Research Article
Arawande JO, Ijitona OO, Olati
Abstract
Water ginger extract (WGE) and ethanol ginger extract (EGE) were obtained by grinding dried ginger and soaking it in water and ethanol for 72 hours, and thereafter the solvents were removed using rotary evaporator. Crude peanut oil (CPO) was stored with varying concentration (200 ppm– 1000 ppm) of WGE, EGE and 200 ppm butylatedhydroxyltoluene (BHT) in a plastic bottle for five months. The refractive index (RI), free fatty acid (FFA), acid value (AV) and peroxide value (PV) were determined monthly for a period of five months. The mean values of these parameters were used to compare the effectiveness of the extracts and BHT against hydrolytic and oxidative rancidity of CPO. The RI of CPO containing EGE ranged between 1.4633 ± 0.0012 and 1.4640 ± 0.0008 while CPO containing WGE ranged between 1.4636 ± 0.0012 and 1.4641 ± 0.0006 and the RI of CPO containing no additive 0 ppm and 200 ppm, BHT were 1.4631 ± 0.0011 and 1.4629 ± 0.0013 respectively. The FFA of CPO with ginger extract was within 0.8356 ± 0.1279 and 0.9139 ± 0.2082% oleic acid while the FFA of CPO without additive and 200 ppm BHT were 0.9400 ± 0.1981 and 1.1228 ± 0.2509% oleic acid respectively. CPO containing EGE and WGE had AV ranged between 1.6106 ± 0.3064 and 1.9223 ± 0.4994 mg KOH/g oil; and that of CPO without additive and 200 ppm BHT were 1.9742 ± 0.4693 and 2.2340 ± 0.4994 mg KOH/g oil. The PV of CPO with EGE and WGE was within 16.3519 ± 12.8410 and 20.7037 ± 15.7827 mEq O2/Kg oil while CPO that contained no additive and 200 ppm BHT were 22.9259 ± 20.2676 and 17.8888 ± 11.1092 mEq O2/Kg oil respectively. Both EGE and WGE are more effective than 200 ppm BHT in combating hydrolytic rancidity of CPO. EGE and WGE at 400 ppm had better antioxidant potential than 200 ppm BHT against oxidative rancidity of crude peanut oil