title: Effectiveness of α-, γ- and δ-Tocopherol in a CLA-Rich Oil.
abstract: Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of octadecadienoic acid with conjugated double bounds. Positive health properties have been attributed to some isomers, such as anticarcinogenic activity, antiartherosclerotic effects and reduction of body fat gain. Hence, oils rich in CLA such as Tonalin(®) oil (TO), normally obtained through alkaline isomerization of safflower oil (SO), an oil rich in linoleic acid (LA), are currently used in functional foods. However, special care must be taken to protect them from oxidation to ensure the quality of the supplemented foods. The objective of this work was to evaluate the oxidation and effectiveness of different tocopherol homologues (α-, γ- and δ-), alone or in combination with synergists (ascorbyl palmitate and lecithin), in TO compared to SO at different conditions, ambient temperature (25 °C) and accelerated conditions in Rancimat (100 °C). The oils, the oils devoid of their antioxidants and the latter containing the antioxidants added were assayed. Results showed great differences between SO and TO in terms of formation of hydroperoxides and polymers and also in the effectiveness of tocopherols to delay oxidation. TO showed higher levels of polymerization and, in general, the effectiveness of tocopherol homologues, alone or in combination with synergists, was also lower in the TO.
authors.affiliation: Instituto de Ciencia y Tecnología de Alimentos y Nutrición (ICTAN-CSIC), José Antonio Novais 10, Madrid 28040, Spain. gmarquez@ictan.csic.es.
authors.forename: Gloria
authors.initials: G
authors.lastname: Márquez-Ruiz
authors.affiliation: Instituto de Ciencia y Tecnología de Alimentos y Nutrición (ICTAN-CSIC), José Antonio Novais 10, Madrid 28040, Spain. bmc_mary@yahoo.es.
authors.forename: María Del Carmen
authors.initials: Mdel C
authors.lastname: García-Martínez
authors.affiliation: Instituto de Ciencia y Tecnología de Alimentos y Nutrición (ICTAN-CSIC), José Antonio Novais 10, Madrid 28040, Spain. pha@if.csic.es.
authors.forename: Francisca
authors.initials: F
authors.lastname: Holgado
authors.affiliation: Instituto de la Grasa (IG-CSIC), Padre García Tejero 4, Sevilla 41012, Spain. jvelasco@cica.es.
authors.forename: Joaquín
authors.initials: J
authors.lastname: Velasco
keywords: CLA; antioxidants; conjugated linoleic acid; functional lipids; lipid oxidation; peroxide value; polymers; tocopherols