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

Researchers in Spain Investigate Positive Organoleptic Attributes of EVOO

Oct. 24, 2022
Paolo DeAndreis

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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