| Abstract | Pokožica komine grožđa potencijalni je izvor biološki aktivnih spojeva, a posebice polifenolnih spojeva. U ovom radu provedena je klasična ekstrakcija kruto – tekuće na dva različita uzorka pokožice komine grožđa. Za eksperiment 1 korištena je samljevena, a za eksperiment 2 prethodno osušena i samljevena pokožica komine grožđa. Pomoću dizajna eksperimenta provedena je analiza utjecaja temperature, vremena ekstrakcije, omjera krute i tekuće faze te brzina miješanja na učinkovitost ekstrakcija. Ekstraktima su određena fizikalna svojstva (vodljivost, TDS, pH) te kemijska svojstva (ukupni polifenoli i antioksidacijska aktivnost pomoću DPPH i FRAP metode). Procijenjeni optimalni uvjeti kako bi se dobila najviša koncentracija ukupnih polifenola i antioksidacijska aktivnost za eksperiment 1 iznosili su: t = 34 minuta i 15 sekundi, T = 80 °C, S/L = 10 g/L i rpm = 625 1/min dok su za drugi ekperiment
iznosili: t = 40 minuta, T = 80 °C, S/L = 15 g/L i rpm = 250 1/min. |
| Abstract (english) | The grape skin pomace is a potential source of biologically active compounds, especially polyphenolic compounds. In this study, a classical solid-liquid extraction was conducted on two different samples of grape pomace skin. For experiment 1, ground grape pomace skin was used, while for experiment 2, previously dried and ground grape pomace skin was used. Using experimental design, the analysis of the influence of temperature, extraction time, solid-liquid ratio, and mixing speed on the extraction efficiency was carried out. The extracts were analyzed for their physical properties (conductivity, TDS, pH) and chemical properties (total polyphenols and antioxidant activity using DPPH and FRAP methods). The estimated optimal conditions to obtain the highest concentration of total polyphenols and antioxidant activity for experiment 1 were: t = 34 minutes and 15 seconds, T = 80 °C, S/L = 10 g/L, and rpm = 625 1/min, while for the second experiment, they were: t = 40 minutes, T = 80 °C, S/L = 15 g/L, and rpm = 250 1/min. |
