Progress of Cryogenics and Isotopes Separation

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The National Conference with international participation on New Cryogenic and Isotope Technologies for Energy and Environment - EnergEn 2018 is organized by the National Research-Development Institute for Cryogenic and Isotopic Technologies - ICSI Rm. Valcea with the scientific participation of the University of Pitesti and the University of Craiova and will be held at Baile Govora, in 2018.
CHANGES IN POLYPHENOLIC CONTENT OF BERRY SKINS FROM DIFFERENT RED GRAPES CULTIVARS DURING RIPENING Print

CHANGES IN POLYPHENOLIC CONTENT OF BERRY SKINS FROM DIFFERENT RED GRAPES CULTIVARS DURING RIPENING


Elisabeta-Irina Geană1,*, Roxana-Elena Ionete1, Violeta Niculescu1, Victoria Artem2, Aurora Ranca2


1National Research and Development Institute for Cryogenics and Isotopic Technologies – ICSI Rm. Valcea, Uzinei Street no. 4, PO Raureni, Box 7, 240050 Rm. Valcea, Romania;  2Research Station for Viticulture and Oenology Murfatlar, Murfatlar 905100, Romania

 

abstract

High quality wines are now increasingly popular, with a high impact to consumers, especially due to the numerous beneficial effects that phenolic compounds have on human health because of their antioxidant activity. The phenolic compounds are found in grape skin, seeds, and pulp of the berry, from where are extracted into wine. To produce high quality wines, the harvesting of grapes at a high phenolic maturity is mandatory.

In this work the phenolic composition of five red wine grape cultivars (Vitis vinifera L.) namely Pinot Noir, Feteasca Neagra, Cabernet Sauvignon, Merlot and Mamaia, originated from Murfatlar viticultural region, South-East Romania, during one ripening season, was characterized and assessed. Individual polyphenol composition and total polyphenols (TP), at different harvest dates, were determined by HPLC-PDA analysis and Folin-Ciocalteu spectrophotometric analysis.

The results showed that (+)-catechin, (-)-epicatechin and rutin were the most representative phenolic compounds in the grape skins, with concentrations between 10.0 ÷ 104.8 µg/100 g, 5.5 ÷ 150.1 µg/100 g and 1.9 ÷ 225.9 µg/100 g, respectively. During grape ripening there were significant changes in phenolic content of the grape skins, and this is important to determine the optimal harvest time, which will ensure grapes with very good quality parameters. Thus, phenolic maturity was reached early for Mamaia and Pinot Noir grape variety, with a maximum of TP values about 6.74 and 20.21 mg GAE/g respectively, while for Cabernet Sauvignon, Feteasca Neagra and Merlot grape variety, the maturity was achieved after a week, with a maximum of TP values about 15.02, 12.53 and 9.71 mg GAE/g respectively.

Keywords: phenolic compounds, grape skins, HPLC, UV-VIS.