Decoloration of raw oil

Dekoloracijom se iz ulja uklanjaju prvenstveno pigmenti, ali i fosfolipidi, tragovi metala, hidroperoksidi, preostali sapuni i drugi nepoželjni sastojci ali i neki prirodni spojevi kao što su vitamini i antioksidansi. Karakteristična žuta boja većine prirodnih ulja potječe od raznih karotenoidnih pigmenata koji se mogu svrstati u grupu lipokroma i u grupu ugljikovodika. Uz te prirodne pigmente u uljima se često nalaze i produkti raspadanja ili oksidacije zbog loše sirovine ili kao posljedica loše vodenog tehnološkog procesa. Uklanjanje obojenih tvari nije u svakom slučaju nužno potrebno ali zahtjevi potrošaća su takvi da traže bistro i pravilno obojeno ulje, a kako obojene tvari koje su ušle u tehnološki proces mogu utjecati i na miris i okus ulja, dekoloracija ulja je postala sastavni dio procesa rafinacije ulja, te se ne koriste samo u slučaju gdje to tradicija i kultura nekog naroda ne dopušta. Dekoloracija ulja može se provesti adsorpcijom i kemijskim sredstvima. Većinom se koristi dekoloracija adsorpcijom, dok se kemijske metode na bazi oksidacije i redukcije uglavnom koriste pri dekoloraciji tehničkih ulja.Decoloration is the proces of rejection pigments, on the first place, then phospholypids,metal marks, hydroperoxydes, soaps and other unacceptable ingredient, some natural compounds like vitamins and antioxidants.Characteristic yellow colour of the most natural oils comes from various carotenoid pigments which are particles of group of lypocroms and hydrocarbons.Besides natural pigments, in oils, there are products of demposition or oxidation which are consequences of lousy raw material or wrong technological process.The rejection of coloured compounds is not always necessary, but because of consumer's demands for clear and regular coloured oil, decoloration becomes a part of rafination process. Coloured compounds, which are in technological process, can have an influence on smell and taste of oil, but decoloration doesn't use only in the case where tradition and the culture of paticular nation doesnt allow it. Decoloration of oils conduts trough adsorption and chemical agens. Therefore, decoloration with adsorption uses mostly as a process in the rafination of oil, whereas chemical methods based on oxidation and reduction uses during decoloration of technical oils