Abstract

TOCOPHEROL CONTENT OF VEGETABLE OILS/ FATS AND THEIR OXIDATIVE DETERIORATION DURING STORAGE

Selina Khan*, Sharmin Akter Lisa, Monira Obaid and Krishna Chowdhury

ABSTRACT

This study was aimed at investigation of tocopherol content in different vegetable oils locally available in Bangladesh as well as their oxidative deterioration during storage. Total tocopherol and individual tocopherols (-tocopherol, -tocopherol and -tocopherol) along with Free Fatty acid (FFA %) and Peroxide value (PV) were evaluated at three months interval during one year storage. The content of - tocopherol was highest in sunflower oil which is 20.76 mg/100g and the content of -tocopherol was highest in soybean oil which is 59.3 mg/100g. Also, soybean oil was the richest in total tocopherol content whereas, banashpati (hydrogenated fat) had the least amount of total tocopherol. Furthermore, total tocopherol in every oil decreased very slightly after one year. But the key parameters of oxidative deterioration, FFA% and PV were increased extensively during storage. However, as tocopherols are important natural antioxidants, vegetable oils those have more tocopherol content were found to deteriorate less during storage. Although the change of oxidative stability depends on some other variables like amount of -tocopherol, storage condition, temperature, moisture content etc, this study conveys the importance of tocopherol in enduring the acceptable quality of vegetable oils.

Keywords: Tocopherol, Free Fatty acid, Peroxide value, oxidative deterioration, natural antioxidants, Vegetable oil.