Is it necessary and possible to deactivate an added pectinase before making jam

Question

I've experimented with pectic enzyme in the past to extract clarified cherry juice for cherry cider. I would blend the cherries, add my pectinase and then siphon the middle layer (of 3 layers) that form. It works very well.

Now I am considering doing this to get clarified mango juice for a jam for a tart. However if I am adding pectic enzyme to get the clarified juice then it seems very likely that I am effectively counteracting the pectin that I would add later for the jam. I guess this is called denaturing the enzyme.

Is there a known method to break down pectic enzyme before my attempt at making jam that will not damage the fruit juice significantly?

Answer 1

As a general rule you can permanently inactivate an enzyme by getting it to a high enough temperature. Boiling will definitely work, lower temperatures like 70 C will likely do so, but it will depend on the particular enzyme. Significant pH change will reduce the effect of the enzyme but may not completely inactivate it: I suspect you don't want to go down that path because it will make your juice taste weird. Given you are making jam you can take your juice, add sugar bring to the boil to denature any residual enzyme and then add pectin later. No point in adding pectin whilst the pectinase is still active!

Answer 2

Disclaimer: I don’t know the exact process to clarify fruit juice so my assumption may be wrong.

While steb is right that heating up your juice will deactivate the enzymes, I fear that you destroyed/filtered out too much of natural pectin to form a jam. If this is the case I suggest that you use a special gelling sugar to make your mango jam or add additional pectin.