Application of cold plasma in isolation of polyphenols from grape skin of grape pomace

Abstract

Komina grožđa koja zaostaje kao nusproizvod pri proizvodnji vina, značajan je izvor polifenola. Razvijene su brojne metode za ekstrakciju polifenola, ali se ispituju i nove metode ekstrakcije koje omogućuju bolje prinose i veću stabilnost tijekom ekstrakcije. Cilj ovog rada bio je ispitati utjecaj hladne plazme (proizvedena je pomoću metode visoko-voltažnog elektičnog pražnjenja) na izolaciju polifenolnih spojeva iz liofilizirane pokožice komine grožđa. Ekstrakcija je provedena primjenom vodenih otopina etanola (10%-tni, 30%-tni i 50%-tni etanol) pri sobnoj temperaturi, a ispitivan je i utjecaj frekvencije i vremena tretiranja. Najveći prinos polifenola (18,59 mg/g) ostvaren je uz upotrebu 50%-tne vodene otopine etanola pri frekvenciji od 120 Hz i vremenu tretiranja od 10 min.Grape pomace, which remains as by-product after wine production, is important source of polyphenols. A numerous methods for polyphenolic extraction are developed but also, there are new extraction methods that are examined and give better yields and higher stability during extraction. The aim of this work was to research the effect of cold plasma (it is produced by high voltage electrical discharge method) on isolation of polyphenolic compounds from lyophilised grape pomace. Extraction is conducted by using aqueous solution of ethanol (10%, 30% and 50%) and the influence of frequency and treating time were tested, too. The highest yield of polyphenols (18,59 mg/g) is achieved using 50% aqueous solution of ethanol at frequency 120 Hz, and treating time, 10 min