Factors affecting initial retention of a microencapsulated sunflower seed oil/milk fat fraction blend

To study the effect of emulsion stability, particle size, emulsifier, and crystalline fat in the oil phase on initial retention of a low-trans fat encapsulated in a trehalose matrix, six emulsions were prepared. The six emulsions were formulated with 20 wt% trehalose solution as the aqueous phase, a lipid phase either with no crystalline fat, sunflower seed oil (SFO), or with a crystalline phase, a 40% SFO in high-melting fraction of milk fat (HMF) blend, and sodium caseinate (NaCas), a 50 wt% blend of the palmitic sucrose esters (SE) P-170 and P-1670, or a 50 wt% blend of NaCas/SE as stabilizers. Particle size did not change or it changed only slightly during the freeze thaw or freeze drying process when the fat phase was SFO. However, when a crystalline phase was present, the volume-weighted mean diameter (D-4,D-3) increased dramatically for SE and NaCas/SE stabilizers. Encapsulation properties were determined by the counteracting effects of particle size and distribution, the presence of crystalline material in the droplets and interactions between interface components, fat phase and trehalose. In addition, retention was less related to emulsion stability. The emulsions selected for this study were stable for at least 30 h which was enough for obtaining a high degree of encapsulation.