The Influence of Pressing and Microwave Heating on the Production and Shelf life of Hemp Oil variety Finola

U ovom radu istraživan je utjecaj procesnih parametara hladnog prešanja sjemenki konoplje na iskorištenje ulja. Ispitivani su parametri frekvencija elektromotora, veličina otvora glave preše za izlaz pogače i temperatura grijača glave preše. Također je istraživan utjecaj mikrovalnog zagrijavanja na oksidacijsku stabilnost ulja konoplje, sa i bez dodatka antioksidansa i sinergista. Od prirodnih antioksidansa korišteni su ekstrakt ružmarina, ekstrakt kadulje, sintetski antioksidans BHA te sinergist limunska kiselina. Uzorci ulja zagrijavani su u mikrovalnoj pećnici kod konstante snage u različitom vremenskom periodu. Također su uzorci zagrijavani kod različite snage uređaja i konstantnom vremenskom periodu. Rezultat testa ubrzane oksidacije ulja konoplje izražen je peroksidnim brojem. Porastom frekvencije elektromotora i veličine otvora glave preše za izlaz pogače dolazi do smanjenja količine proizvedenog ulja konoplje. Porastom temperature glave preše povećava se proizvodnja sirovog ulja i hladno prešanog ulja. Mikrovalnim zagrijavanjem uzoraka ulja u vremenu 10-50 minuta dolazi do porasta temperature i peroksidnog broja, dolazi do porasta oksidacijskog kvarenja ulja. Najveća stabilnost ulja konoplje postignuta je kombinacijom ekstrakta ružmarina i sinergista limunske kiseline.In this study the influence of process parameters of cold pressing hemp seeds on yield oil was researched. Electric motor frequency, nozzle size and nozzle heater temperature were the investigated parameters. The effect of microwave heating to oxidative stability of hemp oil, with and without the addition of antioxidants and synergists, was also researched. Out of natural antioxidants there were used rosemary extract and sage extract, BHA synthetic antioxidant and citric acid synergist. Oil samples were heated in microwave oven at constant power in different time intervals. Samples were also heated with different appliance power and in constant period. The result of accelerated hemp oil oxidation test is expressed by peroxide number. The increase in electric motor frequency and nozzle size results in the quantity decrease of produced hemp oil. The increase in the nozzle size temperature increases the production of crude oil and cold pressed oil. Microwave heating of oil samples in the period of 10 to 50 minutes leads to the increase of temperature and peroxide number which further leads to oxidative degradation. The highest hemp oil stability was achieved by the combination of rosemary extract and citric acid synergists