Measurement of oil and moisture in olives
provides information that enables maximization
of yield through: growth of olive varieties that yield
high oil levels, harvesting the crop at the optimal time,
and optimization of the oil extraction process. Since farmers
often receive payment on the basis of moisture and oil content
and not simply weight, both the Olive Producers and the Olive
Processors profit from being able to make instantaneous on-line
or at-line measurements of these constituents.
Olive Oil Extraction Process
More than one process exists. The more traditional methods
involve hydraulic presses and the more recent, decanter centrifugation
processes. The latter involves grinding the olives and stones
into a fine paste which is malaxed (beaten) in order to break
up the oil/water emulsion and cause the formation of larger
droplets of oil. Water is added to the paste prior to pumping
it into a large horizontal centrifuge/decanter where it is
spun at high speed. This causes the phases to separate according
to their different densities into a solid faction referred
to as pomace (an oil, and vegetable water faction). The two
liquid factions are then centrifuged again at even higher
speeds to separate residual water and oil respectively.
Several measurement locations are feasible:
1. On the paste as it feeds into the centrifuge/decanter.
2. On the pomace exiting the centrifuge/decanter through
a pipe containing a viewing window.
3. On the pomace in the screw conveyor.
Measurement is also feasible at-line using a Benchtop unit
which instantaneously measures the moisture and oil content
of a sample placed in a Petri dish. Please refer to the application
note “Bench Top Olive NIR Tester”