With the addition talc in the kneading phase su olives with a high ripeness index increased the yield of olive oil over 2 percentage extraction yield points, keeping the same amount of phenolic component. Yet Extraction is increased if enzymes are added to the talc, the latter however not permitted in the countries of the European Union. These are the results of an experiment conducted in an oil mill in Campania and illustrated yesterday by prof. Alexander Leo, professor of Machinery and Plants for Transformation at the Aldo Moro University of Bari, during a training meeting organized by the Pieralisi.
The experimentation
The experiment was carried out on a two-phase plant with a capacity of 3000 kg/h., dosing talc 0,7% w/w inside the gramole at 27° of temperature. The variety was Coratin with an ihigh maturation index, equal to 3,714 tons of olives were used for the study.
The increase in industrial yield between a traditional malaxation and one with the addition of talc has passed 86,9% to 89,2%That is to say that on 100 kg of processed olives, significantly less oil ended up in the pomace when talc was used. Practically, an oil yield increased by half a kilo per 100 kg of olives processed. The phenolic component of the extracted oil remained practically unchanged, increasing from 978,9 to 993,6 mg/kg.
When the olives are very ripe
“A significant result to take into consideration – underlined Prof. Leone – when the olives are very ripe and the pastes coming out of the crusher are very moist. In this case, talc, which is a processing aid allowed in oil extraction, dries the paste and increases the rubbing during the malaxation phase, thus increasing the breaking of the vacuoles where the oil droplets are located”.
The addition of talc to the mixer was carried out using internal dosers that allowed the calibration of a controlled quantity proportional to the loaded paste. In this case, 0,7% weight by weight was considered an optimal percentage., although it has been assessed that positive results they could have been reached even with a dosage of 0,5%. During the meeting, Prof. Leone underlined how talc is widely used in Spain and in many other olive oil producing countries.
Adding enzymes
During the experimentation, comparisons were also made with the addition of enzymes (pectolymic with depolymerizing action) not allowed in European Union countries, but widely spread to other countries such as Australia, California, South Africa or Argentina. In this case i results were superior for phenolic content, reaching over 1100 mg/kg. Further experimentation with the simultaneous addition of talc and enzymes instead had an important impact on industrial extraction yield of more than 5 percentage points.
