Phenolic compounds profile of cornicabra virgin olive oil.
This study presents the phenolic compounds profile of commercial Cornicabra virgin olive oils from five successive crop seasons (1995/1996 to 1999/2000; n = 97), determined by solid phase extraction reversed phase high-performance liquid chromatography (SPE RP-HPLC), and its relationship with oxidative stability, processing conditions, and a preliminary study on variety classification. The median of total phenols content was 38 ppm (as syringic acid), although a wide range was observed, from 11 to 76 ppm. The main phenols found were the dialdehydic form of elenolic acid linked to tyrosol (p-HPEA-EDA; 9 +/- 7 ppm, as median and interquartile range), oleuropein aglycon (8 +/- 6 ppm), and the dialdehydic form of elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA; 5 +/- 8 ppm). In many cases the correlation with oxidative stability was higher when the sum of the dialdehydic form of elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA) and oleuropein aglycon (r (2) = 0.91-0.96) or the sum of these two and hydroxytyrosol (r (2) = 0.90-0.97) was considered than was observed with HPLC total phenols (r (2)= 0.91-0.95) and especially with colorimetric determination of total polyphenols and o-diphenols (r (2) = 0.77-0.95 and 0.78-0.92, respectively). 3,4-DHPEA-EDA, p-HPEA-EDA, the aglycons of oleuropein and ligstroside, and HPLC total phenols content presented highly significant differences (p = 0.001-0.010) with respect to the dual- and triple-phase extraction systems used, whereas colorimetric total polyphenols content did not (p = 0.348) and o-diphenols showed a much lower significant difference (p = 0.031). The five variables that most satisfactorily classified the principal commercial Spanish virgin olive oil varieties were 1-acetoxypinoresinol, 4-(acetoxyethyl)-1,2-dihydroxybenzene (3,4-DHPEA-AC), ligstroside aglycon, p-HPEA-EDA, and RT 43.3 contents.
Gómez-Alonso
Sergio
S
Departamento de Química Analítica y Tecnología de Alimentos, Facultad de Químicas, Universidad de Castilla-La Mancha, Avenida Camilo José Cela 10, 13071 Ciudad Real, Spain.
Salvador
María Desamparados
MD
Fregapane
Giuseppe
G
D002851:Chromatography, High Pressure Liquid; D003124:Colorimetry; D004355:Drug Stability; D005419:Flavonoids; D057888:Iridoid Glucosides; D039823:Iridoids; D000069463:Olive Oil; D010084:Oxidation-Reduction; D010636:Phenols / Q000032:analysis*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D010938:Plant Oils / Q000737:chemistry*; D011108:Polymers / Q000032:analysis; D059808:Polyphenols; D011714:Pyrans / Q000032:analysis / Q000737:chemistry; D012621:Seasons
D005419:Flavonoids; D057888:Iridoid Glucosides; D039823:Iridoids; D000069463:Olive Oil; D010636:Phenols; D010938:Plant Oils; D011108:Polymers; D059808:Polyphenols; D011714:Pyrans; C005975:3,4-dihydroxyphenylethanol; C011867:4-hydroxyphenylethanol; C002769:oleuropein; C000352:elenolic acid; D010626:Phenylethyl Alcohol