Optimization and evaluation of wheat germ oil extracted by supercritical CO2

A Box-Behnken design combined with response surface methodology (RSM) was used to optimize the parameters of supercritical CO2 extraction (SEE) of wheat germ oil. The quality of the oil and residual meal obtained by SFE and solvent extraction (SE) were evaluated from proximate analysis, fatty acid composition and antioxidant activity. A maximum oil yield of 10.46% was achieved under the optimal conditions of wheat germ particle size 60-80 mesh; water content 4.37%; pressure 30MPa; temperature 40 degrees C extraction time 1.7h. The oil obtained by SFE showed stronger DPPH radical scavenging ability than SE oil at the same concentration. The fatty acid composition of SEE oil was similar to SE oil. Higher contents of protein (34.3%) and lysine (2.47g/100g) were found in the residual meal obtained by SFE. The results show that oil and defatted meal obtained by SEE can be promising nutritional sources for food.