EFFECT OF GINGER EXTRACT (ZINGIBER OFFICINALE) AS NATURAL ANTIOXIDANT ON SUNFLOWER OIL OXIDATION.

Oil oxidation is significant for acceptability, nutritional quality, and toxicity of edible oils. Antioxidant supplementation for oil is basic and common strategy for improving its oxidative stability and prolonging induction time. Ginger contains natural antioxidants such as phenolic and flavonoids compounds. Ginger extracts were extracted by different solvents (methanol, ethanol, acetone and water). Ethanolic ginger extract had the highest yield (10.52%), while, aqueous extract had the lowest yield (8.10%). Also, ethanolic extract had the highest contents of phenols and flavonoids compounds (75.17 and 19.55 mg/g, respectively) followed by methanolic extract (67.24 and 17.46 mg/g, respectively). Ginger had the ability to scavenge DPPH free radicals. With the increase of ginger extract concentration, there was an observed increase in scavenging ability. The ginger extract had lower DPPH scavenging activity than BHT (synthetic antioxidant). The ginger extract should be added below concentration 600 ppm to sunflower oil. Free fatty acid (FFA), peroxide value (PV), conjugated dienes (CD) and thiobarbituric acid (TBA) value were used to evaluate the effect of ginger extract as natural antioxidant on sunflower oil oxidation. The higher concentrations of ginger extract, the lower FFA, PV, CD, and TBA were. Therefore, ginger extract is recommended as a natural antioxidant to retard sunflower oil oxidation. [ABSTRACT FROM AUTHOR]