Improving Waste Cooking Oil Quality for Biodiesel Production with the Ethanolic By-product of Soybean Oil Extraction

Waste cooking oils (WCO) can be used as feedstock for biodiesel (fatty acid ethyl or methyl esters—FAEE or FAME) production. Their usual high acidity, high moisture, and low stability can impair the reaction yield and generate a low-quality biodiesel. Here, we performed liquid–liquid washings using WCO and ethanol-based solvents with the goal of generating oil-rich miscella as FAEE feedstocks with a higher quality than WCO. Three different solvents were evaluated: 99% ethanol, 95% ethanol, and the soybean oil extraction ethanolic phase (SEP), a by-product with immense unexplored antioxidant potential obtained by extracting soybean oil using ethanol. Washings were performed in a 1000 mL flat-bottom flask at 78.1 °C, using a 1:2 (w/v) oil/solvent ratio, under magnetic stirring (1200 rpm) for 10 min. Ethyl esters were prepared via homogeneous alkali transesterification using WCO and oil-rich miscella as feedstocks. Treatments reduced the acid value by 40–61% and the peroxide value by 15–50%. Improvements in feedstock quality generated 24–54% higher biodiesel yields. The oil-rich phase produced with SEP was 15% more resistant to oxidation than WCO. This was attributed to the transference of isoflavones from the SEP. However, biodiesel from treated samples presented equal or lower oxidative stability than FAEE from WCO. High-performance liquid chromatography (HPLC) analysis showed that no isoflavones remained in biodiesel after purification. Pretreatment of WCO with ethanol-based extracts such as the SEP has great potential to improve WCO quality for biodiesel production as it can be a source of plant-based antioxidants.     

Age and forgetfulness: Managing perceivers' impressions of targets' capability.

Two experiments investigated the effect of positive endorsement on perceivers' impressions of young and old female targets. In Experiment 1, 160 young adult perceivers listened to a tape of a young or old forgetful target being interviewed for a volunteer job. They read a nonelaborative or elaborative reference letter for the target either before or after listening to the tape. Perceivers who read the elaborative letter after listening to the tape rated themselves as more likely to assign tasks to both young and old targets and had a higher general capability opinion of old targets. In Experiment 2, 84 older adult perceivers read an elaborative letter and listened to one of the same taped interviews. Reading the letter after the tape resulted in higher task ratings than reading it before the tape, but letter order had no effect on general capability ratings. Results are discussed in terms of impression management. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The contribution of covert attention to the set-size and eccentricity effects in visual search.

To reexamine the role of covert attention in visual search, the authors directly manipulated attention by peripherally cueing the target location and analyzed its effects on the set-size and the eccentricity effects. Observers participated in feature and conjunction tasks. Experiment 1 used precues, and Experiment 2 used postcues in a yes–no task under valid-, invalid-, and neutral-cueing conditions. Experiments 3 and 4 used a 2-interval alternative forced-choice visual-search task under cued and neutral conditions. Precueing the target location improved performance in feature and conjunction searches; postcueing did not. For the cued targets, the eccentricity effect for features and conjunctions was diminished, suggesting that the attentional mechanism improves the quality of the sensory representation of the attended location. The conjunction set-size effect was reduced but not eliminated. This questions serial-search models that attribute a major role to covert attention in visual search. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling of Tension-Stiffening Behavior of Reinforced Concrete Ties Strengthened with Fiber Reinforced Plastic Sheets

A model to analyze the behavior of reinforced concrete tension ties strengthened with fiber reinforced plastic (FRP) laminates is developed that allows introduction of a nonlinear constitutive relationship for materials and bond-slip laws at the steel and FRP interface. Experimental results are introduced and compared with analytical results confirming the model reliability. By using the model, a numerical study is carried out to provide evidence of the influence of the amount of fibers and the tension-stiffening behavior of strengthened elements. Considering elements with the same mechanical percentage of reinforcement but composed of different amounts of steel and fibers, the stiffness is influenced only after steel yielding, even if the crack width is reduced by the external strengthening. Finally, evidence is provided for the reduction of tension stiffening in strengthened elements due to reduction of crack spacing.     

Study of phase separation in blends of silk fibroin and sodium alginate in solution and in solid state

Silk fibroin (SF) and sodium alginate (SA) are natural polymers with many applications as biomaterials. It is possible to make blends with them in order to improve their properties. Those blends are partially miscible; therefore, understanding the mechanism and phase equilibrium of this system is important to better understand the interaction between these natural polymers. This work analyzed the mechanism of phase separation of SF and SA blends with different composition in solution and in the solid state (as membranes) using small angle light scattering with a He-Ne laser. Polymer interaction and conformation were investigated by Fourier-Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR) and X-Ray Diffraction (XRD), and membrane morphology was analyzed by Scanning Electron Microscopy (SEM). SEM images showed interpenetrated globules in the matrix. Light scattering profile for blends in solution and in the solid state showed a peak of intensity suggesting that phase separation occurs by spinodal decomposition.     

Linear segmented polyurethanes: I. A kinetics study

This work investigates the two‐step polymerization between methylene diphenyl diisocyanate (MDI), two different poly(tetramethylene oxide) macrodiols, and 1,4‐butanediol (BD) as chain extender. At the end of the prepolymerization, the reaction mixture contains MDI in excess and a prepolymer with isocyanate end group. Then, BD and a solvent (tetrahydrofuran) were added to start the finishing stage under nominal stoichiometric equilibrium. The reaction was analyzed by Fourier transform infrared spectroscopy, hydrogen nuclear magnetic resonance (¹H‐NMR), and size exclusion chromatography. ¹H‐NMR was employed to follow global concentrations of unreacted isocyanate end groups and internal urethane groups. This information enabled to estimate the following “effective” rate constants: k₁ = 1.07 × 10^?3 L mol^?1 s^?1 for the prepolymerization; and k₂ = 1.94 × 10^?4 L mol^?1 s^?1 for the finishing stage. These values are subject to errors caused by biases introduced in the recipe, in the measurements, in the reaction conditions, in the quality of reagents, and in the reaction mechanism assumptions. Such errors also explain the dispersion of the published rate constants values. The ¹H‐NMR measurements also enabled to estimate the evolution (with extent of reaction) of the number‐average number of structural units along the prepolymerization and finishing stages; and such estimates reasonably verify Flory's classical expressions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45747.     

Lipid-based nanocarrier for quercetin delivery: system characterization and molecular interactions studies

The flavonoid quercetin (QU) is a naturally occurring compound with several biological activities. However, the oral bioavailability of this compound is very low due to the high pre-systemic metabolism in the colon and liver and its low water solubility. In this context, the development of QU-loaded nanocarriers (NEs) is a promising approach to improve the drug oral bioavailability. This study investigates the variation of the concentration of 12-hydroxystearic acid–polyethylene glycol copolymer, lecithin and castor oil (CO) as to increase the amount of QU encapsulated while maintaining physicochemical characteristics described in previous studies. To better understand the ability to load and release the drug, we investigated the molecular interactions between QU and NE. Lipid-based NEs were prepared using CO as oily phase and PEG 660-stearate and lecithin as surfactants. Hot solvent diffusion and phase inversion temperature were methods employed to produce NEs. The QU-NEs were investigated for physicochemical characteristics and in vitro drug release. Molecular interactions between QU and the NEs were monitored through the complementary infrared (Fourier transform infrared) and NMR. The results revealed that it was possible to incorporate higher amounts of QU in a lipid-based NE with a reduced size (20?nm). The system developed allow a sustained release of QU probably due to the shell formed by the surfactants around the NE and the flavonoid ordering effect in the emulsion hydrophobic regions, which may reduce the system permeability.     

Phenolic Profile of Peanut By-products: Antioxidant Potential and Inhibition of Alpha-Glucosidase and Lipase Activities

Free, esterified, etherified and insoluble‐bound phenolics from three samples, namely meal from whole peanuts (MWP), meal from dry‐blanched peanuts (MDBP) and peanut skin (PS) were evaluated for their total phenolic content (TPC), and phenolic profile using HPLC–DAD–ESI–MSⁿ. The TPC was in the order of PS > MWP > MDBP. Among 37 compounds identified 10 were reported for peanuts for the first time. Proanthocyanidins were detected in peanut skin and MWP, but not in MDBP. The presence of peanut skin in MWP rendered up to 9.8‐fold higher scavenging activity towards the DPPH radical as compared with MDBP. Phenolics from all samples and fractions showed inhibition of alpha‐glucosidase and lipase activities, which are key enzymes involved in the absorption of glucose and triacylglycerols, respectively. Therefore, their antioxidant properties as well as their potential role in the management of diabetes and obesity makes them worthy of further consideration as functional food ingredients.     

Use of Phaseolus vulgaris and Vigna sinensis in a fermented dairy drink

The objective of this work was to develop a new kind fermented dairy drink, partially substituted with clear varieties of Phaseolus vulgaris (caraota) and Vigna sinensis (frijol). The formulation of fermented dairy drinks included sterile extracts of caraota and frijol, as partial substitutes which replaced milk: 10, 20 and 30%. The mixtures were inoculated with 2% of a mixture of Lactobacillus acidophillus, Streptococcus thermophilus and Bifidobacterium sp. and were incubated at 42 degrees C for 7 hours. Mango and guava jams were used as flavorings at 20%. On the basis of the sensorial evaluation the mixtures 10% frijol-mango, 10% frijol-guava, 30% caraota-mango and 20% caraota-guava were selected. In the selected fermented dairy drinks, the levels of protein, soluble and insoluble fiber, available and resistant starches were increased and the protein digestibility was 81%. The technical feasibility of partial substitution of milk with extracts of Phaseolus vulgaris or Vigna sinensis. For the elaboration of a fermented dairy drink similar to the liquid yogurt kind was demonstrated.