Innovative application of confocal Raman microscopy to investigate the interaction between trans-2-hexenal and bovine milk fat globules

Confocal Raman microscopy was applied to detect the partitioning of a volatile compound, trans-2-hexenal, into bovine milk fat globules (MFGs). The interactions between trans-2-hexenal and individual MFGs were reflected by a change of spectral intensity of the volatile compound in the Raman shift region. At a relatively high concentration of trans-2-hexenal (5%, v/v), stronger intensities of the characteristic Raman spectra were found in the interior of the MFGs compared with the milk fat globule membrane (MFGM) region after reaching equilibrium, revealing that the MFG as a whole, rather than the MFGM, plays the major role in volatile compound absorption processes. The current study reports on an innovative instrumental method to investigate interactions among specific volatile compound and individual emulsion droplets.