The invention belongs to the technical field of extraction of
plant ingredients, and discloses a method for preparing
neohesperidin in physiological fallen fruits of grapefruits by an
alcohol / salt double-water-phase
system. The method comprises the following steps: collecting dry grapefruit physiological fallen fruits; crushing the dry grapefruit physiological fallen fruits; pulverizing the dry grapefruit physiological fallen fruits; preparing and constructing a double-water-phase
system; carrying out hot dip extraction; carrying out separation and
phase splitting by a liquid-liquid-
solid three-phase disc separating
machine; concentrating; carrying out water
sedimentation crystallization and filtering; carrying out ultra-
filtration film assisted hot water recrystallization purification; carrying out cooling
crystallization; and carrying out
drying and packing. Advanced processes such as dip extraction through isopropanol / NaH2PO4 inorganic salt double-water-phase
system, ultra-
filtration film assisted hot water recrystallization purification and the like are adopted, and the whole process has the advantages of short production period, mild extracting conditions, simplicity and convenience in operation,
high selectivity to target products, good product quality, small amount of waste water, easiness in treatment and the like, the yield of the prepared
neohesperidin reaches 5.7%, and the HPLC content is greater than or equal to 95%.