Physico-chemical Characteristics of Refined Lake Victoria Nile Perch (Lates niloticus) Viscera Oil

Abstract

Nile perch viscera oil was characterized in terms of its physico-chemical properties. The crude oil was refined by neutralization, deodorization and winterization to obtain low melting point (LMP) and the high melting point (HMP) fractions. The oil fractions were analyzed for omega – 3 fatty acids (eicosapentaenoic acid – EPA and docosahexaenoic – DHA), vitamin A, vitamin E, iodine value (IV), saponification value (SV), density, melting point (MP), and smoke point (SP). Crude was used as control. Data were analysed (p £ 0.05) using GenStat software. The yield of winterized oil (LMP) was 39.8 ± 0.5% of crude and 19.6 ± 0.5% of raw material weight. There were no significant differences in density and vitamin E (tocopherol) content of the three fractions, while there were significant differences in the slip MP, SP, SV, IV and vitamin A (retinol) content. There were also significant differences in EPA and DHA contents. EPA and DHA for the LMP were highest, followed by crude and HMP having lowest. High vitamins A and E as well as omega – 3 polyunsaturated fatty acids (ω – 3 PUFA) contents and high SP make the crude and HMP fractions suitable for use in cooking. The high amount of LMP fraction has high content of ω – 3 PUFA, making it suitable for use in food, feed and nutraceutics.

Keywords: Nile perch; viscera; wet rendering; refining; physico-chemical characteristics