Phytosterol and amino acid profi les of palm kernel oil: Possible metabolic implications

Abstract

C. O. Ibegbulem, D. C. Belonwu

Hypothesis and Aim: Compositions of an edible material can influence its metabolic fate. Palm kernel oil (PKO) contains more saturated fat than unsaturated fat, indicating a propensity to elevate serum total cholesterol and low density lipoprotein-cholesterol (LDL-c). Its phytosterol and amino acid (AA) profiles may also have metabolic implications. The aim of the study was to examine PKO for the presence of phytosterols and its AA profile. Materials and Methods: Palm kernel oil was examined for the presence of phytosterols, AA compositions, AA groupings and essential AA (EAA) scores, using palm oil (PO) as a reference. Results: The PKO did not contain phytosterols and as such may not competitively inhibit uptake of dietary cholesterol. Its total AA content (g/100 g protein) was 6.87 ± 0.49 compared to PO’s 49.45 ± 1.36. The total non-EAA (TNEAA) /total EAA (TEAA, with His) ratios of PKO and PO were 1.04 ± 0.01 and 0.98 ± 0.00, respectively; suggesting that PKO contained more TNEAA than TEAA (with His) while the reverse was the case in PO. The PKO did not contain some EAAs such as Ile, Val, His and Thr and as such its EAAs cannot support protein synthesis based on the all-or-none principle of EAAs in respect of protein synthesis, but would rather be used for energy, converted to carbohydrate or fat, and stored as such. Conclusion: The PKO lacked phytosterols and some essential AAs and these may contribute to its acclaimed atherogenicity.