Ta. Mutoh et al., Relationship between characteristics of oil droplets and solidification ofthermally treated creams, J AM OIL CH, 78(2), 2001, pp. 177-182
The relationship between the characteristics of oil droplets and the change
in appearance of cream was investigated. The model creams (40 wt% oil-in-w
ater emulsion), similar to commercial products, were prepared with vegetabl
e fat, milk protein, and emulsifier. The thermal treatment, in which the cr
eam was exposed to a certain temperature and subsequently recooled, was per
formed on the assumption that the temperature was temporarily elevated duri
ng transportation and storage of commercial products. Solidification of the
cream was observed when it was exposed to a temperature where there was a
small percentage in solid fat content (SFC) of fat in oil droplets and reco
oled, whereas the cream remained in the liquid state when it was exposed to
the temperature where SFC was zero and recooled. When the SFC of oil dropl
ets was 0% at the treated temperature, greater supercooling prior to fat cr
ystallization occurred and the crystallization rate after the initial forma
tion of crystals was much higher. On the other hand, the polymorphism of fa
t in the droplets was not directly affected by the thermal treatment. These
results indicate that the crystallization in oil droplets at the heating t
emperature may be closely connected with the destabilization of oil droplet
s via a partial coalescence mechanism, which will cause the solidification
of cream.