Atomic Force Microscopy Imaging of Food Polysaccharides

Atomic force microscopy (AFM) is a type of scanning probe microscopy that generates images (primarily topographical ones) by scanning the surface of samples with a sharp tip. AFM is applicable to samples with low electric conductivities, and its operating range spans that accessible to both light and electron microscopes, allowing for molecular resolution. These features of AFM enable soft materials to be visualized under natural conditions without harsh or damaging procedures. For food polysaccharides, AFM is capable of visualizing not only dispersed molecules but also molecular assemblies with an advantage over other physical techniques in quantifying the heterogeneity of samples. From these perspectives, AFM is one of the most versatile techniques for obtaining structural information on food polysaccharides, contributing to the progress of this research area. In this article, AFM images of various food polysaccharides are presented along with the usefulness and limitations of this microscopy technique.