The negative-pressure cavitation extraction (NPCE) technique was applied firstly to extract secoisolariciresinol diglucoside (SDG) from flaxseed cakes. The significant extraction parameters were screened by fractional factorial design (FFD). The optimal parameters were determined using the central composite design (CCD) with the two variables, NaOH amount and the liquid/solid ratio. The conditions of the extraction were optimized by using response surface methodology (RSM). Under the optimal conditions, the extraction yield and the extraction purity of SDG was 16.25 mg/g and 3.86%, respectively. The efficiency of NPCE was compared with that of conventional extraction methods. Our results demonstrated that NPCE was comparable to the well-known ultrasound-assisted extraction in term of extraction yield and purity. This extraction technique has advantages of less time-consuming, low solvent usage and high throughput capability.
Keywords: flaxseed cake; negative-pressure cavitation extraction; pilot-scale application; response surface methodology; secoisolariciresinol diglucoside.