Direct structural characterization of agar on red algae by FTIR microspectrometry

FTIR microspectrometry is used to control the quality of agar directly in algae microtom cuts. The gelling ability which defines the quality of this polysaccharide depends on the degree of the galactose unit. FTIR microspectrometry is a powerful tool which responds to our needs because we must analyze small samples (diameter of about 10 micrometers ) coming directly from algae or little quantities of extracted agar. However, the presence of components other than agar in the algae forces us to include other chemical and theoretical methods to achieve our purpose.