Abstract:

Optimal hot water extraction of polysaccharides from Radix Asparagi was explored using central composite design (CCD) combined with response surface methodology (RSM). CCD experimental data were fitted to create two mathematical models describing yield (Y1) and purity (Y2) of Radix Asparagi polysaccharides (RAP) obtained at different levels of critical parameters, such as extraction temperature and time and material/liquid ratio. Results showed that the above parameters all had a remarkable effect on Y1 and Y2, and extraction for 4.2 h at 78 ℃ with a material/liquid ratio of 22:1 (mL/g) resulted in an optimal compromise between Y1 and Y2. The observed values of Y1 and Y2 were 5.24 % and 26.42%, respectively, exhibiting a good agreement with their predicted values. This reveals the good applicability and feasibility of RSM for optimizing extraction process of polysaccharides from Radix Asparagi.

Key words: Radix Asparagi polysaccharides, extraction, response surface methodology, overlay contour plot