1,154 research outputs found

    Efecto de las variables del proceso sobre el rendimiento y la calidad del aceite de almendra de yerivá (Syagrus romanzoffiana) mediante extracción acuosa

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    The fruit from jerivá (Syagrus romanzoffiana) has a kernel which is rich in oil, and has a pleasant smell that reminds one of coconut. It is rich in monounsaturated and saturated fatty acids, in addition to bioactive compounds. In this work, the effect of process variables on the yield and quality of jerivá kernel oil from aqueous extraction was evaluated using response surface methodology. The variables pH, time and temperature influenced the yield and the quality of the oil. High pH and time, along with mild temperature were suitable conditions to extract jerivá kernel oil by aqueous extraction, but excessively high pH, temperature and time negatively impacted the oil’s quality. pH was the only variable that significantly influenced free acidity, with a decrease in free acidity with the increase in pH. On the other hand, the increase in pH, time and temperature increased the peroxide value, which limited some conditions for obtaining jerivá kernel oil by aqueous extraction. The optimal conditions were found to be an extraction at pH 12, 25 °C and 60 minutes, which resulted in a yield of 39%, free acidity of 0.2% and a peroxide value of 5.8 meqO2·kg-1. Aqueous extraction yielded more unsaturated oil than that extracted with hexane, in addition to a higher proportion of caproic, oleic and linoleic acids, thus improving its nutritional characteristics and health benefits, despite decreasing its oxidative stability.La fruta de yerivá (Syagrus romanzoffiana) tiene un grano rico en aceite, que tiene un olor agradable que recuerda al coco, es rico en ácidos grasos monoinsaturados y saturados, además de compuestos bioactivos. En este trabajo, se evaluó el efecto de las variables del proceso sobre el rendimiento y la calidad del aceite de grano de yerivá a partir de la extracción acuosa utilizando la metodología de superficie de respuesta. Las variables pH, tiempo y temperatura influyeron en el rendimiento y la calidad del aceite. pH alto, elevado tiempo y temperatura suave fueron las condiciones adecuadas para extraer el aceite de grano de yerivá mediante extracción acuosa. Sin embargo, el pH, la temperatura y el tiempo excesivamente altos impactaron negativamente en la calidad del aceite. El pH fue la única variable que influyó significativamente en la acidez libre, con una disminución de la acidez con el aumento del pH. Por otra parte, el aumento del pH, el tiempo y la temperatura aumentaron el valor del peróxido, lo que limitó algunas condiciones para obtener aceite de grano de yerivá por extracción acuosa. Se encontró que la condición óptima fue una extracción a pH 12, 25 °C y 60 minutos, lo que resultó en un rendimiento del 39%, una acidez libre del 0,2% y un valor de peróxido de 5,8 meqO2·kg−1. La extracción acuosa produjo más aceite insaturado que el extraído con hexano, además de una mayor proporción de caproico, oleico y linoleico, mejorando sus características nutricionales y beneficios para la salud, a pesar de disminuir su estabilidad oxidativa

    Optimización de superficie de respuesta de múltiples objetivos en la extracción acuosa de aceite de semilla de macauba

