Nitrogen sorption analyses confirmed the microporous nature of the obtained particles after calcination. The Brunauer-Emmett-Teller (BET) surface areas increased from 27 (before calcination) to 684 m2 g-1 (after calcination) for the organosilica particles containing 10.1 mol % of γ-MPS. Fourier transform infrared spectroscopy and 29Si NMR were employed to analyze the chemical structure of the organosilica spheres and provide insight into the mechanism of particle formation. In the second part, hybrid organosilica particles with a core-shell morphology were synthesized through the combination of Pickering emulsion and the sol-gel process. γ-MPS emulsion droplets stabilized by tiny silica particles (formed in a separate step) were first generated and used as seeds to grow a silica shell on their surface through TEOS addition from the top organic layer. Transmission electron microscopy and pore size analyses of the resulting particles after calcination revealed a unique dual-porosity structure with a mesoporous inner core and a micro/mesoporous silica shell with ink-bottle-type pores.

Tea Polyphenols as Inhibitors of Furan Formed in the Maillard Model System and Canned Coffee Model.

In this article, the effects of sugars and amino acids on furan formation via the Maillard reaction in low-moisture model systems were investigated. Glucose and alanine are important furan precursors, and the effects of the heating temperature, heating time, and molar ratio of glucose to alanine on furan formation were studied in glucose/alanine model system by response surface methodology. The heating temperature greatly affected furan formation. The maximum furan concentration was obtained with a glucose-to-alanine molar ratio of 0.83:1.00, by heating at 151 °C for 41 min. Tea polyphenols effectively inhibited furan formation in the glucose/alanine model and a canned coffee model. A high inhibition rate of 42.4% ± 1.5% was obtained in the canned coffee model during sterilization procedure with addition of 84 mg (the mass fraction is 12.1%) of tea polyphenols (99%). However, the content of aromatic components in the canned coffee model was significantly reduced at the same time. This study provides evidence for a good furan inhibitor that can be used in food processing.

Ageing behavior of extruded Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr (wt.%) alloy containing LPSO phase and γ' precipitates.

The effect of long period stacking ordered (LPSO) phase and γ' precipitates on the ageing behavior and mechanical properties of the extruded Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr (wt.%) alloy was investigated. The results show that more ß' phases precipitate during ageing treatment in the LPSO phase containing alloy so that the LPSO phase containing alloy exhibits a higher age-hardening response than the γ' precipitates containing alloy. The precipitation strengthening induced by ß' precipitates is the greatest contributor to the strength of the peak-aged LPSO-containing alloys. Higher strength is achieved in γ' precipitates containing alloy due to the more effective strengthening induced by dense nanoscale γ' precipitates than LPSO phases as well as the higher volume fraction of coarse unrecrystallized grains with strong basal texture. The extruded alloy containing γ' precipitates after T5 peak-ageing treatment shows ultra-high tensile yield strength of 462 MPa, high ultimate tensile strength of 520 MPa, and superior elongation to failure of 10.6%.

The biomimetic immunoassay based on molecularly imprinted polymer: a comprehensive review of recent progress and future prospects.

UNLABELLED: Immunoassay, based on a selective affinity of the biological antibody for its antigen, is one of the most usual analytical methods in food safety and environmental chemistry. However, it presents several drawbacks because of the nature of the antibody. Molecular imprinting technique, due to its high selectivity and stability, ease of preparation and low cost, has shown great potential in producing artificial antibodies in biomimetic immunoassays. This article focuses on the recent states, advantages, current problems and outlooks of molecularly imprinted radio, fluoro, enzyme-linked and chemiluminescent immunoassays, and biomimetic immunosensor, with special emphasis on the challenges in developing biomimetic enzyme-linked immunosorbent assays (BELISAs). The biomimetic immunoassay method will provide an important new analysis platform in food safety, although the sensitivity and specificity is relatively low. PRACTICAL APPLICATION: As a new simple analysis method, the biomimetic immunoassay has attractive prospect, although some limitations were existed in real-sample assay. In this critical review, some promising solutions for overcoming its drawbacks were put forward, which may promote the more quick development and extensive application of this method in food safety.

Determination of trace Para Red residues in foods through on-line molecularly imprinted solid phase extraction coupled with high-performance liquid chromatography.

UNLABELLED: In this article, we prepared a novel imprinted polymer by a room temperature ionic liquid-mediated surface molecular imprinting technique in combination with a sol-gel process. This polymer was characterized by static and kinetic adsorption experiments and exhibited good recognition ability and offered fast kinetics for the adsorption of Para Red. A simple and sensitive analytical method, based on the coupling of molecularly imprinted solid phase extraction with high-performance liquid chromatography (HPLC), had been developed for determination of trace Para Red. With a loading flow rate of 0.42 mL min(-1) for 25 mL, an enrichment factor of 1061 was achieved. Under the selected experimental condition, the detection limit (S/N = 3) of Para Red was 6.6 ng L(-1), and the peak area precision (RSD) for 5 replicate detections of 0.15 microg L(-1) Para Red was 4.1%. The applicability of this method for determination of the blank chili sauce sample, spiked with Para Red at 5 to 25 ng g(-1) levels, was demonstrated, with recoveries ranging from 86% to 95%. PRACTICAL APPLICATION: In this paper, a simple and sensitive analytical method, based on the coupling of molecularly imprinted solid phase extraction with high performance liquid chromatography, had been developed for determination of trace Para Red. It was applied to the analysis of spiking Para Red in chili sauce sample with satisfactory recovery and repeatability. This proposed method has the potential to be used for monitoring the illegal addition of Para Red in foods in the future due to its simple, reliable, rapid, and excellent precision.

Photo-induced lipid peroxidation of erythrocyte membranes by a bis-methanophosphonate fullerene.

Using human erythrocyte membranes (EMs) as a model system, we have examined photo-induced lipid peroxidation by a bis-methanophosphonate fullerene (BMPF) and four other fullerene derivatives including a mono-methanophosphonic acid fullerene (MMPF), a dimalonic acid C(60) (DMA C(60)), a trimalonic acid C(60) (TMA C(60)) and a polyhydroxylated fullerene (fullerol). Lipid peroxidation was assessed as the malondialdehyde (MDA) level measured by the thiobarbituric acid assay. It was observed that BMPF increased the MDA level of EMs after irradiation in both time- and dose-dependent manners. The photo-induced activity became very significant (p<0.01) under the conditions of either the concentration of 10 microM and irradiation time of 30 min or the concentration of 5 microM and irradiation time of 60 min. Involvement of reactive oxygen species (ROS) in the activity was also examined by specific inhibitors of singlet oxygen, superoxide anions and hydroxyl radicals, respectively. While all three kinds were found responsible for the activity, the former two might play more important roles than the last one. Furthermore, the activity of BMPF was the strongest among all tested fullerene derivatives. These results indicated BMPF was a potential photosensitizer that would find application in photodynamic therapy.