AH Chemistry Vitamin C investigation - Need help

The aim of my investigation is to basically determine the vitamin C concentration of various fruit juices (and investigate temp. and storage time).

My question is do I need to find the titration volume of iodine for different concentrations of vitamin C and create a standard curve of vol. of iodine against conc. of vitamin C. I have already done that but realized that it is almost be pointless because when calculating the conc. of vit c in fruit juices I could do it all by calculations, not needing to use the standard curve.

Also can someone help me finding another method than iodine titration since I will probably finish quite quick and could fit another method in. I'v looked at DCPIP titration and Colourimetry but don't know what scores well.

Cheers.