Hull-less Barley Varieties: Storage Proteins and Amino Acid Distribution in Relation to Nutritional Quality

Barley (Hordeum vulgare L.) has had an important impact on human nutrition. Hull-less barley is a genetically improved type that has been widely used in recent years. Six Brazilian hull-less barley varieties (IAC-IBON 214-82; IAC 8612-421; IAC 8501-31; IAC 8501-12; IAPAR 39-ACUMAI; IAC 8501-22) were analyzed for storage protein constituents, amino acid contents, and similarity among the hull-less barley varieties. Albumins, globulins, prolamins I and II, and glutelins were extracted and separated by SDS-PAGE. The total protein amino acid contents of the flour were also determined for each variety by TLC and HPLC. Variations in intensity and appearance and disappearance of protein bands were observed among the varieties suggesting genetic variability. However, the amino acid profile did not indicate any major variations in the amino acid concentrations. The high lysine and threonine total concentrations detected in the seeds of the hull-less barley varieties encouraged an investigation into the regulation of amino acid metabolism and storage protein synthesis.     

Saccharopine Dehydrogenase Activity in the High-Lysine Opaque and Floury Maize Mutants

Lysine is an essential amino acid normally present in very low concentration in cereal seeds. In previous reports we have studied the metabolism of lysine in several distinct high-lysine maize mutants and observed drastic variations in the activity of saccharopine dehydrogenase (SDH), a key enzyme involved in lysine degradation. We have now analyzed the activity of SDH using non-denaturing polyacrylamide gel electrophoresis (PAGE) to identify possible isoenzymes that could explain the patterns of activity previously observed. The results indicated the presence of at least two SDH isoenzymes, one contributing to approximately 90% of the total enzyme activity and a minor form only present in the wild type lines and the opaque-1 mutant. The results suggest that the differences in total SDH activity among the genotypes tested are due to alterations in the predominant SDH isoenzymic form, which is likely to be the bifunctional polypeptide containing lysine 2-oxoglutarate reductase.     

Skew product cycles with rich dynamics: From totally non-hyperbolic dynamics to fully prevalent hyperbolicity

We introduce a two-parameter family of ‘partially hyperbolic’ skew products (G_{a, t})_{a > 0, t ∈ [ ? ε, ε]} maps with one dimensional centre direction. In this family, the parameter a models the central dynamics and the parameter t the unfolding of cycles (that occurs for t = 0). The parameter a also measures the ‘central distortion’ of the systems: for small a, the distortion of the systems is small and it increases and goes to infinity as a → ∞. The family (G_{a, t}) displays some of the main characteristic properties of the unfolding of heterodimensional cycles as intermingled homoclinic classes of different indices and secondary bifurcations via collision of hyperbolic homoclinic classes. For a ∈ (0, log?2), the dynamics of (G_{a, t}) is always non-hyperbolic after the unfolding of the cycle. However, for a > log?4 intervals of t-parameters corresponding to hyperbolic dynamics appear and turn into totally prevalent as a → ∞ (the density of ‘hyperbolic parameters’ goes to 1 as a → ∞). The dynamics of the maps G_{a, t} is described using a family of iterated function systems modelling the dynamics in the one-dimensional central direction.     

Improving chocolate flavor in poor-quality cocoa almonds by enzymatic treatment

Abstract: This paper proposes a method to enzymatically treat poor‐quality cocoa almonds (known as “slate”) to ensure the formation of chocolate flavor precursors. The production of flavor precursors improves the quality of these almonds, which are usually responsible for the low quality of the liquor produced. Proteases and carboxypeptidases from different sources were tested under various conditions. The different treatments were evaluated by chemical analysis (hydrolysis efficiency) and sensory analysis of the treated material compared to good‐quality cocoa almonds. The results show that it is possible, through the use of microbial enzymes, to generate the mixture of compounds that will release, after roasting, the characteristic chocolate flavor in poor‐quality almonds. However, it is necessary to optimize the conditions of enzymatic treatment to obtain better results and thus establish a process that can be used for industrial purposes for manufacturing cocoa and chocolate. Practical Application: The basidiomycete Moniliophtora perniciosa is the causative agent of witches’ broom disease (WBD) of the cocoa tree, whose seeds are the source of chocolate. It is the most important phytopathological problem of cocoa‐producing areas of the American continent, and has decimated the Brazilian cocoa industry. In Bahia (Brazil), M. perniciosa was identified in 1989 and, as a consequence of its spreading, the annual production of cocoa almonds dropped from 450000 to 90000 tons within 12 y, reducing export values from an all‐time high of about US$ 1 billion to 110 million. The high incidence of WBD incapacitates Brazil to produce enough cocoa almonds even for the internal market, leading the country to import low‐quality cocoa almonds mainly from African countries. Our work proposes an enzymatic treatment to increase the quality of that cocoa almonds and, consequently, to improve the quality of the chocolate produced and consumed in the country.     

