Quality evaluation of oils extracted from some selected indigenous spices

Abstract

A food grade solvent (n-hexane) was used in the extraction of oil from some selected indigenous spices which were ehuru (Monodora myristica), njangsa (Ricinodendron heudelotii), uziza seeds (Piper guineense) and cloves (Syzygium aromaticum). The extracted oil samples were evaluated for chemical composition and physical properties. Results obtained from the chemical composition of the extracted oil samples showed that acid value, iodine value, peroxide value, saponification value and thiobarbituric acid value ranged from 0.64mgKOH/g to1.82mgKOH/g, 63.17gmI/100gm to 83.33gmI/100gm, 5.78Meq/ kgto9.66Meq/ kg, 142.07mgKOH/g to 203.66mgKOH and 0.19mg malo./kg to 0.39mg malo./kg respectively. The results of the physical properties of the extracted oil samples also showed that the smoke point, flash point, firepoint, density, melting point and viscosityranged from 166°C to 214°C, 206°C to 254°C, 219.50°C to 275°C, 0.89g/cm³ to 0.94g/cm³, 12°C to 17°C and 58.40cp to104.10cp respectively. From the study carried out, it was concluded that the oils extracted from the selected indigenous spices are acceptable for efficient use in food production and other industrial uses.

Keywords: Indigenous spices, chemical properties, physical properties, oil extract