Eggplant has its issues
Tuesday, October 12, 2010; 10:25 AM
Once you get past the parmigianas, ratatouilles and moussakas of this world, cooking with eggplant becomes an uncertain enterprise. A rich, deeply purple specimen that is lustrous and firm can cause a yawn or a struggle, depending on your particular taste buds. One long, thin Asian variety can have twice the seeds of another that is the same size and weight. Some grill masters always salt the flesh. Some never do.
Inconsistent results stump the casual, non-committed eggplant consumer. The flesh itself tastes neutral at best. A sponge. When eggplant lovers defend them, they'll say, "I just do X and Y and Z," at length, with a follow-up about olive oil. But why work so hard?
American cooks have dealt with the large, elongated globe varieties from the start. They are lovely to behold. They hold up well at the market and can hang around in a fridge for a week or two without signs of decay such as wrinkling and softening. Problem is, the big ones have the highest hit-or-miss tally in the galley.
The eggplant nation is just getting acquainted with the charms of Japanese, Chinese, Thai and Indian varieties: slim or small profile, mild flavor, thin skin, easier prep. It has taken us a decade or so, according to Robert Schueller, spokesman for Melissa's World Variety Produce in Los Angeles.
"Think of the globe eggplant as an orange carrot," he says. "There are all these other varieties, of many colors and sizes. People just don't see them much or know they're out there." But we are learning: Farmers market vendors in the Washington area sell slender violets and neon-purple round Italian ones, even small Black Beauties. Schueller says the double-digit growth in mainstream-market eggplant sales these days is in the newer ethnic kinds.
First things first: The eggplant is a fruit, marketed like a vegetable. Its dual identity, like that of its nightshade cousin the tomato, has not kept cooks from appreciating its versatility. But it does help create confusion.
The fruit's seeds are thought to be the epicenter of bitterness, the main drawback for those who are not fans. The seeds are vessels, to some degree. One source of bitterness is certain: phenolic compounds, specifically from chloragenic, or caffeic, acid. Coffee drinkers are accustomed to that level of astringency because the same acid is predominant in coffee beans.
As it happens, phenolic compounds are good antioxidants, a magic designation in nutrition circles. Eggplant = Super food! Scientists have found the antioxidants in eggplant fruit and seeds. They also found that there were great differences among varieties and that the eggplants with the most antioxidant values were also the ones with the highest concentrations of bitter compounds.
"Our survey was based on the potential health benefits," says Bruce Whitaker, a horticulturist with the USDA's Agricultural Research Service Produce Quality and Safety Laboratory in Beltsville, referring to an eggplant study he and John R. Stommel ran from 1998 to 2003. Whitaker is now researching compounds of wild eggplant varieties to determine whether they could be introduced into commercial types. The compounds might have other pharmacological advantages, such as the ability to lower blood pressure, in addition to boosting our bodies' defense mechanisms.
But the scientists couldn't tackle the bitterness problem. "We needed a trained tasting panel," Whitaker says. Stommel remembers they were a bit stymied by how that would be handled: "We can serve raw fresh peppers. But raw eggplant. Who would eat that?"
Whitaker says he doesn't think removing the seeds from an eggplant would eliminate much of the bitterness, because he found offending-yet-healthful compounds throughout the fruit and especially in the alkaloid skin of dark-purple globes. Nor is salting, a technique firmly rooted in cooking lore to draw moisture out of eggplant's cell walls, the answer.
"Frankly, I don't see that it's going to get a substantial amount of the bitterness out," he says.
What does work? "Roasting degrades the compounds, definitely," he says, confirming the mellowing effect that eggplant cooks know well. Whitaker says the maturity of the eggplant is important; the younger the fruit, the lower its level of bitterness-producing compounds.
Would the public go for a genetically modified eggplant that delivered less bitterness and more antioxidants? Whitaker was skeptical. "Those are scary words these days," he reckoned. "I think it's worth investigating further."
Whitaker dismissed another bit of widely repeated information: that people with an inflammatory disease such as arthritis should steer clear of eggplant, whose alkaloids can exacerbate the condition. "There's some controversy; clinical studies are a difficult thing to do. But I don't think there's anything conclusive at this point," he says.
Salting, and subsequent prolonged pressing, do help extract water from the cell walls, however, creating compact flesh that will not absorb as much oil when you choose to marinate, grill or roast eggplant slices.
Those are steps Scott Drewno follows when he cooks eggplant at home. When his executive-chef toque is on at the Source downtown, he uses Japanese and Chinese varietals that stand up to stir-frying and braising. And those eggplants are not quite as bitter.
"I love it," he says."The bitter edge is nice. It's like radicchio to me. When you're eating a salad, you don't want all the flavors to be neutral."
Still, his bag of tricks includes ways to meet eggplant's challenges. "High heat and a little bit of oil in the pan," he says. "Cook it fast." Palm sugar is another one. "Even on savory dishes, sugar provides a balance. It works the same as salt in sweet dishes. Cooks at home don't think to try it."
In fact, a teaspoon of sugar is commonly added to eggplant by Turkish home cooks. Mary Poppins would approve.