Enzymatic extraction of oil from Gevuina avellana , the chilean hazelnut

Chilean hazelnut ( Gevuina avellana ) oil is highly appreciated in the cosmetic and pharmaceutical industries. Hazelnut oil (oil content calculated on 49% dry basis) is traditionally obtained by pressing, a low‐efficiency process that results in a low‐quality product. In this work, the conventional process was compared with two enzymatic alternatives in which commercial enzymes were used to increase the oil extraction yield: (i) extraction in aqueous medium and (ii) extraction by pressing after an enzymatic treatment. The effect of various parameters on the extraction yield was studied to define the most satisfactory processing conditions. These included reaction time, temperature, enzyme concentration, and, in the aqueous medium extraction process, the water/seed ratio, particle size, and pH. Although pressing is the better alternative, in both processes enzyme treatment improved extraction yields (94 and 98% for aqueous medium extraction and pressing after enzyme treatment, respectively, compared to 52% obtained in the conventional process). Moreover, the quality of the oil obtained is the same as or better than that of oil obtained by the conventional process.