When sourcing frozen yogurt powder, you must evaluate the expansion rate (overrun), which determines the volume of the final product; a high-quality powder should offer a 30% to 50% overrun. Additionally, check the solubility to ensure no graininess remains after mixing. The probiotic count (CFU) is a critical health metric—ensure the powder contains active cultures like Lactobacillus bulgaricus and Streptococcus thermophilus. Lastly, verify the shelf life, which typically ranges from 12 to 24 months when stored in a cool, dry environment.