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How Terroir Affects EVOO Quality in Chile

Feb. 18, 2016
By Sukhsatej Batra

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At the 2015 New York International Olive Oil Competition, Chilean extra virgin olive oils were rec­og­nized with two “Best in Class” awards earn­ing the cov­eted dis­tinc­tion as some of the best olive oils in the world.

The two win­ning oils were a Picual from Las Doscientas and a blend by Olave.
See more: The Best Olive Oils from Chile
Chile is a coun­try that spans a largely diverse geo­graph­i­cal area that has a the highly varied cli­mate and dif­fer­ent soil com­po­si­tions.

To deter­mine how geo­graph­i­cal loca­tion affected EVOO qual­ity, researchers from Chile eval­u­ated the effects of cli­mate, soil com­po­si­tion, and agri­cul­tural prac­tices such as fer­til­iza­tion and irri­ga­tion on sen­sory prop­er­ties of extra virgin olive oil.

They also looked to see if stage of fruit ripeness at har­vest affected the phenol con­tent of extra virgin olive oil pro­duced in Chile.

For the study, the researchers selected cul­ti­vars of olives grown in com­mer­cial orchards in two dif­fer­ent geo­graph­i­cal loca­tions of Chile: the Limari Valley, a Marino sub­trop­i­cal desert with an annual rain­fall of only 22 mil­lime­ters; and the Molina area that has a Mediterranean-like cli­mate with an annual rain­fall of 735 mil­lime­ters.

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The study, pub­lished in the January 2016 edi­tion of the Journal of the Science of Food and Agriculture, found dif­fer­ences in the soil com­po­si­tion of the two areas. The alka­line soil in the Limari valley had a higher con­tent of Ca, Mg, K and Na than Molina soil; whereas the acidic soil of Molina con­tained more iron and mag­ne­sium. Additionally, the clay loamy soil, char­ac­ter­is­tic of arid zones of Limari, had better chem­i­cal fer­til­iza­tion than the soil in Molina.

For the study, olive oil was extracted from olives har­vested in the 2011 – 2012 and 2012 – 2013 sea­sons using the two-phase cen­trifu­ga­tion system and clas­si­fied as extra virgin accord­ing to the offi­cial ana­lyt­i­cal meth­ods.

Phenolic con­tent of the extra virgin olive oil pro­duced from the two geo­graph­i­cal loca­tions was found to be very dif­fer­ent. Extra virgin olive oil pro­duced in the Limari valley had a higher total phenol con­tent than olive oil pro­duced in the Molina area for both sea­sons (473 vs. 326 miiligrams per kilo­gram olive oil in 2011 – 2012; and 493 vs. 208 mil­ligrams per kilo­gram olive oil in 2012 – 2013).

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The higher evapo-tran­spi­ra­tion and lower irri­ga­tion in the Limari Valley orchards com­pared to the Molina orchards could pos­si­bly explain the dif­fer­ences in total phenol con­tent in olive oil from the two areas.

According to the authors, pre­vi­ous stud­ies have shown that EVOOs obtained from tra­di­tional rain-fed orchards had higher phenol con­tent than irri­gated orchards. High water con­tent in irri­gated orchards affects sol­u­bi­liza­tion of phe­no­lic com­pounds and alters release of poly­sac­cha­ride-linked phe­no­lic com­pounds during the olive oil pro­duc­tion process.

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The authors also found that the volatile com­pounds in extra virgin olive oils were affected more by tem­per­a­ture than by irri­ga­tion and evap­o­tran­spi­ra­tion rate. Additionally, the phenol con­tent of EVOO decreased as olive matu­rity at time of har­vest increased.

Based on their find­ings, the inves­ti­ga­tors con­clude that the geo­graph­i­cal loca­tion, soil and cli­mate in Chile had a greater influ­ence on the sen­sory qual­ity of extra virgin olive oil than the olive cul­ti­vars.