Spray Drying of Prickly Pear (Opuntia ficus-indica [L.] Mill) Juice: Effects of Different Carriers on Yield and Powder Properties.

Prickly pear juice (Opuntia ficus-indica [L.] Mill, orange variety) was spray dried with maltodextrin (MD), MD and whey protein isolate in a ratio 199:1 (WPI1), MD and whey protein isolate in a ratio 100:100 (WPI100) (1:1), MD and casein in a ratio 199:1 (Cas) and MD and gum arabic in a ratio 175:25 (GA) (7:1). The ratio of juice solids to carriers was 2:1 in all samples. Large amount of whey protein significantly increased powder yield compared to plain MD (58.47% vs. 43.17%), while the minimal whey protein addition (WPI) exhibited improved yield (49.47%) compared to plain MD. Betalains retention was high in all systems (> 90%) both for betaxanthins and for betacyanins. The retention of betalains during storage for 77 days in the dark was also good in 4°C, 40°C and 60°C, but when the powders were exposed to light in a range of relative humidity (11%-75%), the retention of betaxanthins diminished when the relative humidity exceeded 58%. Storage in relative humidity 44% or higher led to macroscopic powder caking in all systems except for the WPI100 system, in which visible caking appeared in 58% relative humidity. No substantial difference was observed in the absorption curves of the different systems. Understanding the effects and properties of each carrier is crucial when designing appropriate and cost-effective carrier systems according to the desired properties.