Psyllium husk powder is an extremely high fiber food, so it is usually found in the colon cleansing section of your local health food store. In gluten-free baking, it helps with texture, retains moisture, and prevents the bread from being crumbly. It can also lend a slight sourdough-like texture, which I love. Also, it can sometimes lend a purple tinge to foods but it's nothing to worry about - the food is fine to eat