Study of Proton Leakage at Interface of Anion-Exchange Membrane in Solutions of Acids,Salts, and Solvents Using Current/Voltage Characteristics

Water dissociation and proton leakage using the anionic exchange membrane (AMH) are studied by means of current/voltage characteristics and confirmed by simulation of transport number using Hittorf's method. The acids used are HCl, HNO₃, and H₂SO₄ and the salts are NaCl, ZnCl₂, and NaNO₃. Concentration polarization of such membrane is accompanied by a change in the electrolyte concentration/solution interface due hydrolysis reactions. The results show that when the concentration of the electrolyte increases, the limiting current density increases linearly and the transmembrane resistance decreases systematically. The thickness of the diffusion layer is always higher in presence of acid than salt, making in evidence the proton leakage through the membrane. Besides, when the membrane is selectively permeable to chloride anion in the case of ZnCl₂, the thickness of the double layer is rather bigger and far exceeds that of the membrane. The voltamperometry method seems reliable and offers some advantages over that of Hittorf because it shows the effects of some parameters on the value of limiting current: concentration, counter-ion types (Cl^?, NO₃^? SO₄^2?), and the gradient of concentration in the anode and cathode compartments. It can, therefore, allow to optimize the value of the current which should be used in electrodialysis in any form and without a great consumption of energy. Moreover, the simulation carried out for transport number of proton, shows its sensitivity toward the variation in concentration in the receiving compartment. In effect, a small decrease in concentration implies an enormous decrease in its value.     

Can the dietary element content of virgin argan oils really be used for adulteration detection?

Levels of eight dietary elements were assessed by ICP-AES in virgin edible and beauty argan oil samples prepared from four remote locations of the argan forest, and over a three-year period. The data showed sufficiently little variability to assess that all argan oil samples present, in terms of dietary elements, a similar composition, independently from the tree location within the argan forest. Therefore, adulteration detection by trace element analysis in edible and beauty argan oil is a method that can be generalised.     

Structure elucidation of three triterpene glycosides from the trunk of Argania spinosa

Drs. John Elce and Peter Davies, biochemists at Queen's University, Kingston, Ont., are investigating the molecular structure of calpain, an enzyme that has been implicated in the cellular damage that occurs after such events as myocardial infarction and stroke. This damage is precipitated by an imbalance in the regulation of calpain that arises as an indirect result of ischemia. Elce and Davies hope that their research, which involves techniques such as recombinant DNA technology and x-ray crystallography, will lead to the development of a calpain inhibitor that will prevent such damage from occurring and enhance recovery.     

Effect of processing on the quality of edible argan oil

Sensory quality of edible oil is essential to get the consumer acceptance. Modifications during processing can alter edible oil sensory quality. The storage stability and sensory quality of argan oil prepared from (1) mechanically pressed unroasted kernels, (2) mechanically pressed roasted kernels, (3) hand-pressed roasted kernels, and (4) hand-pressed roasted kernels coming from goat-digested fruits was studied at room temperature and under accelerated conditions (60 °C). The roasting process had a positive effect on storage stability of the resulting oils, while argan oil prepared from mechanically pressed roasted kernels provides the optimum storage stability. Oil from hand-pressed roasted kernels originating from goat-digested fruits was not suitable for human consumption because of the unpleasant taste and odoûr. Only oil from mechanically pressed roasted kernels did not produce negative sensory attributes like fusty or Roquefort cheese.     

Sono–Soxhlet: In Situ Ultrasound-Assisted Extraction of Food Products

An improvement of Soxhlet extraction was designed and developed. The extraction process (Sono–Soxhlet) of oils from crushed dried olives was performed using an ultrasonic horn in situ to provided rapid and complete recovery of analytes from the matrix. The results were compared to conventional Soxhlet extraction using physicochemical characterization and gravimetric analysis and showed a substantial reduction in the extraction time without interfering on composition and quality of target extracts.     

Lensless electron reflection microscopy using a coaxial point-source structure

A lensless image of the surface of a crystal is obtained by the reflection on this surface of a low-energy electron beam originated from a point source integrated in a coaxial structure. The point source is a sharp field emission tip and a free propagation of reflected electrons results from the shielding of the tip voltage provided by the coaxial structure. Images are obtained for an incidence angle between 3 and 45 degrees and for nA incident currents with a kinetic energy down to 40 V. On silicon surfaces a magnification up to a few thousands and a spatial resolution of 100 nm are demonstrated.     

Argan oil: Occurrence,composition and impact on human health

Edible argan oil is traditionally prepared by Berber women who manually crunch the roasted kernels of Argania spinosa fruits. Unroasted kernels furnish a cosmetic‐grade oil. Argan groves are currently shrinking due to unfavorable conditions. To stop this trend, a program aimed at increasing the argan tree economical value is in progress in Morocco. Its concept is that the natives will preserve argan trees only if the major part of the wealth resulting from the argan grove production directly benefits them. Because of its high dietary value, argan oil has appeared as the best derivative to rapidly satisfy such assumption. Consequently, year after year, cooperatives have been implanted to produce argan oil of high quality on a large scale. The delicate hazelnut taste of argan oil, combined with its high level in unsaturated fatty acids, has allowed its swift commercial success and, nowadays, argan oil of standardized quality is marketed worldwide. Moroccan farmers are now beginning to plant argan trees, confirming the full success of this ambitious program. This review summarizes the methods used to prepare argan oil, its composition, the strategies available to certify argan oil quality, and finally the impact of argan oil on human health.