Cambios en composición y calidad de aceites de girasol durante su extracción y desgomado

The influence of different stages of processing on composition and quality of crude sunflower oil was studied through the determination of fatty acids, metal and phosphorus contents, free fatty acids, peroxide and anisidine values, tocopherols, polar compounds, waxes and oxidative stability. No significant changes in the content of individual fatty acids and tocopherols were observed during processing. The composition of some minor constituents as metals, waxes and phospholipids was strongly affected by the extraction and water degumming processes. Sunflower oils obtained by hexane extraction presented a higher initial deterioration but also a higher oxidative stability than oils obtained by pressing.Se estudió la influencia de las distintas etapas del procesamiento sobre la composición y calidad de aceite crudo de girasol a través de la determinación de la composición de ácidos grasos, contenido de fósforo y metales, índice de acidez, índice de peróxido, valor de p-anisidina, tocoferoles, compuestos polares, ceras y estabilidad oxidativa. No se apreció durante el procesamiento ningún cambio significativo en la composición de ácidos grasos y tocoferoles. Los contenidos de algunos compuestos minoritarios como metales, ceras y fosfolípidos resultaron apreciablemente afectados con los procesos de extracción y desgomado con agua. Los aceites de girasol obtenidos por extracción con hexano presentaron un grado de deterioro inicial superior y una mayor estabilidad oxidativa con respecto a los aceites obtenidos por prensado

Water-hexane sorption in sunflower meals

Sorption equilibria of water and hexane in sunflower meals were determined at atmospheric pressure and temperatures from 50 to 95 °C. Adsorption-desorption experiments, for both individual vapors and water-hexane mixtures, were carried out using a dynamic technique based on gravimetric measurements with a Cahn electrobalance. The isotherms were fitted to the Guggenheim-Anderson-deBoer sorption equation, and the heat of sorption was evaluated from experimental results. In the range of temperatures investigated, water sorption was several times higher than hexane sorption, the differences increasing with solvent activity. The net heat of sorption that resulted was significantly higher for hexane than for water. Water sorption isotherms were slightly affected by temperature, especially at water activities greater than 0.6. Some hysteresis was observed in water sorption at 50 °C, but it was practically negligible at higher temperatures. Hexane previously adsorbed in the meal did not affect significantly the sorption of water. On the contrary, water previously adsorbed in the meal increased the amount of adsorbed hexane.Fil: Cardarelli, Damián Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional de Río Cuarto; ArgentinaFil: Mattea, Miguel Angel. Universidad Nacional de Río Cuarto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Crapiste, Guillermo Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin