Effect of the structure of commercial poly(ethylene oxide-b-propylene oxide) demulsifier bases on the demulsification of water-in-crude oil emulsions: elucidation of the demulsification mechanism

Water-in-crude oil emulsions are formed during petroleum production and asphaltenes play an important role in their stabilization. Demulsifiers are added to destabilize such emulsions,however the demulsification mechanism is not completely known. In this paper, the performances of commercial poly(ethylene oxide-b-propylene oxide) demulsifiers were studied using synthetic water-in-oil emulsions and model-systems (asphaltenes in organic solvent). No change in the asphaltene aggregate size induced by the demulsifier was observed. The demulsification performance decreased as the asphaltene aggregate size increased, so it can be suggested that the demulsification mechanism is correlated to the voids between the aggregates adsorbed on the water droplets surface.

Nanostructured systems containing an essential oil: protection against volatilization

The goal of this study was to evaluate the feasibility of preparing nanocapsules and nanoemulsions using tea tree oil as oily phase aiming to protect its volatilization. The nanostructures presented nanometric mean size (160-220 nm) with a polydispersity index below 0.25 and negative zeta potential. The pH values were 6.43 ± 0.37 and 5.98 ± 0.00 for nanoemulsions and nanocapsules, respectively. The oil content after preparation was 96%. The inclusion of tea tree oil in nanocapsules showed higher protection against volatilization. The analysis of mean size and polydispersity index of formulations presented no significant alteration during the storage time.

Evaluation of the performance of a castor-oil based formulation in limiting pesticide residues in strawberry crops

A study was made to evaluate the effect of a castor oil-based detergent on strawberry crops treated with different classes of pesticides, namely deltamethrin, folpet, tebuconazole, abamectin and mancozeb, in a controlled environment. Experimental crops of greenhouse strawberries were cultivated in five different ways with control groups using pesticides and castor oil-based detergent. The results showed that the group 2, which was treated with castor oil-based detergent, presented the lowest amount of pesticide residues and the highest quality of fruit produced.

Kinetics of oxidation of biodiesel from soybean oil mixed with TBHQ: determination of storage time

Synthetic antioxidants are an alternative to prevent or retard the degradation of biofuels made from vegetable oils. In this study, it was evaluated the oxidative stability of B100 soybean oil biodiesel, in the presence of tercbutylhydroquinone (TBHQ). The results showed that the induction period, that precedes the seeding process, was delayed in the presence of the antioxidant. Moreover, the obtained results suggest that the B100 biodiesel containing TBHQ can present a storage time at 25 ºC, three times longer than the estimated time for the pure B100.

Towards new botanical pesticides: the toxic effect of Eremanthus goyazensis (Asteraceae) leaves essential oil against Brevipalpus phoenicis (Acari: Tenuipalpidae)

This work reports the chemical characterization of Eremanthusgoyzensis essential oil and its toxic effect over Brevipalpus phoenicis. The essential oil displayed a major composition of sesquiterpenes (61.87%) including trans-caryophillene (26.81%) and germacrene-D (13.31%). The fumigation test indicated a promising bioactivity over adult B. phoenicis individuals at 24 h (2.03 µL/L of air) and 48 h (1.08 µL/L of air) of exposition. A brief discussion of essential oils composition and their singular role on the toxic effect over B. phoenicis is provided here. Our results may contribute to a new and profitable use of a species of Brazilian flora on agribusiness.

Biosorption and removal of chromium from water by using moringa seed cake (Moringa oleifera Lam.)

This study evaluated the adsorption capacity of chromium from contaminated aqueous solutions by using Moringa oleifera Lam. seeds. Parameters such as solution pH, adsorbent mass, contact time between solution and adsorbent, isotherms, thermodynamic, kinetics, and desorption were evaluated. The maximum adsorption capacity (Qm) calculated to be 3.191 mg g-1 for the biosorbent. Activated carbon was used for comparison purposes in addition to the biosorbent. The best fit was obtained by the Langmuir model for both adsorbents. The average desorption value indicated that both the biosorbent and activated carbon have a strong interaction with the metal. The results showed that the biosorbent has advantages owing to its low cost and efficiency in Cr3+ removal from contaminated waters.

