mantou ), fried (e.g.,  puri ), or baked on an unoiled  frying pan  (e.g.,  tortillas ). It may be  leavened  or unleavened (e.g.  matzo ).  Salt ,  fat  and  leavening agents  such as  yeast  and  baking soda  are common ingredients, though bread may contain other ingredients, such as  milk ,  egg