Acid-heat pretreatment assisted aqueous enzymatic extraction of peony seed oil.

With dehulled peony seed as raw material, the effects of soaking peony seeds in citric acid solution, drying, and aqueous enzymatic extraction conditions on the extraction rate of peony seed oil were studied. The results showed that the optimal extraction conditions were obtained as follows: soaking peony seeds in 0.3 mol/L citric acid solution for 6 h and drying at 100°C, and enzymolysis for 1 h at solid-liquid ratio 1:5, 50°C and pH 4.5 with 0.5% complex enzyme, then extraction for 1 h at pH 9 and 50°C, repeated extraction of slag phase in the same condition with water phase after collecting free oil by centrifugation, breaking emulsion with papain. Under these conditions, the demulsification rate was 96.31 %, and the extraction rates of free oil and total oil were 55.31 % and 90.81 % respectively. The acid value and peroxide value of peony seed oil could meet the standard...