Grasas y Aceites, Vol 58, No 2 (2007)

A rapid method for determination of polar compounds in used frying fats and oils


https://doi.org/10.3989/gya.2007.v58.i2.83

S. Marmesat
Instituto de la Grasa (CSIC), Sevilla, Spain

J. Velasco
Instituto de la Grasa (CSIC), Sevilla, Spain

G. Márquez-Ruiz
Instituto de la Grasa (CSIC), Sevilla, Spain

M.C. Dobarganes
Instituto de la Grasa (CSIC), Sevilla, Spain

Abstract


The determination of polar compounds by adsorption chromatography is the most accepted method for the analysis of used frying fats due to its high precision and accuracy. However, this method is expensive and time consuming. In this study, a rapid analytical method to determine polar compounds is proposed. Starting from milligrams of sample dissolved in a solution of hexane containing methyl oleate as internal standard, the nonpolar fraction, which comprises the non-altered triglycerides (TG) and the internal standard, is obtained by solid phase extraction. Then, the non polar fraction is quantitatively analyzed in 15 min by high-performance size-exclusion chromatography (HPSEC) and the polar fraction is determined by difference of weight. Response factors for pure TG and FAME were calculated. Six samples of sunflower oils of different degrees of unsaturation were analyzed in triplicate and the results were compared with those obtained by the gravimetric method based on silica classical column chromatography. Results showed no significant differences between the two methods. In addition, the repeatability of the proposed method was excellent, as the coefficient of variation ranged from 1.5 to 13% depending on the contents of polar compounds.

Keywords


Polar compounds; Response factors; Size exclusion chromatography; Solid phase extraction; Used frying oils

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References


AENOR 1991. Asociación Española de Normalización. Norma UNE 55-011, Catálogo de Normas UNE, Madrid

Dieffenbacher A, Martin E. 1987. Determination of emulsifiers in foods: separation of polar and nonpolar lipids by chromatography on silica-gel microcolumns Rev. Fr. Corps Gras. 34, 323 -328

DGF 2000. German Society for Fat Research, Proceedings of the 3rd International Symposium of Deep-Fat Frying - Final Recommendations. Eur J Lipid Sci Technol. 102, 594.

Dobarganes MC, Velasco J, Dieffenbacher A. 2000. Determination of polar compounds, polymerized and oxidized triacylglycerols, and diacylglycerols in oils and fats. Pure Appl Chem, 72, 1563-1575 doi:10.1351/pac200072081563

Dobarganes MC, Pérez-Camino MC, Gutiérrez González- Quijano R. 1984. Métodos analíticos de aplicación en grasas calentadas. I. Determinación de ésteres metílicos no alterados. Grasas y Aceites 35, 172-177.

Dobarganes MC, Pérez-Camino MC, Márquez-Ruiz G. 1988. High performance size exclusion chromatography of polar compounds in heated and non-heated fats, Fat Sci Technol. 90, 308-311.

Firestone D.1996. Regulation of frying fat and oil, in Perkins EG, Erickson MD.(Eds) Deep frying. Chemistry, nutrition, and practical applications, 323-334.AOCS Press, Champaign, Illinois.

Guinda A, Dobarganes MC, Ruiz-Méndez MV, Mancha M. 2003. Chemical and physical properties of a sunflower oil with high levels of oleic and palmitic acids. Eur J Lipid Sci Technol. 105, 130-137. doi:10.1002/ejlt.200390028

IUPAC 1992 a. Standard Method 2.507: Determination of Polar Compounds in Frying Fats, in Standard Methods for the Analysis of Oils, Fats and Derivatives, 7th Edition, International Union of Pure and Applied Chemistry, Blackwell, Oxford, England.

IUPAC 1992 b. Standard Method 2.508: Determination of Polymerized Triglycerides in Oils and Fats by High Performance Liquid Chromatography, in Standard Methods for the Analysis of Oils, Fats and Derivatives, 7th Edition, International Union of Pure and Applied Chemistry, Blackwell, Oxford, England.

Marmesat S, Rodrigues E, Velasco J, Dobarganes C. 2007. Quality of used frying fats and oils: comparison of rapid tests based on chemical and physical oil properties. Int J Food Sci Technol. 42, 601-608. doi:10.1111/j.1365-2621.2006.01284.x




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