The Effects of Refining Operations on Quality and Quantity of Sterols in Canola, Soyabean and Sunflower Seed Oils

Document Type: Research Paper

Authors

1 M. Sc. Graduated of the Department of Food Science and Technology, Science and Research Branch, Islamic Azad University, Tehran, Iran.

2 Principal Lecturer, School of Human Sciences, London Metropolitan University, London, UK.

Abstract

Sterols due to their properties might be considered as valuable products to be employed in food, pharmaceutical and cosmetic industries. Vegetable oils, namely canola, soyabean and sunflower seed oils, contain considerable quantities of phytosterols, mainly β–sitosterol. The aim of this research is to determine the effect of refining operations, particularly deodorization on this valuable class of compounds. Three popular and common vegetable oils were sourced from local refineries and were subjected to neutralization, bleaching and deodorization procedures. The sterols were determined by saponification of the oils followed by extraction of the nonsaponifiable matter, and isolation of sterols by TLC and their final qualitative and quantitative determination by application to gas chromatography apparatus. The results indicated that sterols are lost in neutralization, bleaching and particularly deodorization stages to some extend and some might be collected in the distillate after deodorization. The distillate that is considered as a valuable source of sterols might be purified and used in various applications and industries.

Keywords


Abidi, S. L. (2001). Chromatographic analysis of plant sterols in foods and vegetable oils. Journal of Chromatography A, 935 (1-2), 173-201.
Dutta, P. C., Przybylski, R. & Eskin, M.N. (2007). Formation, analysis, and health

effects of oxidized sterols in frying fat. In Deep Frying (pp. 111-164). AOCS Press.
El-Mallah, M. H., El-Shami, S. M., Hassanien, M. M. M. & Abdel-Razek, A. G. (2011). Effect of chemical refining steps on the minor and major components of cottonseed oil. Agriculture and Biology Journal of North America, 2, 341-349.
Fernandes, P. & Cabral, J. M. S. (2007). Phytosterols: applications and recovery methods. Bioresource Technology, 98(12), 2335-2350.
Ghavami, M., Gharachorloo, M. & Ghiassi Tarzi. B. (2008). Laboratory Techniques–Oils and Fats. Islamic Azad University, Science and Research Branch Publisher.
Gutfinger, T. & Letan, A. (1974). Quantitative changes in some unsaponifiable components of soya bean oil due to refining. Journal of the Science of Food and Agriculture, 25(9), 1143-1147.
Karaali, A. (1985). The effects of refining on the chemical composition of Turkish sunflower seed oil. European Journal of Lipid Science and Technology, 87(3), 112-117.
Karabulut, I., Topcu, A., Yorulmaz, A., Tekin, A. & Ozay, D.S. (2005). Effects of the industrial refining process on some properties of hazelnut oil. European journal of lipid science and technology, 107(7‐8) 476-480.
Sciancalepore, V. (1981). The influence of processing on the content and composition of free and esterified sterols in sunflower seed oil. Oli Grassi Deriv, 17, 11-12.
Verleyen, T., Verhé, R., Garcia, L., Dewettinck, K., Huyghebaert, A. & De Greyt, W. (2001). Gas chromatographic characterization of vegetable oil deodorization distillate. Journal of Chromatography A, 921(2), 277-285.