EXTRACTION, PURIFICATION AND CHARACTERIZATION OF POLYPHENOLS FROM UVA DI TROIA AD ACINO PICCOLO SEEDS AND SKINS FOR THE DEVELOPMENT OF NEW NUTRITIONAL SUPPLEMENTS

The aim of this Ph.D. project was to study the phenolic composition of Uva di Troia ad acino piccolo (Uva di Troia with small berry) seeds and skins in relation to the vinification process, in order to create a new nutritional supplement based on the benefits of the phenolics extracted. This grape biotype represents an autochthonous Vitis vinifera L. grape variety of Apulia region (South Italy) and is supposed to have significant levels of polyphenols and a great wine aging potential. Grape samples were collected at four different fermentation stages (from no fermentation to complete fermentation), called thesis. The extraction of seeds was performed with a multi-step extraction by maceration either with ethanol or acetone in water and the extracts obtained were characterized by Reversed Phase Liquid Chromatography coupled to Diode Array Detector (RPLC-DAD). Finally, extracts were successfully purified with Ethyl acetate. On the other hand, skins were subjected to a single step extraction with methanol and the extracts were analyzed by RPLC-UV; only Thesis 1 skin extract was also purified using a synthetic adsorbent resin. Data obtained show that the phenolic content of both grape seeds and skins decreases from the beginning of fermentation to the end of the process; these results are related to the extraction of the active compounds by the must during vinification. Moreover, Uva di Troia ad acino piccolo seeds represent a rich font of Flavan-3-ols and further studies will be conducted to produce new nutraceuticals based on this vegetable matrix. Particularly, Thesis 2 seeds represent the best fraction because the partial fermentation allows the concomitant production of wine and of the polyphenolic phytocomplex.