Rapid Method for Extracting and Quantifying Synthetic Antioxidants in All Edible Fats and Oils

Abstract

A simple, rapid, and accurate analytical method was applied to the quantification synthetic antioxidants (SAs) in all kinds of fats and oils, including propyl gallate (PG), tertiary butyl hydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT). Moreover, the activity and function of the added SAs to edible oils were evaluated by quantifying oxidative stability (OS) and peroxide value (PV) of the test samples. For the quantification of SAs, high performance liquid chromatography (HPLC) with the gradient method was applied. Under the recommended conditions, the separation of four SAs was achieved in less than 14 min. In this method, the SAs were extracted from the edible oils using methanol/acetonitrile (1:1, (v/v)). The mixture was subjected to vortex/ultrasonic treatment. The extracts were next kept in a freezer (−20 °C) for 1 h. The upper layer was injected into HPLC. The recovery value of each SA was obtained in the ranges of 89.95–100.38 % for PG, 96.45–100.10 % for TBHQ, 91.57–98.80 % for BHA, and 90.23–95.56 % for BHT. The method was applied for the evaluation of SAs in 57 samples of fats and oils such as sunflower, canola, frying, hydrogenated, soybean, olive, margarine, blended oils, animal butter, and butter oils. The amount of each SA in the test samples was in the legal standard limit set for SAs in the National Standards of Iran (INSO 3608). Results showed that OS was directly related to the amount of SAs and inversely related to PV in all the test samples. PG and TBHQ were detected in almost all margarine and all edible oil samples, respectively.