Effect of Processing Conditions on Oil Point Pressure of Calabash Nutmeg (Published)
The oil point pressure of calabash nutmeg (Monodora myristica) was investigated considering particle size, moisture content, heating temperature and heating time. Freshly harvested seeds obtained from a local market in Ibadan were decorticated and cleaned of all extraneous matter. The kernels obtained were milled and graded into fine and coarse aggregates. The experiment was a central composite design in which two levels of moisture content (17 and 21%wb), heating temperature (50 and 70 ̊C) and time (5 and 15 mins) were considered. The data obtained were analyzed using Design Expert Version 6.0.8. The results showed that oil point pressure increased with time but decreased as heating temperature and moisture content increased. For fine aggregates, the minimum oil point pressure of 0.116 MPa was obtained at a temperature, time and moisture content combination of 60 ̊C, 10 mins and 23%wb, respectively. However, for coarse aggregates, the minimum oil point pressure of 0.144 MPa was obtained at 70 ̊C, 5 mins of heating time and moisture content of 21% (w.b). The results showed that the oil point pressure of fine aggregates was lower than that of the coarse aggregates. From the analysis of variance, heating time had significant effect on the oil point pressure (p<0.05). The minimum oil point pressure of calabash nutmeg was obtained as 0.116 MPa at an optimal temperature, time and moisture content of 64 ̊C, 5 mins and 21% (w.b), respectively.
Keywords: Monodora myristica, Oil expression, Oil point pressure, Processing conditions., optimization