Effect of cream cooling rate and water content on butter microstructure during four weeks of storage

Crystallization, rheological properties and microstructure of butter with varying water content and subjected to different cooling rate were studied during four weeks of storage at 5 C. Using small and large deformation rheology, the elastic modulus (G0) and Hencky strain at fracture was followed. When comparing samples with an equal water content, samples produced from fast cooled cream (7.5 C/min) have a higher G0 compared to butter produced from slow cooled cream (0.4 C/min), at day 1e7. However, no difference in G0 is observed as a function of time, even though the solid fat content increases. Increasing the water content from 20% to 32% decreases G0 at day 1e14, yet X-ray scattering and differential scanning calorimetry shows no difference in crystal polymorphism or crystallinity. After 21 days of storage, no difference in G0 is observed as a function of cream cooling rate orwater content. For all samples, small angle X-ray scattering shows formation of 2L (41 A) and 3L (57 A) lamellar organization, while the wide angle spectra shows mainly b0-crystals (4.2 Å & 3.81 A) together with traces of b (4.6 A). 2012 Elsevier Ltd. All rights reserved.