Homemade preservative for natural aloe-vera gel? I suppose this question can be extrapolated to food in general, but it is the case that I would like to know if there are any methods that would help me to keep the aloe gel fresh, i.e. avoiding it to rot. 

I mostly squeeze the gel and pour it into a small jar. So far I have tried the following methods, being some of them obvious, but would appreciate corroboration anyway:


Sterilize the container and the tools, e.g. boiling or steaming.
Keep it in the fridge.
Stir with C and E vitamin powder to avoid oxidation.


I know little about chemistry, but have heard about pasteurization and some other methods that I couldn't afford at home so, even if you mention those, I will be mainly interested in homemade methods.

PS: I am forced to choose the tags for the post but I am not sure if they are the ones that best suit the question. Please, let me know if I should change them.
I suffer from chronic back pain and have tried just about everything on the market.Now I grow and harvest my own Aloe Vera gel,
put the gel in a 50ml roll-on bottle 1/2 full with gel, a 1/2 tsp vitamin C powder
and 10 drops vitamin E oil then add 98.9% DMSO by syringe
10ml at a time till the strength is good enough for me. I personally use 25ml
DMSO with the Aloe gel for remarkable pain relief