About 4-5 years ago I attempted to preserve some lemons in salt as per lots of recipes for Morrocan preserved lemons for tagine etc.
I didn't ever get around to using any of them and also used an inappropriate clip top jar which allowed gas to escape and the salt badly corroded the metal parts. The lemons turned an unappealing brown colour and also went gross & mushy so I finally tipped them out into the compost today.
The weird thing was the salty juice which seeped out of the lemons had turned into a really well set gel. Everywhere I have looked claims that pectin only sets with sugar and jam also needs cooking to 105 degrees c otherwise no gel will form.
How did these raw salted lemons make a gel?
It would be very cool if I could do the same thing with sugar and make a raw citrus marmalade!
Best Answer
It is possible that you have precipitated the proteins to some extent by the salt concentration (known in biological fields as "salting out"), which might produce a gel-like blob, just like cooking egg-white does.
You can indeed also precipitate proteins with sugars (e.g. here), though it is more commonly used for extraction of organic acids (e.g. decenoic acid) from fruits etc, it will take quite a bit of experimentation to do this as it usually requires a very high concentration of sugar and quite a high concentration of protein too. You are more likely to get the pectin (which is a polysaccharide) to work, before you get the proteins to precipitate in a sugar solution.