Variation of essential oil composition of Tapirira guianensis Aubl. (Anacardiaceae) from two sandbank forests, north of Brazil

Tapirira guianensis (Anacardiaceae) is used in traditional medicine and is important for the recovery of degraded areas and riparian forests because the T. guianensis fruits are highly consumed by wildlife. Volatile components from dried leaves and branches of five individual plants of T. guianensis were collected in two sandbank forests of the State of Pará (Extractive Reserve Maracanã and Area of Environmental Protection Algodoal/Maiandeua), extracted by hydrodistillation using a Clevenger-type apparatus, and analyzed by GC/MS. The ten oils obtained are comprised mostly of sesquiterpene hydrocarbons (58.49 to 100%), with (E)-caryophyllene, β-selinene, α-selinene, β-sesquiphellandrene, and α-zingiberene being the most prominent. The results of the oil compositions were processed by Hierarchical Component Analysis (HCA) allowing the establishment of three groups of essential oils for T. guianensis differentiated by the content of β-selinene/α-selinene (Type I), (E)-caryophyllene (Type II), and β-sesquiphellandrene/α-zingiberene (Type III).

COMPOSIÇÃO QUÍMICA E TEMPERATURA DE CRISTALIZAÇÃO DE ÉSTERES OBTIDOS DE QUATRO ÓLEOS VEGETAIS EXTRAÍDOS DE SEMENTES DE PLANTAS DO CERRADO

The seed oils from four plants (Scheelea phalerata, Butia capitata, Syagrus romanzoffiana, Terminalia cattapa) found in Mato Grosso do Sul were extracted at good yields. Alkaline transesterification of these seed oils to esters using methanol and ethanol was studied and also produced good yields. Oleic acid (30.5/32.3%), lauric acid (30.7/32.9%) methyl and ethyl esters, were the main components of transesterification of the oils from Scheelea phalerata and Syagrus romanzoffiana. Lauric acid (42.2%), capric acid (15.9%) and caprylic acid (14.6%) methyl and ethyl esters were the main ester components of transesterification of the oil from Butia capitata. Oleic acid (37.8%), palmitic acid (33.5%) and linoleic acid (22.6%) methyl and ethyl esters were the main components of transesterification of oil from Terminalia catappa. Based on differential scanning calorimetry (DSC) studies, the first crystallization peak temperature of esters was observed. Esters derived from oils of the family Arecaceae (Scheelea phalerata, Butia capitata, Syagrus romanzoffiana) showed the lowest points of crystallization, despite having high levels of saturated fat. Esters of Terminalia cattapa oil, rich in unsaturated fat, showed the highest crystallization temperature. This difference in behavior is probably related to the high concentration of esters derived from lauric acid and palmitic acid.

CONSTITUENTS OF ESSENTIAL OIL AND HYDROLATE OF LEAVES OF Campomanesia viatoris LANDRUM

The chemical composition of the essential oil and hydrolates of Campomanesia viatoris Landrum were investigated by gas chromatography/mass spectrometry (GC/MS) and a GC flame ionization detector (GC-FID). The major constituents were tasmanone (70.50, essential oil; 74.73%, hydrolate), flavesone (12.77, essential oil; 12.24%, hydrolate) and agglomerone (6.79, essential oil; 10.84%, hydrolate). Tasmonone was isolated and its structure was characterized by spectrometric analysis, specifically 1D and 2D nuclear magnetic resonance (NMR) and mass spectrometry (MS). These findings supports the quimiotaxonomic relationship with Campomanesia and Eucalyptus genera.

DEVELOPMENT AND VALIDATION OF ANALYTICAL METHOD FOR PALM OIL DETERMINATION IN MICROCAPSULES PRODUCED BY COMPLEX COACERVATION

The microencapsulation of palm oil may be a mechanism for protecting and promoting the controlled release of its bioactive compounds. To optimize the microencapsulation process, it is necessary to accurately quantify the palm oil present both external and internal to the microcapsules. In this study, we developed and validated a spectrophotometric method to determine the microencapsulation efficiency of palm oil by complex coacervation. We used gelatin and gum arabic (1:1) as wall material in a 5% concentration (w/v) and palm oil in the same concentration. The coacervates were obtained at pH 4.0 ± 0.01, decanted for 24 h, frozen (−40 ºC), and lyophilized for 72 h. Morphological analyzes were then performed. We standardized the extraction of the external palm oil through five successive washes with an organic solvent. We then explored the best method for rupturing the microcapsules. After successive extractions with hexane, we determined the amount of palm oil contained in the microcapsules using a spectrophotometer. The proposed method was shown to be of low cost, fast, and easy to implement. In addition, in the validation step, we confirmed the method to be safe and reliable, as it proved to be specific, accurate, precise, and robust.

