Electrochemical determination of antioxidants in edible vegetable oils

S. N. ROBLEDO; A. M. GRANERO; M. A. ZON.; H. FERNÁNDEZ

LAP LAMBERT Academic Publising

Lugar: Saarbrucken; Año: 2014 p. 65

978-3-659-61688-4

Fats, oils and lipid-based foods can be deteriorated by oxidation, which causes a decrease in the nutritional value. Therefore, changes in color, texture, odor, flavor, loss of vitamins, and damage to proteins are some of the effects of lipid oxidation. These processes may occur during heating or during a prolonged storage. The manufacturers of lipid-based foods are particularly interested in retarding these deterioration processes. Several methodologies can be applied to retard the lipid oxidation such as preventing access to oxygen, using low temperatures, inactivate enzymes which promote the oxidation, etc. The lipid oxidation can also be delayed by the addition of antioxidants. Most of the synthetic antioxidants are of the phenolic type. Terbutyl hydroxyanisol (BHA), terbutyl hydroxytoluene (BHT), propyl gallate (PG), and terbutyl hydroquinone (TBHQ) are the most widely used synthetic antioxidants. They should be used up to the maximum concentrations allowed by international law. However, in recent years their possible harmful effects to human health have questioned the use of synthetic antioxidants. It is well known that a wide range of natural antioxidants occur in plants and animals such as vitamin E, vitamin C, -carotene, uric acid, etc. Another large number of natural antioxidants of plant origin, called as secondary metabolites, are flavonoids. Chromatographic techniques are the most widely used in the qualitative and quantitative determination of synthetic and natural antioxidants. However, in recent years, electrochemical techniques began to be important both as alternatives and as complementary techniques for making these determinations. This book is designed to provide applications of the most used chromatographic techniques and electroanalytical techniques recently developed in our laboratory for the determination of BHA, BHT, PG, TBHQ and tocopherols (vitamin E) in edible vegetable oils. Therefore, in the first section of the book, we comment about the production of edible vegetable oils in the world, the food stability, products of lipid oxidation and the effects of synthetic and natural antioxidant on the lipid oxidation. In the second section of the book, we give a concise general overview of chromatographic techniques used to detect and quantify synthetic and natural antioxidants in edible vegetable oils, but mainly we present in this section new results obtained from electroanalytical techniques. In the third section, we show very promising results we found for the application of chemometric tools to resolve overlapped voltammetric signals. We hope that this presentation can help people involved in the very important area of analysis of edible vegetable oils, to expand the offer of alternative analysis techniques to the already existing ones. Finally, we wish to thank Mrs. Elena Chercunova and to LAP LAMBERT Academic Publishing for the invitation to edit this book.