PHYSICO-CHEMICAL CHARACTERIZATION OF SOME SOURCES OF GRAPE MARC FROM PIETROASA VINEYARD

'Grape marc' or 'Grape pomace' is a by-product resulting from wine production processes, consisting in seeds, skins and stalks. It can be a valuable source of bioactive substances such as polyphenols, antioxidants, proteins, carbohydrates. The physico-chemical properties of grape pomace can vary depending on factors such as grape cultivar, winemaking process, and storage conditions. The purpose of this study is to determine the physico-chemical properties of different sources of grape pomace (Busuioacă de Bohotin, Merlot, Burgund Mare, Fetească Neagră, Tămâioasă Românească and Riesling Italian cultivar). Results obtained in present paper showed that the samples of grape pomace have shown high values for compounds of interest, such as protein (from 11.01% for the Busuioacă de Bohotin grape cultivar to 14.80% for Fetească Neagră), carbohydrates (from 4.32 g% Merlot to 21.56 g% for the Pinot Noir), the amount of polyphenols (from 15.81 mg GAE/g DM on Busuioacă de Bohotin to 27.41 mg GAE/g DM on Fetească Neagră), and antioxidant activity (from 24.90 mg Trolox equivalent/g DM on Italian Riesling to 33.42 mg Trolox equivalent/g DM on Fetească Neagră).