Phenolic extracts of coconut oil cake: a potential alternative for synthetic antioxidants

Abstract

Limitations of natural antioxidants include relatively low antioxidant activity, narrow range of food systems where the antioxidants are effective and limited thermal stability compared to synthetic antioxidants. In the present study, the phenolic extract of coconut oil cake (COCE) was tested for antioxidant activity-related food stabilization. Heat stabilities of COCE and synthetic antioxidants were determined by measuring the indubbction time of sunflower oil enriched with heat-treated antioxidants. In the β-carotene-linoleate emulsion used for testing antioxidant activity, COCE can retain 96 ± 2% of initial colour intensity while BHT can retain 89 ± 2% of initial colour intensity at 60 µg mL^–1 concentration after two hours. TBARS contents (MDA equivalents / kg of meat) in COCE-treated and control pork samples after 14 days was 2.80 ± 0.57 and 22.55 ± 2.30 respectively. Heat stability varies in the order butylated hydroxytoluene (BHT) < (butylated hydroxyanisole (BHA) < COCE < tertiary butylhydroxyquinone (TBHQ). The results of these experiments suggest that COCE is a versatile and thermally stable natural antioxidant mixture effective in stabilizing many food systems.

Keywords:
coconut oil cake; antioxidants; polyphenols; DPPH; food model systems