Check out
dogfoodanalysis.com.It's an independent site run by the people at boxerworld.com, and they have reviews for virtually every brand of dog food. They list the ingredients for each product, and explain in easy to understand terms why it's either good or bad. Read through the reviews and it should help you make a decision as to what to go with.
Anxiety issues or not, no dog should be eating any food with corn it, or any other grain for that matter (wheat and soy included). The only reason those things are put into dog food is because they are cheap fillers, plain and simple, and they have no nutritional value to your dog. The real kicker is all three of those are known canine allergens. Dogs are carnivores, and their digestive systems are simply not capable of digesting these things. That's why dogs on cheap kibble poop far more than those on better quality kibble, and even more so then those fed a biologically appropriate raw diet.
Being proactive and spending a little more on good food now could potentially save you a lot more in the long run on expensive vet bills later.
"Unnatural diets predispose animals to unnatural outcomes"
- Dr. Tom Lonsdale