Antinutritive Compounds in Different Oilseeds

Different oilseeds, usable as renewable resources, are analyzed for their content of condensed tannins, glucosinolates, phytic acid and its degradation products as well as for sinapine, and the results are presented. Seeds of sunflower, flax, coriander, Euphorbia lagascae, iberic. dragon head, safflor, Camelina sativa, soy, mustard, hemp and rapeseeds are used. Apart from hemp, coriander and Euphorbia lagascae different cultivars or genotypes of each species are investigated. The variation of the results of each cultivar or genotype is shown. Tannins and phytic acid are found in different amounts in all oilseeds, whereas sinapine and glucosinolates are limited to seeds from species belonging to the plant family Brassicaceae.     

Local measurements of fluid and particle velocities in a stirred suspension

An experimental approach is proposed for the measurement of the local behaviour of continuous and dispersed phases in a stirred suspension at low particle concentrations (0.5 vol.%). The basic principle involves the simultaneous measurement of the local velocity and particle size with a phase Doppler velocimeter and the separation of the data obtained from large particles (representing the dispersed phase) and very small particles (representing the motion of the continuous liquid phase).This technique was applied to the investigation of a fully baffled cylindrical vessel, with a flat bottom, stirred by an industrial axial propeller. The diameters of the vessel and the propeller and the vertical clearance were 0.3 m, 0.14 m and 0. l m respectively. The liquid was water and spherical glass particles were used as the dispersed phase.In the absence of particles, the circulation pattern created by the propeller in the middle plane between two baffles revealed a major circulation loop in the lower part of the vessel and a minor contra-rotative loop in the wall surface corner. The calculated pumping coefficient, circulation flow number, non-dimensional time of renewal and circulation time were 0.62, 0.89, 11.76 and 8.15 respectively. The tangential velocities remained at values of less than 15% of the impeller tip velocity in the plane of the measurements.Axial, radial and tangential mean and root-mean-square velocities for the carrier liquid phase and particles were measured in the two-phase flow, using particles with a mean diameter of 253 μm. These measurements showed that the particles lagged behind the liquid phase in the upward parts of the flow field, but were ahead in some downward parts. The root-mean-square axial velocities obtained for the particles were always greater than these obtained for the continuous phase. Non-homogeneities in the suspension were observed by the local mean diameter field. The effects of the stirring rate and size of the particles were also checked in the upward part of the flow in the vessel.     

Study of ash deposition during coal combustion under oxyfuel conditions

This paper presents a comparative study on ash deposition of two selected coals, Russian coal and lignite, under oxyfuel (O₂/CO₂) and air combustion conditions. The comparison is based on experimental results and subsequent evaluation of the data and observed trends. Deposited as well as remaining filter ash (fine ash) samples were subjected to XRD and ICP analyses in order to study the chemical composition and mineral transformations undergone in the ash under the combustion conditions. The experimental results show higher deposition propensities under oxyfuel conditions; the possible reasons for this are investigated by analyzing the parameters affecting the ash deposition phenomena. Particle size seems to be larger for the Russian coal oxy-fired ash, leading to increased impaction on the deposition surfaces. The chemical and mineralogical compositions do not seem to differ significantly between air and oxyfuel conditions.The differences in the physical properties of the flue gas between air combustion and oxyfuel combustion, e.g. density, viscosity, molar heat capacity, lead to changes in the flow field (velocities, particle trajectory and temperature) that together with the ash particle size shift seem to play a role in the observed ash deposition phenomena.     

Volatile lactones from streptomycetes arise via the antimycin biosynthetic pathway

The volatiles released by several streptomycetes were collected by using a closed-loop stripping apparatus (CLSA) and analysed by GC-MS. The obtained headspace extracts of various species contained blastmycinone, a known degradation product of the fungicidal antibiotic, antimycin A(3b), and several unknown derivatives. The suggested structures of these compounds, based on their mass spectra and GC retention indices, were confirmed by comparison to synthetic reference samples. Additional compounds found in the headspace extracts were butenolides formed from the blastmycinones by elimination of the carboxylic acid moiety. Analysis of a gene knockout mutant in the antimycin biosynthetic gene cluster demonstrated that all blastmycinones and butenolides are formed via the antimycin biosynthetic pathway. The structural variation of the blastmycinones identified here is much larger than within the known antimycins, thus suggesting that several antimycin derivatives remain to be discovered.     

Structural evolution at short and medium range distances during crystallization of a P2O5-Li2O-Al2O3-SiO2 glass

Li₂O-Al₂O₃-SiO₂ (LAS) glass-ceramics have important industrial applications and bulk nucleation is usually achieved by using nucleating agents. In particular, P₂O₅ is an efficient agent in glasses containing a low level of Al₂O₃ but its role in the first stages of nucleation is not well established. In this study, we combine structural investigations from local to mesoscales to describe the structural evolution during crystallization of LAS glass-ceramics. Local environment is probed using ²⁹Si and ³¹P MAS-NMR, indicating organization of P in poorly crystallized Li₃PO₄ species prior to any crystallization. To better understand the detailed nanoscale changes of the glass structure, ³¹P-³¹P DQ-DRENAR homonuclear correlation experiments have been carried out, revealing the gradual segregation of P atoms associated with the formation of disordered Li₃PO₄. Small-angle neutron scattering data also show the apparition of nanoscale heterogeneities associated with Li₃PO₄ species upon heating treatments and allow the determination of their average sizes. These new structural information enhance our understanding of the role of P in nucleation mechanisms. Nucleation is initiated by gradual change in P environment implying P segregation upon heating treatments, forming disordered Li₃PO₄ heterogeneities. The segregation of P atoms enables the precipitation of meta- and disilicate phases.     