Structural and Catalytic Studies of a Trimethyltin Vanadate Coordination Polymer

The organotin vanadate [Me₃SnVO₃] (1) has been prepared and characterised in the solid state by powder X-ray diffraction (XRD), thermogravimetric analysis, multinuclear magic-angle spinning (MAS) NMR, IR and Raman spectroscopy. The phase purity and structure of microcrystalline 1 were confirmed by carrying out a full Rietveld structural refinement at ambient temperature and from conventional powder XRD. ⁵¹V and ¹¹⁹Sn MAS NMR data for compound 1 were in agreement with the predicted structure, showing two equally-abundant, nonequivalent Me₃Sn groups and two equally-abundant, nonequivalent vanadium atoms. The compound was applied as a catalyst for the liquid-phase epoxidation of olefins at 55 °C using tert-butyl hydroperoxide (tBuOOH) as the oxidant. The reaction rate for the different substrates followed the order cis-cyclooctene > (R)-(+)-limonene ≅ trans-2-octene > cyclododecene > styrene > 1-octene; the corresponding epoxides were the only observed products. Leaching tests indicated that the catalytic epoxidation of cyclooctene was mainly heterogeneous in nature. This paper is dedicated to Professor Ian Manners and his scientific accomplishments.     

Growth of number of periodic orbits of one family of skew product maps

In this article we introduce a one-parameter family of skew product (G_t)_{t ∈ [?ε, ε]} maps exhibiting a heterodimensional cycle such that the number of isolated periodic orbits inside it has not super-exponential growth. The dynamics in the central direction of the maps G_t is described by a one-parameter family of system of iterated functions.     

Sustainable Desulfurization Processes Catalyzed by Titanium-Polyoxometalate@TM-SBA-15

A titanium-polyoxometalate with a µ-hydroxo dimeric structure [(PW₁₁O₃₉Ti)₂OH]^7? ((PW₁₁Ti)₂OH) was used efficiently for the desulfurization of a model diesel containing a mixture of various refractory sulfur compounds present in real fuels. The catalytic performance of the µ-hydroxo dimeric compound was compared in its homogeneous form and also when immobilized in the trimethylammonium-functionalized SBA-15 ((PW₁₁Ti)₂OH@TM-SBA-15). An optimization study was performed using the homogeneous and heterogeneous catalysts to obtain high catalytic efficiency, sustainability and cost-effectiveness of the system. Different optimized conditions were found using the homogeneous and heterogeneous catalysts. Lower amounts of solvent extraction (MeCN, 175 µL), catalyst (0.5 µmol of active center) and oxidant (50 µL) were used to produce sulfur-free model diesel after 2 h at 70?°C, using the heterogeneous (PW₁₁Ti)₂OH@TM-SBA-15 catalyst. On the other hand, complete desulfurization was achieved with homogeneous (PW₁₁Ti)₂OH catalyst after only 40 min, although higher amounts of MeCN (750 µL), catalyst (1.5 µmol) and oxidant (75 µL) were used. Both systems combined liquid–liquid extraction and catalytic oxidation. Using the heterogeneous catalyst, adsorption of oxidized-sulfur compound was also observed. Both homogeneous and heterogeneous desulfurization systems presented a high capacity to be reused/recycled for consecutive desulfurization cycles.     

Effects of Sulfur Additive EP in Ester Coolants during Friction with CBN

A study was undertaken to investigate the effects of the EP additives during tribological tests using a CBN tool against steel. Ester oil with and without sulfur additive were used as lubricants in a tribometer. Tribochemical interactions between the S additive and steel have been investigated under boundary lubrication conditions by SEM and EDX analysis. The relative abundance of different elements on the surface of the CBN tools, which are present in the workpiece material such as Fe (iron) and Cr (chromium), suggests that adhesion occurred when the ester oil without sulfur additive was tested. Tribochemical interactions between the additive and the steel could be observed when using the ester oil containing the sulfur additive. These interactions contribute to the formation of a uniform layer on the CBN tool. This layer is composed by S (sulfur), Fe, and O (oxygen). The presence of these elements indicate that FeO (iron oxide) and FeS (iron sulfide) were formed.     

Catalytic olefin epoxidation with cationic molybdenum(VI) cis-dioxo complexes and ionic liquids

The complexes [MoO₂Cl(HC(bim)₃)]Y (Y = Cl (1), BF₄ (2) and PF₆ (3)) have been prepared by reaction of MoO₂Cl₂(THF)₂ (for 1) or [MoO₂Cl(THF)₃]Y (for 2 and 3) with the tridentate ligand HC(bim)₃ = tris(benzimidazolyl)methane, and characterized by IR and Raman spectroscopy, and ¹H NMR. The turnover frequencies for the epoxidation of cis-cyclooctene at 55 °C with tert-butyl hydroperoxide (TBHP, in decane) as the oxidant and complexes 1–3 as catalysts are in the range of 70–200 mol mol_Mo^?1 h^?1. 1,2-Epoxycyclooctane is always the only reaction product for reaction times up to 24 h. With the aim of facilitating the recyclability of the complexes, the ionic liquids (ILs) [BMIM]Y and [BMPy]Y (BMIM = 1-n-butyl-3-methylimidazolium, BMPy = 1-n-butyl-3-methylpyridinium; Y = BF₄ or PF₆) were applied as ionic solvents. The catalytic performance for cyclooctene epoxidation depends strongly on the catalyst solubility in the IL. Of the 12 catalyst/IL mixtures examined, the systems 1/[BMIM]PF₆ and 1/[BMPy]PF₆ exhibit the most favorable reaction rates allied with good recyclability. The 1/[BMIM]PF₆ system was further applied using different oxidants (aqueous TBHP, aqueous H₂O₂ and urea–hydrogen peroxide adduct) and olefins (norbornene, cyclohexene, styrene, α-pinene).