Quality attributes and storage stability of locally and mechanically extracted crude palm oils in selected communities in Rivers and Bayelsa states, Nigeria

Abstract

The effect of different extraction methods on the quality of crude palm oil processed using traditional (local) and mechanical methods in selected areas of Rivers and Bayelsa States and their storage stability were investigated. Certain quality determining parameters such as free fatty acids (FFA), peroxide value (PV), saponification value (SV), moisture, impurities and volatile matter (MIV) content were determined prior to and after storage for three months. The free fatty acids (FFA) ranged from 7 to 19 percent, peroxide value (PV) ranged from 3 mEq/kg to 6 mEq/kg and moisture, impurity and volatile matter (MIV) ranged from 0.21 to 0.64 percent for locally extracted crude palm oil samples and mechanically extracted crude palm oil samples. There was no significant difference (p > 0.05) in the FFA of samples A and E before and after storage for 3 months. Also two of the locally extracted crude samples (A and E) stored better while one of the samples (D) showed a high level of deterioration as shown in its high levels of FFA, PV and IV values. Samples A and E resulted in a better quality of oil in terms of FFA (av. 7.25%) and PV (av. 4.5 meg/kg) when compared to the mechanically extracted one (sample C) with FFA (10.0%) and PV (5.78 mEq/kg). However, all the locally and mechanically extracted crude palm oil samples could not meet the industrial and international standard quality for crude palm with FFA (2-5%) and PV (2-3.5 mEq/kg). Among the three different storage containers used under different storage conditions, plastic containers (PC) resulted in a better storage stability of the crude palm oils in terms of FFA, SV, and IV than transparent bottles stored on shelves (TBS) and amber-colored bottles stored on the bare floor (BPF).