ABSTRACT

The effects of different processing methods and storage period on the quality of palm oil were studied in this research. The palm fruits were subjected to four different processing and extraction methods; boiling method (B), soaking with boiling method (SWB), steaming method (ST) and extraction with petroleum ether (SP). Quality indices, functional and physical properties and selected vitamins were determined. The results showed that free fatty acid value ranged from 5.14-6.54 mg/KOH/g, peroxide value from 2.67-10.07 meqlkg, saponification value from 194.48-196.82 mg/KOH/g, iodine value from 49.07-52.24 Wij's. SWB had the highest value in free fatty acid, peroxide, saponification and iodine value. While SP had the lowest value in free fatty acid, peroxide and iodine value. ST had the lowest in saponification value. The values for free fatty acid, peroxide and iodine value increased as storage time increased except for saponification value which decreased. The moisture content ranged from 0.17-0.35 %, specific gravity from 0.89-0.92 g/cm3, smoke point from 231.67-240.00 °C, flash point from 294.00-303.00 °C, fire point from 297.33-309.33 °C. SWB had the highest values in moisture, smoke and flash point. While B and ST method had the highest value in specific gravity and fire point. SP had the lowest values for all the physical properties determined. Moisture content and specific gravity increased while smoke, flash and fire point decreased as storage time increased. Vitamin A ranged from 699.47-718.97 JU/lOOg and vitamin E from 38.87-43.95 IU/lOOg. SP had the highest values for the vitamins while B had the lowest values for the vitamins. Both vitamins decreased as storage time increased. Emulsion capacity ranged from 62.19-100 % and emulsion stability ranged from 42.70-100 %. ST had the highest values for both emulsion capacity and stability while SP had the lowest values. Both emulsions increased as storage time increased. This study has shown that the different methods of palm oil production adopted and the storage time had a significant effect on the oil quality. SP was the best in terms of good quality, followed by ST and B.