Fatty acid composition, physicochemical and thermal properties and crystallization behavior of fats extracted from the seeds of krabok (Irvingia Malayana) and rambutan (Nephelium lappaceum L.) trees grown in Thailand were studied and compared with cocoa butter (CB). The krabok seed fat, KSF, consisted of 46.9% lauric and 40.3% myristic acids. It exhibited the highest saponification value and slip melting point but the lowest iodine values. The three fats displayed different crystallization behavior at 25°C. KSF crystallized into a mixture of β’ and pseudo-β’ structures with a one-step crystallization curve and high solid fat content (SFC). The fat showed simple DSC crystallization and melting thermograms with one distinct peak. The rambutan seed fat, RSF, consisted of 42.5% arachidic and 33.1% oleic acids. Its crystallization behavior was more similar to CB than KSF, displaying a two-step crystallization curve with SFC lower than that of KSF. RSF solidified into a mixture of β’ and pseudo-β’ before transforming to β after 24 h. The large spherulitic microstructures were observed in both KSF and RSF. According to these results, the Thai KSF and RSF exhibited physicochemical, thermal characteristics and crystallization behavior that could be suitable for specific applications in several areas of the food, cosmetic and pharmaceutical industries.
We developed a determination method for sphingoid bases using online post-column high-performance liquid chromatography (HPLC) with O-phthalaldehyde (OPA) derivatization. Good separation was achieved using a reversed-phase column and eluting with 50% acetonitrile containing formic acid and heptafluorobutyric acid. Using these conditions, an excellent linearity (R2 > 0.999) was achieved using standard solutions of sphinganine (d18:0), sphingosine (d18:14t), 4-hydroxy-sphinganine (t18:0), glucosylsphingosine (glc-d18:14t), and galactosylsphingosine (gal-d18:14t). Plant glucosylceramides were hydrolyzed with 1 M aqueous HCl in methanol for 18 h at 90°C, followed by extraction of sphingoid bases with diethyl ether in preparation for analysis using the proposed HPLC conditions. The glc-d18:14t standard was also hydrolyzed and analyzed by HPLC using the same procedure, and the d18:14t peak obtained from the hydrolyzed glc-d18:14t standard was used as a reference for calculation. We also confirmed the applicability of this method to the analysis of sphingoid bases in rice and wheat, obtaining relative standard deviations of 8.0% for rice and 4.6% for wheat. The recoveries of spiked rice and wheat samples were 104% and 106%, respectively. Our proposed method enables the straightforward determination of sphingoid bases without expensive facilities, employing fluorescence detection of OPA derivatives.
Supercritical extraction was employed to produce rosemary (Rosmarinus officinalis L.) extracts with different composition and antioxidant activity. CO2 was utilized as supercritical solvent and diverse extraction conditions (temperature, pressure, amount of cosolvent and fractionation scheme) were applied. The extracts with higher antioxidant content were selected to study their capability as natural antioxidant of several commercial edible vegetable oils. Linseed oil (LO), grape seed oil (GO) and sesame oil (SO) were oxidized under Rancimat conditions in presence of 0, 100, 200 and 300 mg/kg of selected extracts. Antioxidant activity index (AAI) was estimated as the ratio of induction time in presence of extracts to induction time in absence of extract. Induction time in absence of extracts was 3.3, 7.9 and 23.4 h for LO, GO and SO, respectively. Regardless of these different susceptibilities, the highest AAI for the three oils was obtained for the extract with the highest antioxidant-enrichment (33.25% carnosic acid plus carnosol) and added at the highest level (300 mg/kg). However, at such conditions, the AAI was significantly higher (p<0.001) for LO (3.5), followed by SO (2.2) and the poorest value was for GO (1.1). Therefore, the magnitude of the AAI depended on the antioxidant-enrichment of the extracts, the level of addition within the oils, but also on the own individual oils.
