Kinetics of Bleaching of Vegetable Oils

Brimberg, Ulla I.

doi:10.1007/bf02678716

Cited by 63 publications

(22 citation statements)

References 7 publications

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“…When bleaching palm oil with Tonsil Optimum FF, a highly activated clay, she could not find an equivalent effect [5]. The same was found in this study.…”

Section: The Effect Of the Initial Amount Of Watersupporting

confidence: 72%

“…The fundamental work was published by Brimberg [4,5]. She described the kinetics of pigment reduction in a linearised form when plotting the concentration of remaining pigments against the square root of bleaching time:…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…The external mass flux of pigments from the bulk of the liquid to the surface of the clay particle n · f (kg/m 2 s) is given by (5) with β f [m/s] representing the external liquid-particle mass transfer coefficient, C [kg/m] the concentration of pigment in the bulk of the liquid, C s [kg/m] the concentration of the pigment in oil at the outer surface of the clay particle (see Fig. 4).…”

Section: External Mass Transfermentioning

confidence: 99%

“…Around the clay particle an external boundary layer of the thickness δ exists, the pigment is transported through this layer by film diffusion powered by the difference in concentration in oil at the surface of the particle C S and the bulk concentration C (see equation 5). The concentration C S is assumed to be in equilibrium with the adsorbed amount of pigment at the surface q S via the adsorptionisotherm.…”

Section: Internal Mass Transfermentioning

confidence: 99%

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On the bleaching kinetics of vegetable oils — experimental study and mass transfer-based interpretation

Langmaack

Eggers

2002

Eur. J. Lipid Sci. Technol.

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On the bleaching kinetics of vegetable oilsexperimental study and mass transfer-based interpretationThis study focuses on the systematic investigation of the parameters involved in adsorptive vegetable oil bleaching. These parameters range from the quality of oil and bleaching conditions chosen (e.g. amount and activity of clay, initial water content, temperature, pressure) to the effects of the different reactor systems used (agitated vessel, bubble column) on the kinetics. The study of the latter aims to optimise the type and intensity of power input. The most efficient process was shown to take place in the bubble column reactor. The findings result in a kinetic model for the transport phenomena of the pigments from the oil phase into the clay. The model splits the effects in phenomena due to mass transfer resistances inside and outside of the clay particle. By doing so it is possible to describe the bleaching kinetics in dependence of the amount of clay added and on the size of the external mass transfer resistance, which is influenced by the power input into the reactor. Thus a on model-based analysis of the effects as well as the optimisation of the bleaching reactor are made possible.

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“…When bleaching palm oil with Tonsil Optimum FF, a highly activated clay, she could not find an equivalent effect [5]. The same was found in this study.…”

Section: The Effect Of the Initial Amount Of Watersupporting

confidence: 72%

Section: Theoretical Backgroundmentioning

confidence: 99%

Section: External Mass Transfermentioning

confidence: 99%

Section: Internal Mass Transfermentioning

confidence: 99%

See 2 more Smart Citations

On the bleaching kinetics of vegetable oils — experimental study and mass transfer-based interpretation

Langmaack

Eggers

2002

Eur. J. Lipid Sci. Technol.

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“…1 (1998) teño son 7 x 31A y las de las de clorofila son 12 x 15 Â, lo que indica que ambas moléculas podrían'éntrar en poros de radios del orden de 15 Â. Sin embargo, la adsorción de carotenos se obtiene usando poros de diámetros en la región de 50-100 Â mientras que para la clorofila se logra con diámetros de poros entre 50-200 Â. Como éstos son considerablemente mayores que las dimensiones de las áreas transversales que corresponden a las moléculas monoméricas de ambos pigmentos, se confirma la hipótesis de Brimberg (1982) de que se encuentran como coloides dispersos en el aceite y no al estado molecular. En consecuencia, los mejores adsorbentes son aquellos que tienen, simultáneamente, adecuadas concentraciones de sitios fuertemente ácidos y alta superficie especí-fica debida a poros cuyos diámetros se encuentran en la región de 50-200 Â (Taylor, 1989;Boki, 1992).…”

Section: Introductionunclassified

Empleo de arcillas uruguayas pilareadas para el blanqueo de aceite de maiz.

