Studies on the Effect of Pressure on Yield of Mechanically Expressed Neem Seed Kernel Oil.

Abstract

Investigation was carried out to determine the effect of pressure on the yield of neem seed kernel oil expressed using an oil expeller. Matured neem seed kernels were obtained and the initial moisture content determined (8.1%). The initial oil yield in the samples was also determined (37.71%) using solvent extraction method. The seed kernels were then subjected to oil extraction using a multiseed oil expeller with capacity of 15-20kg/h and powered by a 7.5Kw, 3 phase electric motor with in-built reduction gear. The expression was carried out at different pressures which were calculated and arrived at based on preliminary tests carried out prior to the main experiments. The pressures at which the machine was operated are as follows: 602.91, 723.07, 925.84 and 1334.88 KN/m2 . Three replicates of the experiments were done. The recorded oil yield obtained at the different machine pressures was compared with the initial oil content of the seed kernels. The following oil yield values were obtained at the different machine pressures: 16.81% (602.91KN/m2), 20.52% (723.07KN/m2), 24.99% (925.84KN/m2) and 22.38% (1334.88KN/m2). New Duncan’s Multiple Range Test (DMRT) was used to determine the differences in the mean treatment effect of machine pressures on oil yield. From the results, it was observed that higher pressure seems to yield more oil up to a maximum of 925.84KN/m2 . Further increase in applied pressure beyond this point led to a reduction in yield. The highest oil yield of 24.99% was recorded at 925.84KN/m2 while the minimum oil yield of 16.18% was observed at 602.91KN/m2. Thus, more yield was obtained at higher pressure levels up to an extent, beyond this pressure level didn’t yield more oil.