Vegetable of the Month
September – Eggplant
Long prized for its deeply purple, glossy beauty as well as its unique taste and texture, eggplants are now available in markets throughout the year, but they are at their very best from August through October when they are in season.
Eggplants belong to the nightshade family of vegetables, which also includes tomatoes, bell peppers and potatoes. They grow in a manner much like tomatoes, hanging from the vines of a plant that grows several feet in height. While the different varieties do range slightly in taste and texture, one can generally describe the eggplant as having a pleasantly bitter taste and spongy texture.
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.
Eggplant as 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.
Eggplant is Rich in Phenolic Antioxidant Compounds
Researchers at the US Agricultural Service in Beltsville, Maryland, have found that eggplants are rich sources of phenolic compounds that function as antioxidants. Plants form such compounds to protect themselves against oxidative stress from exposure to the elements, as well as from infection by bacteria and fungi.
The good news concerning eggplant is that the predominant phenolic compound found in all varieties tested is chlorogenic acid, which is one of the most potent free radical scavengers found in plant tissues. Benefits attributed to chlorogenic acid include antimutagenic (anti-cancer), antimicrobial, anti-LDL (bad cholesterol) and antiviral activities.
ARS researchers studied seven eggplant cultivars grown commercially in the U.S. and a diverse collection of exotic and wild eggplants from other counties. In addition to chlorogenic acid, they found 13 other phenolic acids present at significantly varying levels in the commercial cultivars, although chlorogenic acid was the predominant phenolic compound in all of them. Black Magic—a commercial eggplant cultivar representative of U.S. market types—was found to have nearly three times the amount of antioxidant phenolics as the other eggplant cultivars that were studied. In addition to their nutritive potential, the phenolic acids in eggplant are responsible for some eggplants’ bitter taste and the browing that results when their flesh is cut. An enzyme called polyphenol oxidase triggers a phenolic reaction that produces brown pigments. Scientists have begun work on developing eggplant cultivars with an optimal balance of phenolics to ensure both optimal nutritional value and pleasing taste.
Cardiovascular Health and Free Radical Protection Provided by Eggplant
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.
Eggplant, or aubergine as it is called in France, is a vegetable long prized for its beauty as well as its unique taste and texture. Eggplants belong to the plant family of Solanaceae, also commonly known as nightshades, and are kin to the tomato, bell pepper and potato. Eggplants grow in a manner much like tomatoes, hanging from the vines of a plant that grows several feet in height.
One of the most popular varieties of eggplant in North America looks like a pear-shaped egg, a characteristic from which its name is derived. The skin is glossy and deep purple in color, while the flesh is cream colored and spongy in consistency. Contained within the flesh are seeds arranged in a conical pattern.
In addition to this variety, eggplant is also available in a cornucopia of other colors including lavender, jade green, orange, and yellow-white, as well as in sizes and shapes that range from that of a small tomato to a large zucchini.
While the different varieties do vary slightly in taste and texture, one can generally describe the eggplant as having a pleasantly bitter taste and spongy texture. In many recipes, eggplant fulfills the role of being a complementary ingredient that balances the surrounding flavors of the other more pronounced ingredients.
The ancient ancestors of eggplant grew wild in India and were first cultivated in China in the 5th century B.C. Eggplant was introduced to Africa before the Middle Ages and then into Italy, the country with which it has long been associated, in the 14th century. It subsequently spread throughout Europe and the Middle East and, centuries later, was brought to the Western Hemisphere by European explorers. Today, Italy, Turkey, Egypt, China and Japan are the leading growers of eggplant.
Although it has a long and rich history, eggplant did not always hold the revered place in food culture that it does today, especially in European cuisines. As a result of the overly bitter taste of the early varieties, it seems that people also felt that it had a bitter disposition—eggplant held the undeserved and inauspicious reputation of being able to cause insanity, leprosy and cancer.
For centuries after its introduction into Europe, eggplant was used more as a decorative garden plant than as a food. Not until new varieties were developed in the 18th century, did eggplant lose its bitter taste and bitter reputation, and take its now esteemed place in the cuisines of many European countries, including Italy, Greece, Turkey and France.
How to Select and Store
Choose eggplants that are firm and heavy for their size. Their skin should be smooth and shiny, and their color, whether it be purple, white or green, should be vivid. They should be free of discoloration, scars, and bruises, which usually indicate that the flesh beneath has become damaged and possibly decayed.
