Effect of Antioxidants and Synergists on the Shelf Life of Hemp Oil

Abstract

U ovom radu ispitan je utjecaj dodatka prirodnih i sintetskih antioksidanasa te sinergista na promjenu oksidacijske stabilnosti (održivosti) hladno prešanog konopljinog ulja. Od prirodnih antioksidanasa korišteni su ekstrakt ružmarina OxyLess CS, ekstrakt kadulje, alfa tokoferol, mješavina tokoferola, ekstrakt maslinove komine i katehin, a od sintetskih antioksidanasa propil galat te butil hidroksianisol. Kao sinergisti korištene su askorbinska i limunska kiselina. Efikasnost dodatka navedenih antioksidanasa i sinergista u stabilizaciji ulja određena je SchaalOven testom oksidacijske stabilnosti kod konstantne temperature 63 ⁰C. Također, primjenom standardnih metoda određeni su osnovni parametri kvalitete konopljinog ulja: peroksidni broj, slobodne masne kiseline, netopljive nečistoće i udio vlage. Rezultati pokazuju da je dodatkom prirodnih antioksidanasa postignuta bolja zaštita ulja od oksidacijskog kvarenja, nego dodatkom sintetskih antioksidansa. Najbolje djelovanje na usporavanje oksidacijskog kvarenja konopljinog ulja pokazao je ekstrakt ružmarina. Sinergisti su dodatno povećali otpornost ulja konoplje prema oksidacijskom kvarenju, a bolje sinergističko djelovanje pokazala je askorbinska kiselina.Aim of this study was to examine the influence of the addition of natural and synthetic antioxidants and synergists on the oxidative stability of cold pressed hemp oil. The natural antioxidants used were rosemary OxyLess CS extract, sage extract, alpha tocopherol, a mixture of tocopherol, olive pomace and catechin, and synthetic antioxidants propyl gallate and butyl hydroxyanisole. Ascorbic and citric acid were used as synergists. The effectiveness of the addition of these antioxidants and synergists in oil stabilization was determined by the Schaal Oven oxidation stability test at a constant temperature of 63 ⁰C. Also, by using standard methods, basic parameters of hemp oil quality were determined: peroxide number, free fatty acids, insoluble impurities and moisture content. The results showed that the addition of natural antioxidants results in better protection of the oil from oxidative deterioration than the addition of synthetic antioxidants. Rosemary extract showed the best effect in slowing down the oxidative degradation of hemp oil. Synergists further increased the resistance of hemp oil to oxidative degradation, and ascorbic acid showed better synergistic activity