Influence of early seeds removal on the physicochemical, polyphenolic, aromatic and sensory characteristics of red wines from Gaglioppo cv

The technique of seeds removal during the fermentative maceration was conceived to limit the extraction of polyphenols from the seeds in order to reduce the natural wine astringency. The influence of this oenological practice on the polyphenolic composition of Gaglioppo wines was studied during three vintages (2010-2012): the wines produced in the presence (WS) or absence (WOS) of seeds were compared for the physicochemical, polyphenolic and volatile composition, as well as for the sensory characteristics. Seeds removal did not cause any important modification in the general physicochemical composition of wines. Regarding polyphenols, no differences in total anthocyanins content were observed between the trials, but a significantly lower total polyphenols content was observed in the WOS wines, regarding in particular total flavonoids, low molecular weight flavans and condensed tannins. Qualitative variations in the composition of condensed tannins were also observed: the WOS wines had a higher mean degree of polymerization (mDP) and a lower galloylation degree. Finally, minor differences in the aromatic profile due to the seeds removal technique were observed between the trials. Despite the important modifications of the polyphenolic composition, the sensory characteristics of the wines, on the whole, were not affected: a significant decrease of the bitter taste in the WOS trial was noticed only in vintage 2010.