1996 Volume 49 Issue 2 Pages 113-118
The radial distribution of proteins and amino acids was determined in barley grain. Sixteen consecutive fractions from the outer layer to the center of the barley grain were obtained by milling with a modification of a machine used for polishing brewer's rice. The protein content of the grain increased from the outer to the middle layers and then decreased toward the center. The protein profile of each fraction was examined comparatively after sequential extraction with water, 0.5M NaCl and 60% propanol solutions. The watersoluble protein fraction decreased from the outer layer toward the center. The NaCl-soluble protein fraction showed a homogeneous distribution throughout the whole grain. The propanol-soluble protein fraction and insoluble protein fraction increased from the outer layer to the middle layer, and then decreased toward the center. These two fractions were major proteins of barley grain. Soluble protein fractions of the outer, middle and central layers, particularly their water, NaCl and lactic acid-soluble fractions, exhibited distinct individuality upon examination by SDS-gel electrophoresis. Examination of the amino acid compositions of each layer revealed that the contents of glutamic acid and proline increased from the outer layer toward the center. Other amino acids decreased from the outer layer to the center or did not change in each layer.
