Microencapsulation of a blend of high melting fraction of milk fat and sundflower oil as effected by emulsifier type, water content and sugar crystallization

SOLEDAD ALVAREZ CERIMEDO; ANALÍA DEL VALLE DIAZ; ROBERTO J. CANDAL; MARÍA LIDIA HERRERA

Florianópolis, Brasil

Congreso; X!! Congreso Latinoamericano de Aceites y Grasas; 2007

Sociedad Brasilera de Oleos y Gorduras y Sección Latinoamericana de la American Oil Chemists´ Society

 A low trans fat blend with crystalline material formulated with 40 wt. % sunflower seed oil (SFO) in a high melting fraction (HMF) of milk fat was encapsulated by freeze-drying emulsions. The matrix was a 20 wt. % trehalose aqueous solution. The selected emulsifiers were a mixed of 50 wt. % of the palmitic sucrose esters (SE) P-170 and P-1670, or sodium caseinate (NaCas) or a 50 wt. % blend of SE and NaCas. The ability of formulation to encapsulate the selected fat system by freeze drying and to retain the core material with time was studied by storing the powders at different water activities: aw of 0.11, 0.33, 0.44, 0.54 or 0.76. NaCas formulation was very efficient to encapsulate the fat phase. Retention value was 89.7 ± 0.1. SE and SE/NaCas formulations, however, were less efficient. Retention values were 64.9 ± 0.8 and 55.5 ± 1.0, respectively. NaCas formulation was also more efficient to retain core material during storage. Medium particle size was 0.56 ± 0.20 up to 2 months of storage both at aw 0.11 and 0.76. After that, powders collapsed and particles dramatically grew. This cause re-encapsulation as was evidenced by the increased in retention values. For SE and SE/NaCas powders initial particle size was high since preparation. Medium sizes were 67.0 ± 1.0 and 69.2 ± 2.1, respectively. This was in agreement with a lower encapsulation with time values obtained. Core retention in NaCas powder was less affected by the presence of fat crystalline material than in SE and SE/NaCas powders