Studies on Rice Protein

Part I Albumin and globulin in rice endosperm; their heterogeneity and the difference in subunit composition among stored, heated, and fresh rice

Abstract

Albumin and globulin in rice endosperm were investigated, on their heterogeneity and the difference in subunit composition among three rice samples, stored, heated and control. Albumins and globulins in rice endosperm were both highly heterogeneous; albumins gave eleven bands and globulins gave eight bands by the starch-gel electrophoresis at pH3.1, albumins gave fifteen and globulins gave eight bands by the starch-gel electrophoresis at pH8.9, albumins gave nine and globulins gave six bands by the disk electrophoresis, and albumins gave four and globulins gave three peaks by the gel-permeation chromatography.
Three albumins extracted from stored, heated, and fresh rice gave bands and peaks at the same positions, they must have very similar compositions. Three globulins gave bands and peaks also at the same positions.
But three albumins as well as three globulins were not completely of the same compositions. Intensity of bands by electrophoresis was appreciably different among the three, and the height of peaks or area of fractions by gel-permeation chromatography was also different.
Albumin and globulin content in stored and heated rice endosperm were smaller than that of the control. A part of albumin or globulin whose solubility had widely changed during storage or heating should not be extracted as albumin nor globulin.