Qualitative phenolic profile (HPLC-DAD-MS) from olive oil mill waste waters at different states of storage and evaluation of hydrolysis process as a pretreatment to recover their antioxidants

Olive oil mill waste water (OOMWW) represents a waste that it is generated during the extraction process of olive oil from olives and it is an important environmental problem because of the huge volume generated in the mills. Nevertheless, it is highlighted in literature the high concentration of antioxidants, especially phenolic compounds, in the OOMWW. Principally, the qualitative phenolic profiles of OOMWW differ depending on the technological process of production of olive oil and the time of storage. The aim of this work was to compare qualitatively the phenolic profile of OOMWW by HPLC-DAD-MS. Glucosilated secoiridoids as oleuropein and ligstroside, their aglycon derivatives and simple phenols were the principal compounds found in these matrixes. Furthermore, different hydrolysis reactions have been studied for the phenolic fraction in the oleuropein standard as well as in the OOMWWsamples.These steps have been evaluated as pretreatment for the selection and a possible subsequent recovery of most interesting phenolic compounds as hydroxytyrosol that has been proved to possess an important antioxidant activity