Scallions (spring onions) are leafy herbs in the allium (lily) family of tunicate bulb vegetables which also includes onion, shallots…etc. Precisely speaking, the term "spring onion" denotes to bulb along with its top greens of Allium fistulosum (Welsh onion) plant, a sub-species in the large onion (allium) family, especially in the west (Europe). The other name of spring onions is green bunching onions.
In general, spring onions are young, immature plants harvested much earlier before the plant grows further bigger and its bulb becomes larger in size. For the same purpose, the crop is planted closely in the field in order to stunt their bulb's growth.
|Beautiful, tender scallions!
Photo courtesy: jorge-11
Unlike its fellow members such as A.cepa (onion), and A.cepa aggregatum (shallots) which produce large underground bulbs, Allium fistulosum (welsh onion) are non-bulbing and cultivated purely for their top crispy greens.
Allium fistulosum (welsh onion) is a perennial, native to the Central Asian region and now widely grown in many parts of Europe, Americas, and Asia. Generally, on the cross-section, its leaves are round whereas, the other allium varieties feature semicircular tubules.
Scallions feature long, slender, erect stalks, rising above a small, elongated root (bulb) from which many straight, hollow, tubular leaves grow.
Scallions are very low in calories; 100 g of fresh leaves provide just 31 calories. Nonetheless, they contain many noteworthy flavonoid anti-oxidants, plant fiber, minerals, and vitamins that have proven health benefits.
Being leafy greens, scallions naturally carry more plant-derived antioxidants, and dietary fiber than their fellow bulb (Allium) members like onions, shallots, etc. 100 g fresh spring onions provide 2.6 g or 7% of daily recommended levels of fiber.
Scallions, like leeks, possess proportionately fewer thiosulfonates antioxidants than that in the garlic. Thiosulfonates such as diallyl disulfide, diallyl trisulfide, and allyl propyl disulfide convert into allicin through enzymatic reaction when its leaves subjected to crushing, cutting, etc. Laboratory studies show that allicin reduces cholesterol production by inhibiting the HMG-CoA reductase enzyme in the liver cells. Further, it also found to have antibacterial, antiviral, and anti-fungal activities.
Allicin decreases blood vessel stiffness by release of nitric oxide (NO), and thereby, bring a reduction in the total blood pressure. Also, It inhibits platelet clot formation and has fibrinolytic action in the blood vessels, which helps decrease an overall risk of coronary artery disease (CAD), peripheral vascular diseases (PVD), and stroke.
Spring onions contain a good proportion of vitamin-A (997 IU or 33% of RDA per 100 g) and other flavonoid phenolic antioxidants such as carotenes, zeaxanthin, and lutein. Together, they help the body protect from lung and oral cavity cancers.
They also have some other essential vitamins such as vitamin-C, and K. In fact, scallions are one of the richest sources of vitamin K. 100 g of fresh greens provides 207 µg or about 172% of daily recommended intake of this vitamin. Vitamin K has a potential role in bone health by promoting osteoblastic (bone formation and strengthening) activity. Adequate vitamin-K levels in the diet help limiting neuronal damage in the brain; thus, has an established role in the treatment of Alzheimer's disease.
Spring onions are plentiful in B-complex vitamins as well as some essential minerals such as copper, iron, manganese, and calcium. The leafy greens contain several vital vitamins such as pyridoxine, folic acid, niacin, riboflavin, and thiamin in healthy proportions. 100 g fresh leaves provide 64 µg of folates. Folic acid is essential for DNA synthesis and cell division. Their adequate levels in the diet during pregnancy can help prevent neural tube defects in the newborn babies.
Fresh scallions can be readily available in the vegetable markets all around the year. They, in general, put for sale in bunches along with other leafy greens. If you are growing them in your backyard and to harvest, gently pull the entire plant when its bulb diameter reaches about ¼ inches in diameter.
In the stores, buy clean, uniform, firm, crispy stalks about pencil-thin size featuring well-formed, green color tubules. Avoid over-mature, yellow leaves as they are more pungent and have a sharp flavor like that of onions. Furthermore, avoid those with withered, yellow discolored, dry tops.
Once at home, wash in cold water, gently pat them dry using moisture absorbent cloth and store inside the refrigerator placed in a perforated plastic bag set at high relative humidity. Well- preserved scallions should last for up to a week or so.
To prepare, trim off roots and peel off 1-2 layers of thick outer leaves until you find an ice-white central stalk. Wash the whole scallion in a bowl of cold water. Mop dry. Chop the leaves closely using paring knife in a way you desire like rings, sticks, diagonals, etc.
Generally, spring onions are used in recipes whenever you desire a subtle flavor of onions but at the same time want to avoid strong pungent flavor of onions. Besides, they also add bright green color to the recipes.
Here are some serving tips:
Freshly chopped scallions are used in raw salads as a garnish.
Spring onions also used in pancakes, soufflés, pasta, fritters, noodles, soup, etc.
In the South Asian region, spring onions added mainly in vegetable stir-fries, noodles, fried rice, rice-pulao, etc.
Although scallions handling may result in mild irritation to skin, mucosa, and eyes but to a lesser extent than other allium members like an onion. A gas known as allyl sulfide is released while chopping or slicing them. When it mixed with moisture (water) in the atmosphere, it converts to sulfuric acid. (Medical disclaimer).
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Visit here for very informative pages on:-
Research articles on nutrition.
1. USDA National Nutrient Database. (opens new window)
2. Stanford School of Medicine Cancer information Page- Nutrition to Reduce Cancer Risk (Link opens in new window).
3. Growing spring onions- PDF.