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    Macauba (Acrocomia aculeata) is a promising tropical palm for the production of vegetable oil for both the food and non-food sectors. In this work, a multi-target response surface optimization of the aqueous extraction of Macauba kernel oil aimed to maximize the oil yield and minimize the free acidy and peroxide value. High yield was achieved at a high pH, long extraction periods and moderate temperatures, but these conditions contributed to elevating the peroxide value of the oil. On the other hand, pH presented the only significant effect on the oil’s acidity, which decreased with the increase in pH in the aqueous medium. Therefore, the multi-target response surface optimization based on a desirability approach showed that pH 11, room temperature (25 °C) and a 60 min agitation time was preferred to obtain high yield and low free acidity and peroxide values. These conditions resulted in 30% yield (63.1% of the yield obtained by solvent extraction), 0.3% free acidity, and a peroxide value of 2.9 meqO2/kg. The oil from the optimized aqueous extraction had a higher saturated fatty acid content compared to that from solvent extraction, especially fatty acids with < 14 carbon atoms, which can make the oil harder and more useful for producing special fats for specific food applications.La macauba (Acrocomia aculeata) es una prometedora palma tropical para la producción de aceite vegetal para los sectores alimenticio y no alimentario. En este trabajo, una optimización de superficie de respuesta de múltiples objetivos en la extracción acuosa de aceite de semilla de macauba tuvo como objetivo maximizar el rendimiento del aceite y minimizar el valor de acidez libre y peróxidos. Se logró un alto rendimiento a pH alto, tiempos prolongados y temperaturas moderadas, pero estas condiciones contribuyeron a elevar el índice de peróxido del aceite. Por otro lado, el pH presentó como único efecto significativo sobre la acidez del aceite, la disminución con el aumento del pH en el medio acuoso. Por lo tanto, la optimización de la superficie de respuesta de múltiples objetivos basada en un enfoque de idoneidad mostró que se prefería pH 11, temperatura ambiente (25 °C) y un tiempo de agitación de 60 minutos para obtener un alto rendimiento y bajos valores de acidez libre y peróxido. Estas condiciones dieron como resultado un rendimiento del 30% (63,1% del rendimiento obtenido por extracción con disolvente), un 0,3% de acidez libre y un índice de peróxido de 2,9 meqO2/kg. El aceite de la extracción acuosa optimizada tenía un mayor contenido de ácidos grasos saturados en comparación con el de la extracción con solventes, especialmente de ácidos grasos con < 14 átomos de carbono, lo que puede hacer que el aceite sea más duro y útil para producir grasas especiales para aplicaciones alimentarias específicas

    Purple dwarfs : New L subdwarfs from UKIDSS and SDSS

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.The first L subdwarf was a discovered only ten years ago. Less than ten L subdwarfs been published in the literature to date. Metal-poor ultracool atmospheres has not been well understood. Halo mass function cross substellar limit has not been measured. We used UKIDSS and SDSS to search for L subdwarfs. We have confirmed some new L subdwarfs and are following up more candidates with ground based large telescopes. We discussed spectral features of L subdwarfs and halo brown dwarfs

    Effect of modified atmosphere on polyphenols during storage of pasteurised strawberry purees

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    The minimum loss of processed fruit nutritional quality must been guaranteed during storage and the atmosphere can be a limiting step. Strawberry pur ees flushed with gas mixtures: 10 kPa O2 þ 90 kPa N2, 100 kPa N2 and air (78 kPa N2 þ 21 kPa O2 þ 0.03 kPa CO2) were stored for 90 days at 4 and 23 C and revealed no effect in total antioxidant activity and in total phenolic content. The compounds (þ)-catechin, ( )-epicatechin and quercetin-3-rutinoside were not affected by the atmospheres for both temperatures and ellagic acid was the exception within strawberry phytochemicals, where its concentration was higher for samples stored in air. Total anthocyanin content was better preserved when strawberry pur ee was stored in 100 kPa N2 at 4 and 23 C, at which temperatures their levels decreased 24 and 77%, respectively. At 4 C cyanidin-3- glucoside presented no significant differences between atmospheres. Pelargonidin-3-glucoside and pelargonidin-3-rutinoside decreased both 27% for 100 kPa N2 and 45% for 10 kPa O2 and air. All the individual anthocyanins were not affected by the atmospheres when stored at 23 ºC.info:eu-repo/semantics/publishedVersio

