Comparative Assessment of Lipids and Physicochemical Properties of African Locust Beans and Shea Nut Oils

Abstract

The lipid composition and the physico-chemical properties of two Nigerian grown seed oils of Parkia biglobosa and Vitellaria paradoxa were investigated. The seeds of Parkia biglobosa were boiled for 12hours, dehusked, sun-dried and grinded into fine powdery form for oil extraction while the fruits of Vitellaria paradoxa were depulped such that its seeds on drying were deshelled and grinded into fine powdery paste for oil extraction.The seeds consist of 34% and 25% (dry w/w) crude oil respectively. At room temperature, the seed oil of Parkia biglobosa is liquid while the seed oil of Vitellaria paradoxa is semi-solid. The physicochemical properties of these oils indicated that mean free fatty acid, saponification, peroxide, acid and iodine values were 4.77%, 175.32mgKOH/g, 3.7mgO₂/g, 9.48mgKOH/g, 82.40 for Parkia biglobosa and 5.93%, 63.77mgKOH/g, 3.0mgO₂/g, 11.7mgKOH/g, 56.35 for Vitellaria paradoxa respectively. The Specific Gravity (SG) of both oils were less than a unit, so they are less dense than water and will float on it. The moisture content is in the range 0.83 – 1.21%, which is generally low hence indicating that the seed oils could be stored for a long period. Both oils were found to have iodine values, which conveniently places them as non-drying oils. The acid values also showed that the oils may be sourced for edible purposes. The saponification value of Parkia biglobosa seed oil indicated that it is good for soap production. The High performance Liuid Chromatography (HPLC) results showed that the oils contain 63% and 54% of triacylglycerol for Parkia biglobosa and Vitellaria paradoxa respectively. Major fatty acid - oleic acid, lauric acid, myristic acid, palmitic acid, stearic acid were 12.5%, 9.0%, 6.7%, 5.0%, 5.3% and 13.1%, 9.5%, 7.0%, 5.3% and 5.2% for Parkia biglobosa and Vitellaria paradoxa respectively.The study indicated a marked significant difference in the lipid composition and  physicochemical properties of Parkia biglobosa as compared with Vitellaria paradoxa.

Keywords: HPLC, Parkia biglobosa, Specific gravity, Triacylglycerol, Vitellaria bigloboxa,.