Optimization and comparison of three methods on anthocyanins extraction from Blackcurrant (Ribes nigrum L.) using RSM

Response surface methodology (RSM) complemented with a central composite design (CCD) was employed to optimize and compare three different anthocyanins extraction methods (solid liquid extraction(SLE), ultrasonic-assisted extraction (UAE) and microwave-assisted extraction (MAE)) from blackcurrant fruits. The aim was to obtain extracts with high anthocyanins content, which would be potentially interesting for commercial applications as natural colorants. Three major independent variables such as extraction time(min), ethanol concentration (%,v/v), solution to solid ratio (mL/g) were coded at five levels and their actual values were selected on the basis of preliminary experimental results. Results indicated that the yields of anthocyanins varied when extracted with different method, the order of anthocyanins yield from high to low was: MAE (95.77%), UAE (93.65%) and SLE (90.82%). Among three reaction parameters, ethanol concentration consistently tended to significantly affect the anthocyanins yield for above three models (p < 0.0001). MAE was the best of three methods in this study and the optimal values were as follows: extract time controlled at 6.3 min, ethanol concentration maintained at 72.8%, solution to solid ratio equaled to 8.1:1 and working power at 400W. The experimental anthocyanins value under above optimum conditions could reach to 95.77 +/- 1.05% that was in perfect agreement with the predicted model 95.52%.