jelly
This is related but not a duplicate of this question.
Apparently, I used fresh kiwi and mango in my jelly, and now it does not set. I know what I did wrong; but what can I do about it?
E.g. Can I add gelatin powder to the mixture to improve the chances of it setting?
I know that as a last resort I can probably take the fruit out and consume them directly, but then the jelly would be wasted (drinking sugar syrup is…not very pleasant).
There's quite a few recipes online.
This one seems pretty simple.
It looks like in general, you:
All gelling agents work only under certain conditions. You need to be in the working range for:
Pectins are more sensitive than gelatine, working in narrower ranges. Also, not every pectin is active in the same range, the main difference is between HM and LM pectin.
You can try if gelatine works with your recipe, but here we get into shelf life problems. If you wanted a refrigerated jelly, gelatine is OK. But if you want a jelly that is shelf stable after canning, you need to have at least 33% sugar by weight, better more, and as far as I know, it won't work with gelatine (I don't know if this is because of food safety consideration or because this is outside of the gelatine's working range).
The better way is to find out what changes to make to the recipe in order to have the proper ranges for pectin to work. Use this table for the pectin properties.
(source: Texture by Martin Lersch)
If your pectin type was not on the label, you're more likely to have HM pectin.
I don't know whether trying to reprocess your current batch of jelly is worth it; it may or may not work. You have to calculate the risk (do you see it violating some of the conditions on this table?), your time, and the cost of the ingredients. Also, you don't say how much sugar you used, but if it was too little, it is not edible after 2 weeks in the fridge.
Best Answer
Your problem is actinidain, an enzyme in the kiwi (and to a lesser degree even in the mango) that causes the jelly to stay liquid. Heat deactivates it, so your first step is to boil the whole thing. The minimum temperature to denature actinidain is 60 C, but I recommend to exceed that, just to be sure. You should then add more gelatin, assume that at least a significant portion of the original gelatin was broken down, as evidenced by the non-setting.
If you don’t like the now-mushy fruit pieces after boiling, I suggest giving it a whirr with the immersion blender and calling it “mousse”. You could even add a bit of whipped cream, mixed in just before the jelly sets. (Note that adding a dairy product will only be ok after boiling, again the enzymes need to be deactivated or the whole thing will turn bitter as well.)