Advanced microscopy techniques for revealing molecular structure of starch granules

Starch is a naturally occurring most abundant plant polysaccharide which is major source of carbohydrate and energy in human diet. Starch granules are synthesized in various plant species differ in size, shape and composition. In this research article, molecular structure of from potato, rice and corn were characterized using optical microscopes and scanning electron microscope (SEM). The micro-scale structure of starch granules were observed; the size was in the range of 1 to 100μm, surface topological and composition was visualized with high spatial resolution. The crystalline and amorphous components of starch granules were identified by second harmonic generation (SHG) and coherent anti-Stoke Raman scattering (CARS) microscopy. SHG and CARS signals are generated from non-centrosymmetric and C-H rich regions of starch granules, respectively.