Destabilization mechanism of whipped cream during freeze-thaw cycles

Non-dairy whipped cream, a frozen aerated emulsion, inevitably undergoes several partial or complete freeze-thaw cycles during storage, transportation and use, which affects its quality. This study investigated the effects of fat crystal shape and size on the stability of whipped emulsions containing hydrogenated palm kernel oil (22.5 % solid fat content) under freeze-thaw cycles at 10, 20 and 30 °C subjected to 1, 3 and 5 cycles. Thermodynamic analysis revealed that the melting and crystallization enthalpy of both oil phase and emulsion significantly increased with increasing temperature. The crystallization enthalpy of the emulsion increased from 52.96 J/g to 56.83 J/g at 30 °C, while decreased from 28.11 J/g to 17.89 J/g at 20 °C with increasing freeze-thaw cycles. Higher crystallization enthalpy facilitated forming larger and thicker fat crystals, thereby reducing interfacial protein content and accelerating fat globules coalescence. Consequently, higher apparent viscosity and larger particle size were observed. This phenomenon ultimately resulted in an unstable structure with decreased overrun and increased firmness. The obtained result provides a conclusive indication of how fat crystals destabilize emulsions during freeze-thaw processes.