Crystallization behavior of emulsified fats influences shear-induced partial coalescence

Abstract

Emulsion stability is desired during production, storage and transportation. However, controlled destabilization by partial coalescence is requisite in the production of e.g. whipped cream, vegetable toppings and ice cream. Partial coalescence in recombined cream (RC) implies the presence of a semisolid fat. Three types of fat, i.e. anhydrous milk fat (AMF), palm oil (PO) and palm kernel oil (PKO), were used in the production of RC. Partial coalescence was initiated by the application of shear and assessed at three temperatures, namely 15, 20 and 25 °C to investigate the relation between solid fat content (SFC) and shear-induced partial coalescence. Despite differences in SFC, shear-induced partial coalescence occurred fastest at 20 °C. On the contrary, a nearly equal SFC at 25 °C resulted in significantly different behavior amongst the fats. This demonstrates that not only SFC determines instability but also fat crystal microstructure, which is dependent on fat composition and on processing conditions. However, SFC could be related to the type of network formed by the partially coalesced fat droplets. The fat crystallization properties, studied in bulk and emulsion, point out a divergent effect of emulsification on the crystallization of the fats which could be explained by differences in crystal morphology.

Keywords: Crystal morphology; Emulsion; Fat crystallization; Milk fat; Palm kernel oil; Palm oil; Partial coalescence.