`Researchers in Spain Investigate Positive Organoleptic Attributes of EVOO - Olive Oil Times

Researchers in Spain Investigate Positive Organoleptic Attributes of EVOO

By Paolo DeAndreis
Oct. 24, 2022 12:32 UTC

New research from the University of Seville and the Higher Council for Scientific Research’s (CSIC) Instituto de Grasa sheds more light on the pos­i­tive organolep­tic attrib­utes of extra vir­gin olive oil.

The lat­est study, pub­lished in Food Chemistry, aimed to under­stand bet­ter the ori­gin and char­ac­ter­is­tics of extra vir­gin olive oil sen­sory and fla­vor pro­files.

The advanced knowl­edge on pos­i­tive attrib­utes beyond those described in the organolep­tic assess­ment method would also con­tribute to intro­duc­ing new vari­ables for opti­miz­ing the (pro­duc­tion) process.- Diego García-González, researcher, Instituto de Grasa

Most research about extra vir­gin olive oil is cen­tered on under­stand­ing the nature and the source of its com­mon sen­sory defects. However, this new study iden­ti­fied and deployed dif­fer­ent meth­ods to process and inves­ti­gate the pos­i­tive char­ac­ter­is­tics of sev­eral extra vir­gin olive oils.

The estab­lished knowl­edge base in terms of sen­sory defects is quite exten­sive. To con­firm the authen­tic­ity of an extra vir­gin olive oil or ascer­tain its ori­gin, the chem­i­cal mark­ers that pro­duce taste and aroma also have been thor­oughly stud­ied by the International Olive Council (IOC), the olive oil indus­try and oth­ers.

See Also:A New Spectroscopy Method to Determine Bitterness and Pungency in Olive Oil

Sensory defects result from the oxi­da­tion or fer­men­ta­tion of the olives or result­ing olive oil, boost­ing the con­cen­tra­tion of cer­tain volatile com­pounds.

On the con­trary, the pos­i­tive attrib­utes, char­ac­ter­ized with a com­plex bal­ance of fruity notes, are more dif­fi­cult to char­ac­ter­ize,” Diego García-González, a researcher at the Instituto de la Grasa and cor­re­spond­ing author of the study, told Olive Oil Times.

The sen­sory dif­fer­ences are due to dif­fer­ent pro­files of volatile com­pounds rather than to the absence or pres­ence or anom­alous con­cen­tra­tion of a few com­pounds,” he added.

The research iden­ti­fied the dif­fer­ent mark­ers that make volatile com­pound pro­files attrib­uted as either green fruity” or ripe fruity.”

Tasting experts can detect these sen­sory pro­files and lay­out objec­tive and repro­ducible results.


Olive oil tasting glasses

Therefore, if sam­ples of both types of aroma are care­fully selected and eval­u­ated by a panel, it is pos­si­ble to study their volatile com­po­si­tion and to extract con­clu­sions,” García-González said.

Still, the researchers wrote that those com­pounds are not nec­es­sar­ily respon­si­ble for the two main sen­sory per­cep­tions. Therefore, they worked on the pos­i­tive attrib­utes and the asso­ci­ated volatile com­pounds, inves­ti­gat­ing the dif­fer­ences between green fruity” and ripe fruity” aro­mas.

To this end, the researchers selected 24 extra vir­gin olive oil vari­etals from Spain, Portugal, Italy, Croatia, Slovenia and Turkey.

The pri­mary selec­tion of the 24 sam­ples out of 105 oils was made by an open tast­ing pro­ce­dure done twice by four trained pan­elists who ten­ta­tively selected those sam­ples with dis­tinc­tive and undoubted sen­sory pro­files of green fruity’ or ripe fruity,’ dis­card­ing those sam­ples with unclear pos­i­tive attrib­utes or a mix­ture of both sen­sory pro­files,” the researchers wrote.

See Also:Scientists Identify Gene Responsible for Olive Oil’s Aroma

The pan­elists then selected 12 sam­ples asso­ci­ated with each green fruity” and 12 other sam­ples with ripe fruity” and ver­i­fied their char­ac­ter­is­tics using the IOC’s offi­cial pro­ce­dure.

In the sen­sory eval­u­a­tion, olfac­tory and gus­ta­tory, the pan­elists con­firmed that the sam­ples did not have any sen­sory defect, and they scored the pos­i­tive attrib­utes included in the IOC reg­u­la­tion,” the study’s authors wrote.

