Chemical Stability of α‐Tocopherol in Colloidal Lipid Particles with Various Morphologies

Colloidal lipid particles (CLPs) are promising encapsulation systems for lipophilic bioactives, such as oil‐soluble antioxidants that are applied in food and pharmaceutical formulations. Currently, there is no clear consensus regarding the relation between particle structure and the chemical stability of such bioactives. Using α‐tocopherol as a model antioxidant, it is shown that emulsifier type (Tween 20 or 40, or sodium caseinate) and lipid composition (tripalmitin, tricaprylin, or combinations thereof) modulated particle morphology and antioxidant stability. The emulsifier affects particle shape, with the polysorbates facilitating tripalmitin crystallization into highly ordered lath‐like particles, and sodium caseinate resulting in less ordered spherical particles. The fastest degradation of α‐tocopherol is observed in tripalmitin‐based CLPs, which may be attributed to its expulsion to the particle surface induced by lipid crystallization. This effect is stronger in CLPs stabilized by Tween 40, which may act as a template for crystallization. This work not only shows how the architecture of CLPs can be controlled through the type of lipid and emulsifier used, but also gives evidence that lipid crystallization does not necessarily protect entrapped lipophilic bioactives, which is an important clue for encapsulation system design. Practical Applications: Interest in enriching food and pharmaceutical products with lipophilic bioactives such as antioxidants through encapsulation in lipid particles is growing rapidly. This research suggests that for efficient encapsulation, the particle architecture plays an important role; to tailor this, the contribution of both the lipid carrier and the emulsifier needs to be considered.     

Extraction of Algal Lipids and Their Analysis by HPLC and Mass Spectrometry

Algae are a promising source of biofuel but claims about their lipid content can be ambiguous because extraction methods vary and lipid quantitation often does not distinguish between particular lipid classes. Here we compared methods for the extraction of algal lipids and showed that 2-ethoxyethanol (2-EE) provides superior lipid recovery (>150–200 %) compared to other common extraction solvents such as chloroform:methanol or hexane. Extractions of wet and dry algal biomass showed that 2-EE was more effective at extracting lipids from wet rather than dried algal pellets. To analyze lipid content we used normal-phase HPLC with parallel quantitation by an evaporative light scattering detector and a mass spectrometer. Analysis of crude lipid extracts showed that all major lipid classes could be identified and quantified and revealed a surprisingly large amount of saturated hydrocarbons (HC). This HC fraction was isolated from extracts of bioreactor-grown algae and further analyzed by HPLC/MS, NMR, and GC/MS. The results showed that the sample consisted of a mixture of saturated, straight- and branched-chain HC of different chain lengths. These algal HC could represent an alternative biofuel to triacylglycerols (TAG) that could feed directly into the current petroleum infrastructure.     

Cell interaction study of amyloid by using luminescent conjugated polythiophene: implication that amyloid cytotoxicity is correlated with prolonged cellular binding

Needles and noodles: Studying amyloid toxicity is important for understanding protein misfolding diseases. Using a luminescent conjugated polythiophene, we found that cell binding of nontoxic filamentous amyloids of insulin and β2-microglobulin was less efficient than that of toxic fibrillar amyloids; this suggests a correlation between amyloid toxicity and cell binding.     

Interlaboratory study on lipid oxidation during accelerated storage trials with rapeseed and sunflower oil analyzed by conjugated dienes as primary oxidation products

