COMPARATIVE STUDY OF OXIDATIVE STABILITY FOR DIFFERENT TYPES OF VEGETABLE OILS

Abstract

Use of oils in the diet requires their protection against oxidation under conditions of high temperature and light. The expiration date is different depending on the type of oil. The presence of light and heat affects its quality: acid value, peroxide value and antioxidant capacity due to the presence of natural oils, antioxidants such as tocopherols, polyphenols, vitamin C, and so on, or artificial, added during the technological processes of obtaining them. Changes in acid value and peroxide may be linked to the antioxidant content assessed by measuring antioxidant activity by DPPH method. Oxidative   stability of sunflower oil, corn oil, extra virgin olive oil, grape seed oil and nut oil was studied before and after keeping them in oven for 5 days at 50 º C. Under these conditions of     accelerated oxidation, oxidative stability was evaluated by measuring peroxide value, antioxidant activity of free acidity. From analyzes it came out that coconut oil has the highest antioxidant capacity and the lowest variation of peroxide value and free acidity in mentioned conditions.