Purple Chinese yam resistant starch and preparation method thereof

The invention discloses purple Chinese yam resistant starch and a preparation method thereof, and belongs to the field of food processing. Purple Chinese yams are utilized as a raw material of the purple Chinese yam resistant starch; and the purple Chinese yam resistant starch is prepared by the following steps: preparing purple Chinese yam starch, conditioning an emulsion, carrying out enzymolysis, carrying out washing by using water, carrying out aging, carrying out purifying, carrying out ethanol treatment, carrying out vacuum drying, carrying out crushing, and carrying out sieving, so that the resistant starch is prepared. The preparation method solves the outstanding problems of purple Chinese yam resistant starch during the preparation processes, including low resistant starch purity, low whiteness and so on; and the prepared purple Chinese yam resistant starch is high in purity, good in anti-digestion effects, and fine in color and luster. The purple Chinese yam resistant starch and the preparation met