A method for preparing mogroside V by molecular distillation, comprising the steps of:
1) After crushing the Luo Han Guo, pass through a 40-60 mesh sieve to obtain the Luo Han Guo powder. Weigh 60 g of Momordica grosvenori powder into a 1000 mL round bottom flask, add 500 mL of ethanol with a volume concentration of 80% to the round bottom flask, put the round bottom flask into an ultrasonic cleaner, and ultrasonically soak it under the condition of 200 KHz for 30 min;
2) After ultrasonic immersion, heat the round-bottomed flask with an electric heating mantle, and conduct reflux extraction for 5 h. After reflux extraction, suction filter and collect the filtrate. The filtrate is concentrated under reduced pressure to remove most of the solvent to obtain Luo Han Guo extract (this extract is a viscous fluid paste), and the yield of Luo Han Guo extract is 30.12%;
3) The Luo Han Guo extract was subjected to the first molecular distillation under the conditions of scraper rotation speed of 140 rad/min, distillation temperature of 40 °C, distillation pressure of 0.1 Pa, and feed rate of 0.3 mL/min to obtain the light The yield of fraction 1#, heavy fraction 2#, and Luo Han Guo heavy fraction 2# was 36.51%;
4) Heavy component 2# was subjected to the second molecular distillation under the conditions of scraper rotation speed of 70 rad/min, distillation temperature of 60°C, distillation pressure of 0.1 Pa, and feed rate of 0.5 mL/min to obtain mogroside-containing Light component 3# of V (the yield of light component 3# of Luo Han Guo extract is 3.63%),
Light fraction 3# containing mogroside V was freeze-dried for 24 h in a freeze dryer to obtain white powder crystals, which was the finished product of mogroside V.
A method utilizing subcritical and molecular distillation to jointly prepare mogroside V, comprising the steps of:
1) Grind the Luo Han Guo with a mortar and pass through a 40-60 mesh screen to obtain the Luo Han Guo powder;
2) Take 200 g of Luo Han Guo powder and place it in a subcritical extraction kettle, add 1200 mL of n-butane and dimethyl ether with a volume ratio of 1:1 into the subcritical extraction kettle as the extraction agent, and extract at the extraction temperature of 10 °C and the extraction pressure Extract for 3 hours under the condition of 2.0 MPa to obtain Luo Han Guo extract;
3) The Luo Han Guo extract was concentrated under reduced pressure to remove 60% of the extractant, and then the distillation temperature was 50°C, the distillation pressure was 0.01 Pa, the scraper speed was 50 rad/min, and the feed rate was 0.1 mL/min. Mogroside V was obtained by molecular distillation at low temperature to obtain light components containing mogroside V, which were then freeze-dried for 24 h in a freeze dryer to obtain white powdery crystals, which was the finished product of mogroside V, with a yield of 13.65%.
The finished product of mogroside V prepared above was subjected to high performance liquid phase detection, and the detection results showed that the purity was 96.95%.