Vibrational microspectroscopy of food. Raman vs. FT-IR

Abstract

FT-IR and Raman spectroscopy are complementary techniques for the study of molecular vibrations and structure. The combination with a microscope results in an analytical method that allows spatially resolved investigation of the chemical composition of heterogeneous foods and food ingredients. The high spatial resolution makes it possible to study areas down to approximately 10×10 μm with FT-IR microspectroscopy and approximately 1×1 μm with Raman microspectroscopy. This presentation highlights the advantages and disadvantages of the two microspectroscopic techniques when applied to different heterogeneous food systems. FT-IR and Raman microspectroscopy were applied to a number of different problems related to food analysis: (1) in situ determination of starch and pectin in the potato cell, (2) in situ determination of the distribution of amygdalin in bitter almonds, (3) the composition of blisters found on the surface of bread, (4) the microstructure of high-lysine barley and (5) the composition of white spots in the shell of frozen shrimps.