Calories in Green onion, (scallion), bulb and greens, root removed

What makes green onion so powerful?

Most green onions sold in American supermarkets are simply bulb onions (Allium cepa) pulled from the ground before their bulbs swell. But true scallions — the variety that culinary traditions in East Asia have cultivated for centuries — belong to a separate species called Allium fistulosum, commonly known as the Japanese bunching onion. Unlike A. cepa, A. fistulosum genetically lacks the mechanism to form a swollen storage bulb; it will always produce straight, uniform stalks no matter how long it grows. This is why scallions in Chinese and Japanese markets tend to look more uniform and slightly sturdier than the supermarket green onions that often show a small bulge at the base. Nutritionally, the two halves of a scallion are surprisingly different. The green tops, exposed to sunlight, produce chlorophyll and accumulate fat-soluble vitamins — particularly vitamin K, which is nearly absent in the white stalk. The white base, by contrast, concentrates the organosulfur compounds responsible for the characteristic allium pungency. These sulfur compounds, including diallyl sulfides, are the same class of molecules that give garlic and onions their studied cardioprotective and antimicrobial properties, just in milder concentrations.