Optimization of extraction process of crude polysaccharides from Plantago asiatica L. by response surface methodology

Polysaccharide production from the aerial parts of Plantaoo asiatica L. was carried out using water decoction. Response surface methodology (RSM), based on a five level, four variable central composite design (CCD), was employed to obtain the best possible combination of extraction time (X1: 1–5 h), extraction temperature (X2: 60–100 °C), number of extraction (X3: 1–5), and ratio of water to raw material (X4: 10–30) for maximum polysaccharide production. The experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis and also analyzed by appropriate statistical methods (ANOVA). The optimum extraction conditions were as follows: extraction time of 3.9 h, extraction temperature of 91 °C, number of extraction of 4, and ratio of water to raw material of 24. Under these conditions, the experimental yield was 4.37 ± 0.13%, which is well in close agreement with value predicted by the model.