The Short Version
The evidence supports a narrower version of this claim — heat pump drying often preserves vitamin C and color better than hot-air convection — but the blanket assertion covering carotenoids, betalains, and vitamins collectively in vegetable powders overstates the available science. Most cited studies are reviews or temperature-sensitivity generalizations, not direct head-to-head comparisons for all three compound classes. Critically, heat pump drying's longer exposure times can increase oxidative losses, sometimes negating the temperature advantage for carotenoid-rich products.