Chemical, sensory and biological characteristics of selected monovarietal extra virgin olive oils

The present study deals with the chemical, biological and sensory characterization of monovarietal extra virgin olive oils (EVOOs) obtained from cultivar grown in Marche region (Italy). EVOO is a food product having interesting beneficial properties, as evidenced by scientific literature [1]. One of the key features contributing to these properties are phenolic substances, which are related to the healthy, sensory and stability properties of EVOOs. They have been also related to the prebiotic activity of the oil [2]. Also volatile substances greatly contribute to the overall quality of EVOO and they are produced in chemical and biochemical pathways whose outcome depends on several factors, one of the most important of which, is the olives health state, and thus the microorganisms present. This study aims to investigate the relations between the chemical characteristics of monovarietal EVOOs mainly related to the overall quality and to correlate them with sensorial properties, prebiotic activity and yeasts characterizing the oils. Because of the influences of yeasts on the final EVOO quality, the high-throughput sequencing of internal transcribed spacers amplicons was employed to study the yeast biodiversity associated to the monovarietal EVOOs. Significant differences in taxa abundance among samples were obtained. Regarding prebiotic activity, it has been investigated by a semi-continuous fermentation system inoculated with a pool of human faeces under anaerobic conditions, to mime a colonic human fermentation [3]. Bifidobacteria, lactobacilli and clostridia and short chain fatty acids have been monitored using RT-PCR and gas-chromatography respectively, during 24h fermentation of each previously digested EVOO. Preliminary results will be presented and discussed. [1]. G. Caramia, A. Gori, E. Valli, L. Cerretani Virgin olive oil in preventive medicine: from legend to epigenetics European Journal of Lipid Science and Technology 2012; 114, 375–388. [2]. Cardona F., Andrés-Lacuevac C., Tulipania S., Tinahonesb F.J., Queipo-Ortuñoa M.I..Benefits of polyphenols on gut microbiota and implications in human health. Journal of Nutritional Biochemistry 2013; 24, 1415–1422. [3]. Zampa A., Silvi S., Servili M., Montedoro G., Orpianesi C., Cresci A. In vitro modulatory effects of colonic microflora by olive oil iridoids. Microbial Ecology in Health and Disease, 2006; 18, 147-153.