Fontes vegetais naturais de antioxidantes

Growing knowledge on the health-promoting impact of antioxidants in everyday foods, combined with the assumption that a number of common synthetic preservatives may have hazardous side effects has led to increased investigations in the field of natural antioxidants, principally those found in plants. Food industries normally discard plant residues that could benefit the human health and diminish undesirable environmental impact. Once estimated the content of antioxidants in these residues, advantageous economical and social alternatives to the discard are possible, for example, their use for preparation of nutraceuticals to be offered to low-income populations. We present here a broad, although not complete, account of the continuously growing knowledge on the antioxidant capacity of whole fruits, seeds and peels, cereals, vegetal oils and aromatic plants, at several physical forms, as well as a description of the usual methods for evaluating their antioxidant capacity and examples of agroindustrial processes that could be harnessed for the production of antioxidant supplement food, along with research perspectives in the area.

Biocombustíveis a partir de óleos e gorduras: desafios tecnológicos para viabilizá-los

Periodically, during petroleum shortage, fatty acids and their derivatives have been used as alternative fuels to those derived from petroleum. Different approaches have been proposed, including the use of neat fats and oils or their derivatives. Indeed, the utilization of biodiesel produced by alcoholysis of triacilglycerides or esterification of fatty acids, or hydrocarbons obtained from cracking of fatty materials were studied and used in several countries. Increasing concerns about energy security and climate changes have lead several countries, including Brazil, to start up biofuels programs. Different technologies are currently being developed in order to produce biofuels with economical feasibility. In this work are discussed alternative fatty raw-materials and processing technologies that are currently being studied in order to produce fuels suitable to sustainable substitute diesel fuel.

Preparação do (+)-±-terpineol a partir do (+)-limoneno: monoterpenos de odor agradável em um projeto para química orgânica experimental

A synthesis of (+)-±-terpineol from (+)-limonene was proposed as a project for undergraduate organic laboratory course. Terpineol is a useful flavor and fragrance compound, and several aspects of this preparation are suited for experimental organic classes, including basic techniques for extraction and analyses of essential oils, different reaction types and the possibility of a high degree of student interest.

Validação de metodologia para a determinação simultânea dos antioxidantes sintéticos em óleos vegetais, margarinas e gorduras hidrogenadas por CLAE/UV

The use of antioxidants either to prevent or retard food's lipids oxidation was approved after inquires that verified their security within a daily intake limit. In this study, the methodology was developed and validated for the analysis of synthetic antioxidants: propylgallate (PG), tert-butylhydroquinone (TBHQ), butylhydroxyanisole (BHA), octylgallate (OG) and butylhydroxytoluene (BHT) in vegetables oils, margarine and hydrogenated fats by high performance liquid chromatographic. The methodology revealed itself efficient, with recovery rates above 90% for all antioxidant substances, besides good linearity in concentration range of 40-240 mg kg-1 (r = 0,999), repeatability with CV < 3,7% and limit of quantification 16.55, 10.32, 1.40, 3.76 and 9.30 mg/kg for BHT, BHA, PG, OG and TBHQ, respectively.

Aceite de almendras dulces: extracción, caracterización y aplicación

The extraction of sweet almond oil at room temperature and reflux is an easy and accessible procedure to obtain natural oil in a laboratory scale for undergraduates' courses in chemistry and related areas. In this paper we show how the utilization of Fourier Transform Infrared (FTIR) spectroscopy can be interesting in the qualitative analysis of these oils. We also propose the preparation of three different skin creams to demonstrate the effective uses of sweet almond oil in cosmetics and pharmaceutical fields.

Variação sazonal da composição do óleo essencial de Myrcia salzmannii Berg. (Myrtaceae)

This work report the seasonal variation of composition of the volatile oils from leaves and from flowers of Myrcia salzmannii harvested in the sand dunes of Salvador, Bahia, northeastern region of Brazil in the years 2001 and 2003. The oils were analyzed by GC-FID and GC-MS being identified 49 components. Nine essential oil samples of leaves collected on different months and years and one sample of flowers were analyzed. β-Caryophyllene and α-humulene were the only compounds present in all of the samples being the first the majority compound.

Avaliação geoquímica de biomarcadores ocluídos em estruturas asfaltênicas

Asphaltenes from two Brazilian crude oils were submitted to mild oxidation to disrupt their structure, releasing the occluded oil. The released hydrocarbons were compared with those from the original crude oil, and used to evaluate the alteration of the oils, especially as a result of biodegradation, but also thermal maturity. The crude oils used are depleted in n-alkanes, which are usually related to biodegradation. However, the released products from the corresponding asphaltenes have n-alkane distributions from nC10 to nC40, suggesting a protection effect from biodegradation. The m/z 191 mass chromatograms showed higher relative intensities for tricyclic terpanes than the hopanes in the crude in comparison with the released ones.

