Hydrolysis of Starch Grains by Polarized Infra-Red Radiation

Abstract

AT the Liverpool meeting of the British Association in 1923, it was shown that polarized radiation had the effect of accelerating the change of starch grains, in a weak suspension of diastase and at ordinary laboratory temperature, into a crystalline reducing substance ; but if the diastase were active or concentrated, no selective effect was observed¹. Earlier experiments in 1922 had shown me that, when ground cereals in plain tap water were exposed to this radiation, a portion of the starch was turned to sugar. This was estimated by Bertrand's method². To meet criticism that the effect might be due to the pressure of the cover glass, the experiment was repeated ; but instead of using a microscope slide, the starch suspension was in a flat-bottomed, very thin-walled flask, the base of which was irradiated by light, polarized and reflected vertically upward by a suspension of diastase in an outer vessel³.