First cut the head and tail, the surface of the layer of dry removed on it, not divided into purple and white, because there are purple onions and white onions. So steak it hand is not yellow.

Onion: alias ball onion, round onion, jade onion, scallion, Dutch onion, skin teeth, etc., . Liliaceae, onion genus biennial herbaceous plants. Onion contains prostaglandin A, can reduce peripheral vascular resistance, reduce blood viscosity, can be used to reduce blood pressure, refreshing, relieve stress, prevent colds. In addition, onions can also remove oxygen free radicals in the body, enhance metabolism, anti-aging, prevention of osteoporosis, is suitable for middle-aged and elderly health food.