Assessment of Trans Fatty Acid Level in French Fries from Various Fast Food Outlets in Karachi,Pakistan

The purpose of this study is to determine the trans fat level in French fries sold in different fast food outlets in Karachi. In the present study, attenuated total reflectance‐Fourier transform infrared (ATR‐FTIR) spectroscopy was used for the quantification of trans fatty acid (TFA). A number of studies have been reported on trans fat in different regions of the world, but no categorical study has yet discussed the trans fat in fast food products in Karachi. Amongst the samples examined, the total trans fatty acid content was in the range of 0.11 ± 0.01–24.00 ± 0.25 %. Most of the samples contain a high percentage of TFA. There is an urgent need to monitor and regulate the level of trans fat in order to reduce the health risk to the consumers of fast food items in Karachi, Pakistan.     

Frying Quality Characteristics of French Fries Prepared in Refined Olive Oil and Palm Olein

The objective of this study was to compare two oils with different polyunsaturated/saturated (P/S) fatty acid ratios, refined olive oil (P/S 0.75) and palm olein (P/S 0.25), in frying French fries. The chemical qualities of the oil residues extracted from the French fries were assayed for five consecutive batches fried at 1-h intervals. The levels of total polar compounds, free fatty acids, p-anisidine value and phytosterol oxidation products (POPs) were elevated in French fries fried in both oils. The level of total polar compounds increased from 4.6 in fresh refined olive oil to 7.3% in final batches of French fries. The corresponding figures for palm olein were 9.8–13.8%. The level of free fatty acid in fresh refined olive oil increased from 0.06 to 0.11% in final products. These figures for palm olein were 0.04–0.13%. The p-anisidine value increased from 3.7 to 32.8 and 2.5 to 53.4 in fresh oils and in final batches of French fries in refined olive oil and palm olein, respectively. The total amount of POPs in fresh refined olive oil increased from 5.1 to 9.6 μg/g oil in final products. These figures were 1.9 to 5.3 μg/g oil for palm olein.     

Effects of Temperature and Heating Time on the Formation of Four Toxic α,β‐Unsaturated‐4‐Hydroxyaldehydes in Vegetable Oils

The formation of four α,β‐unsaturated hydroxyaldehydes, 4‐hydroxy‐2‐trans‐hexenal (HHE), 4‐hydroxy‐2‐trans‐octenal (HOE), 4‐hydroxy‐2‐trans‐nonenal (HNE), and 4‐hydroxy‐2‐trans‐decenal (HDE), was detected in commercial corn, soybean, peanut, and canola oils heated for 1, 3, and 5 hours at 145, 165, and 185 °C. These four toxic aldehydes were investigated using high‐performance liquid chromatography (HPLC). These oils were selected based upon different degrees of unsaturations, especially their linoleic and linolenic acid concentrations. To select the appropriate conditions of temperatures and heating times, preliminary experiments were conducted using the thiobarbituric acid assay, which detects the formation of secondary‐oxidation products such as aldehydes and related carbonyl compounds. After various heat treatments, the formation of HHE, HOE, HNE, and HDE was detected as 2,4‐dinitrophenyl hydrazine derivatives using HPLC. In general, HHE, HOE, HNE, and HDE formation increased in all four oils with higher temperatures, longer heating times, and higher concentrations of linoleic and linolenic acids in the oils. The formation of HNE in the oils was mostly much higher than the other three 4‐hydroxyaldehyde isomers under the same conditions.     

