Eggplant is a member of the Solanaceae (tomato) family and is related to tomato, pepper, and Irish potato. Traders from the East brought seed westward to Europe about 1,500 years ago. The name eggplant likely originated from an early form of eggplant that produced white, egg-shaped fruits. Before it gained in culinary popularity, eggplant was also termed mala insana, which translates to mad apple, owning to the belief that eating eggplant would lead to madness.
While there are over a thousand varieties of eggplant, only a handful are familiar to most Americans. Most are familiar with the deep, dark purple oblong or pear-shaped fruit. Eggplant can also be red, white, pink, green, orange, striped and speckled in appearance. The fruit can weigh over 2 pounds or be smaller than a marble in size. It can also take a wide variety of forms including long and slender, globe-shaped, cylindric, oblong, C-shaped and elongate globular. The covering at the top of the fruit, called the calyx, can be either green or purple.

In addition to featuring a host of vitamins and minerals, eggplant also contains important phytonutrients, many which have antioxidant activity. Phytonutrients contained in eggplant include phenolic compounds, such caffeic and chlorogenic acid, and flavonoids, such as nasunin.

Brain Food

Research on eggplant has focused on an anthocyanin phytonutrient found in eggplant skin called nasunin. Nasunin is a potent antioxidant and free radical scavenger that has been shown to protect cell membranes from damage. In animal studies, nasunin has been found to protect the lipids (fats) in brain cell membranes. Cell membranes are almost entirely composed of lipids and are responsible for protecting the cell from free radicals, letting nutrients in and wastes out, and receiving instructions from messenger molecules that tell the cell which activities it should perform.

Cardiovascular Health and Free Radical Protection

When laboratory animals with high cholesterol were given eggplant juice, their blood cholesterol, the cholesterol in their artery walls and the cholesterol in their aortas (the aorta is the artery that returns blood from the heart back into circulation into the body) was significantly reduced, while the walls of their blood vessels relaxed, improving blood flow. These positive effects were likely due not only to nasunin but also to several other terpene phytonutrients in eggplant.

Nasunin is not only a potent free-radical scavenger, but is also an iron chelator. Although iron is an essential nutrient and is necessary for oxygen transport, normal immune function and collagen synthesis, too much iron is not a good thing. Excess iron increases free radical production and is associated with an increased risk of heart disease and cancer. Menstruating women, who lose iron every month in their menstrual flow, are unlikely to be at risk, but in postmenopausal women and men, iron, which is not easily excreted, can accumulate. By chelating iron, nasunin lessens free radical formation with numerous beneficial results, including protecting blood cholesterol (which is also a type of lipid or fat) from peroxidation; preventing cellular damage that can promote cancer; and lessening free radical damage in joints, which is a primary factor in rheumatoid arthritis.

Choosing the Perfect Eggplant
Look for eggplants that are shiny, plump, firm, and unwrinkled, definitive signs of freshness. The fruit should feel heavy for its size, indicating good moisture content. Another indicator of freshness is the appearance of the stem or calyx. Make sure it is green and bright in color. Press gently with the thumb on the skin of the eggplant. If it is fresh, the skin will spring back quickly.
Older eggplants tend to have a bitter, acidic taste. Eggplants that appear soft, dull in color, and wrinkled are past their prime. If they have scars or bruises on the surface, the flesh  may be bruised and discolored inside. To avoid an overly seedy eggplant, select small (1 lb) and medium (1.5 lb) fruits rather than the giant-size (2 lb).
Storage Tips