Amorphous wall materials properties and degradation of carotenoids in spray dried formulations

The present study investigated structural relaxations of spray dried emulsions with trehalose-maltodextrin (M100), trehalose-maltodextrin (M250), and trehalose-WPI mixtures as wall materials at different aw and wall materials properties on carotenoids degradation. The exponential decrease in structural relaxation times (τ) above the Tg was described using strength of the solids (S). S generally decreased with increasing aw and was affected by the wall materials with carbohydrate-carbohydrate mixtures exhibiting higher S and lower carotenoids degradation rates. Non-Arrhenian temperature dependence of carotenoids degradation was attributed to increased S due to collapse above the Tg. Carotenoids degradation was not only described by S but also by layer-by-layer (LBL) interfacial structure. Single layer and LBL systems with the same wall materials had corresponding S but carotenoids degradation was slower in LBL systems. The use of S allows stability and quality control of food materials during processing and storage, and to estimate degradation of encapsulated bioactives.