[iamchemistry (OP)]

I am looking at titration of citric acid with sodium hydroxide.
I obtained the citric acid from lemonade, but why do I need to boil it first? I know it removes carbon dioxide, but are there any other reasons as to why lemonade is boiled first before a titration?

Also if I did the titration with coca cola instead of lemonade, which contains phosphoric acid (and carbonic acid?), are there any changes I would make to the procedure?

[CliffordK]

I think you are on the right track with boiling off any "contaminants" from your lemonade.

A carbonated beverage might be different as the carbonation is essentially intrinsic to the beverage.  I guess it depends on what you are wanting to determine. 

Perhaps you would want to try your coke both bubbly and flat.  Could you seal your titration apparatus?

What about titrating carbonated water both bubbly and flat?

[Ben29]

If you were to titrate coca cola then you would want to somehow make the coca cola colourless so you can see the  reaction that is taking place.

[Bored chemist]

Clifford, on this side of the pond, lemonade is a carbonated beverage.
Boiling it will remove CO2 which would otherwise react with the NaOH and give a confusing answer.