Phenolic compounds and antioxidant activity in monovariental Croatian virgin olive oils

Different olive cultivars that came from different groves in Croatia were all processed in oil b centifugation system in two phases. Several qualitative parameters were evaluated (free acidity, peroxide value and UV spectrophotometric indices) according to the official method described in the EEC Regulation n. 2568/91 of the Commission of the European Union. The oxidative stability of the olive oil samples was evaluated by OSI. The analysis of major (fatty acid) and minor components (phenolic fraction) and their antioxidant power evaluated by ABTS•+ and electrochemical test was also carried out. Liquid-liquid extraction of phenolic compounds from olive oils was performed following the protocol described by Pirisi et al. (1997), modified according to Rotondi et al. (2004). Quali-quantitative analysis of phenolic compounds have been carried out by HPLC-DAD/MSD according to Rotondi et al. (1999). An amperometric flow injection method (FIA) was used for the evaluation of the antioxidant power (AOP) of the phenolic extracts of the oil samples. The results for all samples have shown belonging to category of extra virgin olive oil, depending on analyed analytical parametres. Moreover, the oils had very good storage capacity, depending on fatty acid composition, and also very good phenols content. Particularly, among the most representative varieties, the tendency to higher antioxidant activity had oils produced from Lastovka variety, followed by oils from Oblica and Levantinka.