Effect of Water Activity on Physical Properties of Conjugated Linoleic Acid (Cla) Microcapsules

The physical properties of spray drying powders must be considered for the design of equipment. Conjugated linoleic acid (CLA) microcapsules were spray dried by using the following as wall materials: whey protein concentrate (WPC), a blend of whey protein concentrate–maltodextrins (WPC‐MD) and gum arabic (GA). These were prepared and their physical properties were studied. The bulk density, packed density, particle density, compressibility and color of the microcapsules were evaluated in a range of water activities from 0.108 to 0.898. No significant differences in the physical properties were found when WPC was used as a wall material in the microcapsules stored at the whole range of water activities tested. Maltodextrins conferred changes in some of the physical properties of the microcapsules (WPC‐MD) upon storage at high water activities. GA microcapsules showed drastic changes in all physical properties studied at water activities above 0.628. PRACTICAL APPLICATIONS This work shows the best conditions for storing conjugated linoleic acid (CLA) microcapsules elaborated with different wall materials, which have been reported to have a high potential as a food additive because of the nutraceutical properties of CLA. This research should reveal the behavior of water activity during storage on physical properties, and make it possible to predict what characteristics need to be added to a food, besides being important for the design of equipment, packing and transport.