`A New Spectroscopy Method to Determine Bitterness and Pungency in Olive Oil - Olive Oil Times

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

Jul. 19, 2022
Paolo DeAndreis

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Some tech­nolo­gies and processes rou­tinely used in research lab­o­ra­to­ries have shown a high level of accu­racy in deter­min­ing the bit­ter­ness and pun­gency of extra vir­gin olive oil.

According to a new study pub­lished in Food Chemistry, the lat­est find­ings could change how these olive oil char­ac­ter­is­tics are deter­mined, which is cur­rently done with expert tast­ing pan­els.

The study sug­gests that the new tech­nol­ogy would not face some of the chal­lenges asso­ci­ated with tra­di­tional panel tests – such as cost, time and orga­ni­za­tion – but would not fully replace them.

See Also:Olive Leaves Can Improve Oil Quality, Researchers Find

Many authors agreed on the con­tro­ver­sies asso­ci­ated with the panel test, con­ducted by a human panel, espe­cially in terms of effi­ciency and robust­ness, point­ing out the need of set­ting up a sup­port­ing instru­men­tal tool for sen­sory eval­u­a­tion,” the researchers wrote.

The vir­gin olive oil cat­e­gory does not require bit­ter and pun­gent attrib­utes to be spec­i­fied on its labels. However, cur­rent reg­u­la­tions allow pro­duc­ers to state the vir­gin olive oil’s inten­sity on the label using spe­cific ter­mi­nol­ogy, such as robust, medium, del­i­cate, well bal­anced or mild.

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Disposing of a fast and effi­cient ana­lyt­i­cal method to mea­sure bit­ter and pun­gent attrib­utes in vir­gin olive oil becomes a need to sup­port the sen­sory panel,” the researchers wrote. We hypoth­e­size that flu­o­res­cence spec­troscopy as such could be the fit-for-pur­pose tool, given that it is selec­tive, fast and sol­vent free.”

Previous stud­ies have already applied this tech­nique to deter­mine olive oil authen­tic­ity, adul­ter­ation, dis­crim­i­na­tion from other edi­ble oils and level of dete­ri­o­ra­tion.

However, no pre­vi­ous study has applied exci­ta­tion-emis­sion flu­o­res­cence spec­troscopy to develop pre­dic­tion mod­els for bit­ter­ness and pun­gency attrib­utes of olive oils.

To explore their hypoth­e­sis, the researchers worked with 255 vir­gin olive oil sam­ples pro­duced from the 2019/20 har­vest by the Institute of Agrifood Research and Technology in Spain.

An expert tast­ing panel cer­ti­fied and rec­og­nized by the International Olive Council assessed and graded the sam­ples, deter­min­ing their pun­gency and bit­ter­ness.

The sam­ples were then used to build and com­pare par­tial least squares regres­sions with the exci­ta­tion-emis­sion matrix. Regression analy­sis allowed researchers to deter­mine which vari­ables mat­tered most and which could be ignored.

The pre­dic­tion of vir­gin olive oil bit­ter­ness and pun­gency was deter­mined by mea­sur­ing the exci­ta­tion-emis­sion matrix.

Errors in pre­dic­tion were always close to the error of the sen­sory ref­er­ence method,” the researchers wrote.

According to the sci­en­tists, the exci­ta­tion-emis­sion flu­o­res­cence spec­troscopy method applied in the study could cor­rectly pre­dict those cru­cial qual­i­ties of vir­gin olive oils.

In view of the results, exci­ta­tion-emis­sion flu­o­res­cence spec­troscopy has proven to be a suit­able tool for bit­ter­ness and pun­gency pre­dic­tion of vir­gin olive oils and could become the fit-for-pur­pose screen­ing tool to sup­port the panel,” the researchers wrote.

They added that the method has sev­eral ben­e­fits, includ­ing its faster speed and lower cost than tra­di­tional pan­els and other meth­ods used to deter­mine olive oil organolep­tic qual­i­ties.

However, the authors warned their method is not imme­di­ately deploy­able at scale.

In spite of the sat­is­fac­tory results, also con­sid­er­ing the error of panel’s per­for­mance, fur­ther research is needed in order to obtain robust regres­sion mod­els,” they con­cluded. Besides, a greater num­ber of vir­gin olive oils sam­ples with a wider range of the attrib­utes of inter­est would be worth being included, as well as to carry out an exter­nal val­i­da­tion of future regres­sion mod­els.”



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