Oxidative stability, fatty-acid and phenolic composition of Cypriot monovarietal virgin olive oils with progressive fruit maturity

Oil content, extractability, chemical composition and oxidative stability of three monovarietal ('Ladoelia', 'Kato Drys' and 'Korakou') virgin olive oils (VOOs) were examined at progressive stages of fruit maturity. Oxidative stability was assessed on a Rancimat System, phenols and tocopherols by HPLC-DAD and fatty acid (FA) profiles by GC-FID. Oil extractability was highly cultivar-specific and unaffected by maturity stage. 'Ladoelia' exhibited excellent extractability and satisfactory VOO composition and oxidative stability, with moderate phenolic and diverse tocopherol content. 'Kato Drys' was rich in monounsaturated FA that imparted superior oxidative stability and poor in polyunsaturated and saturated FA. Monovarietal VOOs exhibited higher correlation of oxidative stability with the C18:1/C18:2 ratio (r = 0.80, p < 0.0001) than with the total phenolic content (TPC; r = 0.436, p < 0.05), suggesting that phenolic association with oxidative stability might be specific to individual phenolic compounds than to TPC. Late harvest of 'Ladoelia' and 'Kato Drys' was liable to drastic rise in free acidity. Poor extractability, low oil and oleic acid contents undermined the suitability of 'Korakou' for VOO production. The current findings contribute towards the establishment of typicity for monovarietal VOOs.