Garden egg, Guinea squash, bitter tomato, aubergine, brinjal, gaji, eggplant- whatever you call it- amidst my comprehensive spread of cookbooks and culinary and world history they offer next to no substance save a single customary eggplant recipe or two and move on. Maguelonne Toussaint- Samat's History of Food, a usual starting point for many-a food research, with an eggplant on the cover of the second edition, offers nothing about eggplant at all, while the other texts say something silly like "Europeans brought it back from India/ Africa. It was bitter."
The eggplant lineage that we eat at some point split to what we can roughly call eggplants from China or India and eggplants from Africa. They are related, but not the same. Thailand, Japan, etc adopted the China/ India eggplant and then Europe claimed all of them including some of the African ones (making pre-European contact historical research about them quite difficult to do as that's where a lot of sources like to begin). Researchers believe eggplants were first domesticated in China/ India but those plant's wild origins came from Africa, where many eggplants still roam wild.
In addition to their excellent fiber, minerals and antioxidants, eggplants are great sponges for fats and sauces. It's commonly known around these parts too that many eggplants need salted and some rest time to remove their natural bitterness. I first heard it from fancy cook Deborah Madison who thinks we're dabbing with paper towels because we aren't eating them fresh. That does seem true, but it's also worth thinking about red eggplants from Africa who are always bitter and moreso the longer they stay on the stem. Picking early is a way to temper the bitterness, however one Ethiopian writer when describing eggplants never mentions any process to de-bitter it, instead he waxes about how prized the bitterest ones are- I guess it's a matter of perspective. Deborah also classifies skin toughness by color which, as a grower of eggplants seemed bunk at first but I'll agree in regards only to green skinned, which also have a neat apple-like tartness. Picked on the younger side seems to make for a more tender skin all around. The lesson here boiled down is clearly to get your eggplants in season from the farmer's market, rather than the grocery store, but also maybe to consider embracing some bitter?
One of the earliest known writings on eggplants by a Persian scholar from around the 900's made a big list of reasons not to consume it because of its harm to your health. He then went on to rattle off a slew of great health benefits it offers after it is prepared for eating. And in the 2000's there was up-to-date confirmation by a researcher from Vietnam who found that fermenting raw eggplant in a salt brine for 8 days purged the anti-nutrients it contained such as tannin, phytate, oxalate, and steroidal glycoalkaloid. Great news considering that since eggplant has such a high water content its perishabilibity is fast on the horizon, that coupled with how we need to buy them in season too, fermentation coming in handy again!
Last year we got really into this pickle & marinate technique for our eggplants. It's very delicious but just be mindful to not over poach your eggos or they'll turn to mush in the marinade. But apparently there is also an Eastern-European tradition of doing something similar that's sometimes called Sour Eggplant. Most recipes describe it as eggplants first roasted whole, then cut in half and stuffed with a shredded carrot mixture (garlic, herbs, etc), then either packed in oil or just left at room temperature covered to allow to ferment and get sour. Otherwise preserving eggplant by lacto-fermentation is a breeze, especially because raw they are quite firm and hold shape and texture no problem. There are also recipes around for things like fermented baba ganoush. While I have made it before I can't honestly say it was on purpose (though the popular technique is to ferment the eggplant and use that instead of roasted eggplant rather than just forgetting baba on the counter).