T. Sugimoto et al., Effects of fat crystallization on the behavior of proteins and lipids at oil droplet surfaces, J AM OIL CH, 78(2), 2001, pp. 183-188
The effects of fat crystallization induced by thermal treatment on the rheo
logical properties of creams and physical phenomena at the oil droplet surf
aces were investigated. Creams A or B were prepared from commercial proprie
tary fats A or B (vegetable oils with different triacylglycerol composition
) and aqueous solution containing proteins. Thermal treatment of the creams
at the "critical temperatures" (temperatures inducing a small percentage o
f solid fats in the oil droplets) caused a rapid increase of solid fat cont
ents in the following cooling process. The thermal treatment of cream B at
the "critical temperature" caused an increase of viscosity of the cream and
an increase of protein surface coverage during the subsequent cooling proc
ess. These results suggest that the oil droplet aggregation induced by the
thermal treatment at the "critical temperature" and the subsequent cooling
occurred via further adsorption of proteins. Electron spin resonance measur
ement demonstrated the dramatic reduction of fluidity of triacylglycerol mo
lecules at the oil droplet surface in cream B during the cooling process af
ter thermal treatment at temperatures below "critical." Based on these resu
lts, we speculated on the mechanism for the destabilization of thermally tr
eated creams during the cooling process.