Effects of Structural Attributes and Phase Ratio on Moisture Diffusion in Crystallized Lipids

The objective of this investigation was to study the effect of crystallization conditions and constituent phase ratio on moisture diffusion in lipids. Lipid samples were prepared by fast (13 °C/min) or slow (0.7 °C/min) cooling of binary trilaurin-triolein blends at 200 s–1 shear rate from 60 to 38 °C. Faster cooling at constant shear rate decreased crystal sizes and increased fractal dimensions (Dbox). Effective moisture diffusivities (Deff) were calculated as a sum of vapor (Dv,eff) and liquid phase (Dl,eff) diffusivities by using measured structural data in a diffusion model. Although no correlation was observed between overall Deff and crystallization conditions, the Deff values increased with triolein content from 5.8 to 7.5 × 10–12 (no triolein) to 1.2 to 1.3 × 10–12 m2/s (40% triolein). Results showed that, due to the large magnitude of water vapor diffusivity in air, the impact of structural variations caused by varying cooling rates on overall Deff was masked. However, there was a strong correlat...