Effects of Methods of Production on Some Quality Parameters of Palm Kernel Oil. Pan-African Journal Series.

Abstract

The effects of methods of production on some quality parameters of palm kernel oil were determined. Two methods of production used are the traditional and mechanical methods. The oil obtained from both methods were compared for yields and quality attributes such as moisture content, ash content, lipid content, crude protein, fat, saponification value, free fatty acids (FFA), iodine value, acid value, peroxide value, intrinsic viscosity, melting point and density. The mechanically extracted oil gave a higher yield of 56.4% as against 34.6% yield for the oil extracted by the traditional method. The traditionally extracted oil had higher values of crude protein, acid value, free fatty acids (FFA) and saponification value which are 12.0%, 32.77mg/KOH/g, 5.75% and 285.16mgKOH/g respectively, while the values for the mechanically extracted oil are 1.75%, 9.98 mg/KOH/g, 3.18% and 219.53 mg/KOH/g respectively. The mechanically extracted oil had higher values of moisture content (1.54%), iodine value (1.34gI2/100g), intrinsic viscosity (2.91dm3/g) and melting point 25.67oC); while the values for the traditionally extracted oil are: moisture content (0.57%), iodine value (1.00gI2/100g), intrinsic viscosity (2.55dm3/g) and melting point 17.73oC) respectively. The higher saponification value recorded for the traditionally extracted oil suggests that it may be industrially useful in manufacture of soaps; while the mechanically extracted oil will be more useful in the production of margarine due to its higher degree of unsaturation. Free fatty acid value of mechanically extracted oil sample was 4.07% while 6.04% was obtained for the traditionally extracted sample. The traditionally extracted oil has the tendency to go rancid faster than its mechanically extracted counterpart due to its higher free fatty acid content. Free fatty acid content value is an important variable in considering the quality of oil because the lower the free fatty acid, the better the quality of the oil. By inference, it therefore implies that the mechanically extracted oil is off better quality than the traditionally extracted sample due to its low free fatty acid (4.07%). The traditionally extracted oil will be useful for medicinal purposes (hair and skin treatment) due to its higher acid value (9.98mg/KOH/g). Acid value is used as an indicator for edibility of oil and suitability for use in the paint industry. There was no significant difference (P>0.05) in the ash and lipid contents of the two samples.