%0 Journal Article
%T ¦Â-carotene in sunflower oil oxidation
%A Marinova
%A E. M.
%A Raneva
%A V. G.
%A Yanishlieva
%A N. V.
%J Grasas y Aceites
%D 2001
%I Consejo Superior de Investigaciones Cient¨ªficas
%X The oxidation kinetics of sunflower oil (SO), as well as of pure triacylglycerols of sunflower oil (TGSO) in the presence of different concentrations (0.001-0.02 %) ¦Â-carotene was studied. The process was ¦Â-performed at high (kinetic regime) and low (diffusion regime) oxygen concentrations at room temperature in the dark and under daylight. The results from the oxidation of SO and TGSO at 100 oC in the presence of ¦Â-carotene were also presented. It was established that in the antioxidant-free lipid system, the ¦Â-carotene did not give any antioxidative protection. It worked as a prooxidant during the oxidation at room temperature and at sufficiently high oxygen concentration, the effect being more pronounced in the dark than under daylight. ¦Â-carotene increased the stability of tocopherol-containing SO during its oxidation at room temperature and under daylight. This effect is more strongly expressed in a kinetic regime of oxidation. The synergism of ¦Â-carotene with the tocopherols was characterized by the stabilization factor F and the activity A. In the kinetic regime of oxidation F and A varied in the interval F=2.0-6.3, and A =2.7-21.0. In the diffusion regime F=1.3-1.5, and A=1.5-2.8. Se estudi¨® la cin¨¦tica de oxidaci¨®n de aceite de girasol (SO), as¨ª como la de triacilgliceroles puros de aceite de girasol (TGSO) en presencia de diferentes concentraciones (0.001-0.02 %) de ¦Â- caroteno. El proceso se llev¨® a cabo a altas (r¨¦gimen cin¨¦tico) y bajas (r¨¦gimen de difusi¨®n) concentraciones de ox¨ªgeno a temperatura ambiente con luz natural y en la oscuridad, y se presentan tambi¨¦n los resultados de la oxidaci¨®n de SO y TGSO a 100 oC en presencia de ¦Â-caroteno. Los resultados indicaron que en los sistemas lip¨ªdicos libres de antioxidantes, el ¦Â-caroteno no dio protecci¨®n antioxidante. Funcion¨® como prooxidante durante la oxidaci¨®n a temperatura ambiente y a concentraciones de oxigeno suficientemente elevadas, siendo el efecto m¨¢s pronunciado en la oscuridad que con luz natural. El ¦Â-caroteno aument¨® la estabilidad del SO conteniendo tocoferol durante su oxidaci¨®n a temperatura ambiente y con luz natural. Este efecto es expresado m¨¢s intensamente en un r¨¦gimen cin¨¦tico de oxidaci¨®n. El sinergismo del ¦Â-caroteno con los tocoferoles se caracteriz¨® por el factor de estabilidad F y la actividad A. En el r¨¦gimen cin¨¦tico de oxidaci¨®n, F y A variaron en el intervalo F= 2.0-6.3, y A= 2.7-21.0. En el r¨¦gimen de difusi¨®n F= 1.3-1.5, y A= 1.5-2.8.
%K ¦Â--Carotene
%K Oxidation
%K Sunflower oil
%K Aceite de girasol
%K ¦Â-caroteno
%K Oxidaci¨®n
%U http://grasasyaceites.revistas.csic.es/index.php/grasasyaceites/article/view/390/393