Pagano¹,

Sergio²,

Montenegro³

et al. 1998

Grasas y Aceites

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RESUMENEmpleo de arcillas uruguayas pilareadas para el blanqueo de aceite de maiz.En este trabajo se estudia la capacidad de adsorción de los carotenos presentes en un aceite de maíz, de una montmorilíoni-ta uruguaya modificada por diferentes procedimientos: intercambiada con iones Na* (M-Na), activada por ácido (Act), intercambiada con iones Ca^* y pilareada con iones Keggin (Pilc-Ca), activada por ácidos y pilareada (Act Pilc-Ca) frente a dos arcillas comerciales: Tonsil Optimum de Süd-Chemie y una Montmorillonita tipo K lOdeAldrich.Los resultados indican que la muestra Act y la Pilc-Ca son tan eficientes como las comerciales pero que la capacidad de la muestra M-Na es considerablemente menor. También se efectuó ensayos con mezclas de Pilc-Ca con las arcillas comerciales, colocadas simultáneamente (en una sola etapa) o agregadas de manera sucesiva (en dos etapas). Dichos procedimientos no mejoraron la eficiencia del blanqueo.En conclusión, la modificación Pilc-Ca permite blanquear un aceite de maíz neutralizado y desgomado a valores similares a los correspondientes a los aceites comestibles comerciales. Este efecto se mejora aún por la acción simultánea con arcillas activadas. PALABRAS-CLAVE: Aceite de maiz -Arcillas pilareadas SUMMARY Using Uruguayan pillared clays for bleaching corn oil.In the present paper adsorptive capacity to remove carotenes from a com oil by an Uruguayan montmorillonite modified by different treatments: exchanae with Na* ions (M-Na), acid-activation (Act), exchange with Ca and pillaring with Keggin ions (Pile-Act), acidactivation and pillaring (Act Pil-Ca), Is studied. Bleaching action of the Uruguayan modified montmorillonites is compared with two commercial days: Tonsil Optimum (Sûd-Chemie) and montmorillonite oftypeKIO(Aldrich).Our results demonstrate that Act and Pilc-Ca samples are so efficient bleaching clays as commercials but M-Na sample Is lower. Also, mixtures of Pilc-Ca with commercial clays, added together in one step or consecutively In two steps, are studied. These procedures do not improved the bleaching action.As conclusion, the modified clay Pilc-Ca allows to bleach a neutralized and degummed corn oil, giving an end product similar to edible commercial oils. Such effect is improved with the simultaneous action with activated clays. KEY-WORDS: Bleaching -Com oil -Montnrorillonite -Pillared clays -Uruguay INTRODUCCIÓNLas grasas y aceites naturales pueden contener diferentes pigmentos: clorofilas (que imparten una coloración verde), más de 70 variedades de carotenoides (que son responsables de un color amarillo/rojo), derivados de las flavinas (que contribuyen al color amarillo), antocianidinas (cuyas sales son azules en medio básico y rojas en medio ácido aunque no se suelen encontrar en cantidades apreciables en los aceites), productos de la oxidación del gossypol (de color oscuro) y de los tocoferoles (que provocan una coloración roja oscura). El tipo y cantidad de pigmentos coloreados que posee un aceite es característico de él por lo que, en cada caso, se debe estudi...

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Adsorptive Separation of Oils

Proctor

Brooks²

2005

Bailey's Industrial Oil and Fat Products

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Vegetable oil refining processes, specifically, silica refining and bleaching, require a working understanding of adsorption or more specifically the physico‐chemical interaction between sorbent, substrate and contaminants. An understanding of adsorption theory and the factors affecting adsorption is useful in controlling these processes. Isotherms have been used as mathematical models to describe the relationship between adsorbed and non‐adsorbed molecules. The Langmuir isotherm theoretically describes oil pigment binding as reversible, monolayer chemisorption, where all adsorption sites are energetically equal. However, many systems conform to a Langmuir isotherm without these suppositions necessarily holding true. Langmuir behavior may provide useful practical information on the variables affecting the adsorption, but it does not provide proof of the adsorption mechanism. The Freundlich isotherm is supposed to describe reversible adsorption of a single solute at equilibrium at a fixed temperature. It also has been successfully used to describe pigment adsorption from vegetable oil and, likewise, has empirical value in describing the effect of processing variables on adsorption performance. In reality, pigment binding onto adsorbent clays is irreversible and there will be more than one oil solute competing for adsorption sites. Adsorptive binding of solute to adsorbent involves a number of forces, including chemisorption and physisorption, all of which affect bleaching efficiency. Adsorbent dosage, acidity, moisture in the system, temperature and pressure, all key factors that can be used to control the adsorption process.

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Kinetics of Bleaching of Vegetable Oils

Cited by 63 publications

References 7 publications

On the bleaching kinetics of vegetable oils — experimental study and mass transfer-based interpretation

On the bleaching kinetics of vegetable oils — experimental study and mass transfer-based interpretation

Empleo de arcillas uruguayas pilareadas para el blanqueo de aceite de maiz.

Adsorptive Separation of Oils

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