Virgin olive oils typ­i­cally con­tain a mix­ture of the two sen­sory pro­files at dif­fer­ent degrees. That is what made this study com­plex and inter­est­ing,” García-González said. To address the study, we focused on sam­ples in which all the pan­elists agreed that they were clearly char­ac­ter­ized with green fruity’ or ripe fruity’ aroma.”

The researchers stud­ied the dif­fer­en­ti­a­tion in the volatile pro­file of extra vir­gin olive oils into those two classes, which were inves­ti­gated by deploy­ing three dif­fer­ent ana­lyt­i­cal meth­ods, includ­ing dif­fer­ent extrac­tion tech­niques and detec­tors and two data pro­cess­ing strate­gies, and their rela­tion with sen­sory results.”


According to the sci­en­tists, such work was needed as the knowl­edge of the indi­vid­ual con­tri­bu­tion of volatile com­pounds to the greener or riper notes of extra vir­gin olive oil is still scarce.

Given the com­plex­ity of pos­i­tive attrib­utes found in extra vir­gin olive oil asso­ci­ated with dif­fer­ent volatile pro­files rather than sin­gle volatile mark­ers, the study of dif­fer­ent isolation/extraction tech­niques and meth­ods are needed to obtain the max­i­mum infor­ma­tion of the volatile pro­file,” they wrote.


According to the results, each method allowed the char­ac­ter­i­za­tion of the two classes, pro­vid­ing infor­ma­tion on dif­fer­ent volatile com­pounds.

García-González said the research on extra vir­gin olive oil’s dif­fer­ent sen­sory attrib­utes is cru­cial given the sig­nif­i­cance of such a prod­uct.

Many olive oil experts might detect plenty of sen­sory notes within the green fruity” or ripe fruity” labels, such as green grass, green tomato, ripe tomato, green banana, ripe banana, and so on.

Those are com­monly detected by pan­elists and con­sumers, and they also have spe­cific volatile pro­files asso­ci­ated,” García-González said. However, not all of them have the same com­plex­ity or the same pos­si­bil­ity for an objec­tive and repro­ducible sen­sory eval­u­a­tion, par­tic­u­larly in the case of some attrib­utes that rarely are present or are less defined.”

The research on the volatile com­pounds respon­si­ble for sen­sory attrib­utes often comes with inno­va­tion in organolep­tic assess­ment.


Olive oil samples to be tested in the lab

According to García-González, these kinds of stud­ies con­tribute to a bet­ter knowl­edge of each per­ceived attribute, the tech­no­log­i­cal fac­tors influ­enc­ing its con­cen­tra­tion, the chem­i­cal and bio­chem­i­cal ori­gin and ulti­mately the improve­ment of its def­i­n­i­tion, which is very impor­tant for the sen­sory eval­u­a­tion.”

Since many con­sumers are unaware of the wide diver­sity of extra vir­gin olive oil’s pos­i­tive organolep­tic qual­i­ties, García-González and his col­leagues believe research can pro­vide new oppor­tu­ni­ties for pro­duc­ers.

The advanced knowl­edge on pos­i­tive attrib­utes beyond those described in the organolep­tic assess­ment method would also con­tribute to intro­duc­ing new vari­ables for opti­miz­ing the process of oil extrac­tion toward an improved qual­ity and a bet­ter char­ac­ter­i­za­tion and pro­mo­tion of the prod­uct,” García-González said.

The researchers noted that there is a long road ahead in under­stand­ing and inves­ti­gat­ing extra vir­gin olive oil’s pos­i­tive attrib­utes.

The next step [of the research] is to extend the study to other pos­i­tive sen­sory attrib­utes within each one of the green fruity’ and ripe fruity’ types and to iden­tify new mark­ers that could be related to par­tic­u­lar pos­i­tive sen­sory pro­files and to estab­lish new deci­sion rules of sen­sory inter­pre­ta­tion based on the volatile pro­file,” García-González said.

The inclu­sion of dif­fer­ent cul­ti­vars and matu­rity stages is nec­es­sary for this par­tic­u­lar objec­tive. On the other hand, stud­ies that involve the response of pan­elists and con­sumers to these attrib­utes are also of inter­est. Studying the pan­elists’ per­for­mance in their eval­u­a­tion for some of the attrib­utes with par­tic­u­lar rel­e­vance for those being eas­ily detected com­pared to oth­ers,” he con­cluded.


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