Effect of superheated steam treatment on yield, physicochemical properties and volatile profiles of perilla seed oil

This study investigated the effect of superheated steam (SHS) treatment on the yield and quality properties, including volatile compounds of perilla seeds oil (PO). SHS treatment resulted in ruptured seed coat and damaged cellular structure, increasing oil yield (78.81 g/100 g seeds), about 2.5-times higher yield than the untreated seeds (33.11 g/100 g seeds). The viscosity (~89 mPa s), color parameters (L*a*b*), acid value (0.19 mg KOH/g), and peroxide value (1.02 meq/kg) of SHS-treated POs were similar with that of the untreated PO, indicating no oil rancidity by SHS treatment. SHS-treated PO showed a dramatic reduction of lipase activity from 37.44 to 0.80 μmol/g, 3-times higher phenolic content and 5-times higher antioxidant activity than that of the untreated PO. The major volatiles were 2,4-heptadienal, 4-methyl-5-(2-methyl-2-propenyl-2(5H)-furanone, 3-(4-methyl-3-pentenyl)furan perillen, and 3-methylpentane in POs. The normalized relative intensities of the volatiles were reduced for SHS-treated PO. Thus, SHS could be an effective treatment for high oil yield without originating odor characteristics compounds in PO.