Over-production of 5-enolpyruvylshikimate-3-phosphate synthase in Escherichia coli: use of the T7 promoter

5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase, the productof the Escherichia coli aroA gene, has been overproduced inE.coli BL21(DE3) under the control of the T7 gene 10 promoterand ribosome binding site, to a level of {small tilde}50% oftotal cell protein. EPSP synthase is the primary target of thepost-emergence herbicide, glyphosate, commonly known as Roundup^TM.A simple two step purification is described, which results in99% pure homogeneous protein (as determined by PAGE). The integrityof the protein has been compared with previously characterizedprotein from .E.coli AB2829(pKD501) by determination of itskinetic parameters, N-terminal protein and DNA sequences, aminoacid analysis and ¹³C-NMR spectroscopy. This new overproducingstrain readily provides the gram quantities of highly pure proteinrequired for NMR studies of the active site and the developmentof novel time-resolved solid-state NMR techniques currentlyunderway in this laboratory.     

FA and tocopherol composition of Vietnamese oilseeds

Seeds of 40 oilseed species from 23 different plant families (Brassicaceae, Cucurbitaceae, Fabaceae, Sapindaceae, Malvaceae, Gnetaceae, Clusiaceae, Bruseraceae, Ranunculaceae, Convolvulaceae, Amaranthaceae, Tiliaceae, Basellaceae, Solanaceae, Umbelliferae, Labiatae, Compositae, Theaceae, Euphorbiaceae, Caesalpiniaceae, Sapotaceae, Anacardiaceae, and Connaraceae) grown in Vietnam were analyzed for oilseed oil content, FA, and vitamin E. The seed oil content varied between 0.2 g/100 g for Mangifera indica and 75.7 g/100 g for Calophyllum inophyllum, whereas only nine seeds contained more than 40% oil. The tocopherol content ranged from 26 (Sapindus mukorossi) to 9361 mg/kg (Litchi chinensis). In nine seed oils unusual FA such as conjugated, cyclopropenoic, or epoxy FA were found.     

Solution- and crystal-phase covalent modification of lysozyme by a purpose-designed organoruthenium complex. A MALDI-TOF MS study of its metal binding sites

Study of the reaction between the transition organometallic complex 4-ruthenocenyl 2,6-dimethylpyrylium tetrafluoroborate and the enzyme hen egg white lysozyme (HEWL) in solution and by diffusion in crystals was performed by use of a combination of spectroscopic and chromatographic methods. Conjugation involving the lysine residues of lysozyme appeared to occur readily, yielding very stable ruthenocenyl pyridinium adducts with average degrees of incorporation ranging from 0.2 to 1.8 metal complexes per protein molecule, depending on reaction conditions. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) revealed that the protein conjugates were in fact mixtures of unmodified, mono-, di- and sometimes tripyridinium adducts. In combination with reversed-phased HPLC, we were able to show that six different monoruthenocenyl pyridinium adducts were formed in solution. This result was confirmed by trypsin digestion of a ruthenocenyl pyridinium conjugate and MALDI-TOF MS analysis of the peptide mixture, which showed that lysines 1, 13, 33, 96, 97 and 116 were involved in the reaction with the pyrylium complex, lysines 13, 33 and 116 being the major binding sites. In the tetragonal crystal state, no binding of the ruthenium complex was shown to occur at lysine 116, owing to steric hindrance at this particular position.     

Comparison of different methods for the determination of the oil content in oilseeds

The investigation and assessment of the oil content of oilseeds are important criteria, especially for the oil milling trade. Standard methods for the determination of the oil content of oilseeds are very time consuming, with extraction periods of 4 to 8 h. Three different oilseeds—rapeseed, sunflower, and soybean—are extracted by supercritical fluid extraction (SFE), accelerated solvent extraction, microwave-assisted extraction, solid fluid vortex extraction, and Soxtherm, and the results are compared with the result of the German Fat Science Society (DGF) standard method B-I 5 (87). Besides, the extracts are analyzed regarding the content of tocopherols as a parameter for mild extraction conditions and the content of diglycerides and free fatty acids as parameters for the content of more polar lipids. The results of the determination of the oil content under optimal conditions are comparable with the results of the DGF standard method B-I 5 (87). There are no significant differences between the different methods. The content of tocopherols is dependent upon the extraction method and the type of oilseed. The highest content is obtained by SFE. The content of diglycerides and free fatty acids varied according to the oilseed.     

Nanoscale Phase Separation in Lithium Niobium Silicate Glass by Femtosecond Laser Irradiation

Understanding the phase transformation in glass and the morphology of related nanostructure after femtosecond laser irradiation is of great importance for fabricating functional optics, in which glass crystallization is involved to obtain nonlinear optical properties. We report on the crystallization inside lithium niobium silicate glass induced by fs laser irradiation. Energy‐dispersive X‐ray spectroscopy coupled to scanning transmission electron microscopy (STEM/EDS) and transmission electron microscopy confirm a nanoscale phase separation whereby LiNbO₃ crystals are embedded in lamella‐shaped frames of amorphous SiO₂. The obtained nanostructure may have applications in fabricating second‐order nonlinear optical devices.