Effect of Different Harvest Stages on Nutritional Components of Purple Yam

The effect of different harvest stages on nutritional components of purple yam had been studied in the open field. The results showed that the content of anthocyanins in purple yam turberous root was the highest, while the content of dietary fiber and starch moderate during the first harvest stage; the content of anthocyanins, dietary fiber and starch began to decline during the second harvest stage; the content of all three gained some instead during the third harvest stage and the content of dietary fiber and starch was the highest; the content of β-carotene and selenium in purple yam turberous root was stable during all harvest stages. In summary, the date between September 30 th and October 15 th which purple yam turberous root containing higher levels of nutrients and is the best harvest stage.