Results and discussion
3.1. Method optimization
3.1.1. Selection of extraction solvents
Acetone, acetonitrile and ethyl acetate are often used. Each has
advantages and disadvantages. Acetone is miscible with water, and
it was difficult to separate acetone from the water phase. Because
of its polarity, acetone was able to extract more impurities from
the sample, pigment in particular. The water content of bitter
gourd is 93.48%, so acetonitrile has more advantages. It is miscible
with water, and can be separated easily by using salt. And
acetonitrile did not extract as much pigment, flavone, and other