Studio dei metaboliti chimici dell'uva finalizzato a valutare le potenzialità enologiche, nutraceutiche ed industriali di alcune varietà di vite e nuovi approcci di metabolomica
Grape, wine and oenology by-products are rich in polyphenols and in particular flavonoids: flavonols, anthocyanins, flavanols and proanthocyanidins. Those molecules are plants secondary metabolites and may also contribute to the bitterness and astringency of grapes and wines. In recent years, epidemiological studies have revealed the great potential of polyphenols and flavonoids in human diet on protection against cancers, infections, their role in anti-aging and also against the development of several chronic diseases such as cardiovascular diseases (CVDs) or diabetes. Their role for human health is attributed mainly to their antioxidant, anti-inflammatory, antimicrobial activities. Therefore these bio-compounds could find promising applications in pharmaceutical, nutraceutical and food industries as active ingredients in supplements with antioxidant activity, value-added ingredients in fortified foods or as natural dyes and preservatives.
The aim of this research is to investigate the contents of chemical metabolites in several unique Vitis vinifera varieties and hybrids, and to examine their potential for oenological, nutraceutical and industrial applications. Modern spectrophotometry, chromatography and mass spectrometry (MALDI/MS, LC/MS, GC/MS) analytical techniques were applied in order to achieve the aims of the research.
Nine Vitis vinifera italian native grape varieties from Friuli Venezia Giulia and Veneto regions, were investigated for their enological potential, by studying the main classes of polyphenols and aroma compounds of grapes and their organoleptic wine characteristics.
In addition 32 hybrid varieties (21 red, 11 white) that belong to the CRA-VIT Grapevine Germplasm Collection located in Conegliano (TV) were studied to evaluate their nutraceutical and industrial potential.
The study of anthocyanins of red hybrids showed that some varieties (e.g. Seibel 8357) have rich content of pigments and are therefore attractive for the production of natural dyes that are used in the food and pharmaceutical industry. Moreover, some varieties (Bacò 1 and Seibel 10878) were also found interesting for their triglycerides content in grape seed oil with high linoleic acid content (up to 70%), which is essential fatty acid effective in reducing LDL cholesterol.
The nutraceutical potential of hybrid varieties was investigated by studying grape seed proanthocyanidins. Oligomeric and polymeric proanthocyanidins with different degree of galloylation were determined in grape seed extracts suggesting potential application of the extracts as antioxidants in nutraceutical products and also as oenological tannins.
Eventually, a new methodology was established for grape metabolome study based on High-Resolution Mass Spectrometry (HR-MS) analysis and the “suspect screening analysis” approach. This method was proved to be very effective due to the ability to identify hundreds of compounds in one single run and also individual classes of grape polyphenol
