Abstract: In this study, cold-pressed hemp seed cake was pulverized and hydrolyzed sequentially by Viscozyme L and alkaline protease Protex 6L, followed by low-temperature re-pressing. Cold-pressed hemp seed cake, produced at 50 ℃ and 3.5 MPa, was found to still contain 21.6% oil. It was pulverized to pass through a 60 mesh sieve and hydrolyzed with 3.0% (m/m) Viscozyme L for 4.5 h. A maximum oil yield of 65.0% was obtained after 2.8 h of hydrolysis with 1.1% Protex 6L at pH 10 and pressing at 52 ℃ and 3.5 MPa, as determined by response surface methodology. The secondary hemp oils obtained with and without enzymatic hydrolysis were compared for their physicochemical properties and contents of cannabinoids and tocopherols. Our results showed that enzyme-assisted low-temperature re-pressing had the advantages of high oil yield, stable physical and chemical properties, and enhanced migration of functional ingredients to the oil phase. This method provides a new theoretical basis and approach for the industrial production of hemp seed oil.

Key words: hemp seed, low-temperature virgin oil pressing, enzyme-assisted re-pressing, oil yield