The development of biochemical analysis techniques to study heterogeneous biological samples is increasing. These techniques include synchrotron radiation Fourier transform infrared (SR-FTIR) microspectroscopy. This method has been applied to analyze biological tissue with multivariate statistical analysis to classify the components revealed by the spectral data. This study aims to compare the efficiencies of SR-FTIR microspectroscopy and focal plane array (FPA)-FTIR microspectroscopy when classifying rice tissue components. Spectral data were acquired for mapping the same sample areas from both techniques. Principal component analysis and cluster imaging were used to investigate the biochemical variations of the tissue types. The classification was based on the functional groups of pectin, protein, and polysaccharide. Four layers from SR-FTIR microspectroscopy including pericarp, aleurone layer, sub-aleurone layer, and endosperm were classified using cluster imaging, while FPA-FTIR microspectroscopy could classify only three layers of pericarp, aleurone layer, and endosperm. Moreover, SR-FTIR microspectroscopy increased the image contrast of the biochemical distribution in rice tissue more efficiently than FPA-FTIR microspectroscopy. We have demonstrated the capability of the high-resolution synchrotron technique and its ability to clarify small structures in rice tissue. The use of this technique might increase in future studies of tissue characterization.

We previously used synchrotron infrared microspectroscopy to describe the biochemical signature of skeletal muscle (biceps brachii) from the frozen ancient remains of a young man. In this current paper, we use light microscopy to assess the state of preservation of cellular components in the trapezius muscle from these same ancient remains and then use mid-infrared analysis at the Canadian Light Source synchrotron facility to further analyze the tissue. We compare spectra between the trapezius samples from the ancient remains and a recently deceased cadaver (control). Infrared spectra indicate preservation of secondary structure, with the α-helix being the principal component, along with triple helical portions of the protein backbone. Our mid-infrared analysis indicates an energy reserve in the skeletal muscle in the ancient remains.