Using low-field nuclear magnetic resonance to investigate the effect of composition, mechanical treatments, and storage on the stability of emulsions

This study investigates the application of low-field nuclear magnetic resonance (LF-NMR) to evaluate emulsion stability, focusing on formulation, mechanical treatments, and storage. The results showed that Emulsion 2 (water: 72.73 %, oil: 18.18 %, and egg yolk: 9.09 %) showed 4.68 % decrease in the longest peak relaxation time (T₂₄) and 14.58 % reduction in T₂₄ peak ratio than Emulsion 1 (water: 85.71 %, oil: 9.52 %, and egg yolk: 4.76 %). Mechanical treatments (high-speed mixing and high-pressure homogenization) increased T₂₄ peak area ratio (>64 %) due to particle size reduction (<200 μm) and enhanced stability. Conversely, centrifuging the mechanically treated samples increased T₂₄ peak ratio (Emulsion 1: 61.95 %, Emulsion 2: 21.88 %), indicating phase separation. After one day of storage, single-component relaxation time (T_2w) doubled, reflecting weaker hydrogen bonding. A peak ratio's relationship with storage time (R² > 0.99) was developed to predict emulsion stability. This study demonstrates LF-NMR's potential for predicting phase behavior and optimizing emulsion formulations and processing technologies.