Probing nanostructures in food with the AFM

Abstract

The atomic force microscope (AFM) provides a tool for probing complex food structures at the molecular level. The advantages of the AFM over electron microscopy are minimal sample preparation, the ability to image in liquid or gaseous environments and novel contrast mechanisms, which provide unique insights into food structures. The ability to visualise the nanostructures present in foods has led to the solution to previously intractable problems in food science. This will be illustrated through research studies on the factors affecting the stability of foams and emulsions and the functional properties of starch.

Genetic Diversity of Rice Grain Quality

“…Within the starch granule, amylose is believed to surround and to bind amylopectin blocklets together (Gallant et al, 1997;Morris, 2006;Ridout et al, 2006;Tang et al, 2006) which suppresses swelling of non-waxy starch granules (Lii et al, 1996). The effect on the swelling capacity of starch granules predictably affects the viscosity profiles of nonwaxy and waxy starch (Allahgholipour et al, 2006;Fitzgerald et al, 2003); hence, viscosity curves can be used to distinguish waxy from non-waxy rice.…”

Foaming and Emulsifying Properties of Porcine Red Cell Protein Concentrate

“…At pH 7.0, no effects of protein content on this foam parameter could be described in the range of protein content from 1.0 to 2.0% (w/v). Usually, increasing protein concentration affects not only foamability but also foam stability, because of the higher viscosity, elasticity and homogeneity of the interfacial structure, although at excessive protein concentrations, less space for protein unfolding is available and the protein adsorption becomes more difficult, thus diminishing their efficiency in stabilizing interfaces (Morris, 2006).…”