It initially helps it adhere to the Apple pieces, sorry I wasn’t very clear. I toss the pieces with cornstarch, then add the lemon juice. After it is brought off the heat it acts as a thickener.

If you do not need thickening then omit it, I leave it out at Thanksgiving when I use apples for stuffing.

I don’t know how acid would change things post canning, I would think it would still firm pectin though, so it might be worth trying.

As I understand it Calcium Chloride is used commercially because it does not change acidity levels, and it adds salt. It is very ‘salty’ but does not increase NaCL (sodium) levels.