Dielectric relaxation of vegetable-based polyurethane

Vegetable-based polyurethane (PU) was prepared in the thin film form by spin coating. This polymer is synthesised from castor oil, which can be extracted from the seeds of a native plant in Brazil called mamona. This polymer is biocompatible and is being used as material for artificial bone. The PU was characterised by dielectric spectroscopy in a wide range of frequency (10(-5) Hz to 10(5) Hz) and by thermally stimulated discharge current (TSDC) measurements. The glass transition temperature (T-g=39degreesC) was determined and using the initial rise method the activation energy was found to be 1.58 eV. (C) 2003 Kluwer Academic Publishers.

Electromechanical properties of 0-3 vegetable based polyurethane and lead zirconate titanate composite.

Composite made of Lead Zirconate Titranate (PZT) ceramic powder and castor oil based polyurethane (PU) were prepared in the thin film form with 0-3 connectivity by spin coating. The composite films were obtained in the thickness range of 100 mum to 300 mum using 33-vol.% of ceramic. The samples mechanical resistance. The material was characterised by dielectric spectroscopy, thermally stimulated discharge current (TSDC), hysteresis measurements and laser-intensity-modulation method (LIMM). The pyroelectric coefficient at 343 K was 7x10(-5) C.m(-2) K-1 for the sample poled with 10 MV/m at 373 K for Ih. The results show that this new composite can be used as suitable piezo and pyroelectric sensors.

Effect of polyol excess on the electrical property of vegetable-polyurethane film

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cholesterol levels and nutritional composition of commercial layers eggs fed diets with different vegetable oils

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Toxicological evaluation of vegetable oils and biodiesel in soil during the biodegradation process

Vegetable oils and their derivatives, like biodiesel, are used extensively throughout the world, thus posing an environmental risk when disposed. Toxicity testing using test organisms shows how these residues affect ecosystems. Toxicity tests using earthworms (Eisenia foetida. are widespread because they are a practical resource for analyzing terrestrial organisms. For phytotoxicological analysis, we used seeds of arugula (Eruca sativa and lettuce (Lactuca sativa. to analyze the germination of seeds in contaminated soil samples. The toxicological experiment was conducted with four different periods of biodegradation in soil: zero days, 60 days, 120 days and 180 days. The studied contaminants were soybean oil (new and used) and biodiesel (B100). An evaluation of the germination of both seeds showed an increased toxicity for all contaminants as the biodegradation occurred, biodiesel being the most toxic among the contaminants. on the other hand, for the tests using earthworms, the biodiesel was the only contaminant that proved to be toxic. Therefore, the higher toxicity of the sample containing these hydrocarbons over time can be attributed to the secondary compounds formed by microbial action. Thus, we conclude that the biodegradation in soil of the studied compounds requires longer periods for the sample toxicity to be decreased with the action of microorganisms.

Evaluation of the thermal diffusivity of vegetable oils during frying by Thermal Lens Spectrometry

In this work we report on the use of the Thermal Lens method to verify the evolution of the thermal diffusivity of sunflower and soybean vegetable oils utilized in preparation of twenty five snacks portions. Our results show that the thermal diffusivity for sunflower oil does not change between 1 and 25 portions of fried snacks. By another hand, the soybean thermal diffusivity exhibits a little decrease for higher portion of fried snacks, indicating that for this oil the triglyceride level is reduced as a degradation process.

Preparation and characterization of castor oil-based polyurethane/poly(o- methoxyaniline) blend film

Blends made up of castor oil-based polyurethane (PU) and poly(o-methoxyaniline) (POMA) were obtained in the form of films by casting and characterized by FTIR, UV-Vis-NIR spectroscopy, and electrical conductivity measurements. Doping was carried out by immersing the films in 1.0M HCl aqueous solution. Chemical bonds between NCO group of PU and NH group of POMA were observed by means of FTIR spectra. The UV-Vis-NIR spectra indicated that the presence of the PU in the blend does not affect doping and formation of the POMA phase. The electrical conductivity research was in the range of 10-3 S/cm. © 2007 Wiley Periodicals, Inc.

