Figure 5 - available via license: Creative Commons Attribution 4.0 International
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Fluorescence microscopy images (×40 objective) and bright-field images of RTR and H-RTR processed samples. Phospholipids were stained with Oregon Green™ 488. White arrows are pointing at heat-induced protein aggregates in milk. Scale = 12 µm.
Source publication
Human milk provides bioactive compounds such as milk fat globules (MFGs), which promote brain development, modulate the immune system, and hold antimicrobial properties. To ensure microbiological safety, donor milk banks apply heat treatments. This study compares the effects of heat treatments and homogenization on MFG’s physicochemical properties,...
Contexts in source publication
Context 1
... intact ring-shaped phospholipid layers were seen at the surface of milk fat globules in all samples, suggesting that the integrity of the MFGM was maintained after thermal processing and homogenization. The additional observation of the same samples under bright-field microscopy indicated that the RTR samples led to heat-induced protein aggregates (indicated by white arrows in Figure 5). Protein aggregates in RTR samples were more frequently seen and larger than those in UHT and UHT+H (Supplementary Figure S1). ...
Context 2
... aggregates in RTR samples were more frequently seen and larger than those in UHT and UHT+H (Supplementary Figure S1). Although RTR processing caused the formation of aggregates, homogenization successfully decreased the size of the aggregates (Figure 5, bright-field images of H-RTR samples). In addition, we observed fluorescence debris in the microscopic images of the RTR samples compared to the raw milk, suggesting the formation of smaller lipid particles in addition to aggregates. ...
Context 3
... when applying RTR, the harsher heating treatment may cause significant changes in the composition and structure of the MFGM, such as denaturation and the release of proteins. These compositional changes may lead to different non-specific complexations and facilitate self-aggregations [44], as visualized in the bright-field images of RTR samples ( Figure 5). In our recent collaborative study, which assessed the thermal stability of human milk proteins subjected to the same processing treatments, we observed the disappearance of bands in SDS-PAGE gels with these treatments, and aggregation was confirmed for select proteins through proteomic analysis [45,46]. ...
