Confirmatory assessments of putative quality and nutritional properties of branded and unbranded commercial edible oils

Abstract

Dietary associated non-communicable diseases have become a major concern and consumption of branded and unbranded vegetables oils may be one out of many probable contributing factors. Thus, the objective of this preliminary study was to access the nutritional qualities and trans-fat contents of 28 randomly selected three commonly consumed vegetable oils (crude palm oil CPO, soybean oil SBO, and peanut oil PNO) from cross-sectional area of the country. CPOs samples exhibited an upper limit of 5.18% for acidity, which is slightly outside minimum standard requirement for crude oil (<5.00%). Similarly, both SBOs and PNOs were above tolerant limit for acidity (>0.30%). Six of the nine CPOs had peroxide value > 8.0 meqO2/kg, while none of the refined oils was <1.63 meqO2/kg – an indication of oxidative instability. Although, moisture content, conjugated trienes and dienes were significantly higher in CPOs, but the oils exhibited lower trans-fat content with a range 0 – 6.27% compared to SBOs (3.73 – 9.72%) and PNOs (0.72 – 7.14%). CPOs were higher in total phenol (TPC), tocopherol (TFR), and carotenoid (CAR) contents, that could make up for the low oxidative stability indices. Among the variables predicting trans-fat contents of the oils using variable important projection (VIP) model, saturated, polyunsaturated (PUFA) fatty acids, acidity, PV and conjugated trienes had positive influence, while TPC, TFR, CAR, monounsaturated fatty acid (MUFA), and MUFA/PUFA ratio showed negative contributions. Thus, only few samples satisfied the ideal quality and nutritional requirements of edible oils.