Pigments in Greek virgin olive oils: occurrence and levels
2001
Psomiadou, E. | Tsimidou, M.
Fifty-two samples of virgin olive oil from various regions of Greece were examined for the presence and levels of chlorophyll and carotenoid pigments using normal phase liquid chromatography and spectrometry. Pheophytin a (Pheo a) was the main pigment in all the oils examined (> 10 mg kg(-1) in more than 70% of samples). Two pheophytin a derivatives (peaks A and B), eluted close to Pheo a, may potentially be used to examine handling conditions and length of storage of oil until analysis. Analysis of 25 Greek commercial oils obtained from retail stores verified the above observations. Chlorophyll a may be present in a virgin olive oil just after production. Its absence should not be exclusively attributed to cultivar characteristics or extraction conditions, since pheophytinisation occurs rapidly. Lutein content varied between 0.2 and 3.9 mg kg(-1) and beta-carotene content from 0.4 to 5.1 mg kg(-1). The lutein/beta-carotene ratio was characteristic (< 1) for samples from Koroneiki, the major Greek cultivar for oil production. The total Pheo a (Pheo a + peak A + peak B)/total carotenoid (lutein + beta-carotene) ratio ranged between 2 and 11 owing to prevailing green hues. This ratio may be used as an indicator of oil typicality along with other analytical parameters.
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