Proso millet (Panicum miliaceumL.): An Evaluation of the Microstructural Changes in the Endosperm during the Malting Process by Using Scanning-Electron and Confocal Laser Microscopy

Abstract

Scanning electron microscopy (SEM) and confocal scanning laser microscopy (CLSM) were used to investigate the micro-structural changes in the endosperm during the malting process. SEM was a suitable tool to characterise the microstructural constitution of starch granules in proso millet and the changes occurring during malting. An early visible degradation (after 24 h) of starch granules located in the floury endosperm, which is close to the embryo, could be observed. Due to this degradation, using confocal scanning laser microscopy, a less dense packaging of this part of the endosperm was observed. Degradation of starch granules in the vitreous endosperm was obvious at a distinct later stage of malting (78 h) and a preferred attack of small granules (>2.5 μm) was detected. Changes in protein structure could not be detected by either SEM or CLSM.