Hello I'm a business-owner that's just opened a donut shop in Honolulu, Hawaii, and I'm looking for some help on creating fruit-flavored coating chocolates.

We have about a dozen recipes that are pretty solid, and have a decent handle on how to incorporate liquids into our chocolate coatings, while still getting them to firm up again after cooling. I'll try to organize this post a bit so you can get a good understanding of what I'm asking;

Basically, our business sells donuts. Donuts that are covered in a single coat of chocolate (dipped, so about half of the donut is covered in the stuff - see photo for an example). Our current flavor offerings are: Honey Glazed (not chocolate), White Chocolate, Dark Chocolate, Matcha Chocolate (everything from here on is Chocolate, so I'm going to omit that from here), Lilikoi (Passion Fruit), Strawberry, Key Lime, Pumpkin Spice, Cookies & Cream, Espresso, Black Sesame & Earl Grey.

Our fruit flavors are based on fruit concentrates or purees (all natural, so far!) mixed with a cream cheese frosting base, that then gets mixed with high quality coating chocolate (Barry Callebaut, confectioner's coating chocolate). We heat and reheat the batches in order to coat the donuts throughout the day. All but 1 of our recipes is nice and consistent, with no real issues - the Strawberry.

We've begun making the strawberry in tiny batches because it browns/grays every time we heat/reheat it. The first batches come out nice and pink, and every re-use (re-heating) subsequent causes a pretty major color shift that we can't seem to get a handle on. We're doing our best to avoid food coloring, although I'm sure that would solve the problem.

I've been doing some research and it seems like I might be able to stop the browning by mixing in some ascorbic acid, or maybe some lemon juice?

Our current recipe looks like this:

Strawberry Puree (made from frozen strawberries)
Apple Cider Vinegar
Softened Cream Cheese
Whipping Cream
Powdered Sugar
----- Mix well in stand mixer until thoroughly incorporated
BC White Coating Chocolate
----- Melt Chocolate in double boiler, add strawberry base & heat, mixing until smooth

Unfortunately, I can't reveal the measurements of each ingredient, but I'm fairly certain that is not necessary to get help with this problem. If anyone has any ideas, please let me know!

Appreciate the help in advanced~