Freezing storage can affect the oxidative stability of not filtered extra-virgin olive oils

In this work the changes, induced by a freezing storage, on the phenolic fraction of not filtered extra-virgin olive oils were investigated. Particularly oil samples from three olive cultivars, coming from two different geographical areas (Italy), were analysed freshly and after a storage at -43 °C for three months, by the following procedures: total phenols and o-diphenols by spectrophotometric assay, phenolic profile by HPLC-DAD/MSD analysis, oxidative stability evaluation by OSI instrument and antiradical power by DPPH tests. Furthermore, the effect of filtration (on cellulose) applied to the samples after freezing storage, was investigated by the same analytical scheme. Then, the filtered oil was deprived of the phenolic fraction, extracted by a liquid-liquid procedure, and the oxidative stability of the residual oil was tested agai