Phenolic compounds extractability from Melnik 55 grape solid parts during fruit maturity

Abstract

Samples from Melnik 55 grape variety (Vitis vinifera) were collected from different stage of grape maturity. Grape seeds and skins from each sample were separated and extracted with model wine solutions with increasing alcohol content simulated alcohol accumulation during wine fermentation. Total phenolic compounds, anthocyanins, skin pigments and tannins in each sample were determined. During grape ripening not only total phenols content of grape skins and seeds are changed but also their extractability. Ethanol released during wine fermentation is strong phenol extragents but its role is getting smaller as riper is the grape. This tendency is more pronounced in seeds phenolics extractability than in skins.