Optimization of ethanol-water extraction of lignans from flaxseed

摘要

The optimal conditions for the extraction of lignans from flaxseed were determined.A second-order regression for rotation-orthogonal composite design was used to investigate the effects of three independent variables,namely ethanol concentration(%),extraction temperature(deg C),and extraction time(h)on the response,the acquired ratio of lignans.The independent variables were coded at five levels and their actual values selected on the basis of results of single-factor experiment.The second-order regression for rotation-orthogonal composite design consisted of 23 experimental points and 9 replications at the central point.Data were analyzed using MATLAB software.The results indicated that acquired ratio of lignans might be beyond 8% at a probability of 95% in the range of ethanol concentration:56.6-83.4%,extraction time:26.7-27.9 h,extraction temperature:38.7-40.1 deg C.And the optimal extraction conditions were ethanol concentration of 70%,extraction time of 28 h and extraction temperature of 40 deg C according to the analysis of response surface.In this condition,the experimental acquired ratio of lignans was 8.975%(w/w;lignans/defatted flaxseed powder),which is close to the predicted value(9.316%).