Lipídios modificados obtidos a partir de gordura do leite, óleo de girassol e ésteres de fitosteróis para aplicação em spreads

The objective of this paper was to evaluate the modifications in milkfat properties with the addition of sunflower oil (SO) and phytosterol esters (PE) and chemical interesterification. Fatty acid composition, softening point and consistency were determined. The saturation degree of milkfat decreased with the addition of SO and PE. Consequently, milkfat presented lower softening point and consistency. Chemical interesterification caused an increase in softening point due to the formation of higher amounts of trissaturated triacylglycerols with rearrangement. The incorporation of unsaturated fatty acids from SO and PE by milkfat triacylglycerols after chemical reaction caused linearization of consistency curves.

Estudo teórico de propriedades ópticas não-lineares de nanotubos de carbono de parede única quimicamente modificados

Structure and first hyperpolarizability for a series of armchair a(5,5) chemically modified carbon nanotubes (CNT) were calculated at semiempirical and density functional levels of theory. The 4,4´-substituted stilbenes were selected as chromophore with substituents at position 4´ set to X=NO2, H, Cl, OH and NH2. The calculated values for static first hyperpolarizability (β) were almost linearly dependent on the electronic effect of the group X, increasing from NO2 to NH2. At DFT level the effect of inserting the chromophore in the CNT surface was to enhance the β value up to 70% relative to the free 4,4´-substituted stilbene.

Organismos marinhos como fonte de novos fármacos: histórico & perspectivas

Though sharing only a short part on the natural products timeline, the studies on marine products has already handed in four new drugs to the clinical arsenal and brought up a long and promising list of unique molecules to pre-clinical and clinical trials. Thus, as the available analytical resources improve and the interest of large pharmaceutical companies arises, medical use of marine products has definitely become a reality.

Hidrogenação eletrocatalítica de substratos orgânicos utilizando eletrodos modificados poliméricos contendo partículas de Ni/Pd e Ni/Pt

Novel modified electrodes bearing dispersed Pd and Pt particles have been prepared from poly (allyl ether of the p-benzenesulfonic acid) films with incorporated nickel particles making use of galvanic displacement reactions. The SEM analysis of the new modified electrodes revealed efficient deposition of Pd but weak up-take of Pt. Electrocatalytic hydrogenation of several classes of organic substrates were carried out using the MEs Ni, Ni/Pd and Ni/Pt. The Ni/Pd ME showed to be the best of them for the hydrogenation of double, triple and carbonyl bonds. The complete hydrogenation of the aromatic rings for the well-adsorbed substrates acetophenone and benzophenone is noteworthy.

Estudio comparativo de la ozonización de aceites de girasol modificados genéticamente y sin modificar

Ozonation of sunflower oils with genetic modification High Oleic and High Oleic-Palmitic (AO and PO respectively) and without modification, High Linoleic (AL) at different applied ozone dosages was carried out with measurement of peroxide and acidity indexes values, fatty acids composition, oxygen percentage content and antimicrobial activity. The comparison of peroxides indexes and oxygen content at different applied ozone dosages in each oil showed good correlation (r = 0,99). Higher amount of oleic acid was consumed at higher applied ozone dosage in PO oil than AO oil, which can be related to the increase of acidity index. The antimicrobial activity was better for AL and PO ozonized oils.

Alteração da atividade enzimática em organismos aquáticos por poluentes de origem agrícola: uma abordagem geral e sobre a suscetibilidade da fosfatase ácida

The input of agrochemicals in the aquatic compartment can results in biochemical injuries for living organisms. In this context, the knowledge of alterations of enzymatic activities due the presence of agriculture pollutants contributes for the elucidation of the mechanisms of toxicity, implementation of economic methods for monitoring purposes and establishment of maximum allowed concentrations. In the present work, the above considerations are discussed, and data concerning changes in enzymatic function by pesticides and fertilizer contaminants are reviewed. Also, we focused on the acid phosphatase due its susceptibility to several pollutants and diversity in cellular functions.

Aspectos coloidais da adesão de micro-organismos

The ability of bacteria to attach to surface and develop into a biofilm has been of considerable interest to food industry. Electrostatic, Lifhistz-van der Waals and Lewis acid-base forces are usually considered responsible for the interactions at the interface of the bacterial adhesion. The study of microbial adhesion thermodynamic is important because it represents the reflection of microbial surface and food processing surface physicochemical characteristics. This review examines the most important aspects involved in bacterial attachment to a surface with emphases in thermodynamics of adhesion process.

Eletrodos modificados por hidróxido de níquel: um estudo de revisão sobre suas propriedades estruturais e eletroquímicas visando suas aplicações em eletrocatálise, eletrocromismo e baterias secundárias

The present review paper describes the main features of nickel hydroxide modified electrodes covering its structural and electrochemical behavior and the newest advances promoted by nanostructured architectures. Important aspects such as synthetic procedures and characterization techniques such as X-Ray diffraction, Raman and Infrared spectroscopy, Electronic Microscopy and many others are detailed herein. The most important aspect concerning nickel hydroxide is related to its great versatility covering different fields in electrochemical-based devices such as batteries, electrocatalytic systems and electrochromic electrodes, the fundamental issues of these devices are also commented. Finally, some of the newest advances achieved in each field by the incorporation of nanomaterials will be shown.

