Determination of toxic and essential elements in sunflower honey from Thrace Region,Turkey

The aim of this study was to determine the levels of copper (Cu), manganese (Mn), zinc (Zn), iron (Fe), cadmium (Cd), lead (Pb), chromium (Cr), nickel (Ni) and selenium (Se) in sunflower honeys obtained from Thrace Region of Turkey. Trace and toxic element determination was performed by atomic absorption spectrometry after microwave digestion. The accuracy of the method was checked by the standard reference material, NIST‐SRM 1515 Apple leaves. The maximum contents of trace and toxic elements in honey samples from Kesan (polluted area) were found as 0.46, 0.82, 1.98, 14.0, 9.86 μg kg^?1, 0.48 mg kg^?1, 137, 115 and 290 μg kg^?1 for Cu, Mn, Zn, Fe, Cd, Pb, Cr, Ni and Se, respectively.     

Dissolution Behavior of Electrodeposited Ni–W Alloys

Nickel (Ni)–Tungsten (W) alloys were electrodeposited galvanostatically (at–10 mA cm^–2) on copper substrate with 3 different W contents under the controlled hydrodynamic conditions and then the anodic dissolution behaviors of the alloys were observed by potentiodynamic polarization and electrochemical quartz crystal microbalance (EQCM) techniques. While the structure of the electrodeposited Ni–W alloy with low W content (15.90% W) was crystalline, that of the alloy with high W content (50.80% W) was nano-crystalline according to X-ray diffraction patterns. The increase in the W content of the electrodeposited Ni–W alloy resulted decrease at pH 3 and increase at pH 7 and 12.5 in the anodic currents of the alloy. The pH dependent dissolutions caused electrodeposited alloy surface to have W—enrichment at pH 3 and Ni—enrichment at pH 7 and 12.5. These observations indicated that the selective dissolution of Ni or W was the main mechanism in the anodic dissolution of the electrodeposited Ni–W alloys. The EQCM experiments conducted at pH 7 supported the presence of the selective dissolution mechanism that the anodic dissolution potential of W was 0.42 V lower than that of Ni in the electrodeposited Ni–W alloys.     

Effect of brewing process and sugar content on 5-hydroxymethylfurfural and related substances from Turkish coffee

The effect of brewing process on 5-hydroxymethylfurfural, 2-furylmethylketone, and 2-furoic acid levels of traditionally prepared and instant Turkish coffee samples containing different amounts of table sugar (0, 2, 4, or 8 g in 20 mL of coffee) were analyzed by high pressure liquid chromatography with diode array detector. The highest change at the levels of furfurals was observed in sample of traditional and instant Turkish coffee named T4 and S4 both of containing 8 g of sugar, respectively. The results showed that 5-hydroxymethylfurfural, 2-furylmethylketone, and 2-furoic acid concentrations in both traditionally prepared and instant Turkish coffee samples increased with increasing sugar concentration. The brewing method and sugar concentration had a significant effect on furfural contents of Turkish coffee (p < 0.05). Daily intakes of furfurals for Turkish population were calculated as 8.14–13.54 and 9.36–10.25 µg kg^?1 body weight for traditionally prepared and instant Turkish coffee samples, respectively, and daily intakes of furfurals were lower than the acceptable daily intake value of 0.5 mg kg^?1 body weight.     

Efficiency of an Otto engine under alternative power optimizations

The proper optimization criterion to be chosen for the optimum design of the heat engines may differ depending on their purposes and working conditions. In this study, a comparative performance analysis is carried out for a reversible Otto cycle based on three alternative performance criteria namely maximum power (mp), maximum power density (mpd) and maximum efficient power (mep). The power density criterion is defined as the power per minimum specific volume in the cycle and the efficient power criterion is defined as multiplication of the power by the efficiency of the Otto cycle. Maximizing the efficient power gives a compromise between power and efficiency. Three different objective functions are defined and maximization of these functions is carried out under different design parameters of the Otto engine. The variations of power, power density and efficient power outputs are derived and presented with respect to the thermal efficiency of the cycle for various temperature ratios. It has been found that the design parameters at mep conditions lead to more efficient engines than that at the mp condition and the mep criterion may have a significant power advantage compared with mpd criterion. Copyright © 2009 John Wiley & Sons, Ltd.     

Equilibrium,kinetics, and thermodynamics of Pd(II) adsorption onto poly(m‐aminobenzoic acid) chelating polymer

This study describes the equilibrium, kinetics, and thermodynamics of the palladium(II) (Pd(II)) adsorption onto poly(m‐aminobenzoic acid) (p‐mABA) chelating polymer. The p‐mABA was synthesized by the oxidation reaction of m‐aminobenzoic acid monomer with ammonium peroxydisulfate (APS). The synthesized p‐mABA chelating polymer was characterized by FTIR spectroscopy, gel permeation chromatography (GPC), thermal analysis, potentiometric titration, and scanning electron microscopy (SEM) analysis methods. The effects of the acidity, temperature, and initial Pd(II) concentration on the adsorption were examined by using batch adsorption technique. The optimum acidity for the Pd(II) adsorption was determined as pH 2. In the equilibrium studies, it was found that the Pd(II) adsorption capacity of the polymer was to be 24.21 mg/g and the adsorption data fitted better to the Langmuir isotherm than the Freundlich isotherm. The kinetics of the adsorption fitted to pseudo‐second‐order kinetic model. In the thermodynamic evaluation of the adsorption, the ΔG° values were calculated as ?16.98 and ?22.26 kJ/mol at 25–55°C temperatures. The enthalpy (ΔH°), entropy (ΔS°), and the activation energy (E_a) were found as 35.40 kJ/mol, 176.05 J/mol K, and 61.71 kJ/mol, respectively. The adsorption of Pd(II) ions onto p‐mABA was a spontaneous, endothermic, and chemical adsorption process which is governed by both ionic interaction and chelating mechanisms. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42533.     