Tocoferois e tocotrienois em óleos vegetais e ovos

The distribution and content of vitamin E isomers was investigated in vegetable oils and raw and cooked egg yolk in commercial restaurants. The analysis of the eight vitamin E isomers was carried out by High Performance Liquid Chromatography (HPLC) with fluorescence detection. The tocopherol and tocotrienol composition of foods varied considerably. Tocopherols were detected in greater quantity and frequency. The α-tocopherol predominated in egg yolks and olive oil while γ-tocopherol was found in high quantities in soybean and canola oils. Cooking did not cause major losses for most of the vitamin E isomers in egg yolks.

Variações no teor e na composição volátil de Hyptis marrubioides EPL: cultivada no campo e em casa de vegetação

This work describes the chemical composition of the volatile oil of Hyptis marrubioides cultivated in field and greenhouse. The experimental design was completely randomized, with ten replications for each type of cultivation. The volatile oil was extracted by hydrodistillation and analyzed by GC-MS. The highest content of volatile oil was found for plants grown in field. The highest percentage of the compounds present in oils was observed in samples grown in the field, such as germacra-4(15),5,10(14)-trien-1-α-ol (16.34%), β-caryophyllene (10.42%), γ-muurolene (12.83%) and trans-thujone (9.98%). However, some compounds were found only in plants grown in a greenhouse, such as cis-muurol-5-en-4α-ol (10.84%), α-cadinol (3.06%) and eudesma-4(15),7-dien-1β-ol (6.82%).

Composição química de óleos essenciais de espécies de Aniba e Licaria e suas atividades antioxidante e antiagregante plaquetária

Leaves and stems from Aniba panurensis (Meisn.) Mez, Aniba rosaeodora Ducke and Licaria martiniana (Mez) Kosterm. were collected in the Reserva Florestal Adolpho Ducke-AM and their essential oils were obtained by hydrodistillation procedures. The oils were analyzed by GC-FID and GC-MS resulting on fifty and six compounds being identified. The major components were linalool in A. rosaeodora, and β-caryophyllene in A. panurensis and L. martiniana. At qualitative assays the oils showed antioxidant and antiplatelet activities, but only weak activities were found at quantitative spectrometric assays.

Modificação bioquímica da gordura do leite

Recent advances for improving physicochemical and nutritional properties of lipids are reviewed, with emphasis on products attaining by biochemical processing of natural fats and oils. Enzymatic interesterification provides an important route to modify physical and nutritional properties of milkfat without generating trans isomers. This process makes use of lipases, a versatile class of enzyme that is able to perform efficiently the target modification in both solvent and solvent free systems. The present review covers important features of lipases, lipase-catalyzed interesterification reactions and their effects on the composition and texture of the resulting product.

Óleos essenciais das folhas de Vernonia Remotiflora e Vernonia Brasiliana: composição química e atividade biológica

The chemical composition of the essential oils, obtained by hidrodistillation, from leaves of two Vernonia species (V. remotiflora and V. brasiliana), was determined by GC-FID and GC-MS. Both essential oils were predominantly constituted by sesquiterpenes (92.0 - 93.4%). The main constituents of the oil from V. brasilana were (E)-caryophyllene (36.7%), germacrene D (35.5%), and α-humulene (11.7%), while (E)-caryophyllene (42.2%) and bicyclogermacrene (20.0%) were the major ones in the oil from V. remotiflora. Although with moderate activity both oils showed acetylcholinesterase and antibacterial activities.

Salinidade em petróleo bruto: otimização de metodologia e proposta de um novo método para extração de sais em petróleo

The quantity of salts in the crude oils depends on the origin and of the wells production and these salts cause several problems during the transport and the process of refine as corrosions, incrustations and deactivation of the employed catalysts in the refineries. In this study were implemented changes for improvements in the execution of ASTM D 6470 method and has also developed a new methodology of extraction system of salts using process of mechanical agitation without heating. The results of the optimization produce larger efficiency and safety to the process compared to the traditional ASTM method.

Produção de biodiesel através de transesterificação in situ de sementes de girassol via catálise homogênea e heterogênea

The objective of this work is to show the results of the in situ transesterification of sunflower seed oil with methanol on basic homogeneous and heterogeneous catalysis for the production of biodiesel. In homogeneous catalysis, the activity of KOH and K2CO3 were evaluated using the same oil:methanol ratio of 1:90. KOH showed to be more active than K2CO3, leading to total conversion in biodiesel after 1h reaction time. In the heterogeneous catalysis the activity of K2CO3/Al2O3 was comparable to the activity of K2CO3 bulk: 53.0 and 66.6% resp. The properties of samples of biodiesel produced by homogeneous and heterogeneous catalysis were evaluated and are in accordance with the recommended fuel properties.

Determinação de metais em óleos lubrificantes, provenientes de motores de ônibus urbano, utilizando a FAAS

This work proposed a procedure to examine ashes produced in burning lubricating oils used in public transportation, in Teresina PI. Sulphanilic acid was added to the oil samples, which were burned at 550 °C for three hours and 650 °C for two hours. The ash solutions were analyzed by FAAS and there were significant differences in the metal contents of the waste oil produced from normal car service. The quantification limits in μg g-1 were 5.9 (Fe), 4.4 (Pb), 1.7 (Ni), 2.1 (Cu), and 1.2 (Zn). The results showed positive accuracy and precision with recoveries between 88 and 108%, and RSD lower than 10%.