Optimization of Pumpkin Oil Recovery by Using Aqueous Enzymatic Extraction and Comparison of the Quality of the Obtained Oil with the Quality of Cold-Pressed Oil

The study was carried out to optimize pumpkin oil recovery in the process of aqueous extraction preceded by enzymatic maceration of seeds, as well as to compare the quality of the obtained oil to the quality of cold-pressed pumpkin seed oil. Hydrated pulp of hulless pumpkin seeds was macerated using a 2 % (by mass) cocktail of commercial pectinolytic, cellulolytic and proteolytic preparations (Rohapect (R) UF, Rohament (R) CL and Colorase (R) 7089). The optimization procedure utilized response surface methodology based on Box-Behnken plan of experiment. The optimized variables of enzymatic pretreatment were pH, temperature and maceration time. The results showed that the pH value, temperature and maceration time of 4.7, 54 degrees C and 15.4 h, respectively, were conducive to maximize the oil yield up to 72.64 %. Among these variables, the impact of pH was crucial (above 73 % of determined variation) for oil recovery results. The oil obtained by aqueous enzymatic extraction was richer in sterols, squalene and tocopherols, and only slightly less abundant in carotenoids than the cold-pressed one. However, it had a lower oxidative stability, with induction period shortened by approx. 30 % in relation to the cold-pressed oil.