Formation of 4‐Hydroxy‐2‐Trans‐Nonenal,a Toxic Aldehyde,in Thermally Treated Olive and Sunflower Oils

4‐Hydroxy‐2‐trans‐nonenal (HNE) is a toxic aldehyde produced mostly in oils containing polyunsaturated fatty acid due to heat‐induced lipid peroxidation. The present study examined the effects of the heating time, the degree of unsaturation, and the antioxidant potential on the formation of HNE in two light olive oils (LOO) and two sunflower oils (one high oleic and one regular) at frying temperature. HNE concentrations in these oil samples heated for 0, 1, 3, and 5 hours at 185 °C were measured using high‐performance liquid chromatography. The fatty‐acid distribution and the antioxidant capacity of these four oils were also analyzed. The results showed that all oils had very low HNE concentrations (<0.5 μg g^?1 oil) before heating. After 5 hours of heating at 185 °C, HNE concentrations were increased to 17.98, 25.00, 12.51, and 40.00 μg g^?1 in the two LOO, high‐oleic sunflower oil (HOSO), and regular sunflower oil (RSO), respectively. Extending the heating time increased HNE formation in all oils tested. It is related to their fatty‐acid distributions and antioxidant capacities. RSO, which contained high levels of linoleic acid (59.60%), a precursor for HNE, was more susceptible to degradation and HNE formation than HOSO and LOO, which contained only 6–8% linoleic acid.     

Sodium azide and metal chelator effects on 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging compounds from methylene blue photosensitized lard

Thermal oxidation of edible oils can generate 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging compounds from oxidized lipids (RSOLs). However, effects of photosensitization on the formation of RSOLs have not been reported yet. Methylene blue (MB) photosensitization and involvement of singlet oxygen and transition metals on the RSOL formations were determined in stripped lard oils. RSOLs were formed in lard containing MB and visible light irradiation only. Addition of sodium azide decreased RSOLs with concentration dependent manner, which implies singlet oxygen was involved on the RSOL formation. Ethylenediammetetraacetic acid (EDTA), a well known metal chelator, accelerated the formation of RSOLs through protecting the decomposition of MB photosensitizer. Results from p‐anisidine values showed that RSOLs from photosensitization may not be formed from the same pathways compared to thermal oxidation. Practical application: Understanding mechanisms of lipid oxidation can help extend the shelf‐life of foods. Photosensitization plays important roles in accelerating the rates of lipid oxidation. The results of this study showed that foods containing photosensitizers can generate radical scavenging compounds from oxidized lipids (RSOLs) under visible light irradiation and singlet oxygen is involved in the formations of these compounds. However, these compounds may not share the same pathways with thermally oxidized lipids. Metal chelating agents accelerated the rates of lipid oxidation and formation of RSOLs which implies that metal chelators can act as prooxidant. Careful considerations are necessary on the addition of metal chelators because non‐polar photosensitizers can act a prooxidant.     

Identification of a Δ4‐desaturase from the microalga Ostreococcus lucimarinus

Very long chain PUFA (VLCPUFA) like DHA are essential and health‐beneficial components of the human diet. Due to a shortfall in VLCPUFA supply, research is ongoing to establish VLCPUFA production in heterologous systems like for example oilseed plants. For this purpose it is crucial to identify the required enzymes from primary producers of VLCPUFA. Here, we describe a cDNA from the microalga Ostreococcus lucimarinus coding for a Δ4‐fatty acid desaturase. It exhibits a cytochrome b₅ domain fused to its amino terminus and three histidine boxes that are typically found in front‐end desaturases. Heterologous expression of the partly codon‐optimized version of the cDNA in yeast revealed that the encoded protein catalyzes the desaturation of (n‐3)‐ as well as (n‐6)‐substrates with a preference for VLCPUFA. In yeast it localized at the endoplasmic reticulum (ER) membrane and analysis of the product distribution into different lipid classes suggested that the enzyme most likely acts in a lipid‐dependent manner. Practical applications : The identified Δ4‐desaturase may be useful for the production of DHA in transgenic oleaginous organisms like annual oilseed crops.     

