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Malt Modification Assessed by Histochemistry, Light Microscopy, and Transmission and Scanning Electron Microscopy
E. Goplin and G.S. Robbins. Barley and Malt Laboratory, USDA-ARS. Madison, WI, are thanked for the barley and malt samples. We thank R. Mueller, Dept. Pathology, Kansas State Univ., Manhattan, KS for use of the SEM laboratory.
Use of firm names or trade products does not constitue endorsement by the USDA over others not mentioned.
ABSTRACT
Modification in a kilned malt sample was studied by a combination of histochemistry, light microscopy, and transmission and scanning electron microscopy. Hydrolysis of cell walls, proteins, and starch was most extensive in the starchy endosperm area adjacent to the scutellar epithelium. Some hydrolysis occurred in areas adjacent to the aleurone layers; hydrolysis decreased as distance increased from the embryo end to the distal end and from the aleurone layer to the center of the starchy endosperm. While no rigid sequence of hydrolysis was observed, generally, cell-wall hydrolysis was more extensive than protein hydrolysis, and starch hydrolysis seemed to take place gradually in the late stages of malting and kilning. Small starch granules were hydrolyzed more extensively than large granules.