INVESTIGADORES
HERRERA Maria Lidia
artículos
Título:
Nucleation behavior of blended high-melting fraction of milk fat as affected by emulsifiers
Autor/es:
CERDEIRA, PASTORE, VERA, MARTINI, CANDAL, HERRERA
Revista:
EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY
Editorial:
WILEY - VCH
Referencias:
Lugar: Weinheim, Germany; Año: 2005 vol. 107 p. 877 - 885
ISSN:
1438-7697
Resumen:
The effect of highly hydrophobic emulsifiers, the sucrose esters P-170 (hydrophobic lipophilic balance, HLB, 1.0) and S-170 (HLB = 1.0) and the polyglycerol esters DAS 7S (HLB = 3.7) and DDB 750 (HLB = 2.6) on nucleation of a high melting point milk fat fraction (HMF) and its blends with sunflower oil (SFO) was investigated by polarized laser light turbidimetry, X-ray diffractometry and polarized light microscopy (PLM). Addition of polyglycerol esters accelerated nucleation giving shorter induction times for the same supercooling. On the contrary, sucrose esters inhibited nucleation since induction times were elongated in all conditions selected. Addition of emulsifiers modified polymorphic behavior in the blends with SFO. The b’- form was promoted especially with addition of S-170. DAS 7S and DDB 750 promoted crystallization. PLM images showed many small crystals that did not appear in HMF images. Addition of P-170 and S-170 delayed nucleation and inhibited crystal growth. Crystals were notoriously smaller than the ones which appeared in HMF images. The Fisher-Turnbull model was used to calculate activation free energies of nucleation. In all cases, sucrose esters elevated the energy barrier for nucleation. Polyglycerol esters, however, if they had an effect on the energy barrier they lowered the values.