Abstract

In this research, methanolic extracts of seed, flower and leaf of Borgardia chrysogonum were extracted, and then the total phenolic compounds and inhibitory activity of free radicals of extracted extracts were investigated in different concentrations (250 ppm, 500 ppm and 1000 ppm). In the next step, the different concentrations of the optimum extract from various parts of the Borgardia chrysogonum were added to refined sunflower oil without antioxidant and the oxidative stability of sunflower oil was investigated for three days by measuring the peroxide value, acid number, index of thiobarbituric acid and duration of the period and finally compared to synthetic antioxidant activity of BHA in amount of 100 ppm. In general, the results showed that by increasing the concentration of seed extract, leaf and flower of Borgardia chrysogonum, the amount of phenolic, antioxidant, and inhibitory activity of free radicals increased, and the concentration of 1000 ppm of seed extract of Borgardia chrysogonum had the highest antioxidant power compared to other concentrations. Therefore, seed extract of Borgardia chrysogonum was selected as the optimum antioxidant extract from various parts of Borgardia chrysogonum (leaf, flower and seed) and was added to refined sunflower oil without antioxidant. By increasing the concentration of seed extract of Borgardia chrysogonum into sunflower oil during a constant maintenance period, oxidative stability index was increased, but the index of peroxide, acid number and thiobarbituric acid index (TBA) decreased. Thus, seed extract of Borgardia chrysogonum can be introduced as a suitable source of natural antioxidants at 1000 ppm.

INTRODUCTION

The oxidation of fats and oils in foods can lead to the development of anti-nutritional factors and undesirable flavor in foods (1). Human health can also be endangered by the undesirable and harmful materials caused by the oxidation of fats and oils. Since fats and oils have a special status in diet in terms of energy and nutrition, knowledge of the control of fat and oil oxidation is considered the basis for the protection of sensory and nutritional quality (2). Hence, the ability to restrict or delay the onset of oxidation of fats and oils in the food industry can be of importance. One of the most effective and common ways to reduce the oxidation of fats and oils is the use of antioxidants (3). According to the specifying of the harmful effects of synthetic antioxidants on consumers, they disrupt the activity of liver enzymes and cause various types of cancers. In the world, their application is limited. Therefore, the identification of natural antioxidants from plant sources is cheap and available, and determination of their oxidative stability on sunflower oil under different conditions is one of the main goals of this research. Therefore, in thi ...