Microbiota modulation by olive oil and pomegranate by-products evacuate in in vitro simulation technology M-Shime

In the last years food by-product promotion became one of the most interesting trend for eco-sustainability, as well as the safeguarding of food excellence of territory. In this work a special olive cake (OC) from extra virgin olive oil production and an hot water extract from pomegranate mesocarp (PM) of the Wonderful cv. grown in Tuscany have been selected to obtain polyphenols enriched extracts. Aim of this research was firstly to provide the phenolic profiles of these extracts by HPLC/DAD/MS, to evaluate the % of polysaccharides in the PM extract, then to test these samples with the gastrointestinal simulator M-SHIME [1]. The OC is a particular destoned cake characterized by a mix of typical polyphenols of the fruit and of the extra virgin olive oil, with tyrosol, hydroxy-tyrosol, derivates of oleuropein aglycone, and verbascoside. The presence of phenols was combined with an high fiber content between 25-30 % dw. The PM extract showed concentrations of total ellagitannins up to 120,3 mg/g with α and β punicalagins as main compounds, and a polysaccharidic fraction up to 12 % of dw. To date no data are available on the polysaccharides of the Wonderful cv. of pomegranate. To investigate potential modulation of microbial community, the extracts were tested in the in vitro gastrointestinal simulator, M-SHIME [1]. Two different feeds were evaluated: a protein diet, totally sugar and fiber free, and a normal feed, including protein, fiber and sugars. Preliminary results (Short Chain Fatty Acids –SCFA and ammonium concentrations) showed that when the bacterial activity was affected by the protein diet, daily treatments of these extracts could improve the general well-being of the microbiota, probably due to the presence of fiber in the extracts. When the system is feed with normal diet, we cannot observe any important changes, but at least a weak antimicrobial activity. Samples were also collected for microbial community characterization and quantification with qPCR, DGGE and Illumina, to better investigate the origin of these differences. HPLC/DAD/MS analysis will be performed on same samples to evaluate presence and amount of phenolic metabolites. These preliminary results suggest the use of these extracts as ingredients of supplements or functional foods, to improve the health of human microbiota and to provide an higher supply of polyphenols.