Impact of Crystalline Milk Fat on Rheological Properties of Ice Cream Mix Emulsions During Aging Time at 4c

Abstract

The influence of aging time at 4C has been studied for three ice cream mix emulsions containing 10% weight fraction of milk fat samples differing by their composition. Milk fat composition was varied by partially replacing anhydrous milk fat (AMF) either by a high melting temperature, stearin (AMF/S), or a low melting temperature, oleain (AMF/O) fraction. Among the three ice cream mix emulsions, the AMF/O emulsion containing the lowest proportion of saturated triglycerides had slightly lower proportion of high‐size fat droplets regardless of the storage time periods, but it presented a higher shear sensitive behavior with aging time. In addition, the structural recovery following a shearing test (100/s for 1 min) observed in fresh emulsions was in the following order: AMF/S > AMF > AMF/O. However, structural recovery decreased faster with aging time for AMF/S than AMF, while it remained unchanged for AMF/O emulsion, where development of crystalline fat was most delayed. Based on these results, it is suggested that different shear stability and structure recovery after shearing can be related to the rate of development of fat crystals in the milk fat droplets which affects the interaction properties between the weak network of biopolymers in the aqueous phase and the fat droplets in the emulsions, depending on milk fat composition. PRACTICAL APPLICATION Our studies indicated an important role of unsaturated milk fat on the functional properties of ice cream mix emulsions, through modifying their rheological behavior as a result of changes in the crystallization properties of the fat in the emulsion droplets. We showed that higher amount of crystallized fat may prevent structure enhancement in the emulsions, and the resultant structure is more sensitive against shearing. This phenomenon will have effects on the aging time of the emulsions at 4C before whipping and, finally, on their overrun and the microstructure of incorporated air bubbles, which have been discussed elsewhere (Bazmi et al. 2007).

Enzymatic and physical modification of milk fat: A review

“…Bazmi, Launay, Cuvelier, and Relkin (2008) showed that the shear-stability and structure recovery of ice cream emulsions is related to the rate of development of fat crystals in the milk fat droplets, which in turn is dependent on milk fat composition; replacing a part of the anhydrous milk fat with high-melting fractions made the initial gel network more stable to shearing. However, during 24 h storage at 4 C, the solid fat content increased and the degree of structural recovery decreased in the emulsion with high-melting milk fat fraction, while these characteristics remained unchanged in the emulsion with low-melting milk fat fraction (Bazmi et al, 2008). On the other hand, during quiescent freezing, the ice cream emulsion formulated with low-melting milk fat fraction was less stable and much more susceptible to fat droplet aggregation-coalescence than the emulsions formulated with high-melting milk fat fraction or intact milk fat (Bazmi & Relkin, 2006).…”

Influence of milk fatty acid composition and process parameters on the quality of ice cream

“…At 5/5 MPa, the D 4,3 measured 1.02 (± 0.15) μm, while a D 4,3 of 0.58 (± 0.02) and 0.52 (± 0.03) μm could be observed at 13/5 and 20/5 MPa, respectively. Also Bazmi et al [4] could not detect a significant influence of ageing on particle size, even though they observed slightly smaller particles in ice cream mix prepared from milk fat enriched with an olein fraction compared to a control milk fat and milk fat enriched with a stearin fraction. In addition, Koxholt et al [17] reported an inverse relationship between homogenization pressure and particle size, which was similar to our findings and followed the homogenization theory.…”

Rheology of Cream‐like Emulsions Prepared with Soybean Milk and Low Trans Vegetable Fat

“…This phenomenon requires the presence of a proportion of solid fat in the dispersed lipid phase, as fat globules are joined when a solid fat crystal from one globule penetrates into the liquid oil portion of another globule [5][6][7]. Thus, the degree of partial coalescence is highly dependant on the solid fat content [6,8]. Other authors were able to imitate this behavior by developing model cream-like emulsions prepared with milk protein and vegetable fat [9].…”