Reuse of discarded deactivated bleaching earth in the bleaching of oils

Abstract

RESUMENReutilización de tierras decolorantes desactivadas desechadas para la decoloración de aceites.Tierra decolorante desechada, fue empleada, tras su reactivación para decolorar aceites de girasol, soja y maíz. La eficiencia de la tierra decolorante reactivada fue comparada con la de la virgen activada. La tierra reactivada ácida (pH 2,5-3) tuvo ligeramente mayor contenido en silicona que la tierra virgen o la reactivada neutra. Los mejores resultados en el color de los aceites de girasol y maíz fueron obtenidos cuando se emplearon niveles del 1 y 2% de tierra reactivada neutra (pH 6-7). La tierra ácida reactivada, usada al 2% consiguió una mayor reducción del color del aceite de soja, que una misma dosis de tierra virgen (pH 3). Ambas tierras reactivadas redujeron el índice de peróxidos, hierro, dienos conjugados y jabón de los aceites, mientras que hicieron aumentar la acidez y los trienos conjugados. Además, estas tierras reactivadas determinaron mayores descensos en los periodos de inducción del aceite que la tierra virgen. Las tierras reactivadas podrían ser usadas durante 5 ciclos para la decoloración de aceites de soja y girasol y durante más de 6 ciclos con aceite de girasol.PALABRAS-CLAVE: Activación de tierra decolorante usada -Reciclado de tierras decolorantes desactivadas -Tierras decolorantes desactivadas y desechadas. SUMMARY Reuse of discarded deactivated bleaching earth in the bleaching of oils.Discarded bleaching earth was used after its reactivation for the bleaching of sunflower, soybean and corn oils. The efficiency of reactivated bleaching earth was compared to the efficiency of virgin activated bleaching earth. Acid reactivated earth (pH 2.5-3) had a slightly higher content in silicone than virgin activated or neutralized reactivated earths. The best results in the color of sunflower and corn oils were obtained when neutralized earth (pH 6-7) was used at 1 and 2 % levels. Acid reactivated earth used at 2 % achieved a higher reduction in soybean oil color than virgin earth (pH 3) at the same dosage. Both reactivated earths reduced peroxide value, iron, conjugated dienes and soap, while they increased acidity and conjugated trienes. Furthermore, these reactivated earths determined higher decrements in the oil induction period than virgin earth. Reactivated earth could be used for 5 cycles for the bleaching of soybean or corn oils and for more than 6 cycles for sunflower oil. KEY-WORDS: Activation of spent bleaching earth -Discarded deactivated bleaching earth -Recycling of deactivated bleaching earth.

Formulation of oil‐in‐water emulsions containing enzymatically modified rabbit fat with pumpkin seed oil

“…Rabbit fat was bleached in order to remove pigments and other substances (ionizable and non‐ionizable forms, residual phospholipids, mucilage, or metal traces) (Girgis, ; Latondress, ). The fat was placed in a double‐neck round bottom flask under reflux condenser, and was maintained at 80 ± 0.5°C.…”

Effect of Alumina Content and Surface Area of Acid‐Activated Kaolin on Bleaching of Rice Bran Oil

“…Acid activation was carried out with mechanical stirring at 90 °C for 4 h. Samples were washed with distilled water until they reached pH 3, a value at which the sorption properties of acidified kaolin have been considered to be good [13]. Other researchers have also reported an optimum pH range of 2-4 for the clay's sorption of organic molecules [16] and 2.5-3.0 for the bleaching of vegetable oil [17]. The washed kaolin samples were then dried in an oven at 80 °C for 24 h and were gently ground with a mortar and pestle.…”

Alternative Fillers for the Production of Bituminous Mixtures: A Screening Investigation on Waste Powders

“…Bleaching clays are aluminium hydrosilicates containing small amounts of Mg, Ca and Fe. They are similar to normal clays, but more hydrated, and have the capacity of removing colored impurities from mineral, vegetable and animal oils, and from other fluids [28]. These materials are divided into Floridinic clays, which are active in the natural state, and bentonite clays, active only after chemical treatment.…”