Investigation of physiochemical and storage conditions on the properties of extracted tiger nut oil from different cultivars

Abstract

Tiger nut oil was extracted from (black, brown and yellow) cultivars using n-hexane. Physiochemical properties (refractive index, specific gravity, acid value, free fatty acid, peroxide, saponification and iodine values of the oil samples were determined. Storage studies on the tiger nut oils were done by monitoring changes in the thiobarbituric acid, peroxide value, free fatty acid and moisture content for twelve (12) weeks. The refractive index, specific gravity, acid value and free fatty acid value ranged between 1.46 [combining short stroke overlay] 1.47, 0.89 [combining short stroke overlay] 0.90, 0.4 [combining short stroke overlay] 1.40mg/g, and 0.20 [combining short stroke overlay] 0.75% respectively. The peroxide, saponification and iodine values ranged between 3.99 [combining short stroke overlay] 4.43meq/kg, 183.25 [combining short stroke overlay] 202.87mg/kOH/g and 29.69 [combining short stroke overlay] 31.74g/l2/g respectively. The major fatty acids (FAs) of the tiger nut oil were oleic (77.71%), palmitic (16.17%), and stearic (5.08%) acids for the black cultivar, oleic (64.12%), palmitic (11.86%), linoleic (11.87%) and dihum [combining short stroke overlay] g [combining short stroke overlay] linolenic (1.71%) for the brown cultivar while the yellow cultivar had oleic (68.89%), linoleic (12.77%), palmitic (13.33%) and stearic (4.46%). During storage peroxide value, free fatty acid, moisture content and thiobarbituric acid of the oil were within the maximum limits as recommended by CODEX Alimentarius.