Molecular structures of some wheat starches

Abstract Molecular structures of amyloses and amylopectins from three varieties of Japanese wheat, Chihoku, Horoshiri, and Norin-61, and two wheat classes, Australian standard white (ASW) and Western white (WW), were characterized. WW amylose was the largest (number-average degree of polymerization dp n , 1570) and Chihoku amylose was the smallest ( dp n 830). ASW and Chihoku amyloses had higher amounts of branched molecules (∼42% by mole) with lower average numbers of chains ( nc ∼ 13 ), than those of others (∼28% by mole, nc ∼ 19 ). The structural features of amylopectins by iodine affinity and chainlength distribution were also characterized by varieties and classes. The amylose contents of the starches were in the range of 21·7–27·4% for ASW and WW, respectively. A lower amylose content and a higher amount of the branched amylose molecule with a lower nc may produce better quality Japanese-type noodle.