ARS | Publication request: Development of maize starch granules

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 10, 2006
Publication Date: November 30, 2006
Citation: Li, L., Blanco, M.H., Jay-Lin, J. 2006. Development of maize starch granules [abstract]. Meeting Abstract.

Technical Abstract: Maize kernels of self-pollinated inbred line B73 harvested on various days after pollination (DAP) were subjected for starch granule development studies. Starch in endosperms was first observed on 6 DAP. A small amount of starch granules (<2% of dry weight) was found in the endosperm on 12 DAP. Starch contents of the endosperms increased rapidly from 14 DAP (10.7%) to 30 DAP (88.9%). Diameters of starch granules isolated from kernels of 14 DAP were around 4-6 micro m and that of 30 DAP were 10-23 micro m. Gelatinization temperatures of starch granules increased with maturation, onset gelatinization temperature increased from 61.3 degrees C on 8 DAP, 63 degrees C on 12 DAP, to 67.5 degrees C on 20 and 30 DAP. Average branch chain length of amylopectin increased from 20 anhydroglucose units (AGU) (12 DAP), 26.7 AGU (14 DAP) to 25.4 AGU (30 DAP). The average amylose content of the endosperm starch increased from 9.2% on 14 DAP to 24.2 on 30 DAP. Mature starch granules harvested on 42 DAP showed substantial number of pinholes. The results suggested that the pinholes are results of enzyme hydrolysis of starch granules. Development of pericarp starch was independent from that of kernels. The starch content of the pericarp maintained around 8 - 11% from 8 to 30 DAP, and the granule sizes and gelatinization temperatures remained unchanged.