Production and stabilization of hazelnut oil with natural and synthetic antioxidants

Lješnjakovo ulje je zlatno-žute boje sa visokim udjelom oleinske kiseline te se svrstava u ulja oleinskog tipa. Cilj ovog istraživanja bio je ispitati utjecaj procesnih parametara prešanja na iskorištenje lješnjakovog ulja. Ispitan je utjecaj temperature zagrijavanja glave preše, frekvencije elektromotora i veličine otvora za izlaz pogače na iskorištenje ulja. Rezultati istraživanja pokazali su da je najbolje iskorištenje ulja postignuto primjenom sljedećih procesnih parametara: otvor otvora preše 8 mm, frekvencija elektromotora 20 Hz te temperatura 105 °C. Hladno prešanom ulju ispitan je utjecaj dodatka antioksidansa na oksidacijsku stabilnost primjenom testa održivosti na 98 °C. Korišteni su prirodni antioksidansi ekstrakt ružmarina, ekstrakt kadulje, α-tokoferol te sintetski antioksidans oktil galat. Najbolje antioksidacijsko djelovanje imao je ekstrakt ružmarina, a neznatno manje antioksidacijsko djelovanje pokazao je i sintetski antioksidans oktil galat.Hazelnut oil has yellow colour with shades of gold colour. This oil is enriched with oleic acid and because of that this oil is part of the oleic type of oil. The aim of this research was to analyze the effect of processing parameters on the amount of produced hazelnut oil during the process of pressing. The influence of temperature head presses, frequency and nozzle size on oil yield and quality was examined. The results showed that the most amount of oil is produced using following parameters: nozzle diametar 8 mm, electromotor frequency 20 Hz, temperature 105°C. The oxidative stability was monitored using the test of sustainability on 98°C. Natural antioxidants such as rosemary extract, sage extract, α- tocopherol and synthetic antioxidant octyl gallate were used. The best antioxidant effect had a rosemary extract, and a slightly less antioxidant effect was also obtained by synthetic antioxidant octyl-galate