Phenolic compounds in Merlot wines obtained through different technologies in Iaşi vineyard, Romania

Abstract

Obtaining red quality wines depends on the raw matter composition and also on the extraction technology, used in the processing of grape and must. Thus, two methods of maceration-fermentation on lees (classical and in rotating tanks), two thermal methods (thermomaceration and microwave maceration) and two methods rarely used industrially in wine-making (cryomaceration and ultrasound maceration) were experimented. Even in the years with less than favorable climatic conditions, from Merlot grape variety one obtained for the most part, legally speaking, quality wines (with the exception of microwave macerated and cryomacerated wines, which had only 21–22 g/L non-reducing extract. In regard to alcohol content, all obtained samples had more than 11% vol. The obtained Merlot wines were rich in glycerol (8–9 g/L), fact that favorably influenced their organoleptic traits. Total phenolic content had values between 1,97 and 2,86 g/L for the Merlot wines obtained through macerationfermentation and thermomaceration. Ultrasound maceration did not favor phenolic extraction from grape skins and the obtained wines were poor in anthocyans and tannins (0,94–1,1 g/L). In regard to the maceration technology used, free anthocyans were found in variable proportions in wines, between 77 and 91%. The sum of acylated anthocyans participation percentages was between 8,8 and 22,7%, and the ratio between the acetylated and cumarilated participation percentages registered small values, varietyspecific, between 1,1 and 2,8.