Choibá (Dipteryx oleifera Benth.) is a promising source of edible oil with high nutritional quality and a significant content of oleic acid (52%-54%). To promote Choibá as source of edible oil is necessary to ensure its stability along the time of production, distribution and storage. Loss of nutritional and organoleptic quality in lipids is mainly due to lipid peroxidation reactions. The aim of this research was to evaluate the oxidative stability of Choibá oil at 100˚C ± 1˚C with aeration (1150 mL air/min) supplemented with rosemary extract (Rosmarinus officinalis L.), at 1000 mg/L (RE1000) and 1500 mg/L (RE1500), and with BHT (200 mg/L) and from this results to evaluate the degradation kinetics and shelf-life of Choibá oil at 35˚C, 45˚C and 55˚C without addition of antioxidants (Control) and with addition of best concentration of rosemary extract obtained from previous study. Progress in oil oxidation was measured through the extent of oxidation products: peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). Results revealed that the addition of rosemary extract at 1500 mg/L significantly reduced de formation of hydroperoxides (PV), more than BHT. Through correlations between concentrations of antioxidant (including control without antioxidant) with peroxide values, the kinetics of degradation and shelf-life of Choibá oil with predictive models are evaluated in real time and accelerated (35˚C, 45˚C and 55˚C) using the Arrhenius equation. In addition, the oxidation reactions of this oil follow a first order kinetic model for PV and zero order kinetic model for TBARS. The rate of formation of PV was dependent on the storage temperature, according to the Arrhenius equation with the activation energy of 4611.5071 J/mol for Control and 7409.5771 J/mol for RE1500 treatment. The result of
Iniciativas gubernamentales de desarrollo profesional para la implementación de políticas lingüísticas y lineamientos curriculares: experiencias, desafíos y opiniones de maestros de educación básica secundaria Les initiatives gouvernementales de développement professionel pour l'implémentation des politiques linguistiques et des lignes directrices curriculaires: expériences, défis et avis des enseignants de l'éducation secondaire Abstract A case study was conducted to explore public secondary school teachers' perspectives, practices, and experiences concerning the design and implementation of the English curriculum, as well as the professional development offered by the government in order to implement language policies and curriculum guidelines in the city of Medellin, Colombia. The study lasted one year and included a survey, the analysis of curriculum documents from five selected institutions, and focus group interviews as data collection instruments. Results indicate that the initiatives provided by the government have not been effective in supporting teachers in this endeavor as they have been very limited in terms of curriculum design, and reflect a technical view of teacher learning. In addition, several contextual and social factors have tremendously affected the implementation of language policies and curriculum guidelines in schools. Besides, teachers point to several needs, including that they have more time to appropriate and implement reforms, that they be included in policy-making as affected parties, that professional development initiatives be freed from political and economic interests and that they be offered a preparation that combines improving their language proficiency, English teaching methodologies and curriculum design.
<p>El aceite de Sacha inchi (Plukenetia volubilis Linneo)ha sido reconocido a nivel mundial por su alto<br />contenido de omegas; sin embargo, la presencia en él de ácidos grasos poliinsaturados hace que sea<br />sustancialmente propenso al deterioro oxidativo. En este trabajo se evaluó el efecto de suspensiones de<br />mortiño (Vaccinium meridionale SW) a 1000, 1500 y 2000 mg L−1 sobre la estabilidad oxidativa del aceite de Sacha inchi (Plukenetia volubilis Linneo)sometido a condiciones de oxidación aceleradas durante 12 horas (60 °Cy flujo de aire a 1700 mL.min−1). La magnitud del deterioro oxidativo fue monitoreada midiendo la formación de compuestos polares (CP), trienos conjugados (TC) y valor peróxido (VP) del aceite, en presencia y ausencia de la suspensión. Los resultados revelaron que el aditivo es eficaz en la estabilización del aceite de Sacha inchi (Plukenetia volubilis Linneo), de tal manera que concentraciones de 2000 mg L−1 reducen el contenido de compuestos polares, trienos conjugados y valor peróxido en un 92,3%, 71,4% y 47,8%, respectivamente. De otro lado, se determinó el contenido de fenoles totales, flavonoides, taninos condensados y antocianinas de la suspensión de mortiño (Vaccinium meridionale SW), de modo que se caracterizara el poder antioxidante; los resultados demuestran que la suspensión es una fuente excepcional de antioxidantes naturales que serían los responsables de prevenir la oxidación del aceite de Sacha inchi (Plukenetia volubilis Linneo).</p>
This case study explored Medellín’s secondary English teachers’ perspectives, practices, and experiences related to English curriculum design and implementation in public schools. Data were collected using a survey sent to all secondary schools’ English teachers, analysis of school curriculum documents, and focus group interviews at five purposefully selected schools. Data indicate that there is a gap between the teachers’ preconceived notions of curriculum as holistic and integrative, and the notion of curriculum implied in the curriculum development process they implement (a more technical one). This gap is also evident in the schools’ general curriculum documents (that state the institution’s educational, holistic goals), and the English syllabus, (that tend to focus on language structures or communicative functions). Data also revealed the many challenges teachers face when designing and implementing the curriculum, including lack of preparation on curriculum development, collaborative work among teachers, and time to develop the contents. In conclusion, English teachers in public secondary schools need more significant and sustainable support in the analysis of contexts, as well as in the adaptation of curriculum guidelines.
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