New quaternized oligomeric surfactants containing 4 or 8 alkyl chains were synthesized using ethylenediamine or poly(amidoamine) dendrimers as the central scaffold. Electrical conductivity, surface tension, and pyrene fluorescence measurements, as well as dynamic light scattering were used to characterize their properties. In addition, the dependence of these properties on the alkyl chain length, number of chains, and dendrimer generation was determined through comparison with previously reported oligomeric surfactants. The relation between surface tension and concentration for the oligomeric surfactants exhibited clear breakpoints, which reflect the critical micelle concentration (cmc). Both cmc and surface tension were lower than those of monomeric alkyltrimethylammonium bromide surfactants, indicating that the synthesized oligomeric surfactants have excellent micelle-forming ability in solution and high adsorption ability at the air/water interface, in spite of the large bulky structure containing multiple alkyl chains and headgroups within one molecule. When the alkyl chain length or the number of chains of the oligomeric surfactants was increased, a unique behavior was observed in that adsorption at the air/water interface and solution aggregation occurred simultaneously at a concentration below cmc (as determined by the surface tension method). This suggests that aggregate formation occurs readily in solution along with the adsorption at the interface because of strong attractive interactions between multiple alkyl chains.
Two long-chain amidoamine derivatives (C13A2AOH and C17A2AOH) bearing three amide moieties were synthesized and their gelation ability and pH responsivity were compared with a similar, previously reported amidoamine derivative gelator with two amide moieties. C13A2AOH and C17A2AOH gels prepared in water and organic solvents acted as ambidextrous low molecular mass gelators. X-ray diffraction and Fourier transform infrared spectroscopy analyses revealed that C13A2AOH and C17A2AOH formed lamellar-like aggregates in the gels, where the amide moieties were in a strong intermolecular hydrogen-bonding state. The gelation ability, i.e., the molar ratio of solvent to gelator, was significantly dependent on the length of the alkyl chain and the number of amide moieties. In addition, the C13A2AOH and C17A2AOH hydrogels exhibited highly pH-responsive gel-sol transitions. The gel-sol transition for the hydrogels was induced by protonation of the ternary amine and the transition was completely reversible by regulating only the pH without heating.
The reaction of olefins with nitriles using iodine as a catalyst under solvent-free conditions was investigated. The reaction of cycloolefins, such as cyclopentene and cyclohexene, with benzonitrile using iodine as a catalyst produced both amide and heterocyclic compounds. The reaction of chiral (+)-camphene with benzonitrile produced racemic (±)-N-isobornylbenzamide (N-((1S,2S,4S)-1,7,7-trimethylbicyclo[2.2.1]hept-2-yl)benzamide). This indicated that skeletal rearrangement of camphene as well as amidation occurred. The optimized conditions were determined to be as follows: temperature, 90°C; molar ratio of nitrile:alcohol:iodine:water, 1:5:0.2:1.0; and reaction time, 18 h. The yield was 87% under these conditions. The reaction of (+)-camphene also proceeded with the other aromatic and aliphatic nitriles to produce racemic isobornylamides. However, except for styrene, complex reactions occurred in the reactions of benzonitrile with other terpenic olefins.
Condensation product of fatty acids and fatty alcohols is termed as wax esters. A series of fatty acids and fatty alcohols both saturated & unsaturated ranging from C 12 to C 22 were synthesised using p-TSA as a catalyst. Carbonyl functionality was confirmed by infrared spectrophotometer. Wax esters were used as friction modifier additives at 1%, 3%, 5% in 150N and 500N commercial petroleum base stocks. These base stocks were characterized by tribological properties like wear scar, weld load and coefficient of friction. All the tribological properties were better for saturated products than the unsaturated ones.
In this study, natural Iraqi low- cost locally available clay (palygorskite) was studied for its potential use as an adsorbent for removal Congo red from aqueous solutions. Batch type experiments were conducted to study the effect of contact time, initial pH of the dye solution, initial dye concentration, adsorbent dosage, and particle size of adsorbent on adsorption capacity of Congo red. The adsorption occurred very fast initially and attains equilibrium within 60 min. When the effect of pH of solution dye on the yield adsorption has been carried in a range of 2-10, the adsorption obtained was nearly the same with very slightly effect of pH and it was reported that above 49.07 mg/g of Cong red by palygorskite clay occurred in the pH range 2 to 10. It was observed that the removal of Congo red increase with increasing initial dye concentration and adsorbent dose, but, adsorption capacity decrease with increasing adsorbent dose. The adsorption capacity increase with decreasing particle size of adsorbent. The equilibrium adsorption data were interpreted using Langmuir and Freundlich isotherm models. The obtained results revealed that the equilibrium data closely followed both models, but the Langmuir isotherm fitted the data better. The maximum adsorption capacity was found to be 99 mg/g at ambient temperature. Results indicate that Iraqi palygorskite clay could be employed as a low cost alternative to commercial activated carbon in wastewater treatment for the removal of colour and dyes.