The stem and cap, on either end of the eggplant, should be bright green in color. As you would with other fruits and vegetables, avoid purchasing eggplant that has been waxed. To test for the ripeness of an eggplant, gently press the skin with the pad of your thumb. If it springs back, the eggplant is ripe, while if an indentation remains, it is not.
At WHFoods, we encourage the purchase of certified organically grown foods, and eggplant is no exception. Repeated research studies on organic foods as a group show that your likelihood of exposure to contaminants such as pesticides and heavy metals can be greatly reduced through the purchased of certified organic foods, including eggplant. In many cases, you may be able to find a local organic grower who sells eggplant but has not applied for formal organic certification either through the U.S. Department of Agriculture (USDA) or through a state agency. (Examples of states offering state-certified organic foods include California, New York, Oregon, Vermont, and Washington.) However, if you are shopping in a large supermarket, your most reliable source of organically grown eggplant is very likely to be eggplant that displays the USDA organic logo.
Although they look hardy, eggplants are actually very perishable and care should be taken in their storage. Eggplants are sensitive to both heat and cold and should ideally be stored at around 50 degrees Fahrenheit (10 degrees Celsius). Do not cut eggplant before you store it as it perishes quickly once its skin has been punctured or its inner flesh exposed.
Place uncut and unwashed eggplant in a plastic bag and store in the refrigerator crisper where it will keep for a few days. If it is too large for the crisper, do not try to force it in; this will damage the skin and cause the eggplant to spoil and decay. Instead, place it on a shelf within the refrigerator.
Here is some background on why we recommend refrigerating eggplant. Whenever food is stored, four basic factors affect its nutrient composition: exposure to air, exposure to light, exposure to heat, and length of time in storage. Vitamin C, vitamin B6, and carotenoids are good examples of nutrients highly susceptible to heat, and for this reason, their loss from food is very likely to be slowed down through refrigeration.
If you purchase eggplant that is wrapped in plastic film, remove it as soon as possible since it will inhibit the eggplant from breathing and degrade its freshness.
Tips for Preparing and Cooking
Tips for Preparing Eggplant
When cutting an eggplant, use a stainless steel knife as carbon steel will react with its phytonutrients and cause it to turn black. Wash the eggplant first and then cut off the ends.
Most eggplants can be eaten either with or without their skin. However, the larger ones and those that are white in color generally have tough skins that may not be palatable. To remove skin, you can peel it before cutting or if you are baking it, you can scoop out the flesh once it is cooked.
To tenderize the flesh’s texture and reduce some of its naturally occurring bitter taste, you can sweat the eggplant by salting it. After cutting the eggplant into the desired size and shape, sprinkle it with salt and allow it to rest for about 30 minutes. This process will pull out some of its water content and make it less permeable to absorbing any oil used in cooking.
Rinsing the eggplant after “sweating” will remove most of the salt.
Eggplant can be baked, roasted in the oven, or steamed. If baking it whole, pierce the eggplant several times with a fork to make small holes for the steam to escape. Bake at 350 degrees Fahrenheit (about 177 degrees Celsius) for 15 to 25 minutes, depending upon size. You can test for its readiness by gently inserting a knife or fork to see if it passes through easily.
How to Enjoy
A Few Quick Serving Ideas
- For homemade babaganoush, purée roasted eggplant, garlic, tahini, lemon juice and olive oil.
- Use it as a dip for vegetables or as a sandwich filling.
- Mix cubed baked eggplant with grilled peppers, lentils, onions and garlic and top with balsamic vinaigrette.
- Stuff miniature Japanese eggplants with a mixture of feta cheese, pine nuts and roasted peppers.
- Add eggplant to your next Indian curry stir-fry.
Eggplant is a very good source of dietary fiber, vitamin B1 and copper. It is a good source of manganese, vitamin B6, niacin, potassium, folate and vitamin K. Eggplant also contains phytonutrients such as nasunin and chlorogenic acid.
In addition to the nutrients highlighted in our ratings chart, here is an in-depth nutritional profile for Eggplant. This profile includes information on a full array of nutrients, including carbohydrates, sugar, soluble and insoluble fiber, sodium, vitamins, minerals, fatty acids, amino acids and more.