The invention discloses a purple yam beverage and a preparation method thereof. The purple yam beverage is obtained through the following steps: pretreating raw materials namely fresh purple yam, performing color protection,
mashing the purple yam after color protection, extracting anthocyan assisted by ultrasonic
waves, pressing and heating the purple yam without the anthocyan, treating the heated purple yam under a static state and extra-
high pressure for preparing
resistant starch, compounding the
resistant starch and the anthocyan so as to obtain a mixture, homogenizing the compounded mixture with nanometer, filling the homogenized mixture, and sterilizing the filled mixture at
high pressure so as to obtain the purple yam beverage. According to the purple yam beverage and the preparation method thereof disclosed by the invention, after the anthocyan and the
starch in the purple yam are separated, the
starch is prepared into the
resistant starch, and then the anthocyan and the resistant
starch are added step by step and are prepared, so that physiological functions of the anthocyan and the resistant starch can be fully utilized; besides, a nanometer homogenizing technology is utilized, so that the particle size of the resistant starch is decreased, and the stability and the mouth feel of products are improved; the prepared purple yam beverage is good in color and stability, is fine and smooth in mouth feel, has the efficacies of resisting
cancer, resisting oxidation and the like, is low in heat, is suitable for
obesity crowds to drink, is high in added value of products and is good in market prospects.