gelatin can be  solved in hot water but crosslinked one can just swell.

compare non-reducing vs reducing PAGE-SDS

Actually, I am planning to examine by FTIR and DSC but I am not sure. I think I can show new bonds with crosslinking. Crosslinking will increase melting point thus I can demonstrate availability. Am I right?

Thanks.

quantitatively speaking, i would most def go with DSC. The changes in the peaks, onset of decomposition would help you understand the extend of cross linking 

You can perform a DSC analysis. The peak temperature of gelatin changes after crosslinking.

Hi Cenk

This is an extract from something I wrote a while back and is a summary of the findings of the thermal changes from one of Bigi's papers examining GTA-crosslinked films:

The Tg of wet and dried GTA crosslinked gelatin films increased with the extent of crosslinking.  The hydration status of GTA crosslinked gelatin, however, influences Tm and the magnitude of ΔHm, most noticeably when the extent of crosslinking ranges between 60 – 80%.  The Tm of hydrated, crosslinked gelatin films increased with the extent of crosslinking, while the Tm of the dried samples remained constant. The ΔHm decreased irrespective of the hydration status of the films, but the magnitude and rate of change in ΔHm with the extent of crosslinking decreased more significantly for the dried films

See Bigi A., Cojazzi G., Panzavolta S., Rubini K., Roveri N. (2001) Mechanical and thermal properties of gelatin films at different degrees of GTA crosslinking. Biomaterials 22: 763-768.

My findings for dried chemically crosslinked gelatins was an increase in Tm and a decrease in ΔHm with increased extent of chemical crosslinking - ΔHm being the most sensitive. 

This data presupposes that you have renaturation.  If you have amorphous films with the same bound water content I found a decrease in Tg

Hope this helps

Please view SDS-PAGE Analysis at following link.

http://www.rndsystems.com/ScientificPoster_sp_recombinant_human_collagens_and_associated_reagents.aspx

Hi,

Sorry I am very late to the party but I would agree with the DSC suggestion for the quantification of the Tg. However if you can, Rheometry may be helpful. Conduct experiments at known solid and solution temperatures with the UV exposure at controlled times. That would be a little less cumbersome, I think.

As for SDS-PAGE, it has a better specificity if you're after the Mw of cross-links and then work back from that. However you have to be aware of the target residues and relative polymer distributions in the gelatin type. I am only speculating here as I don't know full details of your cross-linking system.

Not entirely helpful I know but I am sure it aids to your final answer.