The University of Pisa patented new method of extracting extra virgin olive oil
The advantages of the innovative technique are many: a higher yield, improved nutritional quality of the oil and a greater resistance to oxidative processes
The extra virgin olive oil could be extractedthrough the use of "dry ice", ie carbon dioxide in the solid state.
The research group led by Professor Gianpaolo Andrich and composed by Angela Zinnai, Francesca Venturi, Chiara Sanmartin, Maria D'Agata and Isabella Cutting Boards undertook this research that is still going on six years ago, in 2008.
The advantages of the innovative technique - the researchers explain - are many: a higher yield (average 9% more, ie 17.4 kg instead of 16 kg of product per ton of olives), improved nutritional quality of the oil (which for example contains on average 6% more of vitamin E) and a greater resistance to oxidative processes, so that the oil thus obtained can be kept longer than that obtained using conventional technologies.
"Adding the carbon dioxide in the solid state to the olives before pressing explains Gianpaolo Andrich - is the fundamental operation that characterizes this new extraction system. Solid carbon dioxide causes the freezing of the water present inside the fruit and the formation of ice crystals which in turn determine the collapse of the cellular structure of the pulp, facilitating the escape of substances and their transfer in the oil, which is thus enriched in cellular metabolites of high biological value. Moreover, the gaseous carbon dioxide is heavier than air so it tends to remain above the pulp of the olives in machining, creating a gaseous layer able to avoid direct contact with the oxygen of the air and thus to preserve the cellular constituents from oxidative degradation ".
"The olive oil produced using our patent - said Gianpaolo Andrich - is more closely related to the raw material used, the type of pickled olives and their area of production, and therefore looks like a typical product characterized by clear and unmistakable organoleptic characteristics of the most easily recognizable and identifiable by the consumer. "
But the advantages of this new technique are also for manufacturers. The increase in yield makes it an economically viable early harvesting of the olives, which, being less mature will be more rich in water and bioactive components (polyphenols, tocopherols), while limiting the damage caused by the attacks of Bactrocera oleae (of the fly 'olive tree), one of the most feared adversity by the industry, which can significantly affect both the yield and the quality of the oil produced.