Photocatalytic Selective Oxidation of 4‐Methoxybenzyl Alcohol to Aldehyde in Aqueous Suspension of Home‐Prepared Titanium Dioxide Catalyst

The photocatalytic oxidation of 4‐methoxybenzyl alcohol to p‐anisaldehyde (PAA) was performed in water with organic‐free suspensions of home‐prepared and commercial titanium dioxide (TiO₂) catalysts. The nanostructured TiO₂ samples were synthesised by boiling aqueous solutions of titanium tetrachloride (TiCl₄), under mild conditions, for different times. The crystallinity increased with the boiling time. The 4‐methoxybenzyl alcohol oxidation rate followed the same pattern but the highest yield (41.5 % mol) to PAA was found for the least crystalline sample, that showed a quantum efficiency of 0.116 %. A comparison with two commercial TiO₂ samples showed that all the home‐prepared catalysts exhibited a PAA yield higher than that of commercial ones. The only by‐products present were traces of 4‐methoxybenzoic acid and aliphatic products, carbon dioxide being the other main oxidation product.     

Combination of UDP‐Glc(NAc) 4′‐Epimerase and Galactose Oxidase in a One‐Pot Synthesis of Biotinylated Nucleotide Sugars

The enzymatic epimerization of uridine 5′‐diphospho‐α‐D ‐glucose (UDP‐Glc, 1 ) and uridine 5′‐diphospho‐N‐acetyl‐α‐D ‐glucosamine (UDP‐GlcNAc, 2 ) and the subsequent oxidation of uridine 5′‐diphospho‐α‐D ‐galactose (UDP‐Gal, 3 ) and uridine 5′‐diphospho‐N‐acetyl‐α‐D ‐galactosamine (UDP‐GalNAc, 4 ) were combined with chemical biotinylation with biotin‐ε‐amidocaproylhydrazide in a one‐pot synthesis. Analysis by CE and NMR revealed a mixture (1.0:1.4) of the biotinylated nucleotide sugars uridine 5′‐diphospho‐6‐biotin‐ε‐amidocaproylhydrazino‐α‐D ‐galactose (UDP‐6‐biotinyl‐Gal, 7) and uridine 5′‐diphospho‐6‐biotin‐ε‐amidocaproylhydrazino‐α‐D ‐glucose (UDP‐6‐biotinyl‐Glc, 9 ), respectively, in a reaction started with 1 . One product, uridine 5′‐diphospho‐6‐biotin‐ε‐amidocaproylhydrazino‐N‐acetyl‐α‐D ‐galactosamine (UDP‐6‐biotinyl‐GalNAc, 8) was formed when the reaction was initiated with 2 . It could be demonstrated for the first time that a UDP‐Glc(NAc) 4′‐epimerase (Gne from Campylobacter jejuni) and galactose oxidase from Dactylium dendroides can be used simultaneously in enzymatic catalysis. This is of particular interest since the coaction of an enzyme demanding reductive conditions and an oxygen‐dependent oxidase is unexpected.     

Isothermal kinetics of (E)‐4‐(4‐metoxyphenyl)‐4‐oxo‐2‐butenoic acid release from a poly(acrylic acid‐co‐methacrylic acid) hydrogel

A kinetic study of the release of the drug (E)‐4‐(4‐metoxyphenyl)‐4‐oxo‐2‐butenoic acid (MEPBA) from a poly(acrylic acid‐co‐methacrylic acid) (PAA‐co‐MA) hydrogel was performed. The isothermal kinetic curves of MEPBA release from the PAA‐co‐MA hydrogel in bidistilled water at different temperatures ranging from 20 to 40°C were determined. The reaction rate constants of the investigated process were determined with the initial rate, the saturation rate, and Peppas's semiempirical equation. Also, a model‐fitting method for the determination of the kinetics model of drug release was applied. The influence of α at the values of the kinetic parameters and the presence of a compensation effect was established. A procedure for the determination of the distribution function of the activation energies was developed. This procedure was based on the experimentally determined relationship between the activation energy and α. The mechanism of active compound release is discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Oxidation of 4‐nitrophenol in water over Fe(III), Co(II), and Ni(II) impregnated MCM41 catalysts

