I used defrosted plums from the freezer and now my jam wont set,?

I didnt add any extra water and was wondering if this is why it wont set as there was too much liquid after i had defrosted the plums. Can anybody help with how I can thicken the plum jam to make it set.

I used defrosted plums from the freezer and now my jam wont set,?
Freezing may have killed off the natural pectin in the fruit. By a bottle of pectin from your supermarket (usually neat the sugar) and follow the instructions. Good luck
Reply:If you get pectin, sugar and water in the right proportions, it sets. Try adding finely grated lemon peel. If all else fails, use gelatin.
Reply:simmer it with some gelitin for about 15 mins then drop a small amount in cold water to see if it jelifies or seperates, add a bit more gelitin if it seperates
Reply:THE PASTRY CHEF TO THE RESCUE!...the reason it didn't set is beause of the higher moisture content in frozen fruits than in fresh...if you go to your grocer...in the baking isle...you'll find pectin...it's vry similar to gelatine, but is made made from fruit and vegetable protein rather than animal protein...OR...you can take some cornstarch and a little water and mix it in a bowl (this is called a slurry)...then take a small amount of your jam and return in to the stove...bring that small amount to a boil...then while whisking the small amount of jam add your slurry...bring the mixture back to a boil while continuing to whisk it...remove it from the heat and incorporate the remainder of your jam to it