Influence of methanol and water extracts of orange peel on stability of refined palm kernel oil

Abstract

The antioxidative effect of methanol and water orange peel extracts on Refined Palm Kernel Oil (RPKO) stored for twelve months at room temperature (27 0 C-33 0 C) was determined by monitoring the colour, refractive index, free fatty acid (FFA), acid value (AV) and peroxide value (PV). The oil was dosed with different concentrations (200 ppm to 1000 ppm) of the extracts and butylatedhydroxytoluene (BHT) (Cone. 200 ppm. The colour and refractive index of RPKO containing the extracts ranged between 11.0-13.0 units and 1.458-1.460 respectively whereas the colour and refractive index of RPKO with no additive (0 ppm) and 200 ppm BHT were 10.0 units and 1.460 accordingly. Free fathy acid (FFA) and acid value (AV) of RPKO containing methanol and water orange peel extracts were lower than RPKO containing 200 ppm BHT and they were significantly different at P<0.05 from RPKO that contained no additive (0 ppm). PV of RPKO containing additives were slightly lower than PV of RPKO that contained no additive but they were not significantly different at P<0.05.The methanol and water orange peel extracts are more effective in combating hydrolytic rancidity than oxidative rancidity of RPKO. The methanol and water orange peel extracts have better antioxidant activity than butylatedhydroxytoluene

Effect of Acetone Extract of Sesame (Sesamum indicum L.) and Sunflower (Helianthus annus L.) Meal on Stability of Crude and Refined Soybean Oil

“…Free fatty acid of refined soybean oil containing sesame and sunflower extracts was lower than free fatty acid of oil containing 200 ppm propyl gallate. The result is in agreement with Arawande et al [19]. Free fatty acid of the oil sample containing extracts slightly decreased as the concentration of extracts increased in the oil.…”

“…Free fatty acid of any lipid is measure of hydrolytic rancidity [17]. Higher value of free fatty acid of any lipid, higher the degree of hydrolytic rancidity that set-in [18]. In crude oil, free fatty acid estimates the amount of oil that will be lost during refining steps designed to remove fatty acids.…”

Studies on the Effects of Extracts of Fresh Khat/Catha edulis Leaves on the Oxidation of Niger Seed Oil

“…The analyzed samples; NSO with and without khat leaves extract at different concentrations were prepared as per a reported literature procedure [19] with some modifications. Varying amounts of extracts of Catha edulis leaves (0.02 g, 0.04 g, 0.06 g, 0.08 g, and 0.1 g) were separately added to conical flasks each containing 0.02 g of NSO.…”

“…Lipid oxidation products in analyzed samples of NSO with and without Catha edulis extract were prepared as per literature procedure [19] and studied using the parameters of the peroxide value, iodine value, and conjugated diene value.…”