GEOGRAPHICAL ORIGIN AFFECTS YEAST COMMUNITY COMPOSITION AND THE CONTENT OF MAJOR PHENOLIC COMPOUNDS FROM TWO DIFFERENT AREAS IN TUSCANY. Yeast community of extra virgin olive oil

In this work we utilized a culture-independent method, PCR denaturating gradient gel electrophoresis (PCR-DGGE), to investigate the occurrence, diversity and community composition of yeasts in olive oil produced in two different areas in Tuscany. The content of tyrosol, hydroxytyrosol, oleocanthal and oleacein was also assessed. Cluster analysis of PCR-DGGE profiles separated the oil borne microbial populations from the two geographical areas, with a similarity of 41%. Such findings were confirmed by the NMDS analysis of the DGGE profiles. ANOSIM showed statistically significant differences between microbial communities of the olive oil from the two different geographical areas (R=0.96, p= 0.0001). The sequences of the bands excised from the DGGE gels identified Candida adriatica, Eremotecium coryli and Lachancea fermentati as the main components of the yeast community characterizing the olive oil produced in the two locations in Tuscany. The olive oils produced in the two locations differed in the quantitative composition of polyphenols, in particular oleocanthal and oleacein, consistently with the clusters revealed by PCR-DGGE profile analysis of the microbiota.