Influence of milling conditions on the Æ-tocopherol content of Picual olive oil

Abstract

The aim of this study was to estimate the α-tocopherol content in Picual extra-virgin olive oils obtained from the 2004/2005 harvesting season and to evaluate the influence that different extraction processes and sample handling had on the final vitamin E content in the oils. A new experimental oil extraction carried out at 9 °C enabled us to obtain encouragingly high quantities of α-tocopherol with an average quantity reaching 341.34 ± 50.17 mg/L (n = 13), with significant differences among the same oil types produced from the traditional two-phase system at low (9 °C, p <0.01) and moderate (21.5 °C, p <0.001; 33 °C, p <0.0001) temperatures. The temperature at which extraction was carried out should be considered as a major factor to be taken into account. Additionally, we also developed a precise method for the extraction of α-tocopherol from olive oil samples, which enables high recovery (96 ± 2%) for use in subsequent HPLC/DAD/fluorescence quantification.