and one of them is lecithin. You can add up to 1/2 teaspoon of granular lecithin per cup of flour. Mix it in with the dry ingredients.
Another thing that will help maintain the moisture (and keep the bread softer) is potato flour. For a recipe calling for 4 to 6 cups of flour, stir 2 tablespoons of the potato flour into the dry ingredients.

Hope this helps.
Judy