Surface hydrophobicity and functional properties of myofibrillar proteins of mantle from frozen-stored squid (Illex argentinus) caught either jigging machine or trawling

The surface hydrophobicity and functional properties of actomyosin from the mantle of frozen squid caught either by jigging machines (AME1) or by trawl (AME2) were investigated. Two components of 155 and 55 kDa were present in the gels at zero time of storage. Degradation of the myosin heavy chain and increase in the 155 kDa component occur earlier in AME2. Irrespective of the catch method used, no significant (P>0.05) changes in protein solubility were observed. The reduced viscosity of both AME1 and AME2 decreased up to months 3 and 5 of frozen storage, respectively. At the beginning of storage, the superficial hydrophobicity of AME2 was 30% higher than that of AME1. So 1-anilino-8-naphthalene sulfonic acid of AME2 significantly increased during 3-5 months of storage period and that of AME1 at the end of storage. The emulsion activity index (EAI) of AME2 significantly (P<0.05) increased during the first month and decreased after 3 months of storage. EAI of AME1 decreased at month 3 and remained unchanged thereafter. Emulsion stability (ES) of AME2 showed a behavior that was similar to its IAE and that of AME1 remained unchanged.     

Anatomical,Morphological, and Phytochemical Effects of Inoculation with Plant Growth- Promoting Rhizobacteria on Peppermint (<Emphasis Type="Italic">Mentha piperita</Emphasis>)

Plant growth-promoting rhizobacteria (PGPR) generally exert their effects through enhancement of plant nutrient status and/or phytohormone production. The effects of PGPR on aromatic plant species are poorly known. We measured plant growth parameters, chlorophyll content, trichome density, stomatal density, and levels of secondary metabolites in peppermint (Mentha piperita) seedlings inoculated with PGPR strains Bacillus subtilis GB03, Pseudomonas fluorescens WCS417r, P. putida SJ04, or a combination of WCS417r?+?SJ04. The treated plants, in comparison with controls, showed increases in shoot biomass, root biomass, leaf area, node number, trichome density, and stomatal density, and marked qualitative and quantitative changes in monoterpene content. Improved knowledge of the factors that control or affect biosynthesis of secondary metabolites and monoterpene accumulation will lead to strategies for improved cultivation and productivity of aromatic plants and other agricultural crops without the use of chemical fertilizers or pesticides.     

Concentration of the baculovirus Autographa californica M nucleopolyhedrovirus (AcMNPV) by ultrafiltration

Concentration and retention of a rod-shaped virus during tangential flow ultrafiltration (UF) was assessed to evaluate the potential of membrane-based downstream methods with advantages such as easy scale-up for industrial processes. A recombinant baculovirus of the non-spherical Autographa californica M nucleopolyhedrovirus (AcMNPV), vHSGFP, expressing egfp was filtered using polyethersulfone membranes ranging from 30 to 1000 kDa molecular weight cut-off (MWCO). A 20-fold virus concentration was achieved when a membrane cut-off range of 100 to 1000 kDa was tested. Fouling was observed and cake formation and pore plugging were postulated as concurrent causes with different impact depending on the MWCO. A reduction of virus concentration in the range of 2 to 5 log units in the permeate was observed illustrating the potential of membrane-based virus filtration as a useful unit operation in downstream processing.     

Synthetic Chain Terminators Off‐Load Intermediates from a Type I Polyketide Synthase

Modular biocatalysis is responsible for the generation of countless bioactive products and its mining remains a major focus for drug discovery purposes. One of the enduring hurdles is the isolation of biosynthetic intermediates in a readily‐analysed form. We prepared a series of nonhydrolysable pantetheine and N‐acetyl cysteamine mimics of the natural (methyl)malonyl extender units recruited for polyketide formation. Using these analogues as competitive substrates, we were able to trap and off‐load diketide and triketide species directly from an in vitro reconstituted type I polyketide synthase, the 6‐deoxyerythronolide B synthase 3 (DEBS3). The putative intermediates, which were extracted in organic solvent and characterised by LC‐HR‐ESI‐MS, are the first of their kind and prove that small‐molecule chain terminators can be used as convenient probes of the biosynthetic process.     

Degradation kinetics of epoxidized soybean oil composites filled with sisal fiber

Epoxidized soybean oil (ESO) composites were cured with methyl tetrahydrophthalic anhydride (MTHPA) and 2,4,6-tris(dimethylaminomethyl)phenol (DEH 35) as a catalyst, sisal fibers were added at 10% and 30% of percent per weight. Composites curing was monitored using Fourier transform infrared spectroscopy, whereas the thermal stability and the degradation kinetics were investigated using thermogravimetry (TG). ESO/MTHPA/DEH35/S10 and ESO/MTHPA/DEH35/S30 composites displayed curing temperatures approximately 100°C lower related to ESO/MTHPA/DEH35, as well as higher degree of conversion. Sisal addition improved the thermal stability, shifting the weight loss shifting the weight loss onset to higher temperature (from 82 to 120°C). Thermal degradation energy $$ was determined using Friedman, Kissinger-Akahira-Sunose and Ozawa-Flynn-Wall models. Sisal significantly increased $$, especially in the intermediate phase (α = 0.2 and 0.8). The degradation kinetics was investigated by TG, and the degradation mechanisms modeled using Kamal-Sourour, Sestack-Berggren, and 1st order (F1), showed excellent fit, with R² > 0.99. Acquired results demonstrate that sisal fiber addition benefited the curing process and increased the thermal stability of ESO composites.     

