Dispersed phase destabilization in table spreads

Commercially available butter, regular-fat margarine, and a fat-reduced margarine (38% fat w/w) were stored between 10 and 35degreesC for up to 4 d to elaborate on the relationship between droplet size and solid fat content (SFC) that exists in these spreads. At 10degreesC, the mean volume-weighted droplet size for butter was 4.22 +/- 0.40 mum followed by margarine (6.22 +/- 0.10 mum) and fat-reduced margarine (112.62 +/- 0.28 mum). At higher temperatures, as a result of decreasing SFC, the mean droplet size increased as did the droplet size distribution, leading to eventual coalescence and destabilization in all spreads. In butter, the critical SFC was similar to9%, whereas in margarine notable coalescence occurred at similar to5% SFC. The fat-reduced margarine destabilized at lower temperatures than the other spreads (similar to20degreesC vs. similar to30degreesC), at an SFC of similar to6.5%. In these spreads, two different mechanisms influenced dispersed phase stability: (i) steric stabilization against coalescence via fat crystals located at the droplet interface, known as Pickering stabilization, and (ii) stabilization against droplet sedimentation (and droplet encounters) due to the presence of the fat crystal network.