In situ investigation of cellular water transport and morphological changes during vacuum cooling of steamed breads

Dynamic investigation of the effects of vacuum cooling on cellular water transport and structural changes of steamed bread was carried out using transverse relaxation times (T-2) and proton density-weighted images in a nuclear magnetic resonance (NMR)/magnetic resonance imaging (MRI) analyser, respectively. Initially, both steamed bread at room temperature of 25 degrees C and freshly steamed bread at 85 degrees C had three peaks of T-21, T-22, and T-23, respectively representing the tightly bound water, loosely bound water, and free water, while an additional peak T-24, was observed in freshly steamed bread at 85 degrees C. After vacuum cooling, freshly steamed bread at 85 degrees C had a higher mass loss of 10.29% due to its high initial temperature, and both samples were clearly discriminated with PCA of 88.2%, indicating that the initial food condition affected the vacuum cooling process. Lastly, the NMR/MRI technique and correlations were accurate (R-2 > 0.98), thus suitable for model validation at microscale and macroscale.

Automated summary

Dynamic investigation on the effects of vacuum cooling on cellular water transport and structural changes of steamed bread was conducted using NMR/MRI technique. The study revealed that vacuum cooling caused water loss and structural changes in steamed bread, and the initial condition of the food also influenced the vacuum cooling process.