Frying Performance of No-<Emphasis Type="Italic">trans</Emphasis>, Low-Linolenic Acid Soybean Oils

Two extruded-expelled physically refined soybean oils with reduced contents of linolenic acid, ultra-low- linolenic acid (ULL, 1.5%) and low-linolenic acid (LL, 2.6%), and a extruded-expelled physically refined control oil (control, 5.3% linolenic acid) were evaluated by frying French fries in a commercial-like setting for 6 h day⁻¹ during 23 days. The oils became darker, increased in yellow color at the beginning, and became redder and less green throughout the process. Free fatty acids levels were not different among the oils until day 14, after which, ULL was different from the control for the remainder of frying. The conjugated dienoic acid values were greatest in the control. Generally, ULL and LL oils had lower percentages of polar compounds than did the control, providing a frying life 2 days longer than the control and ~30% increase in frying time. A trained sensory panel evaluated the French fries on days 2, 5, and 6. Buttery and potato flavors decreased, and rancid and painty flavors increased over frying time for all products. Rancid flavor was highest in the fries from the control oil. Overall, the ULL and LL oils performed better than did the control oil and ULL tended to perform better than the LL.     

Gold nanostructures by directional solid-state decomposition

This study addresses a novel approach of obtaining gold nanostructures, via directional eutectoid decomposition and selective etching of Fe-Au alloys. The eutectoid transformation occurs at 2.3%Au, which agrees perfectly with existing DTA and calculated data. The results are thus experimentally supporting the calculated part of the binary Fe-Au phase diagram. Gold nanofibres were rectangular in shape, constrained with two perpendicular crystallographic directions, showing the faceted nature of the Au phase. In addition, it was shown that a range of gold nanostructures, including gold nanoparticles, short nanorods, and nanofibres might be achieved depending on the processing route. The uniformity and regularity of the obtained nanostructures are limited, due to a non-cooperative mechanism of the eutectoid transformation. These homomorph gold nanostructures have the same high potential as other gold nanostructures but also the advantage of being inherently organized in a single crystalline matrix.     

Analytical Determination of the Distribution of Polishing Time over the Surface of Polished Tiles

Several kinds of glossiness pattern can be seen on the surface of porcelain stoneware tiles right after the polishing process, as a function of the kinematics performed by the polishing heads. For the newest generation of industrial polishing trains, where a transverse oscillation is included, there is still a great need for literature about the resulting patterns. This paper intends to find the spatial distribution of time under polishing analytically using the kinematics equations involved in the polishing process. The measured values of glossiness collected from three polished tiles are also presented. The importance of adopting a good kinematics for the polishing process has been highlighted, and the equations developed herein are useful tools for further attempts at optimizing the polishing process.     

Directed evolution of an esterase from Pseudomonas fluorescens yields a mutant with excellent enantioselectivity and activity for the kinetic resolution of a chiral building block

A triple mutant of an esterase from Pseudomonas fluorescens (PFE) that was created by directed evolution exhibited high enantioselectivity (E=89) in a kinetic resolution and yielded the building block (S)-but-3-yn-2-ol. Surprisingly, a mutation close to the active site caused the formation of inclusion bodies, but remote mutations were found to be responsible for the high selectivity. Back mutations gave a variant (double mutant PFE Ile76Val/Val175Ala) that showed excellent selectivity (E=96) and activity (20 min for 50% conversion, which corresponds to 1.25 U per mg of protein).     

Extrusion of feather keratin

Keratin obtained from poultry feathers was extruded at 120°C using a combination of glycerol, water, and sodium sulfite as processing aids. Rheological properties were assessed as a function of water, glycerol, and sodium sulfite content as well as extruder die temperature. The lowest viscosity blends at a constant feather keratin concentration of 60 wt % were found at glycerol concentrations that were higher than the water concentration and sodium sulfite concentrations of 3–4 wt % of the feather keratin fraction. For the melt state, higher or lower sodium sulfite concentrations resulted in increased viscosity. In the solid state, it was observed that processing induced orientation increased the tensile properties of the extrudates. Raman spectroscopy and DSC showed that there was a transition from α‐helix to β‐sheet at sodium sulfite concentrations of less than 4 wt %. At greater sodium sulfite concentration, increased crystallinity was found, because keratin chains could be extended more during processing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1432–1442, 2006     

Modification of maillard browning in a microwaved glucose/glycine model system by water-soluble natural antioxidants and foods containing them

Inhibition of pyrazine formation by natural antioxidants and the foods containing them was measured in a microwaved glucose/glycine model system. Inhibition of lipid oxidation by the same materials was assayed in both bulk and emulsion systems. Pyrazines were determined by solid-phase micro extraction followed by GC. Lipid oxidation volatiles were assayed by polyamide fluorescence produced by either a bulk oil display or a hematin- or 2,2′-azobis-(2-amidino=propane) dihydrochloride-accelerated lecithin or fish oil emulsion. It was shown that (i) the inhibition of pyrazine formation depends on high concentrations of water-soluble antioxidants; (ii) such antioxidants occur naturally in some foods and are usually polyphenols; (iii) during pyrazine inhibition, oxidized polyphenols show enhanced nonfluorescing browning similar to enzymic browning products; (iv) monophenols, which structurally cannot form quinone polymers on oxidation, inhibit pyrazines with less browning; (v) during the final pyrazine-forming phase of the Maillard reaction, polyphenolics and reducing agents such as glutathione and ascorbic acid are partially consumed with some nutritional loss; (vi) fruit powders of grape seed, grape skin, and red wine are highly pyrazine-inhibitory, steeped blueberry strongly so, but plum purees are moderately pro-pyrazine, and freeze-dried vegetables strongly pro-pyrazine; and (vii) black and green tea infusions are highly inhibitory, whereas spices have mixed effects.     

Correction of single‐beam sample absorption error in a hemispherical 45°/0° spectrophotometer measurement cavity

A mathematical model for quantifying single‐beam sample absorption error in a hemispherical 45°/0° measurement cavity is derived and tested by measuring diffuse reflectance standards with a prototype visible‐range spectrophotometer. A methodology is described for using this three‐parameter model to correct for sample absorption error in any single‐beam spectrophotometer. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 436–441, 2014     

Developing an Irreversible Inhibitor of Human DDAH‐1, an Enzyme Upregulated in Melanoma

Inhibitors of the human enzyme dimethylarginine dimethylaminohydrolase‐1 (DDAH‐1) can raise endogenous levels of asymmetric dimethylarginine (ADMA) and lead to a subsequent inhibition of nitric oxide synthesis. In this study, N⁵‐(1‐imino‐2‐chloroethyl)‐L ‐ornithine (Cl‐NIO) is shown to be a potent time‐ and concentration‐dependent inhibitor of purified human DDAH‐1 (K_I=1.3±0.6 μM ; k_inact=0.34±0.07 min^?1), with >500‐fold selectivity against two arginine‐handling enzymes in the same pathway. An activity probe is used to measure the “in cell” IC₅₀ value (6.6±0.2 μM ) for Cl‐NIO inhibition of DDAH‐1 artificially expressed within cultured HEK293T cells. A screen of diverse melanoma cell lines reveals that a striking 50/64 (78 %) of melanoma lines tested showed increased levels of DDAH‐1 relative to normal melanocyte control lines. Treatment of the melanoma A375 cell line with Cl‐NIO shows a subsequent decrease in cellular nitric oxide production. Cl‐NIO is a promising tool for the study of methylarginine‐mediated nitric oxide control and a potential therapeutic lead compound for other indications with elevated nitric oxide production, such as septic shock and idiopathic pulmonary fibrosis.