How to make a stable culinary Parmesan foam
First of all you are better off with Xanthan Gum instead of gelatin. Xanthan gum is relatively heat stable whereas gelatin is renowned for its inability to withstand any heat above 35 °C. 


200g parmesan grated (including rind).
400ml full fat milk.
1 tbsp
soy lecithin.


Bring to simmer 5 min, then blend and pass through fine sieve. Taste for seasoning now, bare in mind you want it to be over powering at this stage.

Allow to cool and then blend in:


another tbsp soy lecithin
one tsp Xanthan gum. 


If warming for serving do not boil or even simmer as this will make the foam weak.

Personally I blend and scoop the foam off the top. However I see no reason why this couldn't work in a siphon. 

Regarding egg white and Hy-foamer (the molecular cuisine equivalent to egg white, where soy lecithin is the substitute for egg yolk). These are used/useful in fat free foams such as raspberry coulis. They don't work well in fat based ones like the Parmesan foam you are attempting.