Process optimization of mechanical oil expression from Moringa (Moringa oleifera) seeds

• Effects of moisture content, heating temperature, heating time and applied pressure on oil yield from moringa seeds investigated.
• Development of predictive models for mechanical oil expression process from moringa seeds.
• Optimization of the oil expression process from moringa seeds.

Optimization has found several applications in various processes widely used in the food industry and has been widely applied in solvent oil extraction as well as mechanical oil expression. In this study, the mechanical oil expression process for moringa seeds was optimized. A 4 × 5 Central Composite Rotatable Design was adopted for the experiments. Experimental factors were moisture content, heating temperature, heating time and applied pressure. Data analyses were done using multiple linear regression at p = 0.05. Predicted optimum conditions were validated using experimental values. Oil yield ranged from 11.42 to 28.6% with the highest obtained at moisture content of 11%, temperature of 80 °C, duration of 30 min and pressure of 20 MPa. Mathematical models were developed relating processing factors to oil yield. Coefficient of determination (R2) for the oil yield was 0.77. Predicted optimum oil yield of 28.20% at moisture content of 11.30%, temperature of 85.57 °C, duration of 27.17 min and pressure of 19.63 MPa was obtained. Deviations between experimental and predicted values were low; and it was established that moisture content, applied pressure, heating temperature and duration influenced quantity of oil recovery from moringa seeds using expeller. Overall, the data generated in the study will serve as a useful tool in process and equipment design for moringa oil processors.

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