Ring Opening of Epoxidized Soybean Oil with Compounds Containing Two Different Functional Groups

Epoxidized vegetable oils are desirable chemicals due to their eco‐friendly characteristics and their being a major source of many green products. Ring opening is one of the ways to convert these epoxidized oils to some new intermediates. The use of mono‐functional amines, alcohols, acid anhydrides and thioethers for epoxy ring opening has been reported in the literature. In this study, thioglycolic acid (TGA) bearing thiol and carboxylic acid as two different functional groups and methyl ester of thioglycolic acid (TGAME) were used. Currently, there is no reported literature describing epoxy ring opening using chemicals bearing two different functional groups simultaneously. In this way, two new polyols were synthesized, one with TGA (polyol 1) and one with TGAME (polyol 2). FTIR and ¹H‐ and ¹³C‐NMR spectroscopy confirmed that the ring was opened by the carboxylic acid group of TGA, and the thiol group was not involved in the ring opening whereas the ring was opened by the thiol group in the case of TGAME.     

Changes in Volatile Compounds of Black Cumin Oil and Hazelnut Oil by Microwave Heating Process

Black cumin and hazelnut oils were subjected to a heating process in a microwave oven for a duration of 2, 4, 6 and 8 min at a constant frequency of 2450 MHz and a power of 0.45 kW. The ultraviolet absorption and volatile products of the oils were investigated in detail during the processes. The experimental evidences obtained show that K₂₃₂ and K₂₇₀ parameters reach values of 4.69 and 1.30 for black cumin oil, 3.22 and 1.75 for hazelnut oil, respectively with the increment of heating time. The headspace SPME method was used to analyze volatile compounds extracted from black cumin and hazelnut oils being exposed to the microwave heating process. The SPME–GC/MS method allowed the detection of 17 identified volatile compounds (hexanal, α‐thujene, α‐pinene, sabinene, β‐pinene, 2‐heptenal, α‐terpinene, limonene, p‐cymene, γ‐terpinene, E‐2‐octenal, nonanal, 4‐terpineol, thymoquinone, E,E‐2,4‐decadienal, α‐longipinene and isolongifolene) in black cumin oils. Of the products, hexanal, 2‐heptenal, E‐2‐octenal, nonanal and E,E‐2,4‐decadienal were determined to be the predominant volatile oxidation products. In fact, the hexanal was found as a major volatile oxidation compound and reached a local maximum point of 7.41 × 10⁶ AU at the end of heating. On the other hand, only 8 volatile oxidation products (hexanal, heptanal, 2‐heptenal, nonanal, E‐2‐decenal, E,Z‐2,4‐decadienal, E,E‐2,4‐decadienal and E‐2‐tridecenal) were identified in hazelnut oils as a consequence of the heating process. Based on the experimental evidence observed, it is reasonable to conclude that the nonanal content dramatically increased at the end of heating and reached a value of 9.22 × 10⁶ AU.     

Influence of Storage on Physicochemical and Volatile Features of Enriched and Aromatized Wax Organogels

In this study, virgin olive oil (VOO) organogels were produced with beeswax (BW) and sunflower wax (SW) and enriched with β‐carotene, vitamin D₃ and E as well as aromatized with strawberry, banana, and butter aromas. The physicochemical, thermal, structural, and sensorial properties of the fresh organogel samples were determined. The peroxide values, antioxidant activities, firmness, and volatile compositions of the fresh samples and those stored for 3 months were also determined. The organogels were not only stable, uniform, and homogenous during the storage period but also the added components did not affect the organogel properties. The panel defined three appearance, four texture, three mouthfeel, four aroma, and four flavor terms to describe the organogels sensorially. Moreover, the added aroma (banana, strawberry, and diacetyl‐butter) components of the fresh and stored organogels were quantified by GC/MS‐SPME. In conclusion, these results demonstrated that beeswax and sunflower wax are very suitable to preserve the aromatic characteristics of these types of spreadable products.     

Comparison of the pomegranate seed oil organogels of carnauba wax and monoglyceride

The aims of this study were to prepare organogels from pomegranate seed oil (PO) with carnauba wax (CW) and monoglyceride (MG), compare the organogels with a commercial margarine (CM) and evaluate 3 months storage stability. At 3% organogelator addition, no gels were formed, while at 7 and 10% additions, the oil binding capacities increased and were always higher in CW organogels, with crystal formation times of 8.0 to 14.0 min. Solid fat content (SFC) of the CW organogels varied between 2.96 and 8.71% at 20°C, while MG gels had 2.89–9.43%, and CM had 29.73% SFC. The peak melting temperatures of the CW organogels ranged from 74.73 to 75.74°C and MG organogels ranged from 11.09 to 50.63°C, whereas CM product exhibited 45.92°C peak melting temperature. The hardness of CW organogels was higher than that of MG organogels. The organogels showed potential as spreadable products. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41343.