Isolamento e seleção de micro-organismos resistentes e capazes de volatilizar mercúrio

Mercury (Hg) occurs in the environment as a natural and anthropogenic element, and through the years the accumulation of mercury has affected the integrity of ecosystems and human health. This study presents a screening of microorganisms resistant to organic and inorganic mercury, the determination of the minimum inhibitory concentration of Hg, the estimation of the mercury volatilization by selected microorganisms and the dynamics of volatilization. Eight Gram-negative bacteria resistant to high concentrations of mercury (60 to 210 mg L-1) were selected, and these isolates showed ability to volatilize the metal. The dynamics of the volatilization of the Proteus mirabilis M50C demonstrated that in only 4 h of incubation it was possible to volatilize 72% of the mercury present in the culture. The results showed promising application for bioremediation strategies.

Adsorção do corante vermelho congo por derivados da o-carboximetilquitosana hidrofobicamente modificados

Hydrophobically modified O-carboxymethylchitosan derivatives were synthesized through a reaction with lauroyl chloride and applied for adsorption of congo red dye. The Langmuir-Freundlich isotherm model was found to be the most suitable one for the VC adsorption and maximum adsorption capacity obtained was 281.97 mg g-1 at a pH value of 7.0 for HL 1.0. The adsorption process follows the pseudo-second-order kinetics and the corresponding rate constants were obtained. The thermodynamic parameters showed that adsorption process is spontaneous (positive ∆Hº) and favorable (negative ∆Gº). The hydrophobic derivatives are able to adsorb the dye even in high pH values.

Filmes de amidos de mandioca modificados para recobrimento e conservação de uvas

In this article, films were produced with six types of cassava's starch mixed with gelatin and plasticized with sorbitol. These films were used in covering of grapes 'Benitaka' (Vitis vinifera L.) as biodegradable packaging. The acetylated starch film showed the best results in solubility, thickness and homogeneity, besides the less water loss the fruit, resulting in better coverage, increasing the shelf life fruits in 12 days. These results demonstrate the great potential of using films in food conservation, adding value to agricultural activity and helping to reduce non-biodegradable plastics in the environment.

Degradação fotoeletroquímica do herbicida bentazona sobre eletrodos de carbono modificados por TiO2

This work involved the study of degradation of the herbicide bentazone in aqueous solution by different routes, in order to search a method that generates safe products to the environment. It was tested electrochemical polarization methods involving positive and negative potential, irradiation with UV light and deposition of TiO2 on the electrode surface, seeking a catalytic effect. After different times of degradation, aliquots were removed and the scan of molecular absorption spectrum of UV-Vis was performed. From the spectra decay of bentazone, the kinetics of different processes was accompanied and the rate constants were determined.

Corais como organismos biomonitores: aplicação, pré-tratamento e determinação de elementos majoritários e minoritários

Corals incorporate major and trace elements in their tissues and skeletons, acting as good proxies for contaminant inputs over time. This incorporation occurs by a variety of mechanisms and depends on the bioavailability of elements. Corals are very susceptible to metal contamination during sample collection. As such, pre-treatment procedures need to include a decontamination step. The high Na and Ca concentrations in the matrix make the determination of trace metals an analytical challenge. The present paper reviews all the information published on coral sample pretreatments, metal determinations in corals, and also discusses the use of coral to monitor metal contamination.

Estudio del coeficiente de reparto de ácidos carboxílicos grasos en sistemas modificados heptano/agua

The use of fatty acids (FAs) as amphiphiles is very important because they have a behaving similar to surfactants. The formulation for the preferential partition of these species was studied by varying the amount of salt at constant acid concentration. As the salt concentration increases, a Winsor I→III→II transition is observed for all the systems studied. Furthermore, the electrolyte concentration required to obtain the optimum formulation varies inversely with the chain length of the acid. The partition coefficient of the surfactant allows one to obtain thermodynamic information on the acid transfer process between the phases of the system.

Adhesivos tipo poliuretano obtenidos a partir de aceite de ricino y almidón químicamente modificados

This study reports the preparation of polyurethane adhesives using polyols obtained from castor oil modified by a transesterification reaction with pentaerythritol and starch modified by glycosylation. The physical properties of the polyols such as hydroxyl value were determined and the infrared spectroscopic analysis of the polyols reported. The effect of varying the hydroxyl value in the polyols on physical properties of polyurethane coatings on wood and steel panels was determined. The characterization of polyurethane coatings carried out by IR spectroscopic analysis, scratch hardness resistance, impact resistance, lap shear strength, T-peel strength measurements, solvent resistance and chemical resistant determination were reported.