| Abstract | Cilj ovog rada bio je ispitati utjecaj brzine miješanja, koncentracije emulgatora i udjela ulja na zeta potencijal emulzija ulja u vodenim ekstraktima mente s dodatkom tri emulgatora (PEG1500, PEG6000 i PEG20000). Optimiranje uvjeta emulgiranja provedeno je metodom odzivnih površina (eng. Response Surface Methodology, RSM). Određeni su optimalni uvjeti pripreme emulzija mente, koji su omogućili pripremu emulzija ulja u vodenim ekstraktima kadulje, lavande, majčine dušice, melise i mente s dodatkom PEG emulgatora. Emulzijama koje su pripremljene pri optimalnim uvjetima ispitivana su fizikalna (zeta potencijal, vodljivost, Feretov promjer) i kemijska (ukupni polifenoli, antioksidacijska aktivnost) svojstva. Dobiveni optimalni uvjeti procesa emulgiranja su: za PEG1500 koncentracija emulgatora 2,10 %, udio uljne faze u emulziji 34,99 %, brzina miješanja 15250 rpm; PEG6000 koncentracija emulgatora 3,52 %, udio uljne faze u emulziji 35 %, brzina miješanja 15000 rpm; PEG20000 koncentracija emulgatora 2,04 %, udio uljne faze u emulziji 25,98 %, brzina miješanja 15900 rpm. |
| Abstract (english) | The aim of this study was to examine the influence of mixing rate, emulsifier concentration and oil content on zeta potential of oil emulsions prepared with aqueous mint extracts with the addition of three emulsifiers (PEG1500, PEG6000, PEG20000). The optimization of the conditions of the emulsification was performed by the response surface methodology (RSM). Optimal conditions for the preparation of mint emulsions were determined, which enabled the preparation of oil emulsions in aqueous extracts of sage, lavender, thyme, lemon balm and mint with the addition of PEG emulsifiers. The emulsions were tested for physical (zeta potential, conductivity, measurement of average Ferret diameter) and chemical (total polyphenolic content, antioxidant activity) properties. The obtained optimal conditions of the emulsification process are: For PEG1500 emulsifier concentration 2.10 %, oil phase content 34.99 %, mixing rate 15250 rpm; PEG6000 emulsifier concentration 3.52 %, oil phase content 35 %, mixing rate 15000 rpm; for PEG20000 emulsifier concentration 2.04 %, oil phase content 25.98 %, mixing rate 15900 rpm. |
