Is there a way to calculate a drop in PH when adding Puree?

[Barrelagedvinyl]

i'm planning on brewing a kettle sour with Passion fruit puree. I'll be adding a 50oz can of puree to a 5gal batch. The can of puree says the Ph is between 2.2 and 3.5 and i was planning on taking a reading of it once i open it. I want to aim for about 3.2ph in the finished product and wasn't sure how steep of a drop i should expect in case i have a really tart batch of Passion fruit.

 

[Jag75]

I've never even thought of the ph of fruit that I add . I dont do the kettle sour I do the co pitch so I dont know if that makes a difference or not but I dont think I'd worry about it if I were you.

Would adding a bit of lactose or maltodextrin maybe help if it is too tart?