It is the pH of the fruit that determines whether it can be substituted or not and with the exception of the few low-acid fruits like mangoes, figs, Asian pears, windfall apples, etc. that all require the addition of lemon juice, they can be subbed and/or combined. As a very general guideline, it is easiest to stay within the type - berries for berries, tree fruit for tree fruit, citrus for citrus, etc. but tons of cross-type recipes also exist.

Yes there will be some effect on set due to the different levels of natural pectin but that variance is so inconsistent that no chart on it is possible. So unless a specific recipe can be found for any unusual combo it is a trial and error issue.

Dave

Bookmark this site: https://foodsafety.wisc.edu/business_food/files/Approximate_pH.pdf

Thanks Dave. Newbie nerves. Just wanted to be sure I had understood correctly. sam