BACKGROUND: Nitrophenols are toxic constituents of the effluents of petroleum, textile, dye, iron and steel, foundries, pharmaceutical and electrical manufacturing industries. Aromatic nitro compounds are particularly resistant to normal chemical or biological oxidation making them environmentally persistent. Advanced oxidation using appropriate catalysts mineralize these organics to harmless final products. In this work, MCM41‐based catalysts incorporating Fe(III)‐, Co(II)‐ and Ni(II)‐ cations were used for oxidizing 4‐nitrophenol in water under variable conditions of reaction time, pH, mole ratio of the reactant and the oxidant, catalyst load, feed concentration, and temperature. RESULTS: The catalysts prepared were characterized with X‐ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), cation exchange capacity (CEC) and atomic absorption spectrometry (AAS) measurements. In typical reaction conditions of temperature 353 K, time 300 min, catalyst load 2 g L^?1 and 10^?3 mol L^?1 4‐nitrophenol, the oxidation was 48.7, 52.2 and 55.2% with H₂O₂ and 42.5, 56.6 and 60.2% without H₂O₂ for Fe(III)‐, Co(II)‐ and Ni(II)‐MCM41, respectively. Pseudo‐first‐order kinetics with kinetic constant of 2.0 × 10^?3 to 5.5 × 10^?3 Lg^?1 min^?1 was proposed along with a possible mechanism. 4‐nitrocatechol, 4‐nitropyrogallol, 1,2,4‐trihydroxybenzene, hydroquinone, acrylic acid, malonic acid, and oxalic acid were identified in the oxidation products. CONCLUSION: Introduction of Fe(III)‐, Co(II)‐ and Ni(II)‐ into MCM‐41 by impregnation produced effective catalysts for wet oxidation of 4‐nitrophenol. The catalysts were able to oxidize 4‐NP even without the presence of an oxidizing agent. The results suggest that the transition metal loaded MCM41 brings about a more effective interaction between 4‐NP molecules and OH radicals. Copyright © 2008 Society of Chemical Industry     

New optically active poly(amide–imide–urethane) thermoplastic elastomers derived from poly(ethylene glycol diols), 4,4′‐methylene‐bis(4‐phenylisocyanate), and a diacid based on an amino acid by a two‐step method under microwave irradiation

A new class of optically active poly(amide–imide–urethane)s (PAIUs) was synthesized via a two‐step diisocyanate route under microwave irradiation. In these reactions, 4,4′‐methylene‐bis(4‐phenylisocyanate) was reacted with bis(p‐amido benzoic acid)‐N‐trimellitylimido‐L ‐leucine and poly(ethylene glycol diol)s (PEGs), such as PEG‐400, PEG‐600, PEG‐1000, and PEG‐2000, to furnish a series of new PAIUs. The effects of different reaction conditions, such as the method of preparation (polyol or acid chain extension), the prepolymerization step (NCO‐terminated oligoamide or NCO‐terminated polyether polyol), the irradiation time and power, the reaction solvent, the soft‐segment length, and the presence or absence of reaction catalysts (e.g., triethylamine, pyridine, and dibutyltin dilaurate), on the properties of the copolymers, including the solubility, viscosity, and thermal behavior, were investigated. The resulting multiblock copolymers had inherent viscosities of 0.15–0.53 dL/g. These multiblock copolymers were optically active, thermally stable, and soluble in amide‐type solvents. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1781–1792, 2005     

Polyurethane‐ and Polystyrene‐Supported 2,2,6,6‐Tetramethyl‐ piperidine‐1‐oxyl (TEMPO); Facile Preparation,Catalytic Oxidation and Application in a Membrane Reactor

