Ma. Dombrinkkurtzman et Ca. Knutson, A STUDY OF MAIZE ENDOSPERM HARDNESS IN RELATION TO AMYLOSE CONTENT AND SUSCEPTIBILITY TO DAMAGE, Cereal chemistry, 74(6), 1997, pp. 776-780
The relative amounts of amylose and amylopectin in maize starch were d
etermined in samples representing hard and soft endosperm. Although di
fferences were small, amylose content differed significantly (P < 0.00
1 and P < 0.05) between the two types of endosperm, with hard endosper
m containing a higher percentage of amylose. Scanning electron microsc
opy was used to determine that the surface appearance of starch granul
es from hard and soft endosperm differed. Starch granules from soft en
dosperm bad randomly distributed pores on their surfaces, which had a
rough appearance. Few pores were observed on granules from hard endosp
erm. A fairly common occurrence with starch granules from soft endospe
rm was the development of wrinkles or fissures upon prolonged exposure
to the beam of the electron microscope. Thus, a correlation existed b
etween endosperm hardness, amylose content, and susceptibility to wrin
kling and fissures. The granules of the soft endosperm of maize, presu
mably less mature than the granules of the hard endosperm, have a lowe
r amylose content (20.5 +/- 1.9% vs. 23.0 +/- 1.0%), exhibit more surf
ace pores, and are more susceptible to wrinkling in an electron beam,
compared with granules of the hard endosperm. Results suggested that t
he composition and internal architecture of the starch granule differ
depending an the hardness of the endosperm from which it was obtained.