Sara Koohikamali
Islamic Azad University
Shahr-E-Qods Branch
Iran
Title: Improvement of the water solubility, oxidative stability and antioxidant effect of conjugated linoleic acid using Lysine
Biography
Biography: Sara Koohikamali
Abstract
Conjugated linoleic acid (CLA) reported to be a functional fatty acid. The water insolubility and oxidative instability of commercial CLA have limited the applications of CLA. Aim of this research was to produce an oxidative stable hydrophilic CLA by attachment of Lysine (Lys), a polar amino acid, into CLA structure. Formation of Lys-CLA was confirmed by FT-IR at 1650 and 1550 cm-1. The highest water solubility was at pH 2, Lys-CLA of ≤ 1.75% with no added salt (two weeks at 25 ± 1 °C). Peroxide value (PV) was increased by approximately 16-fold (12 h at 60 ºC) for CLA; however, the PV of Lys-CLA was increased by only 1.4-fold, showing that oxidative stability of Lys-CLA has been improved compared with CLA alone. Antioxidant activities of Lys-CLA, CLA and Lys were evaluated using ABTS and DPPH assays. All samples displayed radical scavenging activities in both assays. Lys-CLA with the smallest half maximal inhibitory concentration (IC50) showed the maximum antioxidant activity among the rest (p < 0.05). The antioxidant activity of Lys-CLA found to be synergistic in DPPH. This study showed that incorporation of Lys into the CLA molecule can improve the oxidative stability, antioxidant capacity and water miscibility of CLA.