OPTIMIZATION OF OIL EXTRACTION FROM BLACK PLUM (VITEX DONIANA) SEED USING MECHANICAL PRESSING
Black plum (Vitex doniana Sweet) seed is an underutilized agro-industrial by-product with considerable oil-bearing potential, yet information on the optimization of its mechanical oil extraction is limited. This study optimized screw-press extraction of black plum seed oil by investigating the combined effects of seed moisture content, conditioning temperature, and screw speed on oil recovery using Response Surface Methodology (RSM). A three-factor, three-level Box–Behnken experimental design was employed to develop a second-order polynomial model describing the relationship between process variables and oil yield. Crude oil acid value and peroxide value were simultaneously evaluated to assess product quality under varying processing conditions. The fitted quadratic model demonstrated excellent predictive performance (R² = 0.9992), confirming the significant (p < 0.05) influence of linear, interaction, and quadratic effects of the selected variables on oil recovery. Numerical optimization identified the optimum processing conditions as 8.5% seed moisture content, 86°C conditioning temperature, and 28 rpm screw speed, corresponding to a predicted oil yield of 26.90%. Experimental validation produced an oil yield of 26.72%, representing approximately 74.6% extraction efficiency relative to the reference extractable oil content, with acceptable acid (2.40 mg KOH g⁻¹) and peroxide (4.06 meq O₂ kg⁻¹) values. These findings demonstrate that integrating appropriate seed conditioning with optimized screw-press operating parameters substantially enhances oil recovery while maintaining desirable crude oil quality. The study establishes Vitex doniana seed as a promising non-conventional oilseed for decentralized mechanical oil production and provides a robust process optimization framework for future commercial exploitation and industrial scale-up.
Authors : Mohammed, I., Musa, H. and Mari, H.H.
Category : Open Access Volume (Issue) : 12(1) Date Uploaded : 5th August 2026