SURVEY OF THE AMOUNTS OF OXIDIZED TRIGLYCERIDES AND TRIGLYCERIDE DIMERS IN VIRGIN AND LAMPANTE OLIVE OILS

The aim of this work was to ascertain the amount of oxidized triglycerides and triglyceride dimers in virgin and ''lampante'' olive oils: to this effect, 38 samples were collected from different oil-mills. No data on the above compound classes in ''lampante'' olive oils have ever appeared in literature up to now. However, fat autoxidation is known to imply polymerization reactions; so, low amounts of oligopolymers may be formed in oil at a given state of oxidation. This aspect also applies to virgin olive oils because the very few data reported in literature are mainly related to extra virgin olive oils which are classified as high quality oils. Column chromatography and highperformance size exclusion chromatography were used for oil analysis in this work. Triglyceride dimers were either absent or present in traces in virgin olive oils, but were found in ''lampante'' oils with a mean value of 0.07%. Oxidized triglyceride percentages in ''lampante'' oils were more than twice as high as those present in virgin oils. The data obtained suggest the following consideration: the presence of dimers in vegetable oils reveals a rather high oxidation level and is confirmed by the higher oxidized triglyceride values. This is a reliable index of oxidative degradation in oil.