Rights: The University of Waikato Published 1 February 2007 Download

What can 3D microscopy and chromatography techniques tell you about starch? And how can this knowledge help design the perfect snack bar?


Kevin Sutton (Plant & Food Research) We look at the structure of starch in two ways. At a microscopic level, we use a technique called confocal microscopy , which is a three dimensional microscopy technique. It allows us to see the starch and the protein and other components of the food at a microscopic level, and how those are arranged together.

We can use that in developing food structure to affect glycaemic load and see how food processes affect glycaemic load as well.

The reason it’s important to use 3D microscopy is because we need to see how the starch is embedded in the food. In order to do that, we need to scan down through the food and see how the starch is arranged in conjunction with the protein and other food components. Because the three-dimensional structure of the food is very important in the way that it’s chewed and the way it’s digested in the gut.

The second way we look at starch structure is at a molecular level, and we use techniques called chromatography, where we can actually separate the starch into its various components. For example, the very long starch molecules can be separated from much shorter ones. That’s a technique we use to look at the raw materials to decide which ones to use. For example, the vegetable starches have a very different profile of molecular size to those found in cereals.