Routine analytical methods for use in South Pacific regional laboratories for determining naturally occurring antioxidants in food

Naturally occurring antioxidants are compounds that aid in the prevention of oxidative stress that leads to the onset of nutritionally-related chronic diseases including diabetes, cancer and coronary heart diseases. Reliable information on the antioxidant content of traditional South Pacific food is vital in reducing the level of chronic degenerative disorders amongst the local population. This paper describes, with examples from our laboratories, analytical procedures that are suitable for use in South Pacific regional laboratories for determining naturally occurring antioxidants in food and plant material. These include the trolox equivalent antioxidant capacity (TEAC) for measuring the Total Antioxidant Capacity (TAC), the Folin-Ciocalteu method for determining the total polyphenol (TPP) content and a spectrophotometric /pH difference method for determining the total anthocyanin (TAT) content. High performance liquid chromatography with ultraviolet detection (HPLC-UV) is suitable for determining individual antioxidants present in food, e.g. carotenoids and flavonols, while high performance liquid chromatography-diode array detection-tandem mass spectrometry (HPLC-DAD-MS/MS) can be used to identify and quantify low levels of naturally occurring antioxidants, e.g. catechins, present in food and plant material.