Phenolic compounds in different olive varieties were determined by HPLC analysis over 2 years. Demethyloleuropein was found in only two (Coratina and Leccino) of the eight varieties studied, so it could be used as varietal marker. Elenolic acid glucoside and hydroxytyrosol can be considered indicators of maturation for olives. In fact, as the olives ripen, their tenor increases whereas oleuropein decreases.

Phenolic compounds are of fundamental importance to the shelf life of virgin olive oils because of their antioxidative properties. In this paper, the evolution of simple and complex olive oil phenols during 18 mon of storage is studied by high-performance liquid chromatography (HPLC) analysis. The olive oils under examination were from various olive cultivars, harvested in two sectors in the same region at different stages of ripeness. The findings indicate that it is not the variety but rather the ripeness of the olives and the soil and climate that influence the phenol composition of virgin olive oil. In addition, a positive correlation was found between the age of the oils and the tyrosol to total phenols ratio. Lastly, gas chromatography-mass spectrometry analysis confirmed that the unidentified peaks detected by HPLC were of a phenolic nature.

The chemical characteristics, phenolic content and antioxidant activity of olive oils flavored with garlic, lemon, oregano, hot pepper, and rosemary were evaluated during 9 months of storage. At the end of the storage period, the unflavored and the garlic-flavored oils maintained their chemical parameters within the limits fixed for extra-virgin olive oils. After 9 months of storage, a noticeable decrease in phenolic content was observed in all the oils. The highest (35.0 ± 3.9 mg/kg oil) and the lowest (6.3 ± 0.4 mg/kg) phenolic contents were detected in the unflavored and garlic-flavored oils, respectively. Compounds such as 3,4-DHPEA-EDA (3,4-dihydroxyphenylethyl 4-formyl-3-formylmethyl-4-hexenoate, the dialdehydic form of decarboxymethyl elenolic acid linked to hydroxytyrosol) and p-HPEA-EDA (dialdehydic form of the decarboxymethyl elenolic acid linked to tyrosol) were the most abundant in both unflavored and lemon-flavored oils up till 6 months of storage. At the end of the storage period, increases in 3,4-DHPEA (hydroxytyrosol) and p-HPEA (tyrosol) were measured in almost all the oils. During storage, the antioxidant activity coefficients of the phenolic extracts, calculated according to the b-carotene bleaching assay, significantly decreased and, after 9 months, were in a decreasing order: rosemary (51.3 ± 4.2), hot pepper, lemon, oregano, unflavored, and garlic (8.5 ± 0.7).

A study is reported on the chemical and sensorial characteristics of extra virgin olive oil flavored with hot pepper, garlic, oregano and rosemary during 7 months of storage. The oils were prepared by addition of the spice oily extracts at three different levels of concentration to an extra virgin olive oil. The following parameters were monitored: acidity, peroxide value (PV), K 232 , K 270 , (E)-2-hexenal/hexanal ratio and sensorial characteristics. At the end of the storage, all samples showed PV and K 232 values lower than the control, whereas similar values of acidity, K 270 and (E)-2-hexenal/hexanal ratio were observed. These results demonstrated that the herb and spice extracts improved the stability of the extra virgin olive oil. Tasters were able to distinguish among the levels of addition, and at the end of the storage, they preferred the oils flavored with 20 g/L of rosemary, 40 g/L of hot pepper, 40 g/L of oregano and 30 g/L of garlic. PRACTICAL APPLICATIONSThis research is strongly oriented to the industrial application. The obtained results could be immediately applied to flavored olive oil production 3 Corresponding

Phenolic composition and antioxidant activity of extra-virgin olive oils extracted from several Italian varieties were studied at production and during storage. The antioxidant activity was measured according to the following tests: in the aqueous phase, by radical scavenging of the 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation; and in the lipid phase, using the beta-carotene bleaching method. The phenolic content was not correlated to the oxidation indices (peroxide value and spectrophotometric constants). The phenolic contents and profiles of the various cultivars showed remarkable differences. The phenolic content was strongly correlated with the antioxidant activity measured according to the beta-carotene test and weakly correlated with the radical scavenging ability.