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U ovom istraživanju određivana je oksidacijska stabilnost mješavine hladno prešanog lješnjakovog ulja i lanenog ulja u omjeru 50 : 50 sa i bez dodataka prirodnih i sintetskih antioksidanasa te sinergista. Primjenom standardnih metoda, određeni su parametri kvalitete ulja (peroksidni broj, slobodne masne kiseline). Antioksidansi koji su korišteni u ovom radu su ekstrakti nara, ružmarina i kadulje, eterično ulje konopljike, lavande, slatkog pelina, divlje mrkve, smilja, propil galat i mješavina tokoferola te sinergist limunska kiselina. Oksidacijska stabilnost ulja ispitivana je primjenom Oven testa. Rezultati ispitivanja prikazani su vrijednostima peroksidog broja tijekom 4 dana trajanja testa. Primjena ekstrakta ružmarina pokazala je bolju zaštitu mješavine ulja od oksidacije u odnosu na ekstrakt kadulje i nara. Dodatkom eteričnog ulja smilja i lavande postignuta je veća zaštita mješavine hladno prešanog lješnjakovog ulja i lanenog ulja prema oksidacijskom kvarenju. Dodatkom sinergista limunske kiseline, prirodnom antioksidansu ekstraktu ružmarina ostvarena je najveća zaštita mješavine ulja od oksidacijskog kvarenja. In this research was determined oxidation stability of mixture consisted of cold-pressed oil of hazelnut and linseed oil in ratio 50 : 50, with and without natural and synthetic antioxidants and synergists. Using standard methods it was defined oil quality parameter (peroxide number, free fatty acids). Antioxidants that were used in this research are: pomegranate extract, rosmary and sage extract, essential oils of hemp, lavander, sweet wormwood, wild carrot, immortelle, propyl galate, tocopherol mix and syinergistic citric acid. Oil oxidation stability was tested using Oven test. The results of testing are shown in peroxide number value during the 4 days of testing. Use of rosmary extract showed better protection of oil mixture from oxidation in comparison with pomegranate and sage extract. By adding essential oil of immortelle and lavander it was achieved greater protection of mixture consisted of cold-pressed oil of hazelnut and linseed to oxidation degradation. With the addition of synergistic citric acid to natural antioxidant rosemary extract, has been proven the highest protection against oil oxidation.

U ovom radu istraživana je oksidacijska stabilnost biljnih ulja i njihovih mješavina sa sezamovim uljem. Ispitivan je utjecaj dodatka prirodnih antioksidanasa ekstrakta ružmarina Oxy´Less CS (0,3%), ekstrakta ružmarina Oxy´Less CLEAR (0,3%) i ekstrakta maslinovog lista (0,3%) na oksidacijsku stabilnost odabranih biljnih ulja i njihove mješavine sa sezamovim uljem (50:50). Za ispitivanje oksidacijske stabilnosti korištene su sljedeće vrste biljnih ulja: sezamovo ulje, suncokretovo ulje, visokooleinsko suncokretovo ulje, Omega IQ ulje. Određivanje oksidacijske stabilnosti ulja, njihovih mješavina, te utjecaj dodatka antioksidansa provedeno je testom ubrzane oksidacije ulja – Schaal oven testom (63 °C). Rezultat oksidacije ulja izražen je peroksidnim brojem tijekom 4 dana testa. Dodatkom sezamovog ulja u druge vrste ispitivanih biljnih ulja došlo je do porasta stabilnosti mješavine ulja na oksidacijsko kvarenje osim kod mješavine sa visokooleinskim suncokretovim uljem. Prirodni antioksidansi ekstrakt ružmarina Oxy´Less CS i Oxy´Less CLEAR efikasnije štite ispitivana biljna ulja i njihove mješavine od oksidacijskog kvarenja u odnosu na dodatak ekstrakta maslinovog lista. Najbolje antioksidacijsko djelovanje kod ispitivanih ulja pokazuje primjena ekstrakta ružmarina Oxy´Less CS. In this study we have monitored the oxidative stability of vegetable oils and their blends with sesame oil. We examined the influence of the addition of natural antioxidants rosemary extract Oxy´Less CS (0,3%), rosemary extract Oxy´Less CLEAR (0,3%) and olive leaf extract (0,3%) on oxidative stability of selected vegetable oils and their blends with sesame oil (50:50). To test the oxidation stability we used the following types of vegetable oil: sesame oil, sunflower oil, higholeic sunflower oil, Omega IQ oil. Determination of oxidation stability of oils and their blends, and the influence of antioxidant adition was performed with rapid oils oxidation test – Schaal oven test (63°C). The result of oil oxidation is expressed as peroxide value during 4 days of the test. The addition of sesame oil in other vegetable oils that have been tested, we have observed that there was an increase in stability of oil mixture on oxidation degradation except for mixture with higholeic sunflower oil. Natural antioxidants Oxy´Less CS and Oxy´Less CLEAR are more effective in protecting the oils and their blends from oxidative deterioration compared to the addition of olive leaf extract. The best antioxidant activity of examined oils points to the use of rosemary extract Oxy´Less CS. It is by far the most efficent substance with high antioxidant activity.

