Effects of filtration through activated carbons on peroxide, thiobarbituric acid and carbonyl values of autoxidized soybean oil

Boki, Keito; Wada, Tetsuyuki; Ohno, S.

doi:10.1007/bf02660150

Cited by 13 publications

(5 citation statements)

References 11 publications

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“…The results displayed in Table II show that neutralized reactivated bleaching earth (pH = 6 -7) produced a high reduction of about 33.7 % in total color of corn oil during the bleaching compared to acid reactivated bleaching earth (pH = 2.5 -3) which gave a low reduction in the total color (24.2 %) at the same dosage (2%). These results are similar to those recorded by Boki et al (1991) and Hui (1996) who revealed that differences in physical and chemical properties of activated carbons cause differences in activity for reducing color.…”

supporting

confidence: 91%

Reuse of discarded deactivated bleaching earth in the bleaching of oils

Girgis¹

2005

Grasas y Aceites

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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.

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supporting

confidence: 91%

Reuse of discarded deactivated bleaching earth in the bleaching of oils

Girgis¹

2005

Grasas y Aceites

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“…Several column-chromatographic methods (6,(11)(12)(13)(14), as well as activated carbon treatments (15), have been used to purify natural TAG from oils for antioxidant studies. Commercially available corn oil, stripped of tocopherols, has also been used (3,16).…”

mentioning

confidence: 99%

Antioxidant activity of minor amounts of γ‐tocopherol in natural triacylglycerols

Lampi

Hopia

Piironen

1997

J Americ Oil Chem Soc

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The effects of minor amounts of γ-tocopherol on the oxidation of natural triacylglycerols (TAG) of rapeseed (RO) and butter oils (BO) were studied. Four different TAG materials were blended from chromatographically purified TAG that contained 100-25% of RO TAG. The RO TAG contained from <1 to 43 µg γ-tocopherol per gram of TAG, which corresponded to ≤6% of the total tocopherols in the original RO. The TAG were held at 40°C in the dark for 4 wk and followed at regular intervals by measurements of hydroperoxide formation by peroxide values and of secondary product formation by p-anisidine values at regular intervals. In all TAG, minor amounts of γ-tocopherol retarded oxidation. In RO TAG, concentrations as low as 11 µg/g of γ-tocopherol (1.5% of the total tocopherols in the original RO) were enough to decrease hydroperoxide and secondary product formation to 46 and 39%, respectively. The effect was even more important in TAG mixtures that contained BO TAG. There were no significant differences between oxidation of the RO TAG at 24 µg/g, the 75% RO TAG mixture at 11 µg/g, and the 50% RO TAG mixture at 3 µg/g of γ-tocopherol. Even at these minor levels, γ-tocopherol was a significant antioxidant, which is important in oxidation studies of purified model systems. JAOCS 74, 549-555 (1997).KEY WORDS: Antioxidant, natural triacylglycerols, γ-tocopherol.Tocopherols (TocH) are known to act as antioxidants by donating a hydrogen atom to chain-propagating peroxyl radicals (LOO·):and are consumed by the reaction of chromanoxy (Toc•) radicals with other peroxyl radicals or with each other (1). It is generally agreed that the order of hydrogen-donating power of different tocopherols decreases α > β > γ > δ, as was shown by Burton and Ingold (1). Studies of the antioxidative activity of tocopherols in vivo and in vitro, however, have given contradictory results, which have recently been reviewed by Kamal-Eldin and Appelqvist (2). The effectiveness of tocopherols as antioxidants depends highly on the characteristics of the oxidizing material, such as the phase of the lipid (3-4) and its oxidative status (5-6), and on experimental conditions, such as the concentrations of tocopherols (3,7) and the temperature (4,8).When the role of tocopherols in relation to edible oils and fats is studied, it is important to have complex natural triacylglycerols (TAG) as the oxidizing material. Methyl esters and monoacyl TAG are inappropriate substrates, because the TAG structure influences the oxidation (9-11). Natural TAG with various acyl groups must be purified from oils to get material without the pro-and antioxidant activities of minor compounds that are normally present in the oils.Several column-chromatographic methods (6,(11)(12)(13)(14), as well as activated carbon treatments (15), have been used to purify natural TAG from oils for antioxidant studies. Commercially available corn oil, stripped of tocopherols, has also been used (3,16). Data on the concentrations of important pro-and antioxidants of the TAG, however, are not always given...

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“…The decrease in AV and CV using virgin or calcined magnesium hydroxide was related to the properties of the adsorbent surface. The use of activated carbon, aluminum hydroxide, silica gel, and organic and inorganic adsorbents has been previously investigated for the regeneration decreasing the AV or CV of waste edible oil 14,18,19 . Polar compounds generated during the deterioration of edible oil were removed by the adsorbents because of van der Waals interactions 20 .…”

Section: Changes In Av and CV After Adsorbent Treatmentmentioning

confidence: 99%