Abstract
We investigated changes in the quality of palm oil, shea butter and their blend as affected by repeated usage in deep frying of cheese were investigated. Palm oil, shea butter and their blend (1:1 w/w) were used in repeated deep frying of cheese at 150oC for 15 minutes, repeated eight times, repeated for six (6) consecutive days Changes in oil quality indices such as free fatty acid, peroxide value, p-anisidine value, color index, iodine value, acid value, saponification value, specific gravity and refractive index were determined. Kinetic rate and Arrhenius equation were used to determine deterioration rate and activation energy Data were analyzed using ANOVA and regression at α==0.05. The free fatty acid value of palm oil (6.09% − 8.03%), shea butter (2.12% − 2.91%) and blend (3.30% − 4.50%) increased significantly. Palm oil recorded a high value of peroxide (6.20 meqO2/kg), while the lowest value was recorded by shea butter (3.20 meqO2/kg), the p-anisidine value of palm oil was higher (91.77) after the sixth frying cycle than shea butter (11.00) and their blend (46.17). Slight decrease in iodine value was observed in the blend (4.89–3.82), while palm oil decreased sharply (4.73–0.90). A high smoke point was recorded for shea butter (222.7oC and 226.4 oC), palm oil (204.30C and 218.2oC) and the blend oil (212.2oC and 216.6°C) within the six frying cycles.