Oxidative stability of soybean oil added to Lentinus edodes and Agaricus blazei mushrooms extracts in an accelerated storage test

Purpose: The purpose of this paper is to evaluate the oxidative stability of soybean oil added by Lentinus edodes and Agaricus blezei extracts in accelerated storage test. Design/methodology/approach: The following treatments were subjected to accelerated storage test in an oven at 60°C for 15 days: Control (soybean oil without antioxidants), TBHQ (soybean oil + 100 mg/kg of TBHQ), BHT (soybean oil + 100 mg/kg of BHT), L. edodes (soybean oil + 3,500 mg/kg of L. edodes extract) and A. blazei (soybean oil + 3,500 mg/kg of A. blazei extract). The samples were taken every three days and analyzed for peroxide values and conjugated dienes. Findings: At the end of 15 days, the treatments TBHQ, A. blazei, L. edodes, Control and BHT showed 6.47, 8.81, 41.53, 71.28 and 78.40 meq/kg, respectively, for peroxide values and 0.37, 0.40, 0.67, 1.07 and 1.00 per cent, respectively, for conjugated dienes. Originality/value: The research indicates that mushrooms may be a promising source of natural antioxidants. Therefore, natural extracts of mushrooms can be applied to vegetable oils as a way to reduce the degradation caused by lipid oxidation. © Emerald Group Publishing Limited.

ANTIOXIDANT ACTIVITY OF ROSEMARY EXTRACT IN SOYBEAN OIL UNDER THERMOXIDATION

This study examined the antioxidant activity of lyophilized rosemary extract added to soybean oil, subjected to thermoxidation conditions and also its synergistic effect with the synthetic antioxidant tertiary butylhydroquinone (TBHQ). Soybean oil samples with no antioxidant added (SO), 3,000mg/kg rosemary extract (RE), 50mg/kg TBHQ (TBHQ), and a mixture of those two antioxidants (RE+TBHQ) were heated to 180C for 20h. After 0, 10 and 20h, the oxidative stability, total polar compounds, tocopherol content and fatty acid profile were determined. The addition of rosemary extract increased oxidative stability and resulted in a lower formation of total polar compounds and a higher retention of tocopherols. The RE treatment showed the highest amount of polyunsaturated fatty acids after 20h. There was not any synergy between TBHQ and rosemary extract in preventing oxidation of soybean oil. Rosemary extract showed a higher antioxidant potential when compared with TBHQ. PRACTICAL APPLICATIONS: Antioxidants are important ingredients in food processing because they have the capacity to protect foods, containing oils and fats, from damage caused by free radicals and reactive oxygen species. Synthetic antioxidants are widely used in the food industry; however, their utilization has been questioned because of toxicity. Therefore, there is a growing interest in the use of natural antioxidants to reduce or replace the synthetic antioxidants. Several species are used in cooking, medicine and by the pharmaceutical industry, standing out the rosemary. Being rich in compounds with high antioxidant activity, the rosemary extract can be used to replace synthetic antioxidants used in vegetable oils. © 2012 Wiley Periodicals, Inc.

Effect of rosemary (Rosmarinus officinalis) extracts on the oxidative stability and sensory acceptability of soybean oil

Background: Plant extracts have b een used as an alternative to the use of synthetic antioxidants in order to preserve oils fromoxidative degradation. Additionally, these extracts add special flavors and aromas to the food. Thus, the objective of this studywas to evaluate the effect of hydroethanolic extracts of fresh and freeze-dried rosemar y in the oxidative stability of soybean oilunder accelerated storage in an oven. Results: The application of the extracts in the oil showed that that freeze-dried extract was better in reducing the formation ofoxidation products, showing 8.6 meq kg−1of peroxides after 20 days of storage. On the other hand, the mixture of the naturalextract with t-butylhydroquinone conferred better oxidative stability index until the 20th day, 9.7 h. Both extracts prevented theloss of tocopherol, not d iffering between each other (P > 0.05), and present approximately 505 mg kg−1of residual tocopherols.The sensory evaluation revealed that consumers accepted equally the oils added and not added of the rosemary extracts. Conclusion: The extracts are therefore potential sources of natural antioxidants and they would be well accepted by consumersif applied by the food industry to replace synthetic antioxidants.

