ABSTRACT

The present study evaluated the frying stability of edible oils from African oil bean seed oil and sesame seed oil blends. Edible oils from the studied oil seeds were extracted through soxhlet extraction and blended in the following proportions: AB100:SS0, AB0:SS100, AB90:SS10, AB80:SS2C). AB70:SS30, AB60:SS40 and AB50:SS50 respectively. Commercial soybean oil was used as the reference oil sample. Unmixed and blended oils were used to fry potato strips (175±5°C) for 2 minutes. Frying process was carried out for four days with the same quality and variety of potatoes without replenishing the oils. At the end of each daily frying experiment, the oils were allowed to cool then 20 g oils were sampled into a clean glass dark container for peroxide value, free fatty acid value, para-anisidine value, conjugated diene and conjugated triene analysis. Fried potato strips were assessed for sensory properties. Results ofperoxide value ranged from 2.17 to 3.19 meq O? /kg before frying (initial) and 4.65 to 7.65 meq O2 /kg, 5.13 to 10.02 meq O2 /kg, 6.43 to 13.48 meq O2/kg and 7.04 to 17.17 meq O2/kg after first, second, third and fourth frying cycle. FFA increased from 0.04 to 0.25% for control, 4.04 to 9.03% for AB100, 2.87 to 3.99% for SS100, 3.93 to 8.25% for AB90:SS10, 3.81 to 7.90% for AB80:SS20, 3.65 to 6.75% AB70:SS30, 3.38 to 5.94% for AB60:SS40 and 2.99 to 4.69% for AB500:SS500 after four days offrying from the initial value. The initial IVs ofthe oil samples decreased throughout the frying cycle from 111.40 to 88.45 g I2/IOO g for control, 124.50 to 86.23 g I2/IOO g for African oil bean seed oil (AB100), 105.04 to 100.04 g Ij/100 g for sesame seed oil (SS100), 110.02 to 94.25 g I2/l00 g for AB90:SS10, 108.09 to99.90 g I2/IOO g for AB80:SS20, 106.15 to 101.71 g I2/l00 g for AB70:SS30,105.79 to 102.94 g I2/100 g for AB60:SS40 and 103.06 to 102.44 g I2/l00 g for AB50:SS50. For para-anisidine value, during the frying cycle, control increased from 0.07 at the initial value to 11.10 after the 4th day of frying. AB100 increased from 0.57 to 25.73, SS100 increased from 0.05 to 8.84, AB90:SS10 increased from 0.58 to 21.28, AB80-.SS20 increased from 0.48 to 20.00, AB70:SS30 increased from 0.44 to 19.35, AB60:SS40 increased from 0.38 to 15.95 and AB50:SS50 increased from 0.32 to 13.71 respectively. For conjugated diene (CD), control increased from 0.00 to 11.02%, AB100 increased from 5.26 to 21.24%, SS100 increased from 3.60 to 8.83%, AB90:SS10 increased from 5.01 to 19.24%, AB80:SS20 increased from 4.95 to 18.97%, AB70:SS30 increased from 4.10 to 18.09%, AB60:SS40 increased from 3.87 to 15.94% and AB50:SS50 increased from 3.22 to 12.99% respectively. For conjugated triene (CT), the values increased from 0.02 to 1.77% for control, 2.07 to 9.24% for AB100,1.34 to 2.51% for SSI00, 1.99 to 8.59% for AB90:SS10,1.91 to 7.46% for AB80:SS20,1.83 to 7.24% for AB70.-SS30, 1.77 to 6.58% for AB60:SS40 and 1.69 to 4.86% for AB50:SS50 respectively. The scores for general acceptability showed that potato strips fried using the oil samples were liked very much except AB50:SS50 with a score of 7.95 that was liked moderately. However, potato strips fried with control oil sample had the highest score. Conclusively, this study showed that the frying stability of African oil bean seed oil improved significantly (p<0.05) after blending with sesame seed oil but there was no clear benefit of experimental oil samples over commercial oil samples in the sensory properties offried potato strips.