A Cheap, Easy Way to Quantify Biophenols for the EU Health Claim

Summary

Researchers from the University of Bologna and University of Vigo pro­posed a sim­ple and cost-effec­tive col­ori­met­ric assay using the Folin-Ciocalteu reagent to quan­tify phe­no­lic con­tent in extra vir­gin olive oils, in order to meet EU health claim reg­u­la­tions. The find­ings were pub­lished in the European Journal of Lipid Science and Technology, show­ing that this method could be effi­ciently used by small labs and pro­duc­ers to ver­ify com­pli­ance with polyphe­nol health claims.

A group of researchers, includ­ing Enrico Valli, Alessandra Bendini, Giuseppe Di Lecce and Tullia Gallina Toschi from the University of Bologna, Patricia Reboredo-Rodríguez and Jesus Simal-Gándara from the University of Vigo, pro­posed how to use a sim­ple ana­lyt­i­cal method to quan­tify the phe­no­lic con­tent of extra vir­gin olive oils in order to sat­isfy the require­ments intro­duced by the EU Regulation 432/2012, which estab­lishes a list of per­mit­ted health claims made on foods.

The team pub­lished its find­ings in the European Journal of Lipid Science and Technology.

“As it is well known, there are sophis­ti­cated chro­mato­graphic tech­niques, such as the high-per­for­mance liq­uid chro­matog­ra­phy (HPLC) cou­pled to ultra­vi­o­let-vis­i­ble or mass spec­trom­e­try detec­tor that are used to eval­u­ate the phe­no­lic con­tent of vir­gin olive oils,” Di Lecce explained.

“However, these sys­tems require very expen­sive ana­lyt­i­cal tools and qual­i­fied tech­ni­cians, while the promis­ing results obtained in this pre­lim­i­nary study show that the sim­ple and cheap col­ori­met­ric assay based on the use of the Folin-Ciocalteu (FC) reagent can be also effi­ciently applied to ver­ify the com­pli­ance to the polyphe­nols health claim intro­duced by the EU Regulation.”

In order to prop­erly con­vey the healthy prop­er­ties of extra vir­gin olive oil accord­ing to the EU reg­u­la­tion 432/2012, it is nec­es­sary:

- to share an ana­lyt­i­cal pro­to­col to deter­mine the amount of hydrox­y­ty­rosol and its deriv­a­tives hav­ing a demon­strated effect of pro­tec­tion of blood lipids from oxida­tive stress;

- to check, based on this pro­to­col, if EVOOs sat­isfy the EU require­ments for includ­ing the specific health claim on the label.

The FC method is a well-known col­ori­met­ric assay that requires only com­mon and cheap equip­ment and can be exe­cuted in any lab­o­ra­tory. It is com­monly used for the eval­u­a­tion of phe­no­lic com­pounds in hydro-alco­holic extracts of EVOO.

Based on a pre­lim­i­nary study, the researchers pro­posed using hydrox­y­ty­rosol to express the results obtained with the FC method. ​“Tests car­ried out by sta­tis­ti­cal soft­ware found FC data to be fully com­pa­ra­ble with those obtained, after hydrol­y­sis, with the HPLC-UV method using hydrox­y­ty­rosol and tyrosol to express the results,” Enrico Valli con­cluded.

The promis­ing find­ings, which need to be con­firmed by ana­lyz­ing a large num­ber of sam­ples to draw final con­clu­sions, show how an easy method can be effi­ciently applied by small labs and pro­duc­ers to ver­ify or cer­tify the com­pli­ance to the polyphe­nols health claim. This is in agree­ment with the increas­ing need to pro­pose rapid and inno­v­a­tive instru­men­tal approaches for qual­ity and authen­tic­ity of olive oils, as reported by some of the authors in a recently pub­lished review.

With €5 mil­lion of finan­cial sup­port, the Horizon 2020 EU OLEUM Project, recently won by a con­sor­tium coor­di­nated by Tullia Gallina Toschi (University of Bologna), has the over­all objec­tive to assure the qual­ity and authen­tic­ity of olive oils at a global scale.

Within the frame­work of this project, a spe­cific task led by Maria Tsimidou (Aristotle University of Thessaloniki) will be devoted to the setup of a reli­able pro­to­col for the deter­mi­na­tion of phe­no­lic com­pounds in vir­gin olive oils accord­ing to the health claim. Further study, involv­ing many lab­o­ra­to­ries around the world, will be made pos­si­ble by the OLEUM Project to inno­vate and har­mo­nize the quan­ti­ta­tive deter­mi­na­tion of olive oil polyphe­nols.

• A widely used spec­tropho­to­met­ric assay to quan­tify olive oil bio­phe­nols accord­ing to the health claim


• Rapid and inno­v­a­tive instru­men­tal approaches for qual­ity and authen­tic­ity of olive oils