Monitoring of compositional changes during berry ripening in grape seed extracts of cv. Sangiovese (Vitis vinifera L.)

BACKGROUND Seed oil and flours have been attracting the interest of researchers and industry, since they contain various bioactive components. We monitored the effects of ripening on lipids, monomeric flavan‐3‐ols, proanthocyanidins and tocols concentration in seed extracts from organically cultivated cv. Sangiovese vines. RESULTS Linoleic acid was the most abundant fatty acid, followed by oleic, palmitic and stearic acids. The tocols detected were α‐tocopherol, α‐tocotrienol and γ‐tocotrienol. The proanthocyanidins degree of polymerisation ranged from dimers to dodecamers; moreover, monomeric flavan‐3‐ols and polymeric proanthocyanidins were detected. Total flavan‐3‐ols (monomers, oligomers and polymers) concentration in grape seeds decreased during ripening. CONCLUSIONS Fatty acids reached the highest level in post‐veraison. The concentration of these compounds varied considerably during ripening. Capric acid has been found for the first time in grape seeds. α‐Tocopherol and γ‐tocotrienol decreased during ripening, while α‐tocotrienol increased. The HPLC analysis with fluorimetric detection, conducted for the first time on cv. Sangiovese, revealed that the concentration of flavan‐3‐ols monomers, oligomeric proanthocyanidins and polymers greatly changed during ripening. These results suggest that the timing of bunch harvest plays a crucial role in the valorisation of grape seed flour. © 2016 Society of Chemical Industry