Effect of Process Parameters on Efficiency of a Mechanical Expression Rig for Almond Oil and Its Physico-chemical Properties

The process parameters that can affect the extraction efficiency of a mechanical expression rig (MER) for almond kernel ( Terminalia catappa) were investigated in an optimization study using central composite design (CCD). A four factor, five levels of CCD was applied to study the effect of moisture content (6 - 10% w.b), temperature (80 – 100 o C), heating time (10 – 26 min.) and applied pressure (5.84 – 7.01MPa) using the chosen rage. The physico-chemical properties of the expressed Almond oil were also determined using standard procedure. The results of the study showed that all the variables significantly affected the expression efficiency at 95% confidence level. The optimum expression efficiency of 76.35% was obtained at temperature, pressure, heating time and moisture content of 93.34 o C, 6.44MPa, 17.16 minutes and 8.71% wb respectively. This indicates that the MER performed satisfactorily. The experimental values were very close to the predicted values with p<0.05.The regression model obtained has provided a basis for selecting optimal process parameters for the recovery of oil from almond kernel using the MER. The physico-chemical properties investigated showed that refractive index, viscosity, saponification value, iodine value, free fatty acid value, acid value, peroxide value, flash, and fire points are within 2 the range suitable for many purposes as it showed that it is edible and conforms to CODEX standard for edible oil.