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Enhanced oxidative stability and water miscibility of conjugated linoleic acid complexed with lysine and arginine
Author(s) -
Koohikamali Sara,
Kamal Siti Mazlina Mustapa
Publication year - 2015
Publication title -
european journal of lipid science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 94
eISSN - 1438-9312
pISSN - 1438-7697
DOI - 10.1002/ejlt.201300461
Subject(s) - chemistry , conjugated linoleic acid , solubility , oxidative phosphorylation , lysine , aqueous solution , food science , linoleic acid , biochemistry , organic chemistry , amino acid , fatty acid
Conjugated linoleic acids (CLA) are regarded as functional lipids. However, the water insolubility and oxidative instability of commercial CLA are barriers that limit the applications of CLA for fortification of aqueous‐based foods. In this study, production of a derivative of CLA with improved water solubility and extended shelf life through attachment of lysine (Lys) and arginine (Arg) into CLA structure was investigated. The evidence of the formation of Lys–CLA and Arg–CLA complexes was supported and verified by FT‐IR and 13 C NMR analysis. The results indicated that the solubility of the Arg–CLA solution in pure water (pH 7) was greater than that of Lys–CLA at concentrations higher than 0.2% w/v. The peroxide values (PV) of the Lys–CLA and Arg–CLA increased by 1.4‐fold and 1.5‐fold, respectively; however, the PV of CLA increased by 15‐fold (after 12 h of heat treatment at 60°C). The PV mean of Lys–CLA was significantly ( p < 0.05) lower than that of Arg–CLA, revealing that the oxidative stability of Lys–CLA is higher than that of Arg–CLA. This study showed that the incorporation of both Lys and Arg into the CLA can improve the water miscibility and oxidative stability of CLA, and expand the applications of CLA into food emulsions fortification. Practical applications: The water insolubility and oxidative instability of CLA are limiting barriers in application of CLA as a food fortifier. In order to improve the water solubility and oxidative stability of CLA, Lys and arginine, which are polar amino acids, have been incorporated into the CLA structure in forms of Lys–CLA and Arg–CLA complexes. This study showed that Lys can be an appropriate substitute for Arg in the Arg–CLA complex, which was already suggested in earlier works. In fact, the complexation of CLA with Lys improves the oxidative stability, water solubility, and the antioxidative capacity of CLA. Accordingly, the Lys–CLA complex provided and further described here may be used to fortify the liquid foods and drinks and thus, this product may expand the scope of CLA applications. The incorporation of both Lys and Arg into conjugated linoleic acid (CLA) can improve its water miscibility and oxidative stability and expand the applications of CLA in food emulsions fortification.