Microencapsulation of a Low- trans Fat in Trehalose as Affected by Emulsifier Type

摘要

A low-trans fat blend formulated with high linoleic sunflower seed oil (SFO) and a high melting fraction (HMF) of milk fat was encapsulated by freeze-drying emulsions. The selected emulsifiers were a mixed of the palmitic sucrose esters (SE) P-170 and P-1670, sodium caseinate (NaCas) or a blend of SE and NaCas. The ability to retain the core material with time was studied by storing the powders at different water activities (a _w). Efficiency of encapsulation was strongly dependent on emulsifier type. NaCas formulation was more efficient retaining core material during storage. The formulation with a protein and a small surfactant had the lowest performance. The stabilizer also influenced droplet size distribution and matrix crystallinity. For NaCas-stabilized powder volume weighted mean diameter (D _4,3) remained small for up to 2 months of storage (0.56 ± 0.5 μm) and then grew notably in agreement with matrix collapse. There were no significant differences in D _4,3 with water content. For NaCas/SE-stabilized powder, however, D _4,3 was high at the beginning (100 ± 0.5 μm) and then decreased most likely due to particle break-up. Although particle size distribution showed the same behavior for all a _w, retention was strongly dependent on water content. Retention with time was determined by the counteracting effects of these factors.