IMPROVING AND ACCELERATING THE MIGRATION OF BIOACTIVE COMPOUNDS FROM ROSEMARY AND BASIL TO THE EXTRAVIRGIN OLIVE OIL WITH ULTRASOUND TECHNOLOGY

Extra-virgin olive oil (EVOO) is widely recognized as an important ingredient of a healthy diet. There are other products in the market which are produced by the infusion of aromatic herbs, as rosemary or basil, into the EVOO. It is well known that volatile and bioactive compounds migrate slowly from the herbs to the EVOO. In order to verify if the use of ultrasound could accelerate the compounds migration or change the profile of the migrated compounds from the aromatic herbs to the EVOO, our work aimed to compare the use of ultrasound technology to the conventional maceration process. For this, we initially optimized the ultrasound operational conditions (ultrasound amplitude, extraction time and temperature), for rosemary or basil addition. A central composite design for each aromatic herb was executed and, after modelling the responses, the optimal conditions were predicted. The optimal conditions for ultrasound enrichment of EVOO with rosemary or basil compounds were then compared to the conventional infusion, including analysis of the quality parameters (free fatty acids, peroxide value, specific extinction coefficient), total phenolic compounds (Folin-Ciocalteu reagent method), antioxidant capacity (ORAC method), induction and stability time (Rancimat), fatty acid profile (GC-FID) and volatile compounds (HS-SPME-GC-MS). For rosemary infusion, with only 37 min in the ultrasound bath it was possible to obtain almost the same chemical characteristics of the product after 7 days of conventional maceration, while for basil infusion only 10 min in the ultrasound bath was already sufficient. For both products obtained with ultrasound, the induction and stability time were higher than the observed for the conventional maceration. As conclusion, we can state that ultrasound is capable to dramatically accelerate the migration of bioactive and volatile compounds from aromatic herbs to the EVOO, without causing negative effects in the quality parameters and in the stability of the oils.