Abstract
The proportions of agave fructans (FRU), octenyl succinate starch (OSA starch), and whey protein concentrate (WPC) as carrier agents for the encapsulation of pitaya juice composed of a mixture of pitayas red and orange were evaluated using a D-optimal mixture design. The carrier agents had a significant effect on betalains and polyphenol contents and antioxidant activity, as well as on luminosity and b* parameter of resuspended powders resulting the highest values at high proportions of WPC. Also, WPC decreased the hygroscopicity and increased the glass transition temperature with a structure characterized by fissures and porous surfaces in the powders. Optimum encapsulated powder was a mixture of 8.36 % FRU, 81.64 % WPC, and 10 % OSA starch based on reaching the maximum of betalains, polyphenols, antioxidant activity and b* parameter of color. These results suggest that a mixture of carrier agents with high proportion of WPC is a good alternative to improve pigment preservation of pitaya juice.