Changes in the phenolic composition of virgin olive oil from young trees (Olea europaea L. cv. Arbequina) grown under linear irrigation strategies

This study reports the HPLC profiles of phenolic compounds of virgin olive oils obtained from young olive trees (Olea europaea L. cv. Arbequina) and h ow the application of a linear irrigation strategy affected these. Hydroxyt yrosol, tyrosol, vanillic acid, vanillin, 4-(acetoxyethyl)-1,2-dihydroxyben zene, p-coumaric acid, the dialdehydic form of elenolic acid linked to hydr oxytyrosol and to tyrosol, lignans, and the oleuropein aglycon were found i n all the oils. Hydroxytyrosol, tyrosol, vanillic acid, and p-coumaric acid contents in the oils were unaffected by linear irrigation. The concentrati on of lignans was lower in the oils from the least irrigated treatment and the concentration of vanillin increased as the amount of irrigation water a pplied to olive trees increased. However, 4-(acetoxyethyl)-1,2-dihydroxyben zene, the dialdehydic form of elenolic acid linked to hydroxytyrosol and to tyrosol, and the oleuropein aglycon, all of them hydroxyphenyl derivatives , decreased as the level of irrigation water increased. The latter three co mpounds represented the most considerable part of the phenolic fraction of the oils and they were shown to be correlated to the oxidative stability, t he bitter index (K-225), and the bitter, pungent, and sweet sensory attribu tes. Linear irrigation strategy changed the profile of the oil phenolic com pounds and, therefore, changed both the organoleptic properties and the ant ioxidant capacity of the product.