I have tried to measure dried gel color in very easy and convenient way. The published paper is :

An Analysis of the Influence of Growth Periods on Physical Appearance, Acemannan and Elemental Distribution of Aloe vera L. Gel;  Anirban Ray and S. M. Aswatha; Industrial Crops and Products (Elsevier B.V.), 48: 36–42 (2013).

Thanks Anirban Ray

We manufacture a NIR and visible spectrometer that can be used to measure internal flesh color in mango non-destructively.

http://felixinstruments.com/products/produce-quality/f-750-produce-quality-meter

It can also measure Brix and Dry Matter while it is scanning the fruit. We haven't explored its ability to measure phyto-chemicals yet. Which compounds are you interested in?

http://felixinstruments.com/products/produce-quality/f-750-produce-quality-meter

I employed color hunter for measuring the color of both peel and pulp of mango and phytochemicals determination through different methods like antioxidants by FRAP,DPPH methods, Total carotenoids by solvent colorimetry method,,,,,,etc...............gud luck

Thanks Andrea Melnychenko and Nirmal Kumar Meena. 

tellspec