2.7. Raman spectroscopyA Raman microscope with spectroscopy capabilities (DXRRaman, Thermo Fisher Scientific, Madison, WI) was used to measurethe spectra of curcumin, curcumin-encapsulated nanoparticles, andcurcumin–zein–pectin physical mixtures. This instrument used 780 nm excitation and 24 mW laser power through a 10 objective(Olympus, Japan). The aperture was set at 50 lm slit, grating400 lines/mm, and spot size of 3.1 lm. The collection exposure timewas 1.0 s and the sample exposure was 2.0 s. The working distanceof the objective lens to the surface of the gold slide was kept constantat 6.5 mm to minimize variance. At least 15 spectra were recordedper sample and each sample was analyzed 3 times. The meanspectral data were then analyzed using instrument software(TQ analyst, Thermo Fisher Scientific).