I honestly don't know what to tell you. You should definitely choose something without corn and most importantly without corn gluten.
Also, the food you choose should not contain wheat, wheat gluten or brewer's rice.
All these are bad ingredients that cause more trouble than people can imagine.
Take a little time to look at the threads, or even better, start a new thread with your question about food and that way you will get many different suggestions from the members.
Individually owned pet supplies stores normally have foods with better ingredients, those are the best places for finding decent food.