    Effect of thyroparathyroidectomy on urinary acidification in diabetic rats

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    In previous studies we have shown stimulation of renal acid excretion in the proximal tubules of rats with diabetes of short duration, with no important alterations in glomerular hemodynamics; on the other hand, in thyroparathyroidectomized rats (TPTX model), a significant decrease in renal acid excretion, glomerular filtration rate (GFR) and renal plasma flow (RPF) was detected. Since important changes in the parathyroid hormone-vitamin D-Ca axis are observed in the diabetic state, the present study was undertaken to investigate the renal repercussions of thyroparathyroidectomy in rats previously made diabetic by streptozotocin (45 mg/kg). Four to 6 days after the induction of diabetes (DM), a group of rats were thyroparathyroidectomized (DM + TPTX). Renal functional parameters were evaluated by measuring the inulin and sodium para-aminohippurate clearance on the tenth day. The decrease in the GFR and RPF observed in TPTX was not reversed by diabetes since the same alterations were observed in DM + TPTX. Net acid (NA) excretion was unchanged in DM (6.19 ± 0.54), decreased in TPTX (3.76 ± 0.25) and returned to normal levels in DM + TPTX (5.54 ± 0.72) when compared to the control group (6.34 ± 0.14 µmol min-1 kg-1). The results suggest that PTH plays an important vasodilator role regarding glomerular hemodynamics, since in its absence the impairment in GFR and RPF was not reversed by the diabetic state. However, with respect to acid excretion, the presence of diabetes was able to overcome the negative stimulus represented by TPTX.Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL

    Effectiveness of XP-endo finisher in the reduction of bacterial load in oval-shaped root canals

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    This study investigated the effectiveness of XP-Endo Finisher (XPF) associated with XP-Endo Shaper (XPS) or Reciproc Blue (RB) files in reducing bacterial load in oval-shaped root canals (RC) during chemomechanical preparation (CMP) using 0.9% saline solution (NaCl) or 2.5% sodium hypochlorite (NaOCl). Eighty mandibular incisors with single oval-shaped RC were contaminated with Enterococcus faecalis. The teeth were randomly assigned to eight experimental groups (n = 10) according to the CMP, as follows: G1: XPS, G2: XPS + XPF, G3: RB, and G4: RB + XPF. CMP was performed with NaCl or NaOCl. The reduction of bacterial load was assessed by colony-forming unit count before (S1) and after (S2) CMP. Data normality was verified by using Shapiro-Wilk test. ANOVA, Tukey's test, and Bonferroni post-hoc test were used at a 5% significance level. Culturable bacteria were present in all S1 samples (p>0.05). All instrumentation techniques were effective in reducing bacterial load, irrespective of the irrigating solution (p < 0.05). With the use of NaCl, RB was more effective than XPS (p = 0.035). With the use of NaOCl, XPS and RB presented similar effectiveness (p = 0.779). XPF enhanced the bacterial reduction of both systems tested (p < 0.05). The use of NaOCl improved the CMP, irrespective of the instrumentation technique used (p < 0.05). In conclusion, XPS and RB files are effective in reducing bacterial levels in oval-shaped RC. The use of XPF as a method of agitation of the irrigating solution improved the cleaning efficiency of both file systems tested. Mechanical preparation performed with saline solution decreased culturable bacteria from the root canal, but antimicrobial substances such as NaOCl should be used to achieve a significantly better disinfection33CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP308162/2014-5não tem2015/23479-

    Urinary levels of monohydroxyl PAH metabolites in portuguese firefighters: background levels and impact of tobacco smoke

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    Firefighting occupational exposure is classified as possible carcinogen to humans by the International Agency for Research on Cancer and the US National Institute for Occupational Safety and Health [1,2]. Tobacco smoke is a very important factor in the assessment of occupational exposure of workers, since the prolonged exposure to tobacco smoke is by itself the major cause of lung cancer [3]. The consumption of tobacco is responsible for the exposure to many smoke components including more than sixty known carcinogens, including some polycyclic aromatic hydrocarbons (PAHs) [4]. PAHs are ubiquitous compounds formed during pyrolysis or incomplete combustion of organic matter, being well-known for their toxic, mutagenic, and carcinogenic properties to humans [5,6]. So far, the impact of tobacco smoke on firefighters’ total exposure to PAHs is very limited.info:eu-repo/semantics/publishedVersio
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