Choy sum has many names. It is also known as the Chinese flowering cabbage, 菜心 (cai xin), yow choy, and yow choy sum (those with yellow flowers).
I am familiar with it as cai xin, its mandarin name. However I believe in the US and other parts of the world, the cantonese equivalent, is a more common name. Chinese or Cantonese, the name literally translates as "heart of the vegetable".
If you are thinking of finding out more about this vegetable, its scientific name is brassica parachinensis. A mouthful, I know. The stems are pale green while the leaves are dark green.
Unlike the bok choy, the stems are slender and thin. The leaves are slightly bitter. Some people prefer the stems to the leaves.
It is supposed to contain a certain plant hormone that can increase the production of anti-carcinogenic protease. It also enhances the detoxification effect of the liver and is supposed to be quite good for boils and skin blemishes.
Like most Chinese vegetables, this asian vegetable has large amount of vegetable fiber which aids bowel movements and prevent constipation. The fiber also binds with bad cholesterol in other foods and eliminate it through the bowels. This reduces the amount of cholesterol absorbed by the body. It boosts immunity with its high beta-carotene and vitamin C levels.
Finally, cai xin has the highest level of calcium amongst vegetables. Sounds like a super vegetable right?
Yow choy is a very versatile vegetable. It can be prepared in so many ways. Quick-fry, braise, blanch and serve with other condiments, add to fried noodles, and to soups.
Many restaurants like to serve it blanched and drizzled generously with oyster sauce. It is best lined up in a bunch and cut into bite-sized sections using a knife. Do remove the roots first. After cutting, soak in cool water to remove dirt and grit.
Cook it fairly quickly after preparation. Do not leave it to stand for too long. Lastly, do not eat left-over choy sum. It is best consumed fresh.