Aging-related physico-chemical changes in olive oil mill effluent

This paper presents a study on the changes in some physico-chemical charact eristics of olive oil mill effluent (OME) due to aging; OME utilized for th e investigation were obtained from three different olive oil harvests spann ing the period 1996 - 1998. Both filtered and unfiltered OME were analyzed. Two groups of substances, polyphenols and long chain fatty acids (LCFA), w ere studied with particular attention on account of their antibacterial and phytotoxic properties. Results indicate that the composition of OME sample d from different olive oil harvests varies considerably as regards total po lyphenol and LCFA content and the distribution of these substances in relat ion to their molecular weights. Moreover, experiments performed in relation to storage time demonstrate that a stabilized effluent is obtained after a pproximately 45 days of aging, irregardless of the initial olive oil harves t. This is also confirmed by multivariate analysis performed by means of Pr incipal Component Analysis and Cluster Analysis.