Accelerated storage tests are frequently used to assess the oxidative stability of foods and related systems due to its reproducibility. Various methods and experimental conditions are used to measure lipid oxidation. Differences between laboratories make it necessary to determine the repeatability and reproducibility of oxidation tests performed under the same conditions. The objective of the present interlaboratory study was to evaluate the outcome of a storage test for two different bulk oils, sunflower oil (SFO) and rapeseed oil (RSO), during a period of 9 weeks at 20°C, 30°C, 40°C, and 60°C. Sixteen laboratories were provided with bottled oils and conducted the storage tests according to a detailed protocol. Lipid oxidation was monitored by the formation of conjugated dienes (CD) and the activation energy (E_a) was determined for comparative purposes and statistically evaluated. An increase in CD formation was observed for both oils when the storage temperature was increased in all laboratories. The E_a,1 ranged from 47.9 to 73.3 kJ mol⁻¹ in RSO and from 27.8 to 62.6 kJ mol⁻¹ in SFO, with average values of 58.2 and 46.8 kJ mol⁻¹, respectively. The reproducibility coefficients were 10.9% and 18.2% for RSO and SFO, respectively. Practical applications: In order to compare results on oxidative stability of foods derived from different studies, the reproducibility of storage tests and methods employed to evaluate the oxidation level should be considered. This study provides fundamental data on the reproducibility of lipid oxidation under accelerated storage conditions and defines important parameters to be considered for the conduction of experiments.     

Formation of bed agglomeration in a fluidized multi-waste incinerator

A case study was carried out to investigate the bed agglomeration observed in a fluidized bed incinerator when burning blends of three wastes (carbon soot, biosludge and fuel oil). Several instrumental approaches were employed (i.e. XRF, SEM, XRD, and ICP-AES) to identify the bed materials (fresh sand and degrader sand) and clinkers formed in the full-scale incinerator tests. Several elements (V, Al, S, Na, Fe, Ni, P, and Cl), which normally are associated with the formation of low melting point compounds, were found in the waste blends at high content levels. The clinker bridges were identified to be associated with Al, Fe, V, K, Na, S, Ni, and Si elements.The effects of temperature and blending ratio were investigated in a muffle furnace. Carbon soot is believed to be more susceptible to the clinker formation than the other two fuels. Thermodynamic multi-phase multi-component equilibrium calculations predict that the main low melting point species could be Al₂(SO₄)₃, Fe₂(SO₄)₃, Na₂SO₄, NaCl, Na₂SiO₃ and V₂O₅. This information is useful to understand the chemistry of clinker formation. Also, it helps to develop methods for the control and possible elimination of the agglomeration problem for the design fuels.     

Chitosan functionalized with 2[-bis-(pyridylmethyl) aminomethyl]4-methyl-6-formyl-phenol: equilibrium and kinetics of copper (II) adsorption

The complexation agent 2[-bis-(pyridylmethyl) aminomethyl]-4-methyl-6-formyl-phenol (HL) was immobilized in chitosan in order to obtain a new adsorbent material to be employed in studies on adsorption and pre-concentration of Cu(II). The chitosan modified by the complexation agent was characterized by infrared spectroscopy, DSC and TGA. The studies were conducted as a function of the pH of the medium and the mechanism of Cu(II) adsorption in the solid phase was analyzed utilizing several kinetic models. The parameters for the adsorption of Cu(II) ions by chitosan-HL were determined with a Langmuir isotherm, the maximum saturation capacity of the monolayer being 109.4 mg of Cu(II) per gram of polymer. Electron paramagnetic resonance spectroscopy revealed that Cu^II ions coordinate to the donor atoms of the HL ligand anchored to the surface of the polymer forming a stable chelate complex in the solid state.     

High Throughput Screening of Low Temperature SCR and SCD De-NOx Catalysts in Scanning Mass Spectrometer

High-throughput synthesis and screening methods have been developed for the discovery of highly active lead compounds for the selective catalytic reduction as well as direct decomposition of NO in the temperature range 200–300 °C. The discovery libraries for primary screening consisted of 16 × 16 catalyst arrays on 4in. square quartz wafers. Catalysts were prepared by robotic liquid dispensing techniques and screened for catalytic activity in Symyx' scanning mass spectrometer. The scanning mass spectrometer is a fast serial screening tool that uses flat wafer catalyst surfaces, local laser heating, a scanning/sniffing nozzle and a quadrupolar mass spectrometer to compare relative catalytic activities. The feed consisted of NO/NH₃ mixtures with optional O₂ cofeed and Kr as the internal standard in Ar carrier gas. QMS detection allowed for tracking of H₂O, N₂, NO, O₂, N₂O and Kr. Screening protocols for catalytic materials encompassed metal precursors and carriers for supported vanadia systems, extensive doping of V₂O₅/TiO₂, and broad screening of mixed redox metal oxides and supported base and noble metal systems. More than 500 samples could be screened in a single day. Active hits (high NO consumption accompanied by corresponding N₂ production) identified in discovery libraries were re-synthesized as focus libraries for lead confirmation and further optimization. These libraries used shallower compositional gradients, for example 56 points (compositions) per ternary, with four 56-point ternaries per 4in. wafer. Broad screening ternaries were generally 8 or 15 points. The focus libraries more clearly reveal the trends and provide guidelines for secondary screening and scale-up. High conversions were achieved in scanning mass spectrometer so the scalability risk is small for the short contact time reactions.     

