Quality Evaluation of Anthocyanin Extract Obtained from Wine Grape Pomace

Mirjana Bocevska, Vasilka Stevčevska

Faculty of Technology and Metallurgy, The ''Sv. Kiril and Metodij'' University, Ruđer Bošković 16, 91000 Skopje, Republic of Macedonia

Article history:
Received February 28, 1996
Accepted December 18, 1996

Key words:
anthocyanins, grape pomace, multistep extraction, purity of the extract

Summary:
Extraction of anthocyanins from wine grape pomace (grape variety "Vranec") with water containing 0.05-0.5% SO₂ was investigated. A multistage extraction was performed using minimal pomace to solvent mass ratio 1:3 that enabled soaking of pomace, as well as a mass ratio 1:5. Content of anthocyanins and ballast-tannins and nitrogen compounds, were determined in the extracts. The degree of extract purity was estimated by so called quality indicator (QI) value. It indicates the difference between the anthocyanin yield and the average ballast yield. The extracts purity increases as SO₂ concentration increases. The extracts obtained with mass ratio 1:5 were purer.