Detection and transmission of Drechslera avenae from oat seed

Detection, symptoms and symptomless transmission of Drechslera avenae (teleomorph Pyrenophora avenae) from seed were investigated. The present study reported that the D. avenae is frequently found in oat (Avena sativa) seed in Argentina. The prevalence of the seed lot infected was 54%. The incidence of seeds infected by D. avenae in the various seed lots from different regions ranged from 0 to 52% (overall mean of 7%). Besides conidia on conidiophore and immature pseudothecia, D. avenae produced small, spherical to pear-shape picnidia containing tiny conidia, on the seed surface. The pathogen was efficiently transmitted at a rate of 55% from seed to coleoptile tips in symptomless seedlings and at 12.5% to plumules. The importance of the infected seed and its epidemiological role are discussed.

Essential oil of mustard to control Rhizoctonia solani causing seedling damping off and seedling blight in nursery

The essential oil extracted from mustard (Brassica rapa) seeds was evaluated for its effect on suppression of Rhizoctonia solani growth in vitro, and in field soils, for reducing saprophytic substrate colonization and seedling damping off and blight using snap beans as indicator plant, the in vitro growth was completely inhibited at a concentration of 50 mul/l. The saprophytic substrate colonization in soils 24 h after treatment was drastically reduced to 45% at 150 mul/kg soil concentration, in contrast to 100% colonization at concentrations of 0, 50, or 75 mul/kg. This recovery rate gradually declined to 6% and 60%, respectively, in nine days. A control of pre and post-emergence seedling damping off and blight in common beans (Phaseolus vulgaris), without any apparent phytotoxic effect was achieved by irrigating R. solani infested soils with water containing the emulsified essential oil to provide 150 mul/l soil volume ten days prior to planting, gave over 95%. The effect of the mustard essential oil was not influenced by the physical soil texture, and it appears to be a good substitute for methyl bromide fumigation in nurseries for seedling production.

A Semi-Selective agar medium to detect the presence of Xanthomonas axonopodis pv. malvacearum in naturally infected cotton seed

A semi-selective agar medium was developed for detection of Xanthomonas axonopodis pv. malvacearum (Xam) in cotton (Gossypium hirsutum) seed. The basic medium was peptone-sucrose-agar (PSA). Criteria for the semi-selective medium were the typical colony characters of Xam and its pathogenicity on cotton. Several systemic fungicides and antibiotics in different concentrations were tested alone or in combination with others. The final composition of the semi-selective agar medium was established after several attempts in order to inhibit most of the fungal and bacterial saprophytes and favour the development of Xam. It contained PSA + cyclohexamide, cephalexin, pencycuron, triadimenol and tolylfluanid. The bacteria were recovered from naturally infected seeds by the direct plating of 2,000 surface disinfected seeds on the semi-selective medium. The recovery of the pathogen from naturally infected leaf tissues and in dilution plating, on semi-selective medium and on nutrient agar, were comparable. Among the three detection methods tested, the semi-selective medium was found to be the most reliable and quantifiable. Degree of severity of angular leaf spot in the field was not always correlated with the level of infection in the seed. This is the first report of a semi-selective agar medium to detect the presence of Xam in naturally infected cotton seed.

Origin of oil in the Wilmington field in California

No presente trabalho, o autor trata da formação de campo petrolífero que se teria formado às expensas de organismos planctónicos, misturados com areia das dunas, material esse que teria sido transportado pelo vento. Refere-se, assim, o autor, ao campo petrolífero de "Wilmington", situado na Ilha Terminal, ao sul de Los Angeles, California. Esse campo, que já fora descrito, em 1943, por GILLULY & GRANT, faz parte do Mioceno e do Plioceno inferior, achando-se separado dos schistos Jurássicos metamórficos, por uma discordância localizada a 6.000 pés de profundidade. O conjunto das camadas petrolíferas alcança espessura de 1 .500 pés, sendo cada uma delas separada das outras por estratos do "siltstone" (siltito). O tamanho dos grãos, nos dois tipos de rochas, é o de depósitos eólicos, mas, ao contrário do que acontece em depósitos sub-aéreos, esses grãos são angulosos ou sub-angulosos. De acordo com MCNAUGHTON , esses depósitos se teriam formado em profundidade crescente, de 200 a 5.000 pés; esse fato, relacionado com as dimensões dos grãos, leva a crer que o material tenha sido transportado pelo vento. A sedimentação deu-se longe da costa, de maneira muito lenta, provavelmente em consequência de tempestades de excepcional intensidade. O petróleo teria sido produzido por organismos planctónicos que se teriam misturado com areia das dunas, sendo a velocidade da sedimentação desta, muito menor. Os cálculos indicam que foram armazenados somente 23% dos hidrocarbonetos que caíram sobre a areia de sedimentação, sob a forma de organismos mortos. M. V.