Not too long ago, someone on a vegan Facebook page was pushing their powdered aquafaba powder. It's a nice idea, making it so you don't need to open a can for each batch of stuff or require refrigerated storage for leftover. I commented that the price tag he attached to the product was absurd and it would be significantly cheaper to make it at home.
For those that may not know; aquafaba (literally "bean water") is the liquid that remains after cooking pulses, typically chickpeas. I claimed on the vegan page that it would be fairly straightforward to make powdered aquafaba; place the liquid on a fruit roll tray or baking sheet in a dehdrator and turn it on.
The liquid was successfully dehydrated and formed thin crystalline sheets. This is why I deem it a partial success. It was quite difficult to take the sheets off of a fruit roll tray. Baking paper was significantly as bending the paper typically would free the shards. This shards would then need to be ground in a mortar and pestle in order to achieve a powdery consistency.
Unfortunately, I didn't measure the volume of liquid before dehydrating so I'm not sure what dry weight is required in order to match an egg, but given that 3 teaspoons of aquafaba is about 1 egg, I would think that 1 teaspoon of the dry powder would suffice.
I'd also like to make a product that's a bit more suited to going from dehydrator to packaging. As I've already said, baking paper worked better than fruit roll trays for placing in the dehydrator, but I'd like to avoid the peeling step all together if I can.
One potential solution is to mix the aquafaba into breadcrumb before dehydrating. Not only should this make extraction easier, but it'll increase the effective surface area which should reduce the drying time and save energy. The only downsides that I can see thus far is for people with gluten allergies and it possibly leading to a larger liquid requirement to prevent the baked goods drying out (I personally feel this effect is negligible. As we've already established, powder should be more concentrated than so it'll be less than 3 teaspoons of breadcrumb in the very worst case).
I'm looking forward to taking another crack at powdered aquafaba and coming up with a more economical solution for egg substitutes in baking.