W, I share your enthusiasm of bringing new fruits to market and enjoy most sour fruits, but the masses will struggle to adopt a sour fruit choice in place of other similar exotic choices like star fruit. Unless they contain exorbitant amounts of a certain vitamin, purchasing dried or frozen pitangatuba may not strike fire in the hearts of many.
I tried to preserve some pitangatubas in small quail egg containers to no avail. They rapidly degrade. 2-3 days is the max I could keep them before becoming overripe.
I haven't tried to dehydrate yet but will be giving that a go.
I'm inclined to believe there is potential for a small specialty market. If juiced, the taste is quite unique. Profitable, not so much unless you can get a contract for McDs new star cherry siracha burger!