Spinach is an edible flowering plant placed in the family Amaranthaceae. It’s scientifically called Spinacia oleracea. It is an annual plant reaching a length of 30 cm. The plant is rarely biennial. In the temperate regions the plant could even survive in the winter months. The leaves are alternate, simple, and ovate to triangular-based. They may be 2-30 cm long and 1-15cm wide. The larger leaves are found in the base of the plant while small leaves are present around the flowering area. The flowers are inconspicuous, yellow-green and 3-4 millimeters in diameter. They mature into a small, hard, dry, lumpy fruit bunch which measures 5-10 mm.
The word spinach comes from an Arabic word. Spinach is of considerable importance from nutritional viewpoint. It is full of antioxidants especially if fresh, steamed or quickly boiled. It’s a potent source of vitamin A, vitamin C, vitamin E, vitamin K, magnesium, manganese, folate, betaine, iron, vitamin B2, calcium, potassium, vitamin B6, folic acid, Animal Control, copper, protein, phosphorus, zinc, niacin, selenium and omega-3 fatty acids. A present study has shown that spinach also contains opioid peptides known as rubiscolins. Polyglutamyl folate is a very important component of cells and spinach is a rich source of folic acid. Boiling the spinach leaves reduces folate content but microwaving does not affect the folate content.
Spinach along with other green leafy vegetables is regarded as a good source of iron. According to an estimate of United States Department of Agriculture 180 grams of boiled spinach contains 6.43 mg of iron, whereas a 170 g ground hamburger patty contains at most 4.42 mg. The bioavailability of iron depends upon its absorption which is affected by a range of factors. Each of the iron present in vegetables, grains and three-fifth of the animal foods contains non-heme iron. The iron in spinach is poorly absorbed unless and until consumed by a supply of vitamin C. spinach contains iron absorption inhibiting factors along with high levels of oxalate which creates ferrous oxalate upon binding with iron. This form is unstable and can’t be consumed in body.
Spinach also has high calcium content. However oxalate in spinach also binds with calcium ands thus declines its absorption. Calcium and zinc also limit iron absorption. Calcium in spinach is bioavailable of calcium resources. There are three types of spinach available commercially. These are savoy, semi-savoy and flat or smooth leaf spinach. Savoy spinach has dark green, crinky and curly leaves. It is marketed in new bunches. They’re resistant to bolting. The smooth or flat leaf spinach bears smooth leaves and it is not hard to clean this variety when compared with savoy variety. This is very popularly used in soups, processed foods and baby foods. It has the same texture just like that of the savoy spinach and is easier to be cleaned out. It’s developed for fresh and processed foods. Spinach is sold in loose, bunched, prepackaged bags, canned or frozen forms. Fresh spinach loses much of its nutrient value after being stores in refrigerator for few days. Much of the folate and carotenoid content of spinach gets lost upon storage. The cartoon character Popeye the Sailor Man is portrayed as having a strong affinity for spinach, becoming physically stronger after swallowing it.