Atomic force microscopy as a tool for interpreting the rheology of food biopolymers at the molecular level

Atomic force microscopy (AFM) is still a relatively new form of microscopy. Unlike conventional microscopes the AFM generates images by feeling the surface of the sample: the microscope senses the changes in force between the surface and a probe as the sample is scanned relative to the probe. An analogy is a blind person who produces images by touch. Much as the blind person can generate images of surface shape, hardness and stickiness, so the AFM can produce images of surface topography, adhesion, elasticity or charge. This mini review will be concerned solely with topographical imaging and its application to study food biopolymers. Current commercial AFMs per-mit submolecular resolution under gaseous or liquid environments and, under suitable circumstances, it is possible to image molecular processes in real time. This article is intended as a mini review of applications of AFM in food science which permit a molecular understanding of the rheology of food biopolymers. (C) 2001 Academic Press.