Well, not about leavening chemicals, anyway. Reader Rachel writes:
I have been trying to eat healthier, so I have been adding ground flax seeds to my morning oatmeal etc. I did a little research and learned that flax seeds can be substituted for eggs in some recipes. I have noticed that the flax seeds cause the liquid in the oatmeal to gelatinize a little. Do you have any idea how flax seeds work as an egg substitute and can they be used in anything or maybe only just recipes that need to be thickened by eggs?
Flax seeds are interesting in that about a third of the fiber they contain occurs as a polysaccharide goo that’s right under their seed coats. Crush the seeds and immerse them in a watery liquid and the goo disperses, causing that gelation-like effect you describe. In baked goods that goo (technically a gum, I think) works a lot like xanthan gum, helping to thicken, stabilize emulsions, trap and hold gas bubbles, etc..
Make a flax seed “egg” by combing two tablespoons of finely ground flax seeds with three tablespoons of water. Stir and allow to sit for a few minutes until the mixture thickens. You can use this flax “egg” in any recipe that calls for a chicken egg. Except for maybe an omelette…yechhh.