In this contribution, the facile synthesis of two new polymer‐supported 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) catalysts and their application in the catalytic oxidation of alcohols to carbonyl compounds are described. For attachment of the TEMPO group to the polymer an isocyanate functionalized polymer is chosen. This new approach facilitates the synthesis in comparison with previously existing methods which generally require deprotonation of TEMPO prior to reaction with the polymer. Following this approach, polyurethane (PU)‐ and polystyrene (PS)‐based TEMPO catalysts are prepared in a one‐step reaction from commercially available compounds. Both polymer‐supported catalysts showed promising yields for a variety of substrates using inorganic and/or organic co‐oxidants in biphasic and/or monophasic systems. The recyclability of the corresponding catalysts was studied in repetitive batch experiments using filtration or distillation depending on the support type. Furthermore, application of the homogeneous polyurethane‐supported TEMPO for the selective oxidation of benzyl alcohol in a continously operated membrane reactor is demonstrated.     

Biodegradation of poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) by a novel P3/4HB depolymerase purified from Agrobacterium sp. DSGZ

A poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) (P3/4HB)‐degrading strain, Agrobacterium sp. DSGZ, was isolated from sewage by poly(3‐hydroxybutyrate) (PHB) mineral agar plates. A novel P3/4HB depolymerase with a molecular weight of 34 kDa was purified through a novel single‐step affinity chromatography method from the culture supernatant of the strain by using P3/4HB powder as a substrate. The purified depolymerase showed optimum activity at pH 7.0 and 50°C, and was stable at the pH range of 6.0 to 9.0 and temperature below 50°C. Enzyme activity was strongly inhibited by phenylmethylsulfonyl fluoride (PMSF), ethylenediaminetetraacetic acid (EDTA), hydrophobic reagents, and some metal ions. The depolymerase degraded poly(3‐hydroxybutyrate) (PHB), poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV), P3/4HB, and polycaprolactone (PCL), instead of polylactic acid (PLA) or poly(butylene succinate) (PBS). Meanwhile, the depolymerase showed high hydrolytic activity against short‐chain length esters, such as butyrate acid ester and caprylic acid ester. The main degradation products of the depolymerase were identified as hydroxybutyrate monomers and dimers, and the monomers were identified as 3‐hydroxybutyrate (3HB) monomers and 4‐hydroxybutyrate (4HB) monomers. The preparation procedure, crystallinity, and 4HB composition of the P3/4HB copolymer showed evident effect on degradation behavior, and change in crystallinity was the main factor affecting degradation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42805.     

Derivation of a Retinoid X Receptor Scaffold from Peroxisome Proliferator‐Activated Receptor γ Ligand 1‐Di(1H‐indol‐3‐yl)methyl‐4‐trifluoromethylbenzene

PPARγ agonist DIM‐Ph‐4‐CF ₃ , a template for RXRα agonist (E)‐3‐[5‐di(1‐methyl‐1H‐indol‐3‐yl)methyl‐2‐thienyl] acrylic acid: DIM‐Ph‐CF₃ is reported to inhibit cancer growth independent of PPARγ and to interact with NR4A1. As both receptors dimerize with RXR, and natural PPARγ ligands activate RXR, DIM‐Ph‐4‐CF₃ was investigated as an RXR ligand. It displaces 9‐cis‐retinoic acid from RXRα but does not activate RXRα. Structure‐based direct design led to an RXRα agonist.

     

Palladium‐Catalyzed Domino Cyclization (5‐exo/3‐exo), Ring‐ Expansion by Palladium Rearrangement,and Aromatization: An Expedient Synthesis of 4‐Arylnicotinates from Morita–Baylis–Hillman Adducts

Various 4‐arylnicotinate derivatives were synthesized via a palladium‐catalyzed cascade reaction of N‐(2‐bromoallyl)‐N‐cinnamyltosylamides in a one‐pot procedure in good yields. The reaction involves a domino 5‐exo/3‐exo carbopalladation, ring‐expansion by palladium rearrangement, and an aromatization process.     

