The production and stabilization of cold-pressed plum kernel oil

Postupkom hladnog prešanja iz koštice šljive (Prunus domestica L.) dobije se kvalitetno jestivo ulje. Cilj ovog rada bio je ispitati utjecaj procesnih parametara prešanja koštice šljive na efikasnost proizvodnje hladno prešanog ulja te njegovu kvalitetu. Prilikom prešanja mijenjani su sljedeći procesni parametri: frekvencija elektromotora (brzina pužnice), temperatura zagrijavanja glave preše i nastavak za izlaz pogače. Prešanje je provedeno s kontinuiranom pužnom prešom. Primjenom standardnih metoda određeni su osnovni parametri kvalitete proizvedenog hladno prešanog ulja. Ispitan je i utjecaj dodatka antioksidanasa na oksidacijsku stabilnost ulja primjenom Testa održivosti na 98 °C. Korišteni su sljedeći prirodni antioksidansi: ekstrakt zelenog čaja, ekstrakt ružmarina i eterično ulje primorskog vriska te sintetski antioksidans oktil galat. Rezultati ispitivanja pokazuju da procesni parametri hladnog prešanja značajno utječu na iskorištenje ulja koštice šljive. Veće iskorištenje sirovog ulja i hladno prešanog ulja postignuto je kod temperature zagrijavanja glave preše 100 °C, frekvencije elektromotora 35 Hz i nastavka za izlaz pogače 10 mm. Dodatkom prirodnih antioksidanasa postignuta je bolja zaštita ulja od oksidacijskog kvarenja nego dodatkom sintetskog antioksidansa. Eterično ulje primorskog vriska pokazalo je najbolji antioksidacijski utjecaj.The cold pressing of the plum kernel (Prunus domestica L.) is used to obtain high-quality edible oil. The aim of this study was to investigate the influence of process parameters of pressing plum kernel on the efficiency of production of cold-pressed oil and its quality. Following process parameters were investigated: electromotor frequency, temperature of head presses, and nozzle size. Pressing was carried out with a continuous screw press. Using standard methods, the basic quality parameters of produced cold pressed oil were determined. Oxidative stability of oil with added antioxidants was determined by the test of sustainability at 98°C. Natural antioxidants such as green tea extract, rosemary extract, winter savory essential oil and synthetic antioxidant octyl gallate were used. The results showed that the process parameters of cold pressing had a significant impact on the yield of plum kernel oil. Higher yield of crude oil and cold-pressed oil was obtained at a temperature of heating head presses 100°C, electromotor frequency of 35 Hz and using nozzle size of 10 mm. The results showed that natural antioxidants have greater protection of oil in comparison to synthetic antioxidants. Winter savory essential oil had the best antioxidant effect