Influence of fat globule size, emulsifiers, and cream-aging on microstructure and physical properties of butter

The impact of fat globule (FG) size (d3,2 0.24–3.60 μm) of cream and added emulsifiers on physical attributes of butter was investigated under two cream-tempering regimes: aged (10 °C, 15–17 h) and non-aged. Reduction in FG size increased the globular fat populous of butter microstructure, which appeared to promote crystal aggregation. The emulsifier-type, however, strongly influenced the globule-matrix interactions. Comprehensively, the sodium caseinate stabilised FGs (d3,2 0.48 μm) acted as solid filler particles promoting the structure and firmness of butter. In contrast, coexistence of Tween 80 on FG interface (d3,2 0.24 μm) promoted the globule-matrix de-bonding and fracture propagation causing a reduction in hardness, elastic modulus, and friction-coefficient. Butter made from non-aged smaller FGs (d3,2 0.24 μm) remained considerably softer than the native aged cream butter (d3,2 3.49 μm) after four weeks of storage (5 °C), implying the possibility of improving butter spreadability without a conventional cream-aging approach.