Effect of Homogenization Pressure and Oil Load on the Emulsion Properties and the Oil Retention of Microencapsulated Basil Essential Oil (Ocimum basilicum L.)

The objective of this work was to evaluate the influence of oil concentration and homogenization pressure on the emulsion and particle properties during the microencapsulation of basil essential oil by spray drying, using gum arabic as the wall material. Experiments were planned according a 2² rotational central composite design. The independent variables were oil concentration with respect to total solids (10–25%) and homogenization pressure (0–100 MPa). Emulsions were analyzed for droplet mean diameter, stability, and viscosity, and particles were analyzed for oil retention, moisture content, particle size, and morphology. Emulsion viscosity was not affected by any of the independent variables. The increase in the homogenization pressure from 0 to 100 MPa resulted in smaller emulsion droplet size (down to 0.40 µm) and, consequently, higher oil retention (up to 95%). On the other hand, higher oil loads (25%) resulted in poorer oil retention (51.22%). Microencapsulation of basil essential oil using gum arabic as the wall material proved to be a suitable process to obtain powdered basil essential oil, presenting great oil retention with the use of lower oil concentration and higher homogenization pressure.     

Enzymatic production of human milk fat substitutes containing palmitic and docosahexaenoic acids at sn-2 position and oleic acid at sn-1,3 positions

This paper studies the synthesis of structured triacylglycerols (STAGs) rich in palmitic and docosahexaenoic acids (PA and DHA) at sn-2 position and oleic acid (OA) at sn-1,3 positions by a four step process. First, triacylglycerols (TAGs) were obtained with 63–66 mol PA/100 mol total fatty acids and 10 mol DHA/100 mol by acidolysis of tuna oil and commercial PA, catalyzed by the non-positionally specific lipase Novozym 435. Then these TAGs were purified neutralizing the free fatty acids (FFAs) by KOH hydroethanolic solutions and extracting TAGs with hexane; these TAGs were completely recovered as pure TAGs (without FFAs). The third step involved the displacement of fatty acids located at sn-1,3 positions by acidolysis of PA and DHA enriched TAGs with OA rich FFAs, catalyzed by the sn-1,3 specific lipase DF from Rhizopus oryzae, immobilized on Accurel MP-1000; TAGs with 67 mol OA/100 mol at sn-1,3 positions and 52.1 and 15.4 mol PA and DHA, respectively, per 100 mol at sn-2 position were obtained. Both acidolysis reactions were carried out in stirred tank reactors (STRs) with lipase both dispersed in the reaction medium and contained in a cartridge filter attached to the stirrer rod. Finally STAGs were purified and obtained with yields of over 80 mol STAGs/100 mol STAGs in the reaction product (no FFAs were detected).     

Bio-hydrogen production during acidogenic fermentation in a multistage stirred tank reactor

The objective of this study was to evaluate the production of hydrogen in a two-stage CSTR system – both reactors having the same volume – and compare its performance with a conventional one-stage process. The lab-scale two-stage and one-stage systems were operated at five pHs and five hydraulic retention time (HRTs). The maximum volumetric hydrogen productivity and yield obtained with the two-stage system were 5.8 mmol L⁻¹ h⁻¹ and 2.7 mol H₂ mol glucose⁻¹, respectively, at an HRT of 12 h and pH 5.5. Overall, the two-stage system showed, at steady state, a better performance that the one-stage system for all the evaluated pHs. However, a comparison between the one-stage system, operating at 6 h of HRT, and the first reactor of the two-stage system at the same HRT did not show any significant difference, highlighting the positive impact of having a two-stage process. The determination of the ratio between the experimental measured H₂ in the gas phase and the theoretical H₂ generated in the liquid phase (discrepancy factor) indicated that an important part of the hydrogen produced in the first reactor was transferred into the second reactor instead of being desorbed in the headspace. Therefore, the improving of hydrogen production in the two-stage system is rather attributed to the increased transfer of hydrogen from liquid to gas than an actual total hydrogen production increase.     

School location methodology in urban areas of developing countries

This study is concerned with the location of primary public schools. The public system should have the capacity to satisfy all the demand, although students may choose between public and private schools if they can afford the corresponding costs. A number of factors, such as questionable education quality, limited capacity, poor location and social preferences, secure a participation of about 30% to the private school system. The purpose of this study is both the evaluation of the existing public school network and a relocation proposal. The result of the former was the identification of areas with shortage and excess in school offer. The latter suggests school relocation using capacitated and uncapacitated models. ArcView, a software of the geographic information system (GIS) family, was employed, allowing the efficient handling of large problems and improving the presentation and evaluation of the findings. This methodology was applied to the primary public school network in the area of Vitoria, a state capital located in the southeast region of Brazil with about 300,000 inhabitants. Finally, the practical use of this study and its importance for planning purposes are discussed.     

Effect of the extraction and bleaching processes on jojoba (Simmondsia chinensis) wax quality

The aim of the work was to evaluate the effect of extraction method and bleaching on the quality of jojoba waxes from Argentina. Jojoba waxes obtained by cold pressing, Golden wax (expeller‐pressed wax) and Lite wax (bleached wax) were analyzed using standard methods adopted as recommended practices by the American Oil Chemists Society. Physical parameters, fatty acid and alcohol compositions were unchanged among waxes. Cold‐pressed wax was noteworthy by its lower peroxide value, higher amounts of tocopherol and total phenol contents. Accordingly, it presented the best oxidative stability. Bleaching caused a strong decrease in both tocopherol and phenol contents; consequently the bleached wax showed poor oxidative stability.