Optimization of extraction technology by response surface methodology and inoxidizability of saponins from black bean

In this paper, black beans as raw material, the response surface methodology ( RSM) was used to optimize the extraction process of saponins from black bean.Based on one-factor-at-a-time experiments, extract yield of the saponins was used as response for establishing a quadratic regression model. The effects of solvent and solvent concentration, solid-liquid ratio, extraction temperature and time, particle size, p H on the yield of saponins from black beans were investigated. The study results showed that the optimum conditions for extraction of saponin from black bean as follows: extraction solvent 80%ethanol, extraction temperature 80 ℃, solid-liquid ratio 1 ∶ 45 ( g/m L) , extract for 150 min, particle size 40 mesh of raw materials, p H9, the yield of saponins from black beans was 0.72%. The antioxidant activity study showed that abilities of saponins in black beans to scavenge DPPH and hydroxyl radical and superoxide anion were good and the half-scavenging concentration ( IC₅₀) were 0.0506, 0.148, 0.172 mg/m L respectively.Optimization of the extraction process by RSM of saponins of black bean is convenient and feasible. Saponins of black bean has good antioxidant activity and is worth to develop for application.