Tocotrienol-rich fraction from palm oil affects gene expression in tumors resulting from MCF-7 cell inoculation in athymic mice

It has recently been shown that tocotrienols are the components of vitamin E responsible for inhibiting the growth of human breast cancer cells in vitro, through an estrogen-independent mechanism. Although tocotrienols act on cell proliferation in a dose-dependent manner and can induce programmed cell death, no specific gene regulation has yet been identified. To investigate the molecular basis of the effect of tocotrienols, we injected MCF-7 breast cancer cells into athymic nude mice. Mice were fed orally with 1 mg/d of tocotrienol-rich fraction (TRF) for 20 wk. At end of the 20 wk, there was a significant delay in the onset, incidence, and size of the tumors in nude mice supplemented with TRF compared with the controls. At autopsy, the tumor tissue was excised and analyzed for gene expression by means of a cDNA array technique. Thirty out of 1176 genes were significantly affected. Ten genes were down-regulated and 20 genes up-regulated with respect to untreated animals, and some genes in particular were involved in regulating the immune system and its function. The expression of the interferon-inducible transmembrane protein-1 gene was significantly up-regulated in tumors excised from TRF-treated animals compared with control mice. Within the group of genes related to the immune system, we also found that the CD59 glycoprotein precursor gene was up-regulated. Among the functional class of intracellular transducers/effectors/modulators, the c-myc gene was significantly down-regulated in tumors by TRF treatment. Our observations indicate that TRF supplementation significantly and specifically affects MCF-7 cell response after tumor formation in vivo and therefore the host immune function. The observed effect on gene expression is possibly exerted independently from the antioxidant activity typical of this family of molecules.     

The nature of polymer grafts and substrate shape on the surface degradation of poly(l‐lactide)

Surface grafting of functional polymers is an effective method to alter material properties and degradation behavior. Two different substrate shapes of poly(l ‐lactide) (PLLA), i.e., films and microparticles, were surface‐grafted with hydrophilic monomers, and their surface degradation was monitored. Surface grafting with a hydrophilic and acidic polymer graft [acrylic acid (AA)] induced large alterations in the surface morphology and topography of the films. In contrast, hydrophilic and neutral polymer grafts [acrylamide (AAm)] had no significant effect on the surface degradation behavior, while the PLLA reference and co‐monomeric (AA/AAm) polymer‐grafted samples exhibited intermediate surface degradation rates. The grafted PAA chains induced a local acidic environment on the surface of the substrates, which in turn catalyzed the surface degradation process. This effect was more pronounced in the films than in the microparticles. Thus, the nature of the grafted chains and substrate geometry were shown to affect the surface degradation behavior of PLLA substrates. © 2015 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42736.     

Effect of NiO-to-Ni Transformation on Conductivity and Structure of Yttria-Stabilized ZrO2

The conductivity and structure of 8-mol%-yttria-stabilized zirconia with additions of nickel oxide has been investigated, both in the as-prepared state and after reduction of NiO in hydrogen. During reduction at 1000°C, the conductivity decreases by 40%–50% and most of the NiO dissolved in the zirconia is exsolved in the form of nickel particles. This is accompanied by the formation of tetragonal zirconia precipitates of size 10–40 nm and by an increase in the lattice parameter. On reoxidation in air at 1000°C, the change in lattice parameter is partly reversed, but the conductivity shows no further changes.