Process for preparing concentrated solution of fresh siraitia grosvenorii by adopting membrane separation technology

The invention discloses a process for preparing a concentrated solution of fresh siraitia grosvenorii by adopting a membrane separation technology. The process comprises the steps that the fresh siraitia grosvenorii is firstly crushed and repeatedly immersed in water at a temperature of 40 to 95 DEG C for 6 to 16 hours; a filtrate is obtained after the fresh siraitia grosvenorii is pretreated and filtered, and the temperature is reduced to 25 to 55 DEG C; the filtrate is sequentially sent into an integrated membrane combination system under pressure of 0.05 to 3.0MPa via a pressure pump, so as to be gradually separated, purified and concentrated by combinational membrane pieces comprising a MF (microfiltration) membrane piece, an UF (ultrafiltration) membrane piece, an RS (reverse osmosis) membrane piece, and the like; and a concentrated solution product of the fresh siraitia grosvenoriim, which has a baume degree of 16 to 35, is finally obtained. The process method disclosed by the invention has the advantag