| Abstract | Nestabilnosti vina pridonose dušične tvari, proteini, polifenoli, mikroflora, soli kiselina itd.
Cilj stabilizacije je spriječiti mutnoću i taloženje pojedinih sastojaka vina. Postupci stabilizacije vina su bistrenje, taloženje, sumporenje i filtracija.
Filtracijom se iz vina uklanjaju grube i fine čestice mutnoće, na način da se vino propušta bilo kroz filtrirajuci sloj, ploče ili membrane. Filtracija može biti mehanička i membranska. Kod membranske filtracije na membrani zaostaju molekule i ioni. Membranski procesi su mikrofiltracija, ultrafiltracija, nanofiltracija i reverzna osmoza. Međusobno se razlikuju po mehanizmu i principu separacije, a zajednička im je membrana između dvije faze. Za filtraciju vina koristi se membranska filtracija. Tri su značajna faktora koja utječu na kapacitet: otpor koji pruža
materijal od kojeg je načinjena membrana, otpor zbog začepljenja pora membrane, te otpor taloga koji se prilikom procesa filtracije stvara na površini membrane. Kada ukupni otpor dosegne graničnu vrijednost, filtracija se mora zaustaviti, a membrana oprati.
U ovom radu istraživan je utjecaj mikrofiltracije na tvari arome i kemijski sastav vina sorte Graševina. Za filtraciju primijenjen je filter Microstar ukupne površine modula 20 m2. Promjeri kapilare iznose 1,5 mm unutarnji i vanjski 2,5 mm. Promjer šupljina membrane je 0,2 μm, a struktura membrane je asimetricna.
Membranska filtracija nije značajno utjecala na promjene kemijskog sastava i tvari arome vina. |
| Abstract (english) | There are several compounds that influence the instability of wine, such as, nitrogen compounds, proteins, polyphenols, microflora, acid salts etc. The aim of the stabilization is to prevent blurriness and sedimentation of certain ingredients of wine. Processes for wine stabilization are elutriation, sedimentation, sulphuration and filtration.
Through the process of filtration large and small particles of sediment are removed from wine, in a way that the wine is being filtrated either through the filtering layer, plate or membranes. Filtration can be mechanical and membrane based. Using the membrain filtration results in molecules and ions being sedimented on the membrane. Membranic processes are micro – filtration, ultra – filtration, nano – filtration and reverse osmosis. They differ in mechanisms and principles of separation, but have in common a membrane between the two stages. Membrane filtration is used for filtration of wine. There are three major factors that influence the capacity: resistance provided by the material of which the membrane is made of, resistance created due to obstruction of the membrane pore, and residue resistance that is being created on the membrane surface during the filtration process. When the ultimate resistance reaches its limitation value, filtration must be stopped, and the membrane has to be washed.
The objective of this study was to investigate the influence of microfiltration at the aroma substances and the chemical composition of wine sort Graševina has been explored. Microstar filter, with its total proportion of 20 m2 has been used for filtration. The diameters of the capillary amount
to 1,5 mm internal and 2,5 mm external. The diameter of the membrane cavities amounts to 0,2 μm, and the membrane structure is asymmetrical.
Membrane filtration didn't significantly affected chemical composition of wine and aroma substances. |