Decreasing miscibility with greater heterogeneity in ternary polymer blend: poly(cyclohexyl methacrylate), poly(α‐methyl styrene) and poly(4‐methyl styrene)

A ternary blend system comprising poly(cyclohexyl methacrylate) (PCHMA), poly(α‐methyl styrene) (PαMS) and poly(4‐methyl styrene) (P4MS) was investigated by thermal analysis, optical and scanning electron microscopy. Ternary phase behaviour was compared with the behaviour for the three constituent binary pairs. This study showed that the ternary blends of PCHMA/PαMS/P4MS in most compositions were miscible, with an apparent glass transition temperature (T_g) and distinct cloud‐point transitions, which were located at lower temperatures than their binary counterparts. However, in a closed‐loop range of compositions roughly near the centre of the triangular phase diagram, some ternary blends displayed phase separation with heterogeneity domains of about 1 µm. Therefore, it is properly concluded that ternary PCHMA/PαMS/P4M is partially miscible with a small closed‐loop immisciblity range, even though all the constituent binary pairs are fully miscible. Thermodynamic backgrounds leading to decreased miscibility and greater heterogeneity in a ternary polymer system in comparison with the binary counterparts are discussed. © 2003 Society of Chemical Industry     

Preparation of a porous structure in a poly(4‐methyl‐1‐pentene)/diphenyl ether system with a thermally induced phase‐separation method

Poly(4‐methyl‐1‐pentene) was used to prepare porous structures by a thermally induced phase‐separation method. Different porous structures were obtained with poly(4‐methyl‐1‐pentene), which has excellent properties as a polymer, and diphenyl ether as a diluent. The affecting factors, including the polymer concentration and cooling temperature, are discussed. Scanning electron microscopy images and porosity values were obtained to investigate the affecting factors. According to the cloud‐point temperature and crystallization temperature, a phase diagram was also obtained to explain the phase‐separation process. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

C3‐Symmetric Titanium(IV) Triphenolate Amino Complexes for a Fast and Effective Oxidation of Secondary Amines to Nitrones with Hydrogen Peroxide

The efficient catalytic oxidation of secondary amines to nitrones using hydrogen peroxide as primary oxidant is described. The titanium(IV) complex 2 bearing a C₃‐symmetrical triphenolate amino ligand has proved to be an air‐ and water‐tolerant complex that efficiently catalyzes secondary amine oxidations at 60 °C without previous activation [catalyst loading as low as 0.01%, yields up to 99%, turnover numbers (TONs) up to 8000 and turnover frequencies (TOFs) up to 11000 h⁻¹).     

Utilization of 2‐(4‐Nitrophenylsulfonyl)ethoxycarbonyl (Nsc) as a Substitute for 9H‐Fluoren‐9‐ylmethoxycarbonyl (Fmoc) in Liquid Phase Chemistry

2‐(4‐Nitrophenylsulfonyl)ethoxycarbonyl (Nsc) is a useful substitute for the Fmoc group. It is easily removed not only with secondary amines but with tris(aminoethyl)amine (TAEA) and with resin‐bound TAEA, thus allowing for a simplified work‐up: the side products of the deprotection are removed either by extraction with phosphate buffer or by filtration.     

Enantioselective Synthesis of 4‐(Dimethylamino)pyridines through a Chemical Oxidation‐Enzymatic Reduction Sequence. Application in Asymmetric Catalysis

Enantiomerically pure 4‐(dimethylamino)‐3‐(1‐hydroxyalkyl)pyridines and 4‐(dimethylamino)‐3‐[hydroxy(phenyl)methyl]pyridine have been prepared through efficient chemoenzymatic routes. For this purpose different lipases and oxidoreductases have been tested in the preparation of optically active 4‐chloro derivatives and baker’s yeast was found to be an excellent catalyst for the bioreductions of the corresponding ketones. Their applications as enantioselective nucleophilic catalysts have been studied, important catalytic properties were observed in the stereoselective construction of quaternary centers.