Best Practices for Producing Flavored Olive Oil

While olive oils fla­vored with dif­fer­ent herbs and spices are becom­ing pop­u­lar, use of fla­vored olive oil is not a new trend. In fact, olive oil infused with fen­nel, sesame, juniper, mint, cel­ery, sage, water­cress, flow­ers and other spices was used by ancient Romans, Greeks and Egyptians as med­i­cine and in cos­met­ics. Nowadays, fla­vored olive oil is used in spe­cialty salad dress­ings, pasta dishes and as an appe­tizer for dip­ping bread.

The most com­mon process of prepar­ing fla­vored olive oil is the infu­sion method. This is a time-con­sum­ing process where finely ground herbs are soaked in olive oil for spec­i­fied lengths of time accom­pa­nied by peri­odic shak­ing. In the final step, the olive oil is fil­tered to remove traces of the fla­vor­ing agents.

However, as pop­u­lar­ity and demand for fla­vored olive oil increases, there is the need to find a faster method to pro­duce fla­vored olive oil with­out sac­ri­fic­ing qual­ity or nutri­tional value of the EVOO.

To this end, researchers from the University of Bari in Italy tried to stream­line the process of pro­duc­ing fla­vored olive oil on a large scale.

Their aim was to study dif­fer­ent meth­ods for the pro­duc­tion of fla­vored olive oil that would not only enhance the qual­ity of the fla­vored olive oil but also extend the shelf life with­out com­pro­mis­ing the chem­i­cal char­ac­ter­is­tics, polyphe­nol con­tent and rad­i­cal scav­eng­ing activ­ity of the olive oils.

For the study, the researchers extracted olive oil from olives har­vested from olive groves in Andria, Italy in the 2013 – 2014 crop sea­sons and fla­vored it with two pop­u­lar herbs, oregano and thyme.

The three meth­ods used to fla­vor olive oil were sim­ple infu­sion of olive oil with ground herbs; adding herbs to crushed olives before the malax­a­tion step dur­ing extrac­tion of olive oil; and adding herbs to crushed olives before the malax­a­tion step dur­ing extrac­tion of olive oil and treat­ing the with energy pro­duced by sound waves using ultra­sound tech­nol­ogy. The use of ultra­sound tech­nol­ogy boosts cav­i­ta­tion, which could be used to opti­mize arom­a­ti­za­tion of the olive oils with herbs.

The researchers deter­mined the acid­ity, per­ox­ide val­ues , rad­i­cal scav­eng­ing activ­ity and polyphe­nol con­tent of the fla­vored olive oil to assess the qual­ity of the treated oils.

Results showed that the fla­vor­ing method did not affect the acid­ity of the olive oil and all fla­vored olive oils had low val­ues for acid­ity, per­ox­ide value, K232 and K270.

However, irre­spec­tive of the method used to fla­vor olive oil, the addi­tion of herbs was found to sig­nif­i­cantly increase the total polyphe­nol con­tent of the fla­vored olive oil. The great­est increase in polyphe­nol con­tent was observed in fla­vored olive oils pro­duced by the addi­tion of herbs to crushed olives before the malax­a­tion step, which was almost three times higher than that of the con­trol or untreated olive oil.

The authors hypoth­e­size that the water in olive paste may act as a sol­vent and improve extrac­tion of organic acids into the oil while the con­tin­u­ous mix­ing of olive paste could pos­si­bly play a part in increas­ing release of polyphe­nols from oregano and thyme into the olive oil.

The ultra­sound treat­ment of olive paste was effec­tive in main­tain­ing the qual­ity of fla­vored olive oil and found to increased the total polyphe­nol con­tent of olive oil by about 13 per­cent. This could be pos­si­bly due to dis­rup­tion bio­log­i­cal cell walls of the crushed olives and herbs by energy pro­duced by the ultra­sound tech­nol­ogy. This method was found to increase the con­cen­tra­tion of the polyphe­nols — tyrosol, hydrox­y­ty­rosol and oleu­ropein in the fla­vored olive oils.

Furthermore, the addi­tion of herbs to the olive paste before the malax­a­tion step also improved the rad­i­cal scav­eng­ing activ­ity of the fla­vored olive oils.

According to the authors of this study, effi­cient and effec­tive large-scale pro­duc­tion of fla­vored olive oil can be achieved by adding herbs to olive paste before the malax­a­tion step to pro­duce olive oils with higher con­cen­tra­tions of total polyphe­nols and increased rad­i­cal scav­eng­ing abil­ity. They rec­om­mend test­ing the suit­abil­ity of this method in pro­duc­ing olive oil fla­vored with veg­eta­bles, fruits, spices and other herbs as well.

• Plant Foods for Human Nutrition


• The Global Gourmet