Effect of Black Cumin (Nigella sativa L.) Seeds Oil on the Stability of Peanut Oil During Frying Process

Abstract

This study was conducted to evaluate the effect of black cumin (Nigella sativa L.) seeds oil (BCSO) on crude and refined peanut oil stability during frying periods. Crude and refined peanut oil was blended with 5%, 10% and 15% BCSO and commercial antioxidant (CA). The blends were used to fry potato chips for up to 60 min. Black cumin seeds collected from the local market, were analyzed for protein, moisture, fats, fibers and carbohydrates contents then physical properties (colour, refractive index (RI), viscosity, density) and chemical properties (free fatty acid (FFA), peroxide value (PV), saponification value (SV), iodine value (IV), fatty acids composition and tocopherols). The physicochemical properties of the blends were monitored during frying potato chips at 0, 15, 30, 45 and 60 min. Black cumin seeds had 52% oil content and total tocopherols 36.171 mg/100g. The blend of 5% BCSO with crude and refined peanut oil were significantly decreased (P<0.05) in colour, viscosity, FFA, PV when were compared with all other blends and control after 60 min frying potato chipsThe blend of 5% BCSO with refined peanut oil was significantly decreased (P<0.05) in RI when was compared with all other blends and control after 60 min frying potato chips, while the blend of same ratio of BCSO with crude peanut oil there was insignificant difference (P<0.05) in RI when was compared with all other blends and control after 60 min frying potato chips. The blend of 5% BCSO with crude and refined peanut oil was significantly different (P>0.05) in IV when was compared with all other blends and control after 60 min of frying potato chips. Also the general acceptability showed significant difference for fried potato with the blend of crude and refined peanut oil with 5% BCSO compared with fried potato with all other blends and control. Among all blending ratios (5%, 10% and 15%) of BCSO with peanut oil 5% was found to be the best blending ratio during frying potato chip till 60 min.