Oil palm is one of the richest sources of antioxidants such as carotenoids, tocopherols, tocotrienols and phenolic compounds. This study quantified the amount of total phenolic content (TPC) and the antioxidant activity of crude to refined palm oil and palm kernel oil products obtained from palm oil mills. The TPC of the oil extracts was determined using Folin-Ciocalteau method expressed as gallic acid equivalent (GAE). Aqueous oil extraction with methanolic solvent was efficient and extract from crude palm oil (CPO) had the highest concentration of TPC. A reduction in trend was observed along the various stages of the refining steps probably due to losses through absorption of bleaching earth, volatilisation and degradation during the refining processes. The antioxidant activity was determined using 2,2-diphenyl-1-picrylhdrazyl (DPPH) assays. Results showed that the effect of antioxidants on DPPH radical scavenging activity decreases in the order of oil extracts CPO > CPKO > RPO > RPKO > RPOo > PKOo. Overall, it was found that CPO extract exhibited the highest antioxidant activity due to high TPC compared to other extracted oil samples.

Alkyl levulinate, prepared from the esterification of levulinic acid and n-alcohol, has the potential to be used as a fuel additive. Alcohol has also been used as an additive in fuel to improve ignition and combustion characteristics to a certain extent. For this reason, the properties of mixtures containing these compounds are of particular interest. Herein, measurements of density (ρ), surface tension (γ), and refractive index (n) were conducted for three binary mixtures of methyl levulinate–methanol (ML–M), ethyl levulinate–ethanol (EL–E), and n-butyl levulinate–butanol (BL–B). These properties were measured over the entire range of compositions in 0.1 increments of the molar fraction of the components in the temperature range of T = 298.15–323.15 K and at an atmospheric pressure of p = 0.1 MPa. The experimental data were used to calculate the excess and deviation properties, that is, excess molar volumes (V m Ε), surface tension deviations (Δγ), and molar refraction deviations (ΔR). The V m Ε, Δγ, and ΔR values were fitted to the Redlich–Kister polynomial equation. The V m Ε and ΔR values were negative for all compositions, whereas Δγ exhibited both negative and positive values at different compositions. The molecular interactions of the binary mixtures are discussed from these excess and deviation functions. Furthermore, the Jouyban–Acree model was used for the correlation of properties: density, surface tension, and refractive index of the studied mixtures at different temperatures (T = 298.15–323.15 K). The results are expected to provide fundamental data for understanding the properties of alkyl levulinate as a potential bio-based fuel additive.

No abstract

No abstract

Cooking oils are used for daily cooking as well as salad dressing, in processed food, and other various uses. The physico-chemical properties of cooking oils can affect the quality of foods and hence must be evaluated. The aim of the present study was to evaluate the physicochemical properties of palm-based cooking oils (refined, bleached and deodorized (RBD) palm olein). The analyses were conducted on a total of 20 different brands of cooking oil packed in plastic pouches, which were randomly chosen from a local market. The physico-chemical properties of the cooking oils investigated include moisture and impurities (MI), iodine value (IV), peroxide value (PV), slip melting point (SMP), Lovibond colour, and free fatty acid (FFA). The properties were compared with known standards for refined oils such as Malaysian Standard and Codex Alimentarius Standard. Analysis showed that MI, IV, and SMP of all brands were within the requirements set by Malaysian Standard for RBD palm olein. The PV, Lovibond colour, and FFA values of several brands deviated from the Malaysian Standard. Meanwhile, the PV and FFA of all brands of the cooking oil tested were within the value designated by the Codex Standards. The physico-chemical properties of RBD palm olein cooking oils tested in this study were of acceptable and good quality and are considered suitable for consumption. The quality of cooking oil should be regularly monitored to avoid the use of adulterated oil.