Abstracto

Comparison of antioxidative potentials of methanol sweet basil (Ocimum basilicum) extract and butylatedhydroxyltoluene on stability of refined soybean oil.

Arawande JO

Sweet basil leaves were obtained from a backyard garden at Oka in Ondo-City, Nigeria. The
leaves were rinsed with water to remove the dirt, air-dried and ground to powdery sample. The
leaf sample was then extracted with methanol by adding 20 g of the powdery sample into 200 mL
of methanol and left it for 72 hours. The extract was obtained by concentrating the filtrate from
the mixture in a rotary evaporator. The extract was dosed at varying concentration (200-1000
ppm) to refined soybean oil (RSBO). Another set up was made by dosing RSBO with 400 ppm
butylatedhydroxyltoluene (BHT). A control which contained no additive (0 ppm) was also set up.
The oil was stored in a transparent plastic bottle for five months. The antioxidative potential of
methanol extract of sweet basil (MESB) at varying concentrations (200-1000 ppm) was compared
with 400 ppm BHT on RSBO by monthly monitoring their refractive index (RI), free fatty acid
(FFA), acid value (AV) and peroxide value (PV) for five months. There was no remarkable
difference in RI of RSBO containing additives and that of the control sample. The mean value
of FFA, AV and PV of RSBO containing MESB were lower than the RSBO containing 400 ppm
BHT over the five months of storage. There were significance difference (P<0.05) in average FFA,
AV and PV of RSBO containing MESB, BHT and RSBO without additive. It is therefore noticed
that MESB is superior to BHT in combating both hydrolytic and oxidative rancidity of RSBO.