Antioxidant effect of thyme ( -L.) and oregano ( -L.) extracts in soybean oil under thermoxidation

The rancidity of vegetable oils is considered one problem in the food industry,thus, are added antioxidants in food. The objective of this study was to investigatethe antioxidant effect of oregano and thyme extracts in soybean oil underthermoxidation. Soybean oil containing 3,000 mg/kg of oregano and thyme oleo-resins and the mixture of both, as well as soybean oil containing tert-butylhydroquinone (TBHQ; 50 mg/kg) and soybean oil free of were subjected tothermoxidation. Then, the physicochemical properties and fatty acid profile wereevaluated. Oregano and thyme oleoresins applied separately presented a higherprotective effect, inhibiting a greater formation of polar compounds than the anti-oxidant TBHQ, indicating that the addition of 3,000 mg/kg has ensured a betteroxidative protection than the synthetic antioxidant. The increase in the concentra-tion of oleoresins by mixing thyme and oregano extracts has given a higher pro-tective effect.

Transesterification of Palm Oil Catalyzed by Pseudomonas fluorescens Lipase in a Packed-Bed Reactor

Transesterification of palm oil with ethanol catalyzed by Pseudomonas fluorescens lipase immobilized on epoxy-polysiloxane-polyvinyl alcohol composite (epoxy-SiO2-PVA) was performed in a continuous packed-bed reactor (PBR). Two strategies were used for improving the miscibility of the substrates: the addition of the organic solvent tert-butanol and the surfactant Triton X-100. Results were compared to those obtained in a solventless reactor, which displayed a biphasic system that passed through the reactor. Using this system, the ethyl ester yield of 61.6 +/- 1.2% was obtained at steady state. Both Triton X-100 and tert-butanol systems were found to be suitable to promote the miscibility of the starting materials; however, the use of Triton X-100 reduced the yield to levels lower than 20%, because of the enzyme desorption from the support surface, as confirmed by scanning electron microscopy analysis. The best performance was found for the reactor running in the presence of tert-butanol which resulted in a stable operating system and an average yield of 87.6 +/- 2.5%. This strategy also gave high biocatalyst operational stability, revealing a half-life of 48 days and an inactivation constant of 0.6 X 10(-3) h(-1).

Reversible polymerization of novel monomers bearing furan and plant oil moieties: a double click exploitation of renewable resources

Monomers based on plant oil derivatives bearing furan heterocycles appended through thiol-ene click chemistry were prepared and, subsequently, polymerized via a second type of click reaction, i. e. the Diels-Alder (DA) polycondensation between furan and maleimide complementary moieties. Two basic approaches were considered for these DA polymerizations, namely (i) the use of monomers with two terminal furan rings in conjunction with bismaleimides (AA + BB systems) and (ii) the use of a protected AB monomer incorporating both furan and maleimide end groups. This study clearly showed that both strategies were successful, albeit with different outcomes, in terms of the nature of the ensuing products. The application of the retro-DA reaction to these polymers confirmed their thermoreversible character, i. e. the clean-cut return to their respective starting monomers, opening the way to original macromolecular materials with interesting applications, like mendability and recyclability.

Production of methyl and ethyl biodiesel fuel from pequi oil (Caryocar brasiliensis Camb.)

We studied the physical and chemical characteristics of methyl and ethyl esters (biodiesel) produced by transesterification of pequi oil (Caryocar brasiliensis Camb.) in the presence of potassium hydroxide. The oil extracted from pequi seed comprises 60% of the fruit content. Such characteristics as density, acidity, viscosity, and carbon residue of the biodiesel meet ANP (Brazilian National Petroleum Agency) standards. Our tests demonstrated the feasibility of utilizing pequi oil for biodiesel production.

Effect of feeding gilthead seabream ("Sparus aurata") with vegetable lipid sources on two potential inmunomodulator products : prostanoids and leptins

Máster Universitario International en Acuicultura. Trabajo presentado como requisito parcial para la obtención del Título de Máster Universitario Internacional en Acuicultura, otorgado por la Universidad de Las Palmas de Gran Canaria (ULPGC), el Instituto Canario de Ciencias Marinas (ICCM), y el Centro Internacional de Altos Estudios Agronómicos Mediterráneos de Zaragoza (CIHEAM)