[Chris chan]

Is there a sure way to know the products of these types of reactions? I can't seem to find a source for the oxidation equations of acids like chlorogenic acid citric acid with oxygen.

[gespy]

The only SURE way is to check the literature if it was done already. Google is your friend here

That being said, just take the general chemical consideration. Usually the acid fragment is pretty resistant to oxidation (as it's already the end product of oxidation reactions) and only undergoes decarboxylative elimination of CO₂. So, usually what you can expect oxidation of other functional groups, in your case -OH fragments most likely to ketones. 

[Babcock_Hall]

Are you interested in metabolic oxidations or nonbiological oxidations?

[Chris chan]

Are you interested in metabolic oxidations or nonbiological oxidations?

Nonbiological oxidations, specifically what would happen to the acidic compounds in a cup of coffee.