Utjecaj procesnih uvjeta i načina kruto-tekuće ekstrakcije na ekstraktibilnost fenolnih tvari iz sjemenki grožđa
This study was aimed to investigate the influence of solvent (water and aqueous ethanol: 50, 70 and 96%), solid-liquid ratio (10, 20, 30 and 40 mL/g), extraction time (10-200 minutes) and particle size (> 0.63mm, 0.63 - 0.4 mm, 0.4 - 0.16 mm and < 0.16 mm) on yield of solid-liquid extraction as well as influence of temperature (25, 40, 50, 60, 70 and 80 °C) on extraction kinetics of total and individual phenolic compounds. The effect of extraction method (water bath extraction, universal extraction system, combined supercritical fluid extraction and water bath extraction) on phenolic extractability, antioxidant activity and colour of extract was also investigated. The main mechanism of mass transfer during solid-liquid extraction was diffusion. The values of effective diffusion coefficient for total (0.2 - 1.96·10-10 m2/min) and individual (0.02 - 0.69·10-10 m2/min) phenolic compound increased with extraction temperature. All examined exponential mathematical models (modified Fick II, modified Henderson-Pabis and Page) and non-exponential model proposed by Peleg were suitable for describing extraction kinetics. However, Page model showed the best accordance between experimental and model predicted data which was confirmed by several relevant statistical criteria. The highest phenolic yield was obtained from grape seed particle lower than 0.63 mm during 200 minutes of extraction in water bath at 80 °C and solid-liquid ratio 40 mL/g by using 50% aqueous ethanol. Results obtained by universal extraction system were higher in average 6 - 35% in relation to water bath extraction. Oil elimination from grape seed under different regimes of supercritical fluid extraction (300 and 450 bar; 40 and 60 °C) had the positive effect on phenolic extractability by conventional solid-liquid extraction and on antioxidant activity of extracts. The influence of process parameters and extraction method on antioxidant activity and colour of extract was observed. Antioxidant activity of grape seed extracts was strongly correlated with total and individual phenolic content. Relationship between phenolic content and colour of extracts was observed.
|Creator||Bucić-Kojić, Ana (Search Europeana for this person)|
|Collection||Josip Juraj Strossmayer University of Osijek. FACULTY OF FOOD TECHNOLOGY. Department of Process Engineering. Sub-department of Unit Operations.|
|Subject Terms||BIOTECHNICAL SCIENCES. Food Technology. Engineering., Chemical technology. Chemical and related industries, Horticulture. Fruit growing. Viticulture. Gardening, extraction, phenolic compounds, grape seed, kinetics modeling, antioxidant activity|
|Provider||National and University Library in Zagreb|