Variation in the different aromatic classes of virgin olive oils after heating at frying temperature

Frying is one of the few methods of cooking common to the entire Mediterranean area. It is used for both domestic and industrial preparation of food. During frying, as a results of heating, virgin olive oil (VOOs) undergos a complex series of degradation reactions. In the present work, the changes in the different chemical families of the aroma of the virgin olive oil (VOO) subject to a heating at frying temperature (180°C) for 0, 2.5, 5, 7.5 and 10 hours, was carried out. The VOO volatile compounds were extracted by SPME, and analyzed and identified by GC/MS. In the untreated VOOs, the aromatic compounds showed different chemical families, with a predominance of the aldehydic class of the lipoxygenase products (75.2% of total peak area), followed by the class of sesquiterpenes (14.8%), esters (2.5%), monoterpenes (1.2%) and hydrocarbons (0.9%), other aromatic classes are present in trace. After olive oil heating, a newformed aldehydic compounds were observed reaching 84.4% of total peak area, whereas the lipoxygenase products, the mono-and sesquiterpenes showed a remarkable degradation after 2.5h of heating. Other volatile markers of thermoxidation were emitted with different levels depending to the heating time