Noun
An albuminoid substance which occurs in minute grains ("protein granules") in maturing seeds and tubers; -- supposed to be a modification of protoplasm.
Source: Webster's dictionaryThe endosperm is surrounded by the aleurone layer (peripheral endosperm), filled with proteinaceous aleurone grains. Source: Internet
This process drives the flavins in the germ and aleurone layers into the endosperm. Source: Internet