Dobivanje ulja iz uljarica je složen tehnološki proces koji zahtijeva puno pažnje ukoliko se želi dobiti ulje zadovoljavajuće kvalitete. Sirovine koje se uzimaju za proizvodnju moraju biti zdrave i tehnološki zrele te spremne za preradu. Najzastupljenija biljna ulja u ljudskoj prehrani su suncokretovo ulje, maslinovo ulje, ulje bučinih koštica, ulje uljane repice i ulje kukuruznih klica. Procesi dobivanja biljnih ulja su različiti i svaki ima svoje prednosti i mane. Postoje dvije metode dobivanja ulja, a to su metoda ekstrakcije s organskim otapalom i metoda prešanja. Od samih početaka obje metode su napredovale i uređaji za dobivanje ulja su se usavršavali tako da danas imamo visoko iskorištenje ulja iz sirovine. Production of raw oil from oilseeds is complex technological proces which takes a lot of attention if we want to get oil of good quality. Raw materials that are taken for production have to be healthy and technologically mature and ready for processing. The most common vegetable oils in human nutrition are sunflower oil, olive oil, pumpkin seed oil, rapeseed oil and corn oil. Process of obtaining vegetable oil are different and each has its advantages and disadvantages. There are two methods of obtaining oil, method of extraction with organic solvent and method of molding. From the very beginning, both metods have advanced and devices have been improved so today we have a high yield of oil from raw materials.

Hidrogenacija masti je najrasprostranjenija pojedinačna reakcija u industriji jestivih ulja i masti, a sastoji se od direktne adicije vodika na dvostruke veze u lancu masnih kiselina. Hidrogenacija masti sastoji se od nekoliko operacija koje čine samu hidrogenaciju u užem smislu. Osim procesa hidrogenacije kao prateći procesi dolaze dobivanje vodika, priprema katalizatora, suspendiranje katalizatora u ulju i konačno odvajanje katalizatora iz hidrogenirane masti. Hidrogenirane masti se moraju nakon hidrogenacije rafinirati kako bi se izdvojio katalizator, zatim da se odstrane eventualno nastale slobodne masne kiseline kao i neugodan miris hidrogenacije. Hidrogenacija služi u velikoj mjeri u industriji sapuna, tehničkih ulja i industriji jestivih masti za pretvaranje ulja u krute ili plastične masti i za poboljšanje održivosti masti i ulja na oksidaciju i reverziju mirisa. Hydrogenation of fats is most widely used single reaction in the industry of eadible oils and fats and it consists of direct adition of hydrogen on double bonds in fatty acid chain. Hydogenation of fats is consisted with a couple of operations witch make hydrogenation in closer sense. Exept hydrogenation process, there are few processes that come with it like extraction of hydrogen, preparation of catalysts, suspending the catalyst in oil, and final separation of catalyst from hidrogenation fats. Hydrogenationed fats have to be refined so that the catalyst can be extracted, and to remove eventually created free fatty acids and the bad smell of hydrogenation. Hydrogenation is most widely used in soap industry, tehnical oils, eadible fat industry, and for transformation of oils in solid or plastic fats and to amplify the resistance of fats and oils to oxydation and change of smell.