Stabilization of multi-source edible oils from palm olein and sunflower oil using clove (Syzygium aromaticum) extract and powder during accelerated storage

Abstract

The objective of this study was to evaluate the effect of clove buds ethanolic, hexanic extracts and powder in inhibiting 50/50 and 30/70 palm olein/sunflower oil blends during accelerated storage. Clove ethanolic and hexanic extracts were tested for their total phenolic content and antioxidant activities. Clove ethanolic, hexanic extracts and powder were individually added to 100 g of each oil mixture at concentrations 500–2000 ppm. Oil blends with butylated hydroxytoluene served as positive control while the same samples without additives served as negative ones. All oil samples were stored in an electric-air dried oven at 60 °C for 20 days (8 h heating /day). Samples were collected after every 10 days for quality analysis. The peroxide, p-anisidine, TOTOX and thiobarbituric acid values were evaluated. Results showed total phenolic content of 11.80 and 10.77 mg GAE/g respectively for the ethanolic and hexanic extracts. The ethanolic extract exhibited antioxidant activities ranged between 20.29 % and 89.79 % while that of the hexanic extract ranged between 17.12 % and 81.06 %. The effect of clove extracts and powder on the oxidative stability disclosed that the extracts and powder significantly (p < 0.05) delayed the oxidation of the 50:50 and 30:70 palm olein/sunflower oil blends during storage at 60 °C for 20 days. Generally, the Total oxidation value range was 22.85–120.60 for the control and 22.85–101.29 for the oils supplemented with antioxidants.