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The Science of Eggplant (+ Tips to Avoid Spongy Eggplant)
Some vegetables can be thrown in boiling water, scooped out after a couple of minutes and just taste good by themselves (e.g. Brussel sprouts!). Others need a little frying in a frying pan and they’re good to go (bell peppers, onions). An eggplant however, doesn’t seem to fit any of these easy basic prep methods. If you just happen to buy an eggplant without knowing what it is, chances are you might not buy it again if you used one of these two preparation methods. You might have ended up with a dry spongy structure, not that appetizing at all.
The eggplant is a great and unique vegetable once you know how to prepare it. It has a ton of flavour and can be used in stews, dips (Baba Ganoush anyone?) or in a pasta. Once you understand science & structure of the eggplant, you’ll be able to appreciate it even more.
Never knew there’s such a thing as eggplant science? Well, from now on there is :-).
Introducing: the eggplant (aubergine)
The eggplant is not just any vegetable, it has its own emoji so must be something big. And indeed it is, especially in Mediterranean and Arabic dishes the eggplant is a common guest. It’s a purplish fruit with a great top. Even though the most common variety is purple, there are other varieties as well, a very tasty one has white and light purple stripes. These purple colours are caused by the anthocyanins in the vegetable. They can also vary in size, though most are about 15 cm in length.
However, that is all less relevant for how the eggplant cooks. Apart from its distinct flavour and appearance, you might have noticed that an eggplant is pretty light for its size. This is because of the airy structure in the eggplant. There are a lot of small air pockets in between the aubergine cells. Most of the cooking with aubergine evolves on coping with these air pockets in a proper way.
In a way its structure is similar to leafy vegetables such as kale which also contain a lot of air. However, kale is so thin and breaks down so easily, the air escapes a lot quicker!
Cooking eggplant – getting rid of the air
As long as the structure of an eggplant isn’t broken down properly, it will continue to have these air pockets and this squishy, unappetizing texture. When cooking eggplant the main objective is to break down this texture. You aren’t the first who has tried to fry some slices of eggplant in oil and noticed that they simply soaked up all the oil in no time. This is because of these air pockets. By breaking down the texture and releasing the air pockets, frying will be easier and the overall eggplant becomes smooth and pasty.
A risk when cooking eggplant is that the eggplant slices do become drier, but that they don’t become smooth. This can happen when frying raw eggplant with way too little oil. You end up with pretty tasteless dry eggplant slices. The water has evaporated, but the structure hasn’t broken down properly. So how do you overcome this?
Salt the eggplant
A lot of recipes call for salting slices of eggplant before frying them. There’s a lot of reasons why this would be beneficial. One reason is to mask bitter flavours, or even extract them. Whether that’s actually true, not sure.
The effect it is supposed to have on texture sounds more promising. Adding salt on the outside of the eggplant will extract moisture from the outside thanks to osmosis. It might just help a little to extract the water out of the cells and into the air pockets (causing it to lose turgor), but will probably not do miracles.
Frying an eggplant at a moderate heat will only dry out the eggplant. It seems as if a good hit of heat is required to properly cook the eggplant. Only then the structure is properly broken down. Once the structure has started to break down, the cells in an eggplant will break down and separate from one another, as normally happen during cooking. This allows the air to escape and the solids in an eggplant to come together.
By heating the eggplant in a sauce it will help even further to keep the eggplant moist. The eggplant will absorb the moisture over time, while its structure is breaking down, creating a velvety texture.
Another option, which probably is the quickest of all and doesn’t require pre-salting is to “pre-microwave” the eggplant. Microwaving heats food by passing microwaves through the food. These waves are of the right frequency to get water molecules moving and thus heat up. An advantage of the microwave is that these waves travel through the food. Whereas boiling or frying heats from the outside, microwaves literally heat the whole eggplant at the same time.
Pre-cooking the eggplant in a microwave helps to break down all these air cells within. Once they are somewhat broken down, it becomes very easy and fast to fry the remaining pieces or mash them into a dip! It is actually quite similar to pre-cooking potatoes in the microwave before frying them!
Eggplant dip recipe
One of the best ways to prepare eggplant is by heating the eggplant as a whole. This may take a little longer than slices, but it gives a very creamy, smooth texture. By keeping the eggplant whole no moisture is lost, so it doesn’t dry out. When the eggplant comes out of the oven you will also notice that is has shrunk considerably. This again is because the air has all escaped the eggplant!
Fruits and vegetables have their own science as you’ve read here. If you’d like to learn more, we’ve also written about pears, kale, zucchini, pumpkin and bananas.
While researching this article, we found that there’s very little literature on the topic of the texture of eggplant. If you have any other tips, tricks or knowledge, do reach out and we’ll add it here.
Do you need to use any oil on the eggplant?
You can also drizzle some oil on the eggplant into the carvings, but you don’t have to. It depends on your personal preferences :-).
“ Cut the eggplant in half and make slight cuts throughout, being careful not to rupture the skin.”
How do I cut an eggplant in half without rupturing the skin?
Thank you for spotting that. I changed the wording to clarify that you first have to cut the eggplant in half after which you make cuts in the eggplant flesh. Hope this is more clear now!
I started removing the skin (because I was cooking for my elderly parents) and found that there was no more bitterness.
Thanks for sharing that insight! I can imagine that the outside easily becomes bitter